species composition biodiversity change
Systematic biodiversity change - global reorganisation of species pools
The extent to which biodiversity change in local assemblages contributes to global biodiversity loss is poorly understood. 100 time series from biomes across Earth were analysed to see how diversity within assemblages is changing through time. They quantified patterns of temporal alpha diversity, measured as change in local diversity, and temporal beta diversity, measured as change in community composition. Contrary to their expectations, they did not detect systematic loss of a diversity. However, community composition changed systematically through time, in excess of predictions from null models. Heterogeneous rates of environmental change, species range shifts associated with climate change, and biotic homogenization may explain the different patterns of temporal alpha and beta diversity. Monitoring and understanding change in species composition should be a conservation priority.
This study, which appeared in Science, used 80 time series datasets from OBIS.
Dornelas, M.; Gotelli, N.J.; McGill, B.; Shimadzu, H.; Moyes, F.; Sievers, C.; Magurran, A.E. (2014). Assemblage time series reveal biodiversity change but not systematic loss. Science (Wash.) 344: 296-299. DOI 10.1126/science.1248484