Translating Disturbance into Biological Effects: A Case Study in Appalachian Headwater Brook Trout Populations

Headwater streams provide pristine habitat for aquatic communities and are predominant lotic ecosystems in the Appalachian Mountains.  Changes in these habitats may therefore cause a proportional change in biotic systems greater than one would expect.  We have used a long-term brook trout Salvelinus fontinalis dataset which includes fish and habitat data to explore patterns and relationships over the last 10 years in 25 headwater streams in West Virginia, USA before and after the effects of a large hurricane (“superstorm” Sandy).  We first quantified the inputs of large wood (LW) and found varying levels (0-195% change from previous annual data; 0-820 LW pieces km^-1) of new wood additions.  When compared to years prior to Sandy, the rate of LW deposition was significant across all size classes and streams (p < 0.0001).  We also measured fish body composition using bioelectrical impedance analysis (BIA) and created models to associate body composition with habitat variables at multiple scales.  We also measured response to disturbance via changes in habitat variables such as available spawning substrate and production variables such as secondary production biomass.  Translating these uneven effects of disturbance into biological changes may help identify areas more or less resilient to future disturbances.