Abstract ID
Full title
Characterization of riverine floodplain habitats and benthic macroinvertebrates across a human disturbance
gradient in Pennsylvania (USA) rivers
Abstract text
Riverine floodplains in unaltered reaches exhibit a patchy mosaic of aquatic habitats characterized by high
spatial and temporal heterogeneity, providing diverse habitats for multiple taxa. Using techniques of watershed
classification, hydrogeomorphic (HGM) functional assessment, and biological assessment of aquatic
macroinvertebrates, we show that these systems are often subject to high rates of human disturbance from
agricultural activities and urbanization resulting in a loss of particular habitat types and associated biota. In this
paper, we focus on changes in macroinvertebrate taxa in river reaches and floodplain wetlands across a gradient
of human disturbance in Pennsylvania streams in the eastern U.S. The least disturbed floodplain habitats
contained higher proportions of well-connected and more seasonal habitats with a mix of stream insects and
obligatory floodplain taxa, apparently the result of a more stable flow regime consisting of alternating flow and
flood pulses. Impacted floodplains were limited to disconnected channels with tolerant non-insect taxa or
highly ephemeral habitats with opportunistic taxa, indicating a flashier flow regime characterized by high
magnitude flood events and floodplain abandonment. Biological assessments of river channels alone do not
capture the variability of wetland microhabitats or taxa found in systems with high ecological integrity.
Floodplains associated with higher stream orders proportionally encompass smaller areas of watersheds, and due
to extensive alterations, represent a potentially under-represented ecosystem within conservation reserves.
Submission date
Riverine wetlands, floodplain habitat, hydrogeomorphic functional assessment, aquatic macroinvertebrates,
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