The effects of in-stream gravel mining on aquatic macroinvertebrates in Eastern Kentucky gravel bed streams

Gravel mining includes both the removal of gravel from the wetted channel and from adjacent gravel bars. Extensive removal of gravel from stream channels can decrease substrate stability, increase the stream gradient (especially locally), and increase silt deposition. The effects of gravel removal can cause erosion problems to propagate both upstream and downstream from the mined area eventually leading to incision and bank erosion problems for large segments of the stream. Benthic macroinvertebrates within mined streams experience lower densities, lower biomass and changes in community structure as a result of decreased substrate stability and increased silt deposition.;I assessed the impacts of gravel mining on macroinvertebrate communities in four Eastern Kentucky gravel bed streams. Two streams which were experiencing active gravel mining were compared to two streams not actively mined for gravel. Traveling kick-net and multi-habitat composite samples following the Rapid Bioassessment Protocol III method were used to collect samples. Kentucky Index of Biological Indices (KIBI), densities, biomass, community similarity indices, functional feeding groups, percent clingers, and percent sprawlers were calculated to determine differences between mined and non-mined (reference) creeks. One mined and one non-mined stream were also sampled during a 1/3rd bankfull spate event. There were significant differences between mined and non-mined creeks in the KIBI scores (p = 0.000), densities (p = 0.003), wet biomass (p = 0.009), percent clingers (p = 0.000) and percent sprawlers (p = 0.000). The ratio of clingers to sprawlers was nearly 4 times greater in non-mined creeks than in mined creeks. The results indicate that gravel mining has significant effects on lotic macroinvertebrates. Metrics such as the relative proportions of clingers and sprawlers between mined and non-mined creeks are the best indicators of the impacts of gravel mining on macroinvertebrates.