Geographic location, local environment, and individual size mediate the effects of climate warming and neighbors on a benefactor plant
Predictions of plant responses to global warming frequently ignore biotic interactions and intraspecific variation across geographical ranges. Benefactor species play an important role in plant communities by protecting other taxa from harsh environments, but the combined effects of warming and beneficiary species on their performance have been largely unexamined. We analyzed the joint effects of elevated temperature and neighbor removal on the benefactor plant Silene acaulis, in factorial experiments near its low- and high-latitude range limits in Europe. We recorded growth, probability of reproduction and fruit set during 3 years. The effects of enhanced temperature were positive near the northern limit and negative in the south for some performance measures. This pattern was stronger in the presence of neighbors, possibly due to differential thermal tolerances between S. acaulis and beneficiary species in each location. Neighbors generally had a negative or null impact on S. acaulis, in agreement with previous reviews of overall effects of plant–plant interactions on benefactors. However, small S. acaulis individuals in the north showed higher growth when surrounded by neighbors. Finally, the local habitat within each location influenced some effects of experimental treatments. Overall, we show that plant responses to rising temperatures may strongly depend on their position within the geographic range, and on species interactions. Our results also highlight the need to consider features of the interacting taxa, such as whether they are benefactor species, as well as local-scale environmental variation, to predict the joint effects of global warming and biotic interactions on species and communities.
KeywordsArctic–alpine communities Distribution range limits Global warming Plant–plant interactions Stress gradient hypothesis
This project was funded by the Swedish Research Council to W. F. Morris (Ref: 2012-42619-94710-26) and by the Spanish Ministry of Economy, Industry and Competitiveness to M. B. García (CGL2017-90040-R). We would like to thank Q. Canelles, M. Guzmán, K. Kempe, P. Nuche, I. Pardo, H. Petrén, S. Pironon, P. Sánchez, P. Tejero, M. Vass and L. Wikström for field assistance, and M. Villellas, A. Varea and U. Molau for logistic help with the experiment. Two anonymous reviewers helped to improve a previous version of the manuscript.
Author contribution statement
WFM conceived the study and JV and MBG set up the experiment. JV monitored the plants and performed data analysis. JV wrote the manuscript with help from WFM and MBG.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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