Diversity is maintained by seasonal variation in species abundance
1 Centre for Biological Diversity and Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife KY16 9TH, UK
2 Department of Mathematics, Keio University, 3-14-1 Hiyoshi Kohoku, Yokohama 223-8522, Japan
3 CESAM, Department of Biology, Universidade de Aveiro, Aveiro, Portugal
4 Pisces Conservation, IRC House, The Square, Pennington, Lymington, Hants SO41 8GN, UK
BMC Biology 2013, 11:98 doi:10.1186/1741-7007-11-98Published: 4 September 2013
Some of the most marked temporal fluctuations in species abundances are linked to seasons. In theory, multispecies assemblages can persist if species use shared resources at different times, thereby minimizing interspecific competition. However, there is scant empirical evidence supporting these predictions and, to the best of our knowledge, seasonal variation has never been explored in the context of fluctuation-mediated coexistence.
Using an exceptionally well-documented estuarine fish assemblage, sampled monthly for over 30 years, we show that temporal shifts in species abundances underpin species coexistence. Species fall into distinct seasonal groups, within which spatial resource use is more heterogeneous than would be expected by chance at those times when competition for food is most intense. We also detect seasonal variation in the richness and evenness of the community, again linked to shifts in resource availability.
These results reveal that spatiotemporal shifts in community composition minimize competitive interactions and help stabilize total abundance.