Riparian vegetation is strongly liked to freshwater community and ecosystem function, and changes in riparian vegetation may have strong effects on macroinvertebrate community structure. In the southern Appalachians, rhododendron (Rhododendron maximum) has invaded riparian habitat with the loss of eastern hemlock due to hemlock wooly adelgid. To understand best management practices of riparian invasive species removal, invasive rhododendron was removed using two techniques from 300m of each stream by the U.S. Forest Service at Coweeta Hydrologic Laboratory. The U.S. Forest Service removed rhododendron at one site by cutting rhododendron and piling it along the stream in 2014, then the rhododendron was burned the following year. The other treatment they cut rhododendron and left it where it fell, then burned it in March 2016. During this time, two streams were used as references with no rhododendron removal, but one of those references was burned in 2018. To understand how this removal impacts the macroinvertebrate community, we conducted standard benthic macroinvertebrate sampling in 2016 and 2017, and will continue to sample in 2018. We identified benthic macroinvertebrates to genus and organized samples into functional feeding group.
Results/Conclusions
So far, 288 samples have been collected with a total of 61,056 specimens. Results reveal short-term changes in community composition similar to responses found in post-logging studies. Rhododendron removal was associated with a significant increase in collector-gatherers and decrease in filter feeders and predators, regardless of removal technique. At removal 1, the pile and burn treatment, there were significant increases in grazers and decreases in shredder density. Traits shared by collector gatherers also increased at both removal sites. These results demonstrate a possible shift in community trophic structure; likely due to changes in food source availability as algae has become a more important food source due to increased light and decreased leaf litter. Future sampling will continue to look at community dynamics and functional feeding groups while also incorporating habitat measurements and dispersal.