FLOOD SCOURING AND MACROINVERTEBRATE COMMUNITY ASSEMBLY PROCESSES IN COSTA RICAN HEADWATER STREAMS
Changes in climate predictions indicate that storm events are likely to become more intense but also more frequent. These disturbances are important because of their influence in shaping community structure and function. Gaining an understanding of how ecological communities respond to and recover from disturbances is therefore key. Recovery dynamic are applicable in tropical pre-montane streams as frequent rainy season floods alter abiotic conditions and biological communities. Scientists measure community reestablishment after floods by contrasting the effects of stochastic (i.e. neutral) and deterministic (i.e. niche theory) assembly processes. I tested this question with a controlled experiment in headwater streams in Costa Rica by diverting floodwaters from bifurcated channels and examining changes in benthic and leaf-litter macroinvertebrates. No differences were revealed between invertebrate communities in channels with and without floodwaters. However, perMANOVA revealed differences with time. This study fails to support the importance of flooding in structuring tropical macroinvertebrate communities and did not support deterministic assembly in high disturbance conditions. However, the significant temporal signature corresponds to the progression of the rainy season and suggests that communities change as floods progress. The Herrick Aquatic Ecology Research Grant funded this research project.
EmmaLeigh Given (Primary Presenter/Author), Kent State University , firstname.lastname@example.org;
Savannah Justus (Co-Presenter/Co-Author), Virginia Tech, email@example.com;
Ferenc de Szalay (Co-Presenter/Co-Author), Kent State University, firstname.lastname@example.org;
Oscar Rocha (Co-Presenter/Co-Author), Kent State University, OROCHA@KENT.EDU;