Biodiversity and climate warming

Meadow plots at Long-Term Ecological Research Station in Cedar Creek

Climate warming is predicted to alter species interactions, which could potentially lead to extinction events. However, there is an ongoing debate whether the effects of warming on biodiversity may be moderated by biodiversity itself.

A team of ecologists from the German Centre for Integrative Biodiversity Research (iDiv) and the University of Minnesota conducted long-running field experiments in 30 different meadow plots, some with only one plant species , and others with up to 16 different plant species. They warmed the meadows with heating lamps to approximately 3°C above ambient temperature. Subsequently, they recorded how this affected soil nematodes which were chosen for their important role for several ecosystem functions.

The colleagues found that warming can both increase and decrease biodiversity, and that the direction of the effect depends on how much biodiversity there is in the first place. After warming the monoculture plots the diversity of nematodes in those substantially declined. However, when the researchers warmed the plots with a high number of different plant species, the number of nematode species increased. However, those nematode species were also more closely related to each other. The reason was that these species had all been selected for a common characteristic, namely tolerance to a warmer environment. This increase in similarity can have implications for how well biological communities can respond to future environmental changes, potentially limiting the "insurance" effect inherent in a higher numbers of species.

The monoculture meadow created for the experiment resembled meadows found in intensively managed agricultural land. These new research findings therefore support conservationists who are advocating for more species-rich ecosystems and farmland to sustain biodiversity, in a warmer world.