Speaker: Xueke Lu
Title: Drought rewires the cores of freshwater food webs
Abstract:
Network approaches have been shown as a useful tool to study how food webs are influenced by climate change. For instances, a field mesocosm experiment simulating the drought condition showed that from a species-level perspective, extreme drought condition significantly reduced biomass of most basal-level species. From a system-level perspective, huge biodiversity loss and species invasion haven been recorded. However, current food web analysing approaches cannot detect what kind of underlying architecture of food web preserves the robustness and overall connectance of stream food webs under drought condition. Here we applied a core profiling metric to show that all the food webs possessed a densely connected core containing high degree species, surrounding by a periphery of species with lower degree. Drought eliminated a relatively higher proportion of species from the periphery and triggered a large proportion of species moving between core and periphery. This made the core size to be consistent before and after drought. Link density among high degree species quantified using rich-club coefficient was reduced under drought condition, while this phenomenon became indistinguishable from the whole-network perspective. This was due to the extensive link rewiring happened across the whole network. With the help of advanced network science metrics, we are able to detect food webs responses to climate change from a new perspective, and have shown that the adaptability behaviour of food webs helps retain resilience in the face of extreme perturbations.
Venue: Eng. 209
Time and Date: 2 to 3 PM, Wednesday, 14/04/15.