Reduced water-availability lowers the strength of negative plant–soil feedbacks of two Asclepias species
Negative plant–soil feedbacks can serve as a mechanism for plant species coexistence. Despite predicted changes in precipitation patterns due to climate change, little is known as to how the strength and direction of feedbacks change under differing soil moisture regimes. We performed a fully reciprocal greenhouse experiment where seedlings of two co-occurring Asclepias spp. (milkweed) were grown either with their own or the other species’ microbial communities under high or low watering treatments. We found that seedlings of each species were smaller when exposed to conspecific relative to heterospecific soil biota, perhaps due to a build-up of specific soil pathogens. Importantly, this negative feedback diminished under reduced water-availability, and also in the absence of live soil organisms. Our findings suggest that the ability for plants to coexist may be fundamentally altered in areas that face increased drought.
KeywordsDrought Stress Belowground interactions Plant–microbial interactions Plant–soil feedback
We are grateful to Dr. Scott Mangan, Mike Dyer and the greenhouse staff at Washington University for their guidance and assistance with this project. We would like to thank Amy Patterson for assisting in the harvesting of these plants. This project was supported by undergraduate research awards provided to A. Snyder from Washington University in St. Louis.
Author contribution statement
AES and ANHT conceived and designed the experiment. AES and ANHT performed the experiment. AES analyzed the data. AES and ANHT wrote the manuscript.
This study was funded by Washington University in St. Louis.
Compliance with ethical standards
Conflict of interest
The authors declare they have no conflict of interest.
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