In-stream decomposition and macroinvertebrate community dynamics: a comparison between invasive Glossy Buckthorn and native Silky Dogwood leaf litter

Invasive species are a major threat to the biodiversity of an ecosystem. Their ability to establish and thrive in foreign habitats and often outcompete natives have led to changes in ecosystem dynamics in both terrestrial and aquatic habitats. However, the influence of riparian invasive plants on adjacent aquatic insect communities is understudied. This is important because riparian zones provide essential leaf litter resources for aquatic communities. To test this question, we studied how aquatic invertebrate communities varied between leaves of invasive Rhamus frangula and Cornus amomum. Leaf litter bags with either leaf type were constructed and deployed into Swine creek allowing aquatic invertebrates to colonize for over three months. No differences in macroinvertebrate community composition between Rhamus frangula and Cornus amomum leaves were observed, however, there were differences in the rate leaf litter decomposition and the numbers of shredders and predators present on the leaf material. The mechanisms behind these differences in decay and invertebrate preference are still not completely understood, however it can be said that with the increased invasion of glossy buckthorn into swine creek’s riparian zone, changes to ecosystem dynamics and potentially the food web may be observed.