Factors Influencing Brook Trout Population Dynamics and Resilience in Central Appalachian Headwater Streams

Abstract

Central Appalachia has a unique history of human perturbation due largely to its historical economic reliance on extractive industry and timber harvest. Legacy impacts from these historic disturbances along with contemporary stressors in the form of continued industry, changing climates, altered land use, habitat fragmentation, and introduced species can present great threats to the region’s aquatic ecosystems. Brook Trout Salvelinus fontinalis are a species that has recreational and economic importance to the communities of central Appalachia but declines in size and abundance have been observed. Given the disturbances that threaten Brook Trout populations, understanding how their populations will respond to disturbance, its resilience is of great importance. Management actions aimed at imparting resilience to a population could help maintain their sustainability. Understanding a population’s dynamics is a key aspect in understanding its resilience. A population can be defined by its recruitment, growth, and mortality. By understanding these vital rates, how a population will respond to a perturbation can be modeled. Through these modeling efforts, we can begin to understand what factors contribute to the resilience of a population. A wide variety of factors can affect resilience such as environmental, population, landscape, and genetic factors. This greater understanding can then help to guide management actions aimed at restoring population resilience. The objectives of this research were aimed at gaining a greater understanding of the population dynamics and the resilience of central Appalachian headwater Brook Trout populations. My first objective was to evaluate the effects of stream flow on stock/recruitment relationships in Brook Trout. The second objective was to use yield per recruit modeling as a tool to evaluate population resilience. My third objective was to create a hypothesis based on long-term data that describes the mating system used in headwater Brook Trout. Finally, my fourth objective was to evaluate relationships between population genetic parameters and population resilience metrics. My first chapter is a literature review containing previous research that has come out of the long-term Brook Trout monitoring project at West Virginia University Additionally, descriptions of the methods used and background about the streams sampled by the long-term project are described. Research regarding the different aspects and quantification of population resilience is also covered. Resilience has historically been difficult to define and quantify and as such, many different techniques have been presented to do so. These are themes that show up at multiples places in the dissertations and this chapter helps