Climate change and primary production: Forty years in a bunchgrass prairie

RESEARCH ARTICLE Climate change and primary production: Forty years in a bunchgrass prairie Gary E. BelovskyID1*, Jennifer B. Slade2 1 Environmental Research Center and Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States of America, 2 Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States of America * belovsky.1@nd.edu, belovsky.2@nd.edu Abstract Over the past 109 years, a Montana intermountain bunchgrass prairie annually became warmer (0.7˚C) and drier (27%). The temperature and precipitation trends continued since 1978, as we studied nitrogen availability, annual aboveground primary production (ANPP), plant phenology and species composition. Given the annual increase in temperature and decrease in precipitation, ANPP might be expected to decline; however, it increased by 110%, as the period of greatest production (late-May–June) became wetter and cooler, counter to the annual pattern, and this was strongest at lower elevations. Grass production increased by 251%, while dicot production declined by 65%, which increased grass relative abundance by 54%. Summer temperatures increased 12.5% which increased plant senes- cence by 119% and decreased fall plant regrowth by 68%. More intense summer senes- cence changed plant species composition in favor of more drought tolerant species. The greater ANPP and summer senescence may increase susceptibility for fire, but fire toler- ance of the plant species composition did not change. Invasive plant species increased

108% over the study with annual grasses accounting for >50% of this increase, which further increased summer plant senescence. Therefore, seasonal climate changes at a smaller geographical scale (local), rather than average annual climate changes over a larger geo- graphical scale (regional), may better reflect plant community responses, and this makes ecological forecasting of climate change more difficult. Introduction Anthropogenic induced changes in temperature and precipitation are projected to impact ter- restrial primary production, e.g., [1–5]. Most of these projections focus on large spatial scales, such as biomes or across a large geographic region (>>1000 km2) [6], not a local ecosystem or habitat within an ecosystem (<1000 km2) [7–9]. In addition to climate change (e.g., tempera- ture and precipitation), concurrently there may be increases in nitrogen availability (e.g., cli- mate changing nitrogen mineralization, and atmospheric deposition of industrial/agricultural inputs) [10], the nutrient most often limiting terrestrial plant production. Finally, these anthropogenic changes may affect more than primary productivity, if they modify the PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0243496 December 23, 2020 1 / 21 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Belovsky GE, Slade JB (2020) Climate change and primary production: Forty years in a bunchgrass prairie. PLoS ONE 15(12): e0243496. https://doi.org/10.1371/journal.pone.0243496 Editor: Angelina Martı´nez-Yrı´zar, UNAM, MEXICO Received: August 1, 2020

Accepted: November 20, 2020 Published: December 23, 2020 Copyright: © 2020 Belovsky, Slade. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: Funding to 1st author GEB: National Science Foundation: NSF - www.nsf.gov NSF DEB- 78-02069, NSF BSR-83-07352, NSF DEB-93- 17984, NSF DEB-97-07564, NSF DEB-04-15390, NSF DEB-09-18306, NSF DEB-1456511 National Geographic Society Grant FY79 - https://www. nationalgeographic.org; University of Michigan Rackham Graduate School - https://rackham. umich.edu/; University of Michigan Vice-President of Research Grant - https://www.research.umich. edu; USDA/GHIPM (1989-1994) - www.ars.usda.