We just got a biodiversity-related paper published in Nature Communications.
We manipulate nutrient enrichment in aquatic microcosms in subtropical and subarctic mountain regions (China and Norway, respectively) in 2013, and show the interactive effects of temperature and nutrients on microbial diversity along mountain elevation gradients. This macroecological experimental framework can be easily adapted also to latitudinal gradients to investigate the effect of temperature on biodiversity.
We find clear segregation of bacterial species along temperature gradients. The bacterial communities at higher elevations in China are more similar to those in Norway, and the communities at lower elevations in Norway share more species to those in China. This segregation of species along elevations or climatic zones is, to our knowledge, the first reported for microbes, and agrees well with the classic observations of higher organisms.
We also find that there is a decreasing alpha and gamma diversity toward higher nutrients. The temperature dependence of species richness is greatest at extreme nutrient levels, whereas the nutrient dependence of species richness is strongest at intermediate temperatures. The finding of the strongest effect of temperature on species richness at extreme values of nutrients has implications of the vulnerability of biodiversity under global change. Spatially, nutrient concentrations are usually lower at higher elevations or latitudes, and the corresponding aquatic ecosystems might be facing biodiversity loss in local endemic species regarding climate warming than lower elevations or latitudes. The good thing for higher elevations or latitudes is that the biodiversity will increase when temperature increase; the bad thing is, however, that the species composition there will be more similar to those at lower elevations or latitudes, and local endemic species will be losing.
For species turnover rates, temperature effects are strongest at intermediate and two extreme ends of nutrient gradients in subtropical and subarctic regions, respectively. Species turnover rates caused by nutrients do not increase toward higher temperatures.
These findings illustrate direct effects of temperature and nutrients on biodiversity, and indirect effects via primary productivity, thus providing insights into how nutrient enrichment could alter biodiversity under future climate scenarios.
More details can be found below:
Wang, J., Pan, F., Soininen, J., Heino, J. & Shen, J. (2016). Nutrient enrichment modifies temperature-biodiversity relationships in large-scale field experiments. Nat. Commun., 7, 13960. [Full Text] [Video]