Soil microbes that may accompany climate warming increase alpine plant production
Climate change is causing species with non-overlapping ranges to come in contact, and a key challenge is to predict the consequences of such species re-shuffling. Experiments on plants have focused largely on novel competitive interactions; other species interactions, such as plant–microbe symbioses, while less studied, may also influence plant responses to climate change. In this greenhouse study, we evaluated interactions between soil microbes and alpine-restricted plant species, simulating a warming scenario in which low-elevation microbes migrate upslope into the distribution of alpine plants. We examined three alpine grasses from the Rocky Mountains, CO, USA (Poa alpina, Festuca brachyphylla, and Elymus scribneri). We used soil inocula from within (resident) or below (novel) the plants’ current elevation range and examined responses in plant biomass, plant traits, and fungal colonization of roots. Resident soil inocula from the species’ home range decreased biomass to a greater extent than novel soil inocula. The depressed growth in resident soils suggested that these soils harbor more carbon-demanding microbes, as plant biomass generally declined with greater fungal colonization of roots, especially in resident soil inocula. Although plant traits did not respond to the provenance of soil inocula, specific leaf area declined and root:shoot ratio increased when soil inocula were sterilized, indicating microbial mediation of plant trait expression. Contrary to current predictions, our findings suggest that if upwardly migrating microbes were to displace current soil microbes, alpine plants may benefit from this warming-induced microbial re-shuffling.
KeywordsBacteria Fungi Plant microbiome Plant traits Rhizosphere
We thank the Rudgers-Whitney lab for comments on early analyses for the project and two anonymous reviewers for their helpful comments. Thanks to M. Mann, T. Farkas, and W. Noe for giving up much of a weekend to harvest the experiment. The project was funded by the University of New Mexico Biology Department Grove Summer Scholarship, American Philosophical Society Lewis and Clark Fund, and the United States National Science Foundation Division of Environmental Biology 1701221 awarded to JSL. Additional funding was provided by the United States National Science Foundation Division of Environmental Biology 1354972 to JAR. The experiments comply with USA law. Data associated with this manuscript was deposited in https://environmentaldatainitiative.org with the following DOI address: https://doi.org/10.0311/FK2/577f2bf2aa7b74653627a3252ff38d11.
Author contribution statement
JSL and JAR conceived of the study, JSL and DAD collected the data, JSL analyzed the data, and JSL led the writing with contributions from all authors.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
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