Comunities and ecosystems represent aggregates of lower-level orders of
organization - generally, individual species, and populations of those
species. There is considerable research in the Department, primarily
concerned with analysis and understanding of the dynamics of populations,
and how these dynamics might vary within and among species.
The following highlights just a
few of the
several
'population' research projects currently active in the Department (for a
more complete
listing, click here. Alternatively, consult web
pages of the people
associated with research in this
area):
Population response to removal of introduced species | Declines in native fish populations have been associated with the establishment of introduced smallmouth bass (Micropterus dolomieu) populations in the northeastern U.S. Introductions of non-native smallmouth bass have limited the abundance and diversity of native soft-rayed fishes, altered the trophic status of lake trout, and reduced brook trout biomass in Adirondack lakes and other northern waters. This study is designed to demonstrate whether the impact of a widely introduced, non-native fish predator (smallmouth bass) can be reversed in Little Moose Lake, a 200 hectare Adirondack lake. Historical accounts have indicated, and recent research projects have confirmed, that the introduction of smallmouth bass in Little Moose Lake, New York, has had adverse effects on the native fish community, including brook trout, lake trout, pumpkinseed, creek chubs, and common shiners. In the spring of 2000 through the fall of 2001, a total of 19,529 smallmouth bass were removed from Little Moose Lake, predominately by boat electrofishing. Pre-removal population estimates indicate that at least 90% of the adult smallmouth bass population has been removed. Abundance indices (CPUE) of native littoral prey fish and crayfish species have increased following the reduction of the smallmouth bass population. Predation risk, measured by tethered creek chubs, has significantly declined for native littoral prey fishes. Growth and condition of the remaining smallmouth bass have improved, likely a result of lowered intraspecific competition. We expect improved growth and increased abundance of native char and prey species due to reduced predation and interspecific competition by smallmouth bass. | | | 
swan project | Atlantic Flyway Tundra Swan Project - Tundra Swans are a long-lived species with relatively low annual recruitment. Since swans breed in remote areas, little is known about their breeding ecology and distribution. In addition, the species is hunted in North Carolina, Virginia, North Dakota, South Dakota, and Montana. Harvest management would be more effective if more was known about their vital rates, migratory patterns, and distribution. Objectives of this study include: to determine the breeding range and migration stopover locations of the Eastern Population (EP) of Tundra Swans, as well as patterns of movement between these areas; to determine fidelity and possible sub-population affiliations of Tundra Swans to Atlantic Flyway wintering locations within years and between subsequent years; to increase precision of survival rate estimates for EP swans; and to determine extent and nature of winter movements of Tundra Swans in relation to habitat use and human disturbance. What makes this project unique is it’s scale and size: hundreds of birds have been marked over most of their Eastern wintering areas, providing a fairly representative sample of the Eastern Population. | | | 
Harvest of
structured
populations | Optimal harvest of structured populations - Population dynamics are in simplest terms governed by the balance between realized fecundity and recruitment, and mortality (or permanent emigration). For harvested species, this poses the potentially complex problem of determining the harvest practice which, by some criterion, is determined to be "optimal". Optimality decisions are generally derived with reference to the conditions under which population growth is maintained at some sustained equilibrium, either naturally, or through the harvest itself. The calculation of the optimal harvest conditions are often complex, especially where harvesting is variable with respect to time. Many analyses of optimal harvesting assume no age-structure, and continuous time. However, for many populations, this assumption of no age- or stage-structure, and continuous time, is clearly unrealistic. Failure to account for this can contribute significantly to sources of uncertainty, which affects our ability to successfully manage the resource. Preliminary analysis indicates failing to adequately account for structure in the harvested population can lead to unpredictable results in some cases. This result also has significant implications for biodiversity and management of resources, since it allows a flexible framework to assess the relative importance of individuals of a particular age or stage, and in a particular location, to a complex structured system. This is increasingly important in assessing viability of populations in fragmented landscapes. | | |
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