The Appalachian Stream Syndrome: Metacommunity Deflation of Stream Invertebrate Assemblages Caused by an Interaction of Mining and Urbanization

Metacommunity theory suggests multiple local disturbances can cause large-scale deflation of assemblage diversity through disruption of local demographic and regional dispersal processes. Through a regional assessment of the mountaintop removal-valley fill (MTR-VF) mining region of West Virginia, we tested the hypothesis that local (site-specific) and neighborhood (within a 5km buffer) conditions combine to control macroinvertebrate assemblage structure and that the strength and pattern of regional effects is dependent upon taxon-specific tolerance and dispersal capabilities. We found evidence that both local conditions, as measured by local water quality, and neighborhood conditions, as measured by landcover, influenced macroinvertebrate community composition (multi-metric index condition, EPT and P richness, and %EPT, %E, and %Chironomidae). Invertebrate taxa with limited dispersal ability were more strongly correlated with neighborhood condition than were good dispersers. Tolerant species proliferated in development altered neighborhoods.  In contrast, sensitive species deflated in mined neighborhoods.  Continuing trends in land cover alteration will likely result in regional scale impacts to aquatic communities through disruption of large-scale metacommunity processes.  Such regional impacts are more likely in watersheds affected by multiple land use stressors.