Functioning of vertebrate metacommunities in dynamic riverine landscapes: an innovative approach using eDNA metabarcoding

Wider research context / theoretical framework One of the most important advances in community ecology is that biodiversity patterns are not only influenced by local scale determinants, but by dispersal from the regional species pool. While former metacommunity studies are temporal snapshots, more recently, community ecology is emphasizing the importance of dynamic community organization. Therefore, we focus on the importance of temporal changes in dispersal rates and environmental conditions for metacommunity organization and diversity using a highly dynamic, pulsed and interlinked landscape as model system – river floodplains. Our study organisms, fish and amphibians, depend largely on the dynamics of hydrologic conditions in the floodplain environment. Hypotheses / research questions / objectives We expect a large range of metacommunity organization paradigms. Preliminary analysis proves the presence of a large array of different habitats expanding the gradient of hydrological pulsing, habitat connectivity and temporal variability. Depending on the hydrological pulsing level, we expect a temporal shift from species sorting (environmental filtering and biotic interactions) to a mass effect driven community as well as dispersal limitation during long periods of low flow dependent on the level of connectivity of the different water bodies. Approach / methods Bias in species detection can alter the analysis of community structure and its turnover. Such limitations with traditional sampling methods for fish and amphibian are well known. To overcome this problem, we implement eDNA metabarcoding as sampling technique for metacommunities. In a first step, we will compare eDNA approach with traditional sampling methods. In a second step, we will do a two years temporal study to test for the sensibility of the fish and amphibian metacommunities to hydrological pulsing. Level of originality / innovation The interactive effects between environmental gradients, biotic interactions, dispersal and their temporal variability are poorly understood, in particular in temperate river-floodplain systems. One more innovative aspect of our project is to use eDNA metabarcoding technique.