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AN INDIVIDUAL-BASED MODEL OF COTTUS POPULATION DYNAMICS
Citation:
Rashleigh, B AND G. Grossman. AN INDIVIDUAL-BASED MODEL OF COTTUS POPULATION DYNAMICS. Presented at Ethology, Evolutionary, Ecology of Fishes Meeting, Athens, GA, May 20-24, 2000.
Impact/Purpose:
This research project sets out to design and conduct an assessment of the long-term ecological consequences of alternative management choices. As the first project to be done at this scale using predictive ecological endpoints, we will seek to identify the appropriate components of such an analysis. We will use experience gained in the conduct of this BASE analysis to identify key research and data needs for address, to estimate timing, resource needs, etc., for future analyses. We will extend this analysis beyond previous and ongoing studies in two ways: by incorporating biological endpoints, primarily properties of fish communities, and by introducing the concept of sustainability of ecological state under future scenarios contrasted with the present state of those same ecological resources. Requirements that are identified during the course of this study will permit the recommendation of specific capabilities that should be incorporated in a general modeling system currently under development to support BASE and other environmental assessments. Finally, the analysis is intended to be of value for establishing environmental management choices that will be beneficial and those that would be detrimental to the sustainability of ecological resources of the Albemarle-Pamlico Basin.
Description:
We explored population dynamics of a southern Appalachian population of Cottus bairdi using a spatially-explicit, individual-based model. The model follows daily growth, mortality, and spawning of individuals as a function of flow and temperature. We modeled movement of juveniles and adults among discrete habitat patches according to length-based ideal despotic distribution rules. Abundance, length, and weight of juveniles and adults were calibrated to 10 years of bi-yearly sampling data from Ball Creek, North Carolina, USA. Model results for abundance were in good agreement with observed values. Simulated mean lengths and weights were within the range of field data but the model was not able to reproduce all of the observed temporal patterns in these variables. Population dynamics in the model appear to be influenced by competition for patches, density-dependent juvenile mortality, and variations in hydrology. Although the model contains many simplifying assumptions, it may be a useful tool in understanding the regulation of natural populations.