Teacher’s Manual
by Marianne
Krasny, Cynthia Berger, and Adam Welman
Using this Manual – Note to Teachers
Long-term Research and the National Science
Education Teaching Standards
LTER Education and the National Science
Foundation
The Long Term Ecological Research Network
Why Conduct Long-term Research?
National Science Education Standards covered:
Teacher’s Notes for PowerPoint Slideshow
Presentation
Student Handout: PowerPoint Presentation
Questions
Teacher’s Example
Answers to “PowerPoint Presentation Questions” Handout
Student Handout: LTER site “Virtual Tour”
Questions
National Science Education Standards covered:
Long-term Research on Soil and Water Systems
National Science Education Standards covered:
National Science Education Standards covered:
Exploring Long-term Research: Your Community
National Science Education Standards Covered:
The Future of Long-term Research
National Science Education Standards Covered:
Student Handout: Possible Research Ideas
Student Handout: National Science Foundation
Proposal Review Criteria
The activities in this manual introduce students to the National Science Foundation’s Long Term Ecological Research (LTER) program and to the variety of research being conducted at LTER sites. The activities are also designed to make students aware of the value of long-term research as a basis for conservation management and regional planning decisions. Twenty-four LTER sites are located in different biomes across the US and the Antarctic, and many international sites are found throughout the world.
A variety of activities have been selected, from experimental design and hands-on fieldwork to manipulation and examination of actual data sets collected by LTER scientists. Organizationally, the activities follow a logical progression. The first activity demonstrates the value of long-term research for detecting environmental changes that may not be evident in the short term. The second activity introduces students to the range of sites in the LTER network and to the goals of the LTER program. Subsequent activities are designed to allow students to explore some of the five core questions that serve to organize research efforts at LTER sites, to investigate local long-term datasets, and to conduct long-term studies in their schoolyard. In the concluding activity, students role-play scientists who are presenting new proposals for long-term research to a mock review panel.
In this teacher’s manual we provide background information, instructions for 6 activities, science standards covered by individual activities, suggestions about how to make the activities run smoothly, ideas for further study, and links to files containing data, graphs, and presentations necessary for the activities. We also have provided a companion student manual that includes an introduction to long-term ecological research and background, procedure, and supporting materials for each activity. The activities are appropriate for students in grades 9-12, and may be adapted for use in some 5-8 classes.
In 1996 the National Research Council published the National Science Education Standards, a set of guidelines for the teaching of science in grades K through 12. These standards move science teaching away from vocabulary lists and “canned” laboratories with pre-set outcomes and toward the teaching of science as an active process that requires not only knowledge but reasoning and thinking skills.
The activities in this book are designed to embrace the philosophy set forth by the creators of the National Standards, which is that students of science must have both “hands-on” and “minds-on” experiences. By its very nature, long-term ecological research requires that students learn to think and analyze in terms of systems — an approach that is a key goal of the new standards. As they carry out the activities in this manual, students will take an active approach to learning through group discussions and presentations. They also will plan and conduct research activities, and communicate and defend their findings.
Long-term ecological research is inherently interdisciplinary. It creates a bridge between life sciences and Earth sciences as students learn how living organisms interact with their physical environment. What’s more, long-term ecological research is clearly science with a social perspective, since the outcome of such research can be key for environmental management and policy-making. Thus, the activities in this book will help teachers to address National Science Education Content Standards in several areas including “Science as Inquiry,” “Life Science,” “Earth Science,” “Science and Technology,” “History and Nature of Science,” and “Science in Personal and Social Perspectives.” Accompanying each activity is a list of Standards covered.
The National Science Foundation, which funds LTER research, is committed to enhancing K-12 science education. The LTER program is presently in the process of working with scientists, graduate students, teachers, and other educators to develop a model for inquiry-based, experiential learning at the LTER sites. Ultimately the LTER program hopes to include the following:
1) K-12 teacher enhancement programs that offer teachers a chance to conduct research at LTER sites
2) Satellite programs that establish field sites on or near school grounds so children can take part in research activities
3) Educational materials and techniques for K-12 teachers that help to put experiential learning into practice
4) Improved school access to LTER data sets via the internet
5) Complementary funding efforts for K-12 educator programs and student participation in LTER research
Many LTER sites already have significant educational programs. You may want to check the site nearest you to ask about participating.
Imagine the following scenario. An oak tree takes up nutrients from the soil. A gypsy moth caterpillar then eats the oak leaves and the caterpillar’s droppings return to the layer of dead leaves, twigs, and other organic matter on top of the soil. Microorganisms next break down the droppings and they again become part of the soil.
Now imagine yourself as an ecologist (a scientist who studies ecology). What sorts of questions might an ecologist ask about the oak tree and caterpillar in the forest? Ecologists might examine such questions as: Why are caterpillars plentiful in some years and rare in others? Do bird populations increase when there are more caterpillars for them eat? What happens to trees and to the entire forest when caterpillars eat the trees’ leaves? How do plants growing along the ground respond when trees lose their leaves or die and more sunlight reaches the ground?
Asking questions such as these is an essential part of conducting science. Scientists usually ask many more questions than they can answer, and only some of the questions they ask can feasibly be developed into a research project. So how do scientists narrow down their questions to determine which ones should become the focus of research? Through reading the work of other scientists, making careful observations, conducting small preliminary experiments, and talking to their peers about their ideas, scientists narrow down their questions to the few that they could reasonably hope to answer. Once ecologists have narrowed down their questions, how might they go about answering them?
Answering questions about ecosystems is neither quick nor easy for several reasons. First, ecosystems consist of biological (living) things interacting with physical (non-living) things, and these interactions can be complex. Second, ecosystems vary in size — from something as small as a classroom terrarium to something as large as an entire river valley. Answering ecological questions is especially challenging because many ecosystem processes happen slowly or occur only once in a great while. It can take tens or even hundreds of years for a fallen tree to decay and for the nutrients in that tree to cycle back to the soil. It may take hundreds or even thousands of years for a lake to fill with soil and become a grassy meadow. A forest or city park may experience only small changes for hundreds of years — a tree dying and new plants slowly filling the space left by the dead tree. But, in the space of one afternoon, a tornado may rip through the forest or park, topple all the trees, and turn it into what looks like a wasteland. Which of these processes might we fail to notice if we conduct only short term, two-three year, studies?
In addition to happening over long and unpredictable time scales, ecological processes occur across large areas. Salmon swim from the ocean hundreds of miles inland. When they die and decompose, they have cycled nutrients from smaller fish they consumed in the ocean to the water of small streams. Similarly, acid rain produced in the Midwest may affect plants and animals thousands of miles away in the northeastern states. When studying processes that occur over long time periods and over large areas, it is difficult to find all the answers in laboratory studies. Thus, ecologists often conduct research outside in the ecosystems they are studying.
One approach to answering ecological questions is conducting long-term research in real ecosystems. Scientists use a variety of methods, including monitoring changes in plant and animal populations or in atmospheric conditions. For example, bird watchers may monitor the date of first arrival of spring migrant birds and meteorologists record the peak and low temperatures over many years. Field experiments are another kind of long-term research. As opposed to monitoring, where scientists observe changes occurring naturally, in field experiments scientists actually change something in nature and then compare the area they have altered to an area that is left intact. For example, you may have heard about experiments where scientists have added iron to the ocean, and are comparing populations of microscopic plants in areas where the ocean has been fertilized with iron to areas where nothing is added. The purpose of this experiment is to determine whether we might be able to decrease the amounts of CO2 in the atmosphere by increasing the populations of ocean plants that absorb CO2.
In the activities in this manual, you will be exploring long-term monitoring studies and field experiments. These monitoring and experimental studies are being conducted by ecologists and volunteers at Long Term Ecological Research sites across the US and internationally. After exploring how scientists conduct long-term research, you will learn how to set up long-term research in your own schoolyard.
Many scientists conduct research with a small number of colleagues and students. But when the public and scientists become aware of a problem that can only be solved by large-scale research, the government sometimes provides funds for large research projects involving hundreds of scientists and students. For example, when the US decided it wanted to be the first to reach the moon, the government funded many scientists from labs throughout the country to work with the National Atmospheric and Space Agency (NASA) to realize that dream.
Similarly, in the late 1970s, ecologists realized that many ecological questions could not be answered by individual or small groups of scientists conducting short-term research. Thus, in 1980, the National Science Foundation (NSF) established the Long Term Ecological Research (LTER) network to support research on long-term ecological phenomena in the US. Although it is much smaller than NASA, the LTER program is the first ever to support long-term ecological studies over such a large area.
As of 2001, the LTER Network includes 24 sites representing different biomes across the US and Antarctica. A biome is a major, regional, ecological community of plants and animals. For example, one of the major biomes in South and Central America is the “tropical rain forest.” The LTER biomes range from prairie in Kansas to the towering coniferous forests of Oregon, from alpine tundra in Alaska to tropical forests in Puerto Rico, and from coastal marshes in Virginia to dry deserts in Arizona and New Mexico (see Table 1). Furthermore, the US LTER network includes two sites in Antarctica, and other countries around the world are beginning to develop an International Long Term Ecological Research network (ILTER). Brazil, Canada, Hungary, Costa Rica, and Israel are among the many countries that already have ILTER programs.
In addition to representing different biomes, LTER sites vary in a number of ways. Some sites have a long history of ecological research. For example, scientists had already been monitoring streamflow and water quality at North Carolina’s Coweeta Forest for 50 years before it became an LTER site. Some sites are mostly undisturbed by humans, such as the Toolik Lake site in the Alaskan tundra. Others have seen much human activity, such as Cedar Creek in Minnesota, which includes a series of abandoned farm fields of varying ages. (What questions might scientists be able to answer with fields of different ages?) Recently, as ecologists are more and more viewing humans as important parts of the environment, the LTER program added two urban sites: one in Phoenix, Arizona, and the other in Baltimore, Maryland.
More than 1,100 scientists and students currently conduct ecological research at the 24 US LTER sites. This research ranges from simple monitoring to large-scale field experiments. For example, scientists at the North Temperate Lakes LTER have monitored the date that ice forms and melts on lakes in Wisconsin for 150 years. Although when they first began recording ice data in the 1850s no one had ever heard of global warming, today these long-term data are important in helping us to understand climate change. In an ecosystem experiment also associated with the North Temperate Lakes LTER site, scientists divided a lake in half with an underwater curtain. On one side of the curtain, they added sulfuric acid while the other side was left intact. Scientists compared the chemistry and biota in the two halves of the lake to help us understand the effects of acid rain on lake ecosystems.
Sometimes LTER scientists at different sites cooperate to study how ecological processes differ in different ecosystems. For example, ecologists are aware that dead wood and leaves play an important role in the cycling of carbon, nitrogen, and other nutrients from living trees to soils. They are interested in how fast dead wood and leaves break down in soil in different ecosystems. Thus, scientists from 28 LTER and ILTER sites around the world are using similar methods to measure the decomposition of wood and leaves. Similar to the divided lake field study described above, this study involves comparing different treatments. However, unlike the lake study, where scientists actually changed the ecosystem to make two treatments (added sulfuric acid to one half of the lake), in the decomposition study, scientists did not alter the ecosystem. Instead, each LTER site serves as a different treatment. Because each LTER site differs in many ways, the decomposition study is not as well controlled as the lake study. Can you think of some factors that might differ at different LTER sites and that might affect how fast wood and leaves decompose?
The results from LTER research have already been used to help solve environmental problems. For example, scientists at the Luquillo LTER in Puerto Rico have monitored shrimp populations and studied the effect of dams on shrimp and fish mortality. Their findings have influenced watershed managers, who have stopped taking water from the Culebrinas Rivers at crucial hours of the day and have installed a fish ladder so migrating fish can get around the dam.
Table 1. LTER Sites in the US and Antarctica.
|
Name |
Location |
Biome |
|
H.J
Andrews Experimental Forest |
Cascade Mountains, Oregon |
Temperate
coniferous forest |
|
Arctic
Tundra |
Toolik
Lake, Alaska |
Arctic
tundra (lakes and streams) |
|
Baltimore
Ecosystem Study |
Baltimore,
Maryland |
Eastern
deciduous forest: urban landscape |
|
Bonanza
Creek Experimental Forest |
Fairbanks,
Alaska |
Taiga |
|
Central
Arizona-Phoenix |
Phoenix,
Arizona |
Desert (Sonoran desert scrub, river, residential
mix) |
|
Cedar
Creek Natural History Area |
Minnesota |
Eastern
deciduous forest; tallgrass prairie (old fields) |
|
Coweeta
Hydrologic Laboratory |
Southern
Appalachian Mountains of North Carolina |
Eastern
deciduous forest |
|
Harvard
Forest |
North-central
Massachusetts |
Eastern
deciduous forest |
|
Hubbard
Brook Experimental Forest |
White
Mountains, New Hampshire |
Eastern
deciduous forest |
|
Jornada
Experimental Range |
Southern
New Mexico |
Desert
(hot) |
|
Kellogg
Biological Station |
Central
Michigan |
Tallgrass
prairie (Row-crop agriculture) |
|
Konza
Prairie Natural Research Area |
Flint
Hills, Kansas |
Tallgrass
prairie |
|
Luquillo
Experimental Forest |
Luquillo
Mountains, Puerto Rico |
Tropical
rainforest |
|
McMurdo
Dry Valleys |
Antarctica |
Tundra
(polar desert oases) |
|
Niwot
Ridge-Green Lakes Valley |
Rocky
Mountains, Colorado |
Mid-latitude
continental alpine tundra |
|
North
Temperate Lakes |
Northern
Wisconsin |
Eastern
deciduous forest (north temperate lakes) |
|
Palmer
Station |
Antarctic
peninsula |
Pelagic
polar marine |
|
Plum
Island Sound |
Rowley
Basin, Massachusetts |
Coastal
estuary |
|
Sevilleta
National Wildlife Refuge |
Central
New Mexico |
Subalpine
mixed conifer (riparian forest); grassland; desert (hot & cold) |
|
Shortgrass
Steppe |
North
Central plains of Colorado |
Native
grassland |
|
Virginia
Coast Reserve |
Oyster, Virginia |
Coastal
barrier islands |
|
Florida
Coastal Everglades |
Everglades
National Park, Florida |
Fresh
& saltwater marshes, estuaries |
|
Georgia
Coastal Ecosystems |
Central
Georgia coast |
Coastal
barrier island/marsh complex |
|
Santa
Barbara Coastal |
Southern
California coast |
Semi-arid
coastal zone / giant kelp forests |
Ever since the industrial revolution, cars, power plants, and other machines have been adding CO2 and other “greenhouse gases” to Earth’s atmosphere. The overwhelming majority of scientists now agree that global warming caused by humans is occurring at a rate unprecedented in the Earth’s long history.
How can scientists measure whether or not the climate is changing? We have all experienced daily fluctuations in weather — the natural highs and lows that occur from day to day and year to year. How can these be distinguished from true, long-term changes? In this activity, you will examine data collected over a period of nearly 150 years to try to answer this question.
The data set that you will be working with is somewhat unusual. It consists of the dates of spring “ice-out” (the break-up of winter ice cover) on Wisconsin’s Lake Mendota. Lake Mendota is part of the North Temperate Lakes LTER site. Although it has only has been part of the LTER network since 1981, different people have been noting and recording the date of Lake Mendota “ice-out” since 1855 — which is long before the LTER program had been established, and indeed long before the term “ecology” had even been invented!
“Ice-out” data are particularly useful as an indicator of global climate change. When you look for evidence of global warming by analyzing other kinds of climatic data, such as air temperature, you face some challenges. For example, air temperature measurements can be biased by what time of day the observations are made (midday temperatures are warmer than morning or evening readings), where the temperature is measured (elevation and exposure to sunlight can affect temperature readings), and how the measurements are made (thermometers vary in both precision and accuracy). So even if long-term air temperature readings exist for a site, over the years, people may have collected information in different ways. Those procedural differences can hide the real changes, or make small changes look bigger than they actually are. Figure 1 presents data on mean annual air temperatures in central Wisconsin from 1895-1991. Do you see a trend in these data?
Ice-out data naturally average ups and downs in air temperature over many days. A single data point — the day that ice cover breaks apart in early spring — actually expresses the cumulative effects of local weather conditions over the winter season. For example, when cold temperatures come early in the fall, ice forms sooner than usual. Or, if the winter is mild, the ice melts sooner than usual. So if the ice-out dates show a significant change over many years, that is a good indicator that the climate really has changed.
Even though ice-out dates are a better indicator of climate change than air temperatures, they still are not perfect. For example, although air temperature is the most important factor influencing the date of ice-out, other factors — the amount of snow on the lake, the average wind speed, and the amount of cloud cover — also influence how quickly the ice melts. Local geography can affect snow cover and wind speed — a lake in a protected hollow might accumulate less snow and experience less cooling from wind than a lake in a more exposed location. So data from lakes in different locations could suggest different climate trends even though none existed.

Another complication in interpreting ice-out and other climatic data is that certain regular climatic events, such as El Niño, cause predictable changes in weather conditions on a time scale of years to decades. So a long-term global warming trend could be obscured by a short-term cooling trend casued by El Niño. Local land use also may influence ice-out dates. For example, urban development near a lake can raise the air temperature locally, because concrete absorbs heat from the sun and tall buildings block the wind. Or, warm water flowing out of a power plant can raise the lake water temperature.
Finally, observer bias is a concern. How do you define “ice-out?” One person may say the ice-out date is when cracks appear in the ice and it starts to break apart; another might define ice-out as the day when the surface of the lake is completely open and free of ice. We do not know whether all the observers who collected data over the past 150 years used exactly the same standards.
In spite of these potential problems, the Lake Mendota ice-out data are still among the best indicators of global change. Since all measures of the environment have certain drawbacks, ecologists choose indicators that are the best among those available.
In this activity, students will graph 150 years of ice data from Lake Mendota. The student procedure indicates that they will receive printed spreadsheets of these data, but if you prefer, you can alter these instructions by telling your students they will receive electronic copies of the data and will use database software to manipulate and graph them. We have provided the data in formats suitable for either option.
The files needed for Activity 1 are located on this website. If you would like your class to manually graph the data, you will need the file “Activity 1 Data.” This file is in both MS Word and PDF formats and contains ice-out data necessary for this activity as well as example graphs for your reference. You can print this file and give the data to your students in printed spreadsheet form.
If you would like your students to use database software, you will need two files: “Activity 1 Data Teachers (Excel),” and “Activity 1 Data Students (Excel).” Both of these files are in MS Excel format and contain raw data necessary for this activity. The teacher’s version also contains examples of graphs for your reference.
The Word, PDF and Excel files are all located under the
“supplementary files” section of the LTER teacher’s manual website (http://www.dnr.cornell.edu/ext/LTER/manual.asp).
We have written this activity assuming students will choose to graph ice duration. However, we also have provided the data for date of ice formation and date of ice breakup. You can encourage students to explore these data sets also.
For this activity, divide your class into about 10 teams (either pairs or small groups). Assign each group 15 years of data to work with (e.g., 1855 - 1869, 1870 - 1884, and so on). Ask each group to evaluate its own 15-year data set to determine whether ice-out dates show a changing trend within this period. Students will find pronounced oscillations in the data set, resulting from normal yearly fluctuations in weather. Encourage them to propose explanations for these short-term variations. Next, ask the groups to tape their individual graphs together and post them on the classroom wall to create one long-term graph. Then they will compare small-group results to the combined result and look for evidence of a changing trend in ice-out dates over the longer term. Note that prior to starting the work, all students will need to work together to standardize the labeling for the x and y-axes of their graphs, so that the graphs can be successfully merged at the end of the activity.
These and other data may be available through the LTER website (http://lternet.edu/). In the past, data available on the LTER website were difficult to use directly off the web. Thus, we have downloaded and transposed the data so that they are easy to graph. The LTER Network hopes to add data sets that are readily usable for educational purposes in the future, so check the LTER website periodically.
In the “Suggestions for Further Study,” we have included an activity that allows students to see how data may be manipulated — sometimes inaccurately or unfairly — to represent a particular point of view. Ask students to pick a point of view with respect to global warming that they want to present. Then encourage them to play around with the data, using software-graphing features or hand-drawn graphs, in an attempt to use the data to best substantiate their points of view. Some ways they can change the presentation of the data include graphing a limited segment of the data set that does not appear to show any trends and changing the scale of the x or y axis. Have the students experiment with different ways to present the data and then use their results to present a particular point of view to the class. Other students should ask questions about how the data were analyzed, forcing the presenter to defend his/her argument or to admit holes in his/her reasoning. You can challenge students to find similar examples of data manipulation in the media.
Develop an understanding of the importance of long-term data
Learn to graph by hand or using Excel software
Interpret graphs showing ice-out dates over a period of 150 years
Learn about one method scientists use to measure global warming
Understand how data can be manipulated to support different points of view
Science as Inquiry – Development of:
Abilities necessary to do scientific inquiry (5-8 & 9-12)
Understandings about scientific inquiry (5-8 & 9-12)
Science and Technology – Development of:
Abilities of technological design (5-8 & 9-12)
Understandings about science and technology (5-8 & 9-12)
Earth Science – Development of an understanding of:
Structure of the Earth System (5-8)
Energy in the Earth System (9-12)
Science in Personal and Social Perspectives – Development of an understanding of:
Populations, resources, and environments (5-8)
Science and technology in society (5-8)
Natural and human-induced hazards (5-8 & 9-12)
Environmental quality (9-12)
Science and technology in local, national, and global challenges (9-12)
History and Nature of Science – Development of an understanding of:
Nature of science (5-8)
Nature of scientific knowledge (9-12)
1. Examine the spreadsheet handed out by your teacher. This spreadsheet includes the original ice data collected at Lake Mendota over a 150-year period.
2. Notice the headings at the top of the columns.
· The first column is labeled “year.”
· The second column is labeled “Ice On (Date).” This gives the date on which the ice froze in the fall.
· The third column is labeled “Ice Off (Date).” This shows the date on which the ice melted in the spring.
· The column labeled “Ice Duration” tells you how many days the ice was frozen.
3. Take a look at the first row of data, for the winter of 1855-56. In this winter, the ice froze on December 18 and melted on April 14. So the “Ice Duration” was from Dec. 18 to April 14—a total of 118 days.
4. Notice that, in addition to being expressed as dates, “Ice On” and “Ice Off” are also expressed as numerals—the number of days since January 1. For example, look in the sixth column. The “Ice Off (Day of Year)” for 1855 is 105; that’s because from January 1, 1856 to April 14, 1856 is 105 days.
5. Your teacher will either tell you, or you will decide as a class which data you will graph (ice-on, ice-out, or ice duration). Which do you think will give you the most useful information, or the clearest evidence of a trend?
6. For each graph you create, use the x-axis (horizontal axis) to indicate the years, from oldest to most recent. Which values will you plot on the y-axis?
7. Before making your graphs, the entire class needs to agree on a labeling system and scale for the graphs. At the end of this activity, you will be merging your graphs with other groups’ graphs. It is essential that you label the values on the axes in exactly the same way and have the same scale on all the graphs.
8. On the y-axis, what should be the lowest value? What should be the highest value? What are the units? You will need to make a scale that can incorporate the highest and lowest values for the entire 150-year data set.
9. Using pencil and graph paper, draw the axes and label them. Also give each graph a descriptive name. (If your teacher has given you an electronic copy of these data, you will be using Excel or other database software to create these graphs.)
10. Graph your 15 years of data. For each graph, answer the following questions:
· Is there much variability from year to year, or only a little?
· Do you see a trend? As time elapses, does the value tend to increase, decrease, fluctuate, or stay the same?
11. Pair up with one other group and compare your results. Did you reach the same or different conclusions based on your data set?
12. Now, combine the graphs from the entire class. Tape them together so they form a continuous graph. Answer the following question as well as questions you come up with on your own. With the longer-term data set, do you see a trend?
13. If you graphed ice duration, answer the following questions. (You may want to adapt these questions for ice formation and ice-out data, using the numeric value for date.)
· What is the average ice duration in your data set?
· How does this compare to the average ice duration over 150 years?
· What is the longest period of ice duration in your data set?
· What is the shortest period of ice duration in your data set?
· What are the longest and shortest periods of ice duration in the entire data set? In what years do they occur?
14. On your graph, draw a line to indicate average ice duration (or date of formation or ice-out) over 150 years. You may need to remove your graph from the others to do this; be sure to replace it when you are done. If you are working with a graphing program, have the program calculate the average for you (you may ask your teacher for assistance). Within your short-term data set, how many years have longer-than-average ice duration? How many years have shorter-than-average ice duration? Compare these values among all of the groups. Do you see a trend in years with longer or shorter than average ice duration over time?
15. To conclude the activity, think about the implications of your data analysis. You should answer the following questions as well as any others the class comes up with.
· Is the “picture” you get about lake ice any different in the shorter-term from the longer-term data set?
· What does analysis of the data sets tell you about the importance of short-term vs. long-term data?
· Do these data sets provide evidence for climate change?
Some scientists who examined the North Temperate Lakes ice data concluded that there have been three significant climatic periods since 1855. The first period, lasting from 1855 to 1890, had, on average, years with the longest ice duration. A second period, from 1890 to 1980, had ice durations of intermediate length. During the third period, from 1980 to the present, ice duration had the shortest length. These scientists think that air temperatures during these three climatic periods caused the differences in ice durations. That is, during the first period, winter and spring temperatures were, on average, colder than they were during the second period, and temperatures during the second period were on average colder than during the third climatic period. The scientists go on to state that these changes in ice duration are consistent with changes expected due to the greenhouse effect and resulting global warming.
Others scientists have argued that the area around Lake Mendota has become much more urbanized — so the trends in ice-out data could be a result of warming from urbanization that raised the air temperature around the lake, instead of global warming due to greenhouse gases. How might you test these two hypotheses?
A study conducted in Lake Michigan shows the value of extended ice cover to whitefish. Whitefish populations are largest in summers following winters with long periods of ice cover. Why? Whitefish eggs are laid in fall and develop over the winter. If there is a protective cover of ice, the eggs do not get tossed around by wind-whipped waves, so more of them survive to hatch. You may want to research requirements for other species and think about the implications of changing ice duration on animals and plants living in lakes.
If you are using Excel software, you can manipulate the data themselves and gain insight into some interesting issues about the interface of science and politics. Scientists almost always “fool around” with different ways to graph their data. Eventually, they decide on a way to present their data that most accurately reflects the trends they observed. Although the public often views scientists as completely neutral and uncreative, there is often a good deal of judgment and creativity that goes into deciding how to present data.
Unlike scientists, who try to find a way to present their data that most accurately reflects reality, politicians, advocacy groups, and the media are notorious for changing the scale of axes on a graph to exaggerate a trend or to make a large change seem smaller. These differences in the way data are presented often lead to confusing messages about what data actually mean. Although nearly all scientists now believe that climate change is real, many politicians still choose to ignore its implications for humans and other organisms. You may want to choose a point of view about climate change and experiment with different ways to present the data to support your view. Without changing any data values, experiment with graphing the data in order to present your point of view. Is changing the axes to support a particular point of view ethical for scientists or politicians?
You may want to identify which of the last 50 years have been “El Niño” years. Can you find any correlation between El Niño years and changes in ice-out dates? If your classroom has Internet access, look for information on El Niño years. You may find the National Oceanic and Atmospheric Administration’s (NOAA) website useful: www.elnino.noaa.gov.
You can research US or global temperature trends to see if they support or refute results obtained in the ice-out activity. Many scientists believe that the global rise in atmospheric carbon dioxide (CO2) levels is responsible for increasing global temperatures. You can explore the relationship between increasing global carbon dioxide levels and increasing global temperatures using Internet resources including the National Oceanic and Atmospheric Administration (NOAA) (www.noaa.gov), the National Climatic Data Center (www.ncdc.noaa.gov), and the Environmental Protection Agency (www.epa.gov/globalwarming/) sites.
You can explore LTER websites for similar ice data. For example, the North Temperate Lakes site has shorter-term data sets on a number of other lakes. Niwot Ridge in Colorado also has a few years’ worth of lake ice data, and the Palmer Station in Antarctica has sea ice records. You may also want to explore other climatic data, such as temperature and rainfall, on the LTER websites.
A desert, an arctic lake, and a prairie are just some of the different ecosystems represented in the network of LTER sites. What do we mean by the word “ecosystem?” It does not refer to a place, such as a forest or a lake. Nor is an ecosystem a collection of plants and animals.
Think of the root word, “system.” Similar to other systems (for example, a school system or a network of computers), an ecosystem is a functioning unit in which the parts are constantly interacting and changing. Some of the parts of ecosystems are living – from the large and obvious, such as plants and animals, to the small and hidden, such as soil microbes and parasites. But an ecosystem also includes the physical factors – temperature, moisture, and nutrients – that act upon and are influenced by the living organisms. All ecosystems have similarities – for example, they all have nitrogen and water cycles. Yet each ecosystem also differs in important ways from other ecosystems – in climate, types of soil, and species of plants and animals.
It is important to remember that the words “ecosystem” and “biome” have different meanings. A biome is a major regional ecological community of plants and animals. There are probably fewer than 20 well-defined biomes in the entire world. An ecosystem, however, can be something as small as a terrarium, as long as it has boundaries and includes both living and non-living things and their interactions.
At each of the LTER sites, scientists try to answer five core questions about the way ecosystems work. By studying the same questions in the different LTER ecosystems, scientists learn what processes are common to all ecosystems and how these processes differ between sites.
1) What controls the growth of plants? For example, why do plants grow where they do? What factors control how quickly they can grow, and how big they can get?
2) What causes populations of plants and animals to vary over time? Why is a species abundant one year but not the next, or found in different places at different times?
3) What happens to the organic matter that plants produce? For example, when leaves fall to the ground, what factors control how quickly they decay?
4) How do inorganic nutrients, such as nitrogen and carbon, move through soil and water?
5) How do disturbances, such as fire, drought, or logging, affect ecosystems?
In this activity, you will first view a PowerPoint presentation and then use the Internet to “tour” the various LTER sites. Next you will choose one LTER site and answer some questions about the research being conducted there. This activity will help you to see how different experimental and monitoring approaches can be used to investigate the five key LTER and many other research questions.
The PowerPoint introduction to the LTER sites is provided on the LTER manual web page (http://www.dnr.cornell.edu/ext/LTER/manual.asp) and is located under the “supplementary files” heading. You need to have PowerPoint software to access this file. Click on the link and, using the “save as” option under your file menu, save the file as a PowerPoint presentation to a disk or your hard drive.
We suggest you show the presentation to the class to promote discussion among students. Before you begin the presentation, give your students a copy of Table 1 (see the Introduction to this manual), which lists the 24 LTER sites. Let each student choose an LTER to investigate. Alternatively, you could have your students choose a site during the PowerPoint presentation, which contains a map of all and pictures of many of the LTER sites. During the presentation and the subsequent Internet exploration, each student should take notes about the site he or she has chosen. You may want to use the teacher notes below for additional information to convey to your students during the presentation; these notes also contain questions you may want to ask your students during the presentation to promote discussion. After you have run the PowerPoint presentation, lead a follow-up discussion. We have provided you with a student handout containing topic ideas (following teacher notes).
If you prefer, you can have students view the presentation individually or in small groups. The PowerPoint presentation is also available in a web version on the same webpage (“HTML” is adjacent to the link). If your students are using older computers or software they may have trouble viewing this version. The discussion questions available in the teacher notes are also in the web version of the PowerPoint presentation. If you have trouble, contact Marianne Krasny at mek2@cornell.edu to obtain a copy of the file.
Students will need computers with Internet access for this activity. Plan for students to work at the computers individually or in pairs. We have provided a handout with questions students should answer as they explore their chosen LTER site. The “Suggestions for Further Study” include an activity in which students visit a nearby LTER site. If there is an LTER site near your school, you may want to familiarize yourself with it before this activity; most LTER websites have information on tours and whom to contact for information. Another Suggestion involves meeting a scientist who does research at an LTER site and/or is a professor at a nearby university or college. Most LTER websites also have contact information for scientists. Furthermore, many university scientists conduct research at LTER sites very far away from their schools. It is possible for you to live in California and have a nearby university professor who conducts research at an LTER site in Alaska.
Activity 2: Exploring the LTER network
Use these liner notes to engage your class in discussions about the LTER network and some of the individual slides. Questions marked with a “·” are intended for you to pose to your students.
Welcome to the Long Term Ecological Research network.
Introduction to LTER. The LTER network started in 1980 with only six sites, and as the next slide will show, currently has 24 sites.
· What is the definition of ecology? Ecology can be defined as the “study of the relationship between organisms and their environment.”
· Why do we need to study ecology?
The people pictured in this photo are using a GPS system in the Bonanza Creek Experimental Forest LTER in Fairbanks, Alaska.
Introduction to LTER, continued. LTER sites are present in many biomes not mentioned in this slide. You can refer to Table 1 in the Introduction and at the end of these notes for a list of sites.
· In what biome is your school located? Students may find it helpful to examine biology textbooks for example of biomes throughout the world.
· How many LTER sites are located in similar biomes?
· Why do you think it is important to have LTER sites in many different biomes?
The animal pictured on the slide is an Eastern newt (Notophthalmus viridescens) in the red eft stage; this newt was found in the Coweeta Hydrologic Laboratory in North Carolina
Map of all 24 LTER sites. You might want to pause a moment and encourage students to look at sites they want to explore later in Activity 2. This map is also located at http://lternet.edu/.
The HJ Andrews Experimental Forest LTER site, located in Oregon. The bare patches are logging sites.
SLIDE 6
Konza (pronounced “Kwanza”) Prairie
Natural Research Area LTER site in Kansas.
SLIDE 7
Virginia Coast Reserve LTER site.
SLIDE 8
Jornada Experimental Range LTER site
in southern New Mexico. The Sevilleta National Wildlife Refuge LTER site is
also located in New Mexico.
SLIDE 9
The Palmer Station LTER site is one
of two LTER sites in Antarctica, and is located on the coast. The McMurdo Dry
Valleys LTER site is inland.
SLIDE 10
Luquillo Experimental Forest LTER
site, Puerto Rico.
SLIDE 11
The Baltimore Ecosystem Study is one
of two urban LTERs; the other is located in Phoenix, Arizona. These two new
LTER sites are the first to include humans as components of the ecosystems
being studied. At these sites sociologists and ecosystem scientists are working
together to understand how humans interact with and affect their
environment.
· Why might it be important to
study how humans interact with the ecosystems in which they live?
SLIDE 12
Map of International LTER sites. If
your students are interested in these sites, they can visit the ILTER website
at: http://www.ilternet.edu/. One of the
“Suggestions for Further Study” involves exploring the ILTER network.
SLIDE 13
Why the LTER mission. One of the
reasons the LTER network is so successful is because there is continuity over
the years and from scientist to scientist.
· Why is it important to have
an overall mission for 1100 scientists at 24 sites to follow?
· What might happen if there
were no such mission, or set of guiding principles?
The photo is of a fish weir that was designed to contain fish in the
experimental reaches of the Kuparuk River, Arctic Tundra LTER site, North Slope
of Alaska.
SLIDES 14-17
Mission of the LTER network. These
four slides present the LTER network mission edited to be more readily
understood by students. A different mission goal is presented in each slide.
Listed here are the mission goals as presented in the slides, followed in
italics by the official goals as written by the LTER network. You may want
to pause at each slide and discuss the mission goal.
·
To help scientists at different sites work together. Conducting
major synthesis and theoretical efforts.
The
LTER network thinks it is important for scientists from many different sites to
gather and discuss their respective research results (synthesis) in an effort
to understand how different processes and patterns (for example, net primary
productivity) vary between very different ecosystems. Many LTER scientists also
develop models (theoretical efforts) in an attempt to better understand and
predict ecosystem functioning.
·
To understand ecology over large areas and long periods of
time. Understanding general ecological phenomena that occur over long
temporal and broad spatial scales.
LTER
scientists are interested in understanding how basic ecological phenomena (for
example, forest succession or human-induced acid rain) vary over very long
periods of time and across very large areas.
·
To help solve
environmental problems. Providing information for the identification and
solution of societal problems.
This
goal is straightforward: LTER scientists examine how humans interact with and
affect their surrounding ecosystems, and propose ways to solve environmental
problems.
·
To develop long-term experiments that can be used by
scientists in the future. Creating a legacy of well-designed and documented
long-term experiments and observations for use by future generations.
It
is crucial that LTER scientists consider the long-term aspects of their
research. For example, scientists at the Hubbard Brook Experimental Forest LTER
site have recently initiated a 50-year study. Most of the scientists currently
leading the project will have retired well before the study is over, so it is
important that experiments, protocols, and data are well-documented and
designed for understanding over the long-term. Furthermore, samples need to be
collected in a way that can be continued for a very long time, and need to be
stored or otherwise archived.
The photos include a pronghorn
antelope in the Shortgrass Steppe LTER site in Colorado and a lake at the
Harvard Forest LTER site in Massachusetts.
SLIDE 18
Five Research Topics. This slide
quickly introduces the idea that LTER scientists study five main research
topics.
SLIDE 19-23
Core Research Areas. These slides
contain an edited version of the five LTER core research areas. As with the
previous set of slides, the text of the slides is listed and then followed
in italics by the official core research areas of the LTER.
What happens to the organic matter that plants produce? For example, when leaves fall to the ground, what factors control how quickly they decay? What happens after decay?
What causes populations of plants and animals to vary over time? Why is a species abundant one year but not the next, or found in different places at different times? How do populations of one organism affect other populations or organisms?
How do inorganic nutrients, such as nitrogen and carbon, move through soil and water? Nitrogen is an example (there are many others such as phosphorous and calcium) of inorganic elements that plants need to survive and flourish. LTER scientists want to know how these elements are used by various ecosystem components, such as trees and streams, and how they cycle between these components.
Net primary production is the rate at which biomass, or energy stored in material by plants, accumulates. What controls the growth of plants? For example, why do plants grow where they do? What factors control how quickly they can grow, and how big they can get?
How do
disturbances, such as fire, drought, or logging, affect ecosystems? How often
do natural disturbances occur, and what regulates them? How important are
disturbances to ecosystem health?
SLIDE 24
Biotic (living) and abiotic
(non-living) components of ecosystems. Research conducted at LTER sites is
often designed to look at the interactions between biotic and abiotic components
of ecosystems.
· What are some examples of
biotic factors in ecosystems? Abiotic factors?
SLIDE 25
Examples of biotic factors. Biotic
factors include all living things that affect organisms. The photos include
cacti at the Central Arizona - Phoenix site in Arizona and two ground beetles
from the HJ Andrews Experimental Forest LTER site in Oregon.
SLIDE 26
Examples of abiotic factors. Abiotic
factors include all non-living things that affect organisms. Some other
examples include pH, humidity, salinity, sunlight, nutrient availability, and
elevation. On the left is a photograph of a meteorological stand that measures
a variety of variables including temperature and wind speed and direction. On
the right is a photo of the Palmer Station site in Antarctica.
SLIDE 27
Abiotic and biotic interactions.
This is a good opportunity to ask your students to discuss why it is important
to study both types of factors. You may also want to have your students discuss
how these ecosystem components interact. For example:
· How does yearly
precipitation affect plant growth (i.e., less vs. more precipitation)?
· How could the size of a
predator population affect the number and behavior of prey populations? For example, how could the number of owls
(that eat mice) present in an area affect the number and behavior of mice in
that same area?
· What would happen if you
ignored all biotic (or abiotic) factors when researching an ecosystem?
This photo shows research examining
nitrogen (nutrient) cycling at the Shortgrass Steppe LTER site in Colorado. The
next several slides are examples of some different types of research being
conducted at many LTER sites.
SLIDE 28
Sampling periphyton in a freshwater
marsh at the Florida Coastal Ecosystems LTER site. Periphyton are sessile
organisms, such as algae and small crustaceans, that live attached to surfaces
projecting from the bottom of a freshwater aquatic environment.
SLIDE 29
A seed trapping experiment at the Arctic Tundra site in Alaska is pictured
in the upper left corner; in the lower right corner is a photo of a Central
Arizona - Phoenix graduate student examining a data logger.
SLIDE 30
This helicopter was used to add
calcium to an entire watershed at the Hubbard Brook Experimental Forest LTER in
an experiment designed to examine some of the long-term effects of acid rain.
Acid rain has leached many essential nutrients, including calcium, out of the
soil at Hubbard Brook over the past several decades; many scientists are
concerned that this may negatively affect tree health. In this experiment
scientists are adding calcium back to forest soils to see how trees respond.
SLIDE 31
On the left: melting an ice hole in
the McMurdo Dry Valley LTER site in Antarctica. On the right: a photo taken at
the North Temperate Lakes LTER site in Wisconsin.
SLIDE 32
These ladders are used in a
rhododendron-removal experiment in the Coweeta Hydrologic Laboratory LTER site
in North Carolina. By removing rhododendron from the forest and seeing what
happens, scientists will better be able to understand how rhododendron affects
forests. For example, if the forest erodes more quickly after removing
rhododendron plants, scientists might conclude that rhododendron is an
important component in keeping forest soils intact. This could help forest
managers better understand how to manage their land. Ladders have been put in
places so researchers can access the site without disturbing it.
· What might scientists learn
by removing rhododendron plants and watching how the forest responds?
SLIDE 33
This weir at the Jornada
Experimental Range LTER site in southern New Mexico measures water runoff
during major storm flooding events. All
the water from areas higher than the weir (behind it) flows through the “V” and
can be measured by scientists.
· Why do you think scientists
might be interested in how much water runs off the desert after large
rainstorms?
SLIDE 34
This site is part of a snowpack enhancement study at the Niwot Ridge LTER site in Colorado. (It is summer in the slide – the snowpack is altered in winter by the addition of a fence.)
· What do you think scientists might learn by using a fence to keep snow off the ground in one area, and to accumulate to a greater depth in another area? The fence is used to stop blowing snow.
Importance of long-term ecological research. If you have already conducted Activity 1, your class may already understand the importance of long-term research. In fact, later in this presentation we use an example from the North Temperate Lakes LTER site (Lake Mendota, the same lake used in Activity 1) to show why short-term research might overlook long-term trends.
“Why do we need long-term research?”
…to learn about: slow processes, infrequent events, and ecological trends. The next three slides will provide examples of these.
Slow
processes. Many ecological processes are very slow. For example, it can take a very long time for a tree to fully
decompose.
· Can you think of other very slow
ecological processes?
SLIDE 39
Infrequent
events. Not all ecological events happen often. For example, hurricanes or
fires can be rare and infrequent in many sites, yet still have large and
long-term effects on those sites. The El Niño and La Niña weather patterns are very important in North America, but do not
happen every year.
· Can you think of other
infrequent events? Some examples: gypsy moth forest defoliation and
droughts.
· Can you think of infrequent
events on a very small scale? For example, an animal dying on a certain patch of
forest might be an infrequent event for the organisms that live in the soil
there.
SLIDE 40
Ecological trends.
Long-term research can help scientists identify human-induced trends such
as global warming.
· Can you think of other ecological trends? An example is the shifting (maybe north or south) of a plant or animal habitat range.
There are many examples of long-term research conducted at LTER sites.
SLIDES 42-46
The next few slides use Lake Mendota
data as an example of the need for long-term data. Activity 1 in this manual
deals extensively with these data.
SLIDE 47
End of presentation. Your students should proceed with Part B of this exercise – an Internet exploration of an LTER site.
SLIDE 48
Photo credits.
Activity 2: Exploring the LTER Network
Student Name(s)
1) Discuss daily, monthly, and annual variability in such things as weather. For example, does it snow or rain more one year than the next year? Is it often colder in one year than another? Would short-term research allow scientists to understand this variability? Why or why not?
2) Describe some research questions that would be hard to answer with a short-term study. What are some of the advantages of long-term as opposed to short-term ecological research?
3) Why is it important to have LTER sites all over North America?
4) Can you think of any drawbacks to conducting long-term research?
5) What are some other examples of infrequent ecological events?
6) List some other natural or human-induced disturbances that may affect a very large area.
7) Discuss other “slow processes,” in addition to tree decomposition.
Activity 2: Exploring the LTER Network
Activity 2: Exploring the LTER Network
1. What is the name of the LTER site you chose to visit?
2. Why does it interest you?
3. Where is it located? (Name the state and the nearest big city.)
4. Describe the ecosystem(s) present at your site. Is it a forest, desert, lake, etc? Note that more than one ecosystem may be represented at the site you have selected.
5. What kinds of plants are present at the site? How can you tell? (For example, do you see them in pictures of the site, or are they mentioned in a research report?)
6. What kinds of animals are present at this site? How can you tell?
7. What is the weather like at this site? (Lots of rain or little rain? Cold or warm in winter? Sunny or cloudy?)
8. How might the climate influence the organisms that are present?
9. If you could visit this site in person, what would you most want to see?
10. If you were the chief scientist for the project, what would you like to study here?
11. Describe one or more of the current research projects at your chosen site. What are some of the results from this research? What have scientists learned about the ecosystem(s) at this site?
12. LTER scientists generally conduct studies to address one or more of the following questions. Can you tell which of these questions are being studied at your site? How might you design a study to address one or more of these questions at your site? (Note: You do NOT have to answer the questions listed below. Just tell whether or not they are being studied at your LTER site, and what sorts of studies might be used to answer them.)
· What controls the growth of plants? For example, why do plants grow where they do? What factors control how quickly they can grow, and how big they can get?
· What causes populations of plants and animals to vary over time? Why is a species abundant one year but not the next, or found in different places at different times?
· What happens to the organic matter that plants produce? For example, when leaves fall to the ground, what factors control how quickly they decay?
· How do inorganic nutrients such as carbon and nitrogen move through soil and water?
· How do natural disturbances such as fire, drought, or logging affect the ecosystems at your site?
13. What else did you learn about your chosen site?
Students will:
Become familiar with the network of LTER sites
Use the worldwide web to pay a “virtual visit” to an LTER site (http://lternet.edu/)
Identify the types of research being conducted at that site and explain how this research fits in the five core LTER research questions
Science as Inquiry – Development of:
Abilities necessary to do scientific inquiry (5-8 & 9-12)
Understandings about scientific inquiry (5-8 & 9-12)
Science and Technology – Development of:
Understandings about science and technology (5-8 & 9-12)
Science in Personal and Social Perspectives – Development of an understanding of:
Science and technology in society (5-8)
Science and technology in local, national, and global challenges (9-12)
History and Nature of Science – Development of an understanding of:
Science as a human endeavor (5-8 & 9-12)
Nature of science (5-8)
Nature of scientific knowledge (9-12)
You have already viewed a PowerPoint presentation about the LTER network. Now you will be using the Internet to take a “virtual tour” of some of the 24 different LTER sites funded by the National Science Foundation. Follow the steps listed below and answer the questions in the accompanying handout your teacher has given you.
If you are lucky, your school may be located near one of the LTER sites, and it may be possible to organize a field trip to the site. You may be able to contact the LTER education coordinator to ask about this possibility.
Even if an LTER is not within field-trip distance of your school, you may be able to identify a scientist who conducts research there but works at a college or university close to your school. You may be able to recruit this researcher to visit your class and discuss his or her work at the LTER site.
You may want to “visit” another LTER site – either in the US or in another country (international LTER website: (http://www.ilternet.edu/). While you are exploring this site, think about the following questions:
· What biomes are represented at your second site? How are the two sites physically different from each other?
· How does the research at the second site differ from the first? How is it similar?
· Are you more interested in the research being conducted at one of the sites? Why?
· If you were a scientist at a university, what sort of research would you do, at which site, and why?
Research at the Hubbard Brook Experimental Forest started about 50 years ago. At that time, the northeastern states were experiencing a drought and many communities were suffering from water shortages. Knowing that plants (especially trees) take up large volumes of water from the soil and convert it to water vapor, scientists wondered whether cutting down trees might increase water supplies. They developed a hypothesis that could be tested through long-term research: if trees were cut down and therefore not using as much water, more water would flow into the reservoirs.
Hubbard Brook flows through New Hampshire’s White Mountain National Forest and drains a range of small mountains. The tributaries of Hubbard Brook form a set of discrete watersheds, separated by mountain ridges. Because these watersheds share many characteristics in common (for example, similar size and vegetation), they provide an ideal setting for conducting ecosystem experiments.
In the laboratory, scientists use controls to compare with results of experiments. For example, a scientist studying the effect of salt on plants would expose some plants to salt (treatment) and compare their growth to plants growing without salt (control). Similarly, scientists at Hubbard Brook devised experimental treatments for three watersheds to see whether different ways of cutting trees would affect the amount of water reaching the stream. When scientists manipulate the world outside of the laboratory, they are conducting a field experiment.
In one watershed, researchers cut all the trees in the middle of winter and left them lying on the snow so that the soil was not disturbed. In another watershed, all the trees were cut and entirely removed. In a third watershed, researchers divided the forest into 25-meter-wide strips. In the first year, they cut and removed all the “merchantable” materials (leaving branches and tree tops) in every third strip. In subsequent years, they returned and cut the adjacent strips. This treatment was designed to investigate less damaging ways of cutting an entire watershed. And finally, the last watershed was left intact, similar to a control. However, unlike laboratory studies, the ecosystem experiments did not have true controls. Although the different watersheds were similar in size and vegetation, they were not exact replicates. (It is virtually impossible to have true replicates or controls in nature because of differences in soil, plants, etc.) Thus, the watershed that was left intact is referred to as the “reference” rather than the control watershed.
To measure the changes in water flowing out of the different watersheds, scientists installed special gauges on forest streams, called “weirs.” Weirs are permanent concrete structures consisting of a large basin with a v-notch cut on the side of the downstream end. The stream flows directly into the basin where it slows down and becomes still, and then flows out over the v-notch. By constantly measuring the stream height as it passes over this v-notch, and entering this height into a known formula, researchers can determine streamflow volume. A picture of a weir at Hubbard Brook is on the next page.
In addition to measuring water quantity, the scientists at Hubbard Brook measured nutrients in the water, including nitrogen and sulfate, and pH. These data have helped us to understand how nitrogen and other nutrients cycle through the plants, soil, water, and atmosphere. The pH and related measurements have helped us to understand the impact of acid rain on northeastern forests. The scientists also erected weather stations with precipitation collectors to measure water and nutrients coming into the watersheds from rain and snow.
While scientists at Hubbard Brook have conducted a great deal of research on disturbances caused by humans, they have also conducted research on natural disturbances. For example, they have studied how outbreaks of leaf-eating caterpillars affect water and nutrient cycling, and how powerful ice storms can affect forests. Hubbard Brook is truly an “experimental” forest.
In this activity, you will be looking at some of the original streamflow data collected at Hubbard Brook to determine the short-term and long-term results of a forest tree-cutting experiment. You will be examining data from Watersheds 2 and 3. Watershed 2 is the clear-cut treatment watershed and Watershed 3 is the reference watershed. All trees in Watershed 2 were cut in December 1965 and left on top of the snow. In the summers of 1966, 1967, and 1968 two herbicides were applied to the entire watershed to prevent the regrowth of any vegetation. Herbicide application was useful in answering the hypothesis discussed above (i.e., does deforestation cause an increase in streamflow?), and it helped other, collaborating scientists that were studying nutrient cycling. Because this second group of scientists was interested in how nutrients cycle in an ecosystem after a major disturbance and without any trees or plants, they applied herbicide for three years to inhibit the growth of all new plants. It is important to note that the herbicides did not themselves affect the overall nutrient cycles in the watershed, and that, aside from inhibiting terrestrial plant growth, the herbicides had no negative effects on organisms either in the watershed or downstream.
The photograph below shows a scientist applying herbicide with a backpack sprayer.

In each Hubbard Brook watershed, scientists collected streamflow data on a daily basis as instantaneous flow rates: liters of water per second. They then integrated these values over time and standardized them for the area of the watershed. The results are reported as millimeters per day per standard area. This conversion makes it possible to conveniently compare streamflow to precipitation, and to compare streamflow in watersheds of different sizes. For example, in 1958 in Watershed 2, a value of 645.15 is listed in the data files. This means that during 1958, 645.15 mm of water (for any given area – for example, 1 square meter or 100 square meters) flowed out of Watershed 2.
The file containing easily printable spreadsheets is located in both PDF and MS Word formats on the LTER Manual webpage (http://www.dnr.cornell.edu/ext/LTER/manual.asp), under the “supplementary files” heading. It contains annual streamflow and precipitation data for both Watersheds 2 and 3 in a handout for students. There is also a teacher’s section that includes another data column containing the difference between Watershed 2 and Watershed 3 (i.e., W2 – W3). The teacher’s file also contains several graphs of precipitation and streamflow, for your reference.
There are two MS Excel computer files: one for teachers, and for students. They are named, respectively, “Activity 3 Data Teachers (Excel),” and “Activity 3 Data Students (Excel).” The teacher’s file contains annual precipitation, streamflow, and streamflow difference in Watersheds 2 (treatment) and 3 (reference), and also includes graphs for your reference. The student version does not contain graphs or streamflow difference values. Both of these files are located on the same webpage.
Your students will use either graph paper or spreadsheet software to generate a figure that shows streamflow changes over time in the treatment and reference watersheds. Begin the activity by having the entire class review the data set and discuss the best approach for data analysis.
Students should create two separate graphs: annual streamflow in W2 and annual streamflow in W3, or one graph containing both. One interesting way to compare the treatment and reference watersheds is to transfer the graph for W3 (reference) to a transparency, so that it can be superimposed on the graph for W2 (treatment). It is also instructive to graph the annual average precipitation for each watershed on transparencies and superimpose it on the two streamflow graphs.
Students will first graph results from the five years immediately following the clear-cut, and will then examine the remaining 18 years. Through comparing the short-term and long-term data, students should gain an understanding of how short-term trends can be misleading in ecology. One option for the activity’s classroom organization would be to have your students graph the baseline data individually or in small groups, and then gather as an entire class to discuss what the data indicate (using the questions in the Procedure). Repeat this for the second data section (the five years after the clear-cut) and again for the third section (the final 18 years).
In addition to graphing changes in the two watersheds over time, students can use the annual streamflow values to calculate the difference in streamflow (W2 - W3) between the watersheds. They will observe a pre-treatment difference between W2 and W3. Then they will observe that in the years immediately after the treatment, the difference between W2 and W3 increases dramatically. Streamflow in W2 increased an average 32 % in the three years after clear-cutting.
With time, however, the difference between the two watersheds returns to baseline values. And then, something very interesting happens. Streamflow in W2 becomes even smaller than it was before the treatment. Thirteen to 23 years after treatment, the average streamflow in W2 is 7% less than it had been BEFORE treatment.
What’s going on? For three years after the trees were cut, herbicides were applied to prevent any vegetation from re-growing. But once the herbicide treatments stopped and the vegetation was allowed to grow back, water yields declined rapidly. The original forest had been composed of mature hardwood species such as sugar maple, American beech, and yellow birch. But when the scientists stopped applying herbicides, the regenerating forest had a different composition. Most of the trees were pin cherry and paper birch. Studies at Hubbard Brook have demonstrated that these two species transpire more, and thus take up more water from the soil, than the original mature forest species. Data on total vegetative biomass in W2 can be found on the Hubbard Brook website (see “Suggestions for Further Study”).
The story is not over, however, because pin cherry trees do not live very long — usually only about 30 years. The data set provided only goes through 1988, 23 years after treatment. As pin cherry trees die off at Hubbard Brook, they should be replaced by the original hardwood species — maple, beech, and yellow birch. So the trend in water yield could change again.
Table 1. Hubbard Brook Watershed Treatments.
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2 |
15.6 |
Clear-cut in winter 1965-66. Trees left on the ground. Herbicides applied in 1966, 1967, 1968. |
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3 |
42.4 |
Reference (no treatment). |
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4 |
36.1 |
Strip-cut in 3 phases, in 1970, 1972, 1974. Trees removed from watershed. |
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5 |
21.9 |
Whole-tree harvested during the dormant season of 1983-1984. |
For students who would like to carry out an additional activity, data from a second treatment (strip cutting in Watershed 4) can be located on the Hubbard Brook LTER website. This activity is in “Suggestions for Further Study,” below. Watershed 4 was divided into 49 strips, each strip 25 meters wide. In autumn of 1970, every third strip of forest was cut. A second set of strips was cut in 1972. In 1974, the third and final set of strips was cut. In contrast to W2, where all the felled trees were left in place, on W4 the trees were removed. However, no herbicide was applied to prevent vegetation regrowth.
Develop an understanding of the importance of long-term data
Learn to graph by hand or using Excel software, making decisions about what data to graph
Interpret graphs showing ecosystem response to an experimental treatment
Learn about methods scientists use to examine ecosystem functions
Examine the importance of “controls” in experiments
Examine how hypotheses are not always completely correct
Learn about human attempts to modify ecosystems
Science as Inquiry – Development of:
Abilities necessary to do scientific inquiry (5-8 & 9-12)
Understandings about scientific inquiry (5-8 & 9-12)
Life Science – Development of an understanding of:
Populations and ecosystems (5-8)
Matter, energy, and organization in living systems (9-12)
Science and Technology – Development of:
Understandings about science and technology (5-8 & 9-12)
Science in Personal and Social Perspectives – Development of an understanding of:
Populations, resources, and environments (5-8)
Science and technology in society (5-8)
Science and technology in local, national, and global challenges (9-12)
Natural resources (9-12)
Environmental quality (9-12)
History and Nature of Science – Development of an understanding of:
Nature of science (5-8)
Nature of scientific knowledge (9-12)
· Pencils, graphing paper or access to computer workstations with spreadsheet/graphing software such as EXCEL
a) The first column is labeled “year.” Data from 1958-1988 are presented.
b) Streamflow data from the different watersheds (columns B and C) are presented as annual streamflow in mm per standard area per year. These values have been adjusted to account for the difference in size between the watersheds.
c) For each watershed, mean annual precipitation values are also provided (columns D and E). As you can imagine, the amount of rain usually varies from year to year, and the amount of rain that falls on the watershed obviously influences how much water comes out in streamflow.
Find vegetation data on the Hubbard Brook website that might help explain short- vs. long-term Watershed 2 streamflow results following clear-cutting. The Hubbard Brook website can be found by first going to the National Long Term Ecological Research program’s website at http://lternet.edu/ and then following appropriate links.
You could do the same graphing steps using the data for Watershed 4, where trees were strip cut over the course of a four-year period. Visit the Hubbard Brook website (see immediately above), where you should be able to find the Watershed 4 streamflow information by clicking on the “data” button and following links to “stream.” Getting data off of the HBEF website can be difficult: the data need to be downloaded and reformatted for database software. You may need to ask your teacher for help, or click on the “email” link of the HBEF website to ask the HBEF data manager for assistance.
Hubbard Brook is very famous because it was here that scientists first discovered acid rain. The knowledge gained from Hubbard Brook acid rain research was instrumental in the development of the federal Clean Air Act and subsequent amendments. The Clean Air Act and its amendments called for a reduction in acid rain-causing emissions from coal-fired power plants and other pollution sources. Because Hubbard Brook is a long-term ecological research site, scientists have had the opportunity to continue studying the effects of acid rain on northeastern forests after the passage of the Clean Air Act. And, unfortunately, while research shows that precipitation is generally becoming slightly less acidic, current studies indicates that acid rain and its effects are still a big problem.
In March 2001, Hubbard Brook scientists issued a news release urging the public to continue to work to reduce acid rain. "The science on this issue is clear," says Dr. Gene Likens, director of the Institute of Ecosystem Studies in Millbrook, New York, and one of the scientists who discovered acid rain at Hubbard Brook. "Current emission control policies are not sufficient to recover sensitive watersheds in New England. The deeper the emissions cuts, and the sooner they are achieved, the greater the extent and rate of ecological recovery from acid deposition." Dr. Likens’ work is a powerful example of how scientists can influence policy at the national level. You may want to visit recent HBEF acid rain publications, located at: http://www.hbrook.sr.unh.edu/hbfound/hbfound.htm.
You may want to do more research on the Clean Air Act and acid rain using internet sources, including the Hubbard Brook website. Check out the Environmental Protection Agency’s (EPA) acid rain website at http://www.epa.gov/airmarkets/arp/, or the National Atmospheric Deposition Program (NADP) at http://nadp.sws.uiuc.edu/. The National Science Teachers Association is another good source for acid rain materials, at http://www.nsta.org/.
Many ecological studies start out as observational or monitoring studies, such as the study that monitored ice-out at the North Temperate Lakes LTER (see Activity 1). Such monitoring data are invaluable because they allow us to become familiar with ecosystems and to observe changes that occur over time. Furthermore, many monitoring studies raise questions that can later be tested with experiments. For example, scientists at the North Temperate Lakes site monitoring the pH of lakes noticed an increase in the acidity of the water. At the same time, they observed declines in health and populations of many lake organisms. They wondered whether the problems the plants and animals were suffering could be due to acid rain. To test this hypothesis, they conducted an ecosystem study where they added acid to one lake and left a second lake untreated as a reference. It turned out that the decline in pH (increase in acid) in lakes did cause many of these organisms to decline. Thus, careful observations followed by ecosystem experiments led to a better understanding of acid rain.
The protocols in this activity are adapted from the Central Arizona - Phoenix LTER site. Both scientists and students are using the protocols to collect monitoring data in schoolyards and other sites in Phoenix and the surrounding area. Because the scientists do not have the time or money to collect data from a wide range of sites, they have asked students to help collect data at sites the scientists are not able to visit. Students who are careful in their data collection are making a real contribution to the LTER study and to our understanding of ecosystems.
In this activity, you will set up a long-term monitoring project at your schoolyard or other place in your community. You may want to contact scientists at a nearby university or LTER site to see if they might be interested in collaborating with you on this project. It may be possible to form a student-scientist partnership in which the scientists help you to design your study and use your results. If you are able to collaborate with a scientist, you will likely need to adjust these protocols according to his or her suggestions.
We have included several protocols below. We suggest that everyone start out with the Mapping Your Schoolyard, Site History, and Site Management protocols, and then choose an ecosystem component you are interested in monitoring (e.g., arthropods or birds). Your teacher will discuss with your class what is most appropriate for your class and your school.
Depending on which activities you will be doing, you may need the following student worksheets included below: Habitat Description, Bird Data, or Arthropod Data. The Habitat Description worksheet should be used by your students in both the Arthropods and Birds activities.
In this activity, the procedure calls for students to obtain a map of the schoolyard. You may decide that this is a good classroom activity (i.e., assign student(s) to obtain a map from the principal or other school administrators), or you might obtain the map yourself. It is important that the map is as recent as possible. You may want to consider only mapping the section of the schoolyard that your students will use in their research activities, as mapping the entire schoolyard can be very time consuming.
This activity instructs students to locate old maps and/or aerial photographs of their schoolyard. You may have luck contacting your local town or city government for older maps; or consider visiting websites such as:
This site may have current aerial photographs of your area. Type in the address, click on the map, and if an aerial photo is available for your location, a tab labeled “aerial photo” will appear next to the tab labeled “street map.” Both maps and photos can provide land-use history that will help your students with this activity.
· http://terraserver.homeadvisor.msn.com/default.asp
You may be able to find current aerial photographs of your area on this site. Type in your town name in the “find a specific place” box, and go from there. This site also has topographic maps.
This site has topographical maps for most of the country available online.
The United States Geological Survey’s site has a great deal of information about maps and photographs and how to order them.
There are a number of ways that you and your class can develop a site history. You could work on this as an entire class developing one site history together, or you could work with the maps and photos as a class and then ask students to individually write up site history reports. There is no single, correct way to do this – what is important is helping students understand that scientists first try to understand the history of research sites before proceeding with monitoring and experiments.
The same basic instructions apply to the Site Management activity as the Site History. There is no correct or absolute way to do this, as long as students are able to develop an understanding that current use is also crucial to understanding how a system works and will influence how research on a system can be conducted.
In this activity your students will be installing “pitfall traps” to collect and monitor ground arthropods. If you and your students decide to monitor arthropods over the long term, you may want to consider monitoring several different habitats or conducting a field experiment. For example, you could examine what types of arthropods are present in different habitats, how the types and number of arthropods change over time (e.g., you could collect arthropods every month for the entire school year and track changes), or how arthropods respond to an experimental treatment in your schoolyard. For example, you could ask your site manager to stop mowing one area of lawn, or you could have your students regularly add water to an otherwise dry area.
You will need to find local arthropod identification guides that will allow your students to identify arthropods to Order. Consult local universities or bookstores for arthropod and/or insect and other guidebooks. The Practical Entomologist by Rick Imes has a simply key to common insect orders; and the Peterson’s Field Guide series has a book on insect identification. A university or LTER website may also be a good source of information about local arthropods. If you cannot find a good identification guide, you can have your class simply discover the arthropods they discover into groups with similar physical characteristics. If you choose this option, be sure that your students take very specific notes so that you may use the same grouping characteristics in subsequent sampling efforts. It is preferable to use a real identification guide. Use the Arthropod Data worksheet below to record the number of arthropods collected.
In this activity, students will use a method called “point counts” to monitor birds. They will need to be able to identify the birds in their schoolyard. You may want to check with your school library or local bookstore to see if they have any bird identification books. The Audubon Society’s and Peterson bird identification field guides are both excellent. You may be able to locate a local bird watcher who is interested in helping your class. Check with your state Audubon society (visit http://www.audubon.org/ for more information). You will need the Bird Data worksheet found below to record the number of birds seen during point counts.
You may want to consider making both the Arthropod and Bird activities into long-term research projects. If you carefully design and record the sampling scheme for the monitoring or field experiment, it should be possible for students in subsequent years to use exactly the same protocols to continue the research. Students may find it rewarding to be part of long-term ecological monitoring, and future classes may be able to look at many years of data and analyze trends.
The term “replicate” is used in the bird activity. You may want to discuss this term with your students and help them incorporate it into their research design. A replicate can be defined as a “repetition of an experiment or procedure.” Scientists use replicates so that they do not make erroneous conclusions based on a single experiment or sampling point. For example, if scientists are interested in determining what types of birds live near parking lots, they will conduct many point counts at different locations that are all near parking lots. One of these sites might have an unusually high number of house sparrows, and no other birds; and perhaps the other sites all have similar mixes of sparrows, rock doves, and starlings. If only one site had been studied (the one with only house sparrows), scientists might incorrectly conclude that only house sparrows live near parking lots. If many replicates were studied, then scientists would be able to learn that many different birds live near parking lots – and perhaps they would then try to determine why one specific parking lot has many house sparrows. In general, replicates help account for and determine what types of variability exist in natural systems. You may want to help your students design their point counts to include replicates of the habitat(s) they are studying.
Develop an understanding of how scientists study sites before conducting experiments
Gain experience working with maps and/or aerial photographs
Learn about local land-use history and maintenance
Learn about arthropods and how to identify them
Learn about birds and how to identify them
Learn about the importance of long-term environmental monitoring
Develop
long-term monitoring sites in their schoolyards
Science as Inquiry – Development of:
Abilities necessary to do scientific inquiry (5-8 & 9-12)
Understandings about scientific inquiry (5-8 & 9-12)
Life Science – Development of an understanding of:
Populations and ecosystems (5-8)
Diversity and adaptations of organisms (5-8)
Behavior of organisms (9-12)
Science in Personal and Social Perspectives – Development of an understanding of:
Populations, resources, and environments (5-8)
Natural resources (9-12)
Environmental quality (9-12)
History and Nature of Science – Development of an understanding of:
Nature of science (5-8)
Nature of scientific knowledge (9-12)
Activity
4: Schoolyard LTER
You need to provide a description of the habitat at each of your arthropod or bird monitoring research locations (for example, at each individual pit trap or point count location). This description includes the amount and type of vegetation and physical features at different heights in each location. This description will provide an additional piece of data to use when analyzing results.
Date _________________
Observers’ Names ________________________________________________________
Overall Site (name or description) ___________________________________________
Bird Point Count or Arthropod Pit Trap Site Name _________________________
· Record information for the 5 meter by 5 meter area surrounding each individual pit trap
· Record information for the each entire (20 meter radius) bird point count area
Total Area Surveyed (use 5 meter edge or 20 meter radius to calculate) _____________
1. Ground Cover (% gravel/soil; lawn; all other vegetation; pavement or building)
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
2. Vegetation between 15 cm and 1.5 m tall (% coverage) _______________________
____________________________________________________________________
____________________________________________________________________
3. Vegetation over 1.5 m tall (% tree canopy coverage) _________________________
____________________________________________________________________
____________________________________________________________________
4. Record other useful notes about the habitat you are describing. Be specific.
Activity
4: Schoolyard LTER
Observer’s Name ________________________________________________________
Date ________________________ Pit Trap Number _____________________
Name of Person Identifying Sample __________________________________________
Record notes about the sampling design (for example, did you follow step #2 in the procedure exactly, or did you use a grid system?)
________________________________________________________________________
________________________________________________________________________
Comments (for example, “It rained over the sampling period and the cups filled with water.”)
________________________________________________________________________
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Activity
4: Schoolyard LTER
Observer’s Name ________________________________________________________
Date ________________________ Point Count Site _____________________
Time Start ___________________ Time End __________________________
Weather (wind speed, temperature, and cloud cover) ____________________________
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Other Notes: ____________________________________________________________
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Ecologists map research sites as a first step in documenting the living and non-living aspects of an ecosystem. A map also establishes the boundaries of the research site. In this activity you will map all, or a part of, your schoolyard. You will use your map for a variety of purposes: showing your data collection locations, comparing features of your schoolyard to other schoolyards, and comparing changes to the schoolyard over time.
Why would you want to know the history of your site? One of the questions ecologists try to answer is: Why do plants grow where they do? Often knowing about past ecological conditions helps us to answer this question. For example, knowing when the last fire or clear-cut occurred in a forest might help explain why certain plant species are present. At the Hubbard Brook LTER, pin cherry and paper birch appear shortly after a clear-cut, whereas sugar maple, American beech, and yellow birch dominate the mature forest that has not been disturbed for many years.
At the Central Arizona - Phoenix LTER, ecologists are particularly interested in the impact of humans on the ecosystem. The past actions of humans are among the most important factors explaining why plants grow where they do. For example, mature saguaro cacti are rare on Arizona State University’s "A" mountain. Without considering past human influence, you might think that the absence of saguaro cacti is due to unfavorable soils or micro-climate. By ignoring human factors, you would overlook the main reason for the lack of mature saguaro cacti – people removed them.
Where might you find information on the history of your school site? One way to find such information is to locate old maps and aerial photographs. You may be able to locate maps and photographs from your local town or city government, or your school principal may have them. You may also be able to locate maps and photographs on the Internet. Ask your teacher for assistance with where to find maps and photos. Your teacher will also tell you what format to use as you write the site history.
· What was at your site before it became a school?
· Is there a written site history?
· When did it become a schoolyard (for example, perhaps the site was transformed from desert to agricultural field in 1935; then in 1975 the school was built)?
· What kind of vegetation was planted before and after the school was built?
· Have parts of the schoolyard changed from the original design?
· If so, why were the changes made?
Why should you look at how your schoolyard is used and maintained? We often forget that humans play an important role in ecosystems, particularly urban ones. For example, people disturb ecosystems by simple things such as mowing the grass. These disturbances can create changes in the plant and animal communities. To conduct a study in your schoolyard, you need to build partnerships with the people responsible for maintaining the property.
Your answers to the following questions will be useful as you decide when and where to collect data. For example, you will want to schedule data collection at times when pesticides are not being sprayed. The answers will also be useful when you get to the point of interpreting data. Your teacher will help you determine the format of your Site Management report.
· How is the schoolyard used?
· Who takes care of the schoolyard?
· Describe the maintenance schedule. How often is the grass watered and mowed? How often are herbicides/pesticides used? What else do school workers do to manage the schoolyard?
· Which teachers currently use the schoolyard for class projects (find out when and how often)?
· What areas do students use at recess and/or breaks? How do the staff and faculty use part of the schoolyard during their breaks?
· Which areas are used more during specific times of the school year (for example, are the shadier parts used mostly when it is hot during fall and spring)? What are those areas used for? Does anything happen differently in different seasons, and if so, how and what (for example, if you live in a region that receives snow, what area gets plowed or shoveled, and where do they put the snow)?
· What after-school activities take place in the schoolyard?
· How is the schoolyard used over the school vacations?
In addition to mapping a site and determining its history and management, scientists need to describe the habitat of a particular area they are studying. In the arthropod and bird activities, you will choose a few areas in your schoolyard to monitor these animals. After you choose the monitoring sites, you should describe the habitats as follows:
· Gravel or soil
· Lawn
· All other vegetation
o Vegetation with a height of 15 cm to 1.5 m.
o Vegetation over 1.5 m (trees). Try to estimate the percent that is shaded by the tree trunk, branches, and leaves, not just the area of the trunk.
· Pavement or building
You are undoubtedly familiar with insects, such as ants, butterflies, beetles, bees, and flies. Similarly, you are likely familiar with arachnids, such as spiders, ticks, and scorpions. Together these two classes of organisms form a larger group, or phylum, called arthropods.
Scientists search for characteristics that allow us to separate organisms into groups. One important characteristic of arthropods is that they have bodies developed into different segments, like the head and abdomen of spiders, or the head, thorax, and abdomen of insects. Another important characteristic of arthropods is that they do not have an internal skeleton like birds, reptiles, amphibians, fish, and mammals. Instead, they have a hard shell or skeleton on the outside of their bodies called an exoskeleton.
Arthropods are important components of any food web. In a single collection you might find arthropods that are decomposers, herbivores, predators, and parasites. Furthermore, because they have short life cycles, arthropods respond quickly to disturbances (for example, mowing a lawn, clear-cutting, fire) and changes in soil and vegetation. Thus, if you monitor ground arthropods at your schoolyard, you can see how they react to disturbance or change (such as new construction next to your school). We can also compare arthropod populations in areas with different land uses to get an idea of how human activities affect biological diversity. For example, students in the Ecology Explorers program of the Central Arizona - Phoenix LTER are comparing data they collect on arthropod populations in schoolyards to similar data collected by scientists in desert, residential, industrial, and farm ecosystems. Within your schoolyard, you may want to monitor arthropod populations in grass, gardens, gravel or dirt areas, and compost piles or other areas where yard waste are left to decompose.
Observing and recording what is present in your ecosystem is the first step in many long-term ecological studies. Using the protocol below, you will observe and record the arthropods collected in your schoolyard. Once you have learned how to trap, observe, and identify insects, you may want to design some comparative studies: for example, you could compare arthropod populations in different habitats. You or your class might come up with your own questions to guide your investigations. You might want to look at the LTER websites, particularly the Central Arizona-Phoenix site (http://caplter.asu.edu/) to get some ideas about possible questions to investigate. Consider making this a long-term study – perhaps you will monitor arthropods every month during the entire school year, or perhaps you will set up the study so that students in next year’s class can continue your monitoring efforts.
1. Use pit traps to collect arthropods once a month. The pit traps consist of two 16-ounce Solo cups, one inside the other, buried in the ground so that the top of the cup is ever so slightly below the surface of the soil. (If the top of the cup is above the ground, the bugs will walk around your trap instead of into it.)
2. Use a bulb planter to dig 10 holes in a line, 5 meters apart. If the area in your schoolyard is not long enough for this kind of arrangement, use a grid pattern, but be sure to keep 5 meters between the traps. You may want to set up a line (or grid) in several different areas in your schoolyard. And be sure to indicate the arrangement on your data sheet. Do not worry if the line goes from lawn to shrubs or by trees. Assign a number to each trap. For example, perhaps you are collecting 10 samples from the northeast area and 10 others from the west end of the schoolyard at Jone’s Middle School. You could name the first ten traps Jone’s NE1 through Jone’s NE10 and the second ten traps Jone’s W1 through Jone’s W10.
Birds play important roles in many ecosystems. For example, birds eat seeds and eliminate them at other sites, thus helping spread plants to new locations. Birds are important predators of insects, and sometimes of small mammals, fish, and amphibians. The disappearance or appearance of particular bird species may reflect habitat changes. These changes could be related to pesticide use, cutting down forests to build houses and businesses, building new homes with lush gardens in the desert, and farmlands reverting back to forest. For those species that migrate in the winter, changes in what species are present may also reflect changes in their southern wintering grounds.
Whether you live in an urban, suburban, or rural area, you can monitor bird populations in different habitats, such as city parks, residential areas, and schoolyards. Students associated with the Ecology Explorers program of the Central Arizona - Phoenix LTER are monitoring bird populations in urban areas with different types of landscape plants. This information may help people living in Phoenix design landscapes that attract a wider variety of bird species.
For both the insect and bird activities, once you have learned how to identify the animals, you and your class should consider the design of your study. What are the goals of your study? Are you interested in long-term monitoring only, or would you like to experimentally manipulate part of your schoolyard?
For long-term monitoring, are you interested in what birds are in one type of habitat, or would you like to monitor several habitats? You may want to consider doing bird surveys in nearby parks if you have a small schoolyard. How long will your study last – one month, or many years? Why? How do your point counts change with varying weather conditions? If you will monitor populations over many years, how will you record your data and site descriptions so that students in next year’s class will be able to use them? Much of the work at LTER sites is focused on understanding long-term trends; this can only be done successfully by designing studies that are consistent over long periods of time.
If you and your class decide to do an experiment, how will you design it? How long should you monitor birds to get baseline data? Will it take one month, many months, or a year or more? If you change something in your schoolyard (for example, you could add a feeder or a bird bath, or you could plant shrubs or trees), what will you use as a reference (see Activity 3 for a discussion of controls and references)? How long will you need to fully understand how birds respond to your experimental treatment? Many LTER experiments are designed to examine effects of a treatment over many years – how can you design your experiment so that future students can monitor responses?
Ecologists use “point counts” as one method for surveying birds. In a point count, one person counts all the birds located within a circle with a radius of 20 meters for 10 minutes. When conducting a point count you will record data on the “Bird Data Sheet.” Follow these steps before you actually do a point count survey:
Long before the LTER network was created, many scientists were already conducting long-term studies. Long-term research often examines ecosystem processes over a large geographic area – an area that is far too big for a single scientist to cover. That’s why researchers have sometimes relied on informal networks of ordinary people – so-called “citizen scientists” – to help collect data over large areas and at regular intervals.
One example is a study of sea-surface temperature at the Scripps Institute of Oceanography in La Jolla, California. The study started back in 1916 when a scientist at Scripps had the idea of collecting a bucket of water off the end of the Scripps dock every week to measure such things as water temperature and salinity. Over the years, Scripps scientists recruited people in other California coastal areas to do the same thing. Librarians, high school science teachers, and many other people contributed information to the study. Now Scripps has a remarkable data set that documents changes in California’s coastal waters over many decades.
The people who collected buckets of water for the sea-surface study are just one example of ordinary people helping to collect data for a long-term study. In this activity, you will identify people in your own community who are involved in “citizen science.” You may also examine the data they have been collecting to look for short-term and long-term trends.
What sorts of citizen science projects are happening in your area? In many places, people are involved in the study of birds. For example, bird watchers have been taking part in the National Audubon Society’s annual Christmas Bird Count for over a century. Called “the oldest and largest wildlife survey in the world," the Christmas Bird County was launched in 1900 as an alternative to traditional New Year’s Day hunting parties. Today, bird watchers conduct their counts at more than 1,500 sites in North America. This one-day count gives scientists an indication of the abundance of winter birds.
Other North American bird watchers help to conduct the spring Breeding Bird Survey, which was launched in 1966. This survey provides information about changes in bird populations across the continent. The participants go out on a day in June to look and listen for birds along 3,500 different roadside “routes.”
Bird studies are not the only field in which you are likely to identify citizen-based long-term research efforts. Your local science museum or nature center may keep records on the timing of other natural phenomena: for example, when the first spring wildflowers appear, when local trees get their first leaves, or the date on which spring peepers are first heard. The local management authority for a dam or reservoir may keep records of the date of “ice-out” in spring. Your state’s Department of Fish and Wildlife or Department of Environmental Conservation may keep records of when fish return to spawning streams.
Discover citizen science projects being conducted in their communities
Develop an understanding of the importance of communication between communities and
scientists
Learn how they can contribute to scientific research
Examine datasets gathered in their communities
Science as Inquiry – Development of:
Understandings about scientific inquiry (5-8 & 9-12)
Science and Technology – Development of:
Understandings about science and technology (5-8 & 9-12)
Science in Personal and Social Perspectives – Development of an understanding of:
Science and technology in society (5-8)
Science and technology in local, national, and global challenges (9-12)
History and Nature of Science – Development of an understanding of:
Nature of science (5-8)
Nature of scientific knowledge (9-12)
In this activity, you will research citizen
science projects in your community. You will consult local phone directories,
the Internet, and members of your community to determine what types of citizen
science might be going on near your school. You can then try to locate and look
for trends in data gathered by these citizen scientists. Several places to
start are presented below.
One option for this activity is to identify a local bird club and find out if any members participate in the Christmas Bird Count or Breeding Bird Survey. To see if there is a local Audubon bird club in your area, check the National Audubon Society website http://www.audubon.org/. The American Birding Association website http://www.americanbirding.org/ may also list some local bird clubs or resources. Ask to see data for your local area. Choose two or three bird species of interest and look for trends in the data. Compare these data to changing local, national, and global climate patterns. Use some of the resources described in Activity 4 to obtain aerial photographs and use these photos to compare changes in land use to changes in bird populations.
An alternative
to calling up birders at your local bird club is getting data off the Breeding
Bird Survey website. For general information, go to: http://www.mbr-pwrc.usgs.gov/bbs/bbs.html.
To select your state and see the routes that were surveyed, go to
http://www.mbr-pwrc.usgs.gov/bbs/trend/rtehtm98a.html.
Try clicking on the regional trend maps.
The home page for data collected by the Christmas Bird Count participants is http://www.birdsource.org/cbc/. Data are collected from areas known as “count circles.” To identify a “count circle” near your school, click on the “CBC Database Online” icon on the Christmas Bird Count home page (or go to http://birdsource.tc.cornell.edu/cbcdata/). You’ll see an entry form. In the space labeled “Find a Circle ID,” enter your state or province. Then, from the list of circle IDs provided, choose the one nearest your school and enter it at the top of the form, along with other information as requested.
Consult your local phone book for nature centers or museums that may be located in or near your community. Ask other teachers in your school. Your local conservation commission, state or county park, or land trust may be able to provide some leads.
Look up your State’s Department of Natural Resources, Water Resources, Fish and Game, Environmental Conservation, etc. Visit their website and follow “science,” “education,” or similar links. Contact the agency directly and inquire about local or statewide citizen science programs.
Ask your teacher for the name of local colleges and universities, and contact outreach coordinators or professors in a science department that interests you (for example, biology, natural resources, astronomy, etc).
Monitoring aquatic insects and water chemistry is a popular citizen science activity. There may a local watershed monitoring effort coordinated by a nearby school, town government, or watershed or lake association.
Become a participant in one of the citizen science programs you have discovered in this activity. You may consider involving your class, or perhaps your family or friends.
In the preceding activities you learned about the network of LTER sites that has been established throughout the United States and abroad, and about how these sites are designed to investigate five core LTER research questions. You also examined original data collected at a number of different LTER sites to investigate the importance of long-term research in understanding of ecosystem processes. In this final activity, you will use what you have learned to develop a proposal for a new Long Term Ecological Research site – a site that could be situated on your school grounds.
Your class will be divided into several teams. Each team will role-play a group of scientists at one of several universities in your area who are developing and submitting a new LTER site proposal for consideration by the National Science Foundation. You will decide what types of ecological questions you and your teammates hope to answer with your study. Then you will develop procedures for a study to answer those questions. Finally, you will draw up a list of the materials you would need to carry out your research.
After your team develops a proposal, you will put together an oral or a poster presentation of your ideas. You will make your presentation at a classroom mock conference where your teacher and/or other invited guests will act as members of a National Science Foundation review panel. This panel will later provide you with written feedback on your proposal. Next, you will have an opportunity to revise and resubmit your proposals. Finally, the review panel will announce which projects have been selected for funding and why.
One good model for schoolyard LTER investigations is the research on grassland and old-field plots being done at the Cedar Creek LTER site. This kind of work might be adapted for grassy plots on school grounds. You could start your proposal by visiting the Cedar Creek or other LTER website to get some ideas for research projects. Then, you should survey your school grounds to identify areas and habitat that could serve as a site for research plots. Finally, you will develop some research questions that could be answered at your site and write up your proposal. The process you will be following, from finding out what has been done, to making observations of your site, to writing up a proposal, is similar to the process scientists use when trying to obtain funding for their research. Similarly, the use of a panel of “expert” scientists to review proposals and make decisions about what gets funded is patterned after the procedure that the National Science Foundation uses to make decisions about what research gets funded.
This activity can even go a step further – with permission from school administrators, you might want to actually establish some long-term research plots at your school. A long-term research site right on school grounds would be a valuable resource for students of all ages. Activities tailored to different age levels could complement and supplement the traditional laboratory and field experiences that most science classes already offer. You may also want to develop the Bird and Arthropod activities in Activity 4 into long-term schoolyard research endeavors.
Your students should be familiar with the types of research going on at LTER sites. If they have conducted several of the activities in this manual, they should have this knowledge. We have also provided two handouts you may want to pass out to the students: Possible Research Ideas and National Science Foundation Proposal Review Criteria. The NSF Review Criteria can be found at: http://www.nsf.gov/pubs/2001/nsf012a/start.html. After your students are familiar with this background information, take them on a walking tour of your school grounds to help them look for possible LTER study sites. If your class has already participated in Activity 4, you may want to consider using those sites. You could conduct the walking tour as a sort of field trip during class, or students could do it before or after school or during a study hall.
In this section students are asked to develop research questions for the LTER proposal. You might want to review experimental design with your students, making sure to emphasize the importance of both monitoring and field experiments and the need for both reference and treatment plots in field experiments. Most LTER proposals include many questions. This activity calls for your students to develop one or two short- and long-term questions, though you should feel free to change this number if you think it would be more appropriate for your class.
The procedure for students specifies the different sections that should be included in the proposal (step 5). Students may also want to look at some real LTER proposals on-line. Although they should be able to get an idea of the outline or sections of the proposal (e.g., research objectives, methods), the language describing specific procedures will likely be too technical for high school students.
Whereas actual LTER proposals have budgets associated with them, we did not include budget planning in this activity. (If you are presenting the proposal for actual funding, you will need to add this step.)
Proposals submitted to the National Science Foundation are generally sent to several reviewers who are typically doing research similar to that being proposed. These reviewers then send the National Science Foundation written comments about the proposal, with very specific comments and their thoughts on whether or not the proposal should be funded. This is referred to as the outside review process. The National Science Foundation then convenes a panel of experts to review all the proposals in a specific area (e.g., all LTER proposals in any one year). The panel again makes comments on the quality of the proposed research, and ranks the proposals in terms of funding priority. Together, the outside and panel reviews constitute what is referred to as “Peer Review” of research proposals. Finally, the National Science Foundation program officer makes a decision on what should be funded, drawing on the outside and panel reviews. In this activity, you – and any guests you choose to invite – will act as these peer reviewers. You can have students present their proposals in writing (as would be the case with the National Science Foundation) or to make it more interesting and to promote discussion, you can have them present their proposals orally in addition to in writing. After proposals have been presented, you and your reviewers should give each team written comments on their proposal. Ask questions about the proposal, comment on its strong and weak points, and indicate what the team would need to do to submit a proposal that would be more likely to receive funding.
You can have the students resubmit the proposals taking into account the reviewers’ comments. After you – and others on the panel – have reviewed the final rewritten proposals, you should present a final set of written comments indicating why the proposal was or was not funded. You may choose to present some or all of these comments verbally to your class followed by a general discussion of the strengths and weaknesses of the proposals. You and your students may also be interested in learning more about the grant submission process by visiting the NSF’s website at http://www.nsf.gov/
Learn about submitting an LTER grant proposal to the National Science Foundation
Design a proposal for a new LTER site
Develop ecological research questions they could study in their schoolyard
Gain experience working as a team of “scientists”
Science as Inquiry – Development of:
Abilities necessary to do scientific inquiry (5-8 & 9-12)
Understandings about scientific inquiry (5-8 & 9-12)
Life Sciences - Development of an understanding of:
Populations and Ecosystems (5-8)
Interdependence of organisms (9-12)
Science in Personal and Social Perspectives – Development of an understanding of:
Science and technology in society (5-8)
Environmental Quality (9-12)
Science and technology in local, national, and global challenges (9-12)
History and Nature of Science – Development of an understanding of:
Nature of science (5-8)
Science as a human endeavor (9-12)
Nature of scientific knowledge (9-12)
Activity 6: The Future of Long-Term Research
In this activity you and your team members will be developing an LTER site research proposal. Of the many components of such a proposal, the most important one is: what research questions will you address at your new site? You may want to consider visiting the Cedar Creek LTER website (http://www.lter.umn.edu/) to look for ideas, as many of the research questions being addressed at that grassland and “old-field” (areas that used to be farm fields) site could be adapted to a schoolyard. Additionally, we have provided some example questions below. After reading through these ideas, you should develop several research questions of your own. Your teacher will indicate if you should do this as a class or individually, and will indicate how many questions you should develop.
Activity 6: The Future of Long-Term Research
The
National Science Foundation reviews a great deal of research proposals,
including those such as the ones you and your team are developing. In 1997 the NSF devised very broad, general
criteria by which all proposals are judged.
You should refer to these criteria, listed below, as you develop your proposal.
How important is the proposed activity to advancing knowledge and understanding within its own field or across different fields? How well qualified is the proposer (individual or team) to conduct the project? (If appropriate, the reviewer will comment on the quality of prior work.) To what extent does the proposed activity suggest and explore creative and original concepts? How well conceived and organized is the proposed activity? Is there sufficient access to resources?
How well does the activity advance discovery and understanding while promoting teaching, training, and learning? How well does the proposed activity broaden the participation of underrepresented groups (e.g., gender, ethnicity, disability, geographic, etc.)? To what extent will it enhance the infrastructure for research and education, such as facilities, instrumentation, networks, and partnerships? Will the results be disseminated broadly to enhance scientific and technological understanding? What may be the benefits of the proposed activity to society?
Principal Investigators should address the following elements in their proposal to provide reviewers with the information neces