Interactive effects of temperature and nutrients on biodiversity along mountain elevation gradients

What is it about?

Increased temperature and nutrient pollution are key features of anthropogenic change, but their dual effects on biodiversity remain unclear. Here, Wang et al. conduct field experiments at mountain elevation gradients to show that temperature and nutrients have independent and interactive effects on microbial biodiversity.

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Why is it important?

(1) A macroecological experimental framework was proposed, which can be easily adapted also to latitudinal gradients to investigate the effect of temperature on biodiversity. (2) Bacterial community compositions were mainly structured by temperature or elevational climatic zones. Bacterial communities at higher elevations in low latitudes were more similar to those in high latitudes, and the communities at lower elevations in high latitudes shared more species to those in low latitudes. 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. (3) 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. (4) The findings show the clear link between bacterial biodiversity and the interactive effects of temperature and nutrient concentrations, and that this link may explain global patterns of biodiversity, and provide insights into how nutrient enrichment could alter biodiversity under future climate scenarios.