Use of Benthic Macroinvertebrate Taxa and Landscape Variables to Identify Stream Reaches Suitable for Brook Trout Reintroduction in Maryland

In Maryland, brook trout have been extirpated from 62% of their historic habitat range.  Historic land use conversions, mining, urbanization, competition with introduced fish species, and thermal impacts are some of the major factors leading to the loss and degradation of brook trout populations.  Remaining brook trout populations are highly fragmented and restricted to headwater stream reaches in a few watersheds in the western and central regions of the state.  However, we hypothesize that environmental conditions in some streams within these regions have improved and can now support brook trout as a result of broad, landscape scale changes and effective implementation actions, but are isolated from source brook trout populations for recolonization.  The presence of certain benthic macroinvertebrate taxa can be used as indicators of high quality stream reaches that could potentially support brook trout.  These benthic macroinvertebrate taxa may capture the niche requirements (e.g., thermal regime, physical habitat and water quality conditions) of brook trout. Using data from the Maryland Department of Natural Resources, Maryland Biological Stream Survey, we identified benthic macroinvertebrate taxa and land use characteristics strongly associated with brook trout presence.  This information has been used to identify eight stream reaches in Maryland that would be good test sites to attempt brook trout reintroduction, or streams that could support brook trout after minimal low cost restoration actions.  The results of this study will assist multiple entities currently working to preserve and restore Eastern brook trout populations.