Legumes get help from soil biodiversity to reduce effects of climate change
dr. Gaowen Yang
Postdoctoral Scholar, Freie Universität Berlin, Germany
Global environmental change, including factors such as drought, nitrogen (N) deposition and warming, has been shown to threaten plant and soil biodiversity. It is well known that global change can dramatically alter plant community composition, and reduce ecosystem functions as a result of plant diversity loss. However, whether soil biodiversity loss can further influence plant community responses to global change is still poorly understood.
Figure 1. Soil biodiversity loss reduced the performance of legumes under warming. A heating cable was wrapped around the outside of the pot and was covered by aluminum foil to reduce thermal radiation to adjacent pots. Temperature controllers for each pot switch the heating cables off and on to maintain a set temperature with ±1°C dynamics in the pot.
Soil biodiversity, including numerous soil organisms, plays fundamental roles in the dynamics of plant community composition, and for the maintenance of plant diversity and multiple ecosystem functions. Thus, we predict that soil biodiversity loss will destabilize plant community composition and lead to plant diversity loss when faced with global change. To simulate a realistic loss of soil biodiversity during global change disturbances, we used the dilution-to-extinction approach to create a gradient of soil biodiversity. Experimental grassland plant communities with soil biodiversity gradients were established under greenhouse conditions. We tested the effects of soil biodiversity loss on plant communities during and following manipulations simulating global change disturbances in experimental grassland.
In general, we found that the growth of grasses and herbs was not sensitive to global change disturbances. However, global change disturbances decreased the performance of legumes (Figure 1), particularly under reduced soil biodiversity and the loss of soil biodiversity suppressed the recovery of legumes following disturbances.
Legumes, associating with rhizobia to fix atmospheric N2, have a profound effect on multiple ecosystem functions. The reduction of legumes can decrease N input, which could potentially alter multiple ecosystem functions. Moreover, given that most native grasslands in the world are dominated by grasses or grass-like plants, our study emphasizes that soil biodiversity is crucial for legume persistence and plant diversity maintenance when faced with environmental change. Our study highlights the importance of soil biodiversity as a potential buffering mechanism for plant diversity and community composition in grasslands.
Publication: Yang G, Roy J, Veresoglou SD, Rillig MC (2020) Soil biodiversity enhances the persistence of legumes under climate change. New Phytologist. In press. https://doi.org/10.1111/nph.17065.