Oral Presentation Australian Society for Limnology Conference 2016

(Another) truce with neutral theory – local conditions, species traits and spatial factors interact to drive community assembly (#58)

Ross Thompson 1 , Laura Caffrey 2
  1. University of Canberra, Bruce, ACT, Australia
  2. Integrated Water and Catchments, Department of Environment, Land, Water and Planning, Melbourne, Victoria, Australia

Understanding the interplay between local conditions, species traits and spatial factors is critical foundation knowledge for effective management of biodiversity. We sampled aquatic communities in three chain-of-pools stream systems in central Victoria over three years. We sampled at the scale of the pool, the reach and the sub-catchment. We assessed a range of local habitat factors at each scale, and calculated simple Euclidean, stream network and resistance-weighted stream network measures of connectivity between all pools. Species were attributed dispersal traits from existing databases. Community composition was strongly structured by spatial factors in interaction with dispersal traits. A set of common taxa were present at all scales and were characterised by good dispersal ability and/or factors that made them resistant to reduced flows. Other taxa showed evidence of being dispersal limited, with a strong spatial signature in their occurrence. Local conditions were important for a small group of taxa, particularly shredders, but the communities were generally characterised by habitat and trophic generalists. These results show the importance of a whole-of-network perspective in managing local conditions for biodiversity.