@article {4049, title = {Invertebrate assemblage responses and the dual roles of resistance and resilience to drying in intermittent rivers}, journal = {Aquatic Sciences}, year = {2015}, abstract = {

ABSTRACT: Intermittent rivers are naturally dynamic ecosystems in which flow cessation and riverbed drying cause temporal fluctuations in aquatic biodiversity. We analysed datasets from intermittent rivers in different climate zones across the world to examine responses of aquatic macroinvertebrate assemblages to drying, in relation to both taxonomic composition and traits of resistance and resilience. First, we compared the differences in taxonomic richness and turnover and in trait diversity, richness and redundancy before and after intermittent sites dried with the differences in concurrently sampled perennial sites. We found such high levels of variation in the before-after differences at intermittent and perennial sites that we could not detect statistical differences between them. Second, we examined the effects of climate (arid, Mediterranean, temperate) and durations of dry and post-dry (flowing) periods on responses to drying at intermittent sites. Only climate had a detectable effect; the proportion of taxa at intermittent sites that persisted through drying-rewetting phases was greatest in arid-zone rivers. Regardless of climate, the invertebrates that persisted at intermittent sites were dominated by taxa resistant to drying. By contrast, taxa that persisted at perennial sites had fewer traits conferring resistance but more conferring resilience. The contributions of resistance and resilience combined with the presence of both intermittent and perennial reaches likely supports the long-term stability and persistence of communities in intermittent rivers, despite the inherently high variation in short-term responses to drying.

}, doi = {DOI:10.1007/s00027-015-0427-2 }, author = {C. Leigh and N. Bonada and A.J. Boulton and B. Hugueny and S.T. Larned and R. Vander Vorste and T. Datry} } @article {4048, title = {Towards understanding the organisation of metacommunities in highly dynamic ecological systems }, journal = {Oikos}, year = {2015}, abstract = {

ABSTRACT: Community ecology recognises today that local biological communities are not only affected by local biotic interactions and abiotic environmental conditions, but also by regional processes (e.g. dispersal). While much is known about how metacommunities are organised in space in terrestrial, marine and freshwater ecological systems, their temporal variations remain poorly studied. Here, we address the question of the dynamics of metacommunities in highly variable systems, using intermittent rivers (IRs), those rivers which temporarily stop flowing or dry up, as a model system. We first review how habitat heterogeneity in space and time influences metacommunity organisation. Second, we compare the metacommunities in IRs to those in perennial rivers (PRs) and develop the idea that IRs could undergo highly dynamic shifts due to the temporal variability in local and regional community processes. Third, we develop the idea that in IRs, metacommunities of the wet and dry phases of IRs are closely intertwined, thereby increasing even more their respective temporal dynamics. Last, we provide a roadmap to stimulate further conceptual and empirical developments of metacommunity research and identify possible applications for improving the management of IRs and other highly dynamic ecological systems.

}, doi = {doi: 10.1111/oik.02922}, author = {T. Datry and N. Bonada and J. Heino} }