Climate change alters slug abundance but not herbivory in a temperate grassland

RESEARCH ARTICLE Climate change alters slug abundance but not herbivory in a temperate grassland Daniel Weber1, Rebecca K. McGrailID1*, A. Elizabeth Carlisle1, James D. Harwood2¤, Rebecca L. McCulley1 1 Department of Plant & Soil Sciences, University of Kentucky, Lexington, KY, United States of America, 2 Department of Entomology, University of Kentucky, Lexington, KY, United States of America ¤ Current address: Institute of Plant and Environment Protection, Beijing Academy of Agricultural & Forestry Sciences, Beijing, China * rkmcgrail@gmail.com Abstract Climate change will significantly impact the world’s ecosystems, in part by altering species interactions and ecological processes, such as herbivory and plant community dynamics, which may impact forage quality and ecosystem production. Yet relatively few field experi- mental manipulations assessing all of these parameters have been performed to date. To help fill this knowledge gap, we evaluated the effects of increased temperature (+3˚C day and night, year-round) and precipitation (+30% of mean annual rainfall) on slug herbivory and abundance and plant community dynamics biweekly in a pasture located in central Ken- tucky, U.S.A. Warming increased slug abundance once during the winter, likely due to improving conditions for foraging, whereas warming reduced slug abundance at times in late spring, mid-summer, and early fall (from 62–95% reduction depending on month). We found that warming and increased precipitation did not significantly modify slug herbivory at

our site, despite altering slug abundance and affecting plant community composition and forage quality. Climate change will alter seasonal patterns of slug abundance through both direct effects on slug biology and indirect effects mediated by changes in the plant commu- nity, suggesting that pasture management practices may have to adapt. Introduction Herbivory is an important ecological process in most ecosystems [1, 2], but especially in grass- lands which typically co-evolved with considerable levels of mammalian and insect herbivory [3–5]. A lesser studied, but potentially significant, herbivore of grass-dominated ecosystems are molluscs [6, 7]. Gastropods, including slugs, are particularly abundant and problematic in cereal crops where dense stands of annual grasses are grown in cool, wet climates [8–10]. While slugs can have a large negative effect on the yield of row crops [11], it is not always sim- ple to determine the effects of slug or overall mollusc herbivory in pastures or other grasslands where vegetation is more heterogeneous and diverse than croplands [12, 13]. Slugs can both positively and negatively affect plant biomass production depending on a myriad of environmental and biological factors [14–16] and can alter overall plant species PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0283128 March 14, 2023 1 / 17 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Weber D, McGrail RK, Carlisle AE, Harwood JD, McCulley RL (2023) Climate change alters slug abundance but not herbivory in a

temperate grassland. PLoS ONE 18(3): e0283128. https://doi.org/10.1371/journal.pone.0283128 Editor: Harald Auge, Helmholtz Centre for Environmental Research - UFZ, GERMANY Received: September 6, 2022 Accepted: March 3, 2023 Published: March 14, 2023 Copyright: © 2023 Weber et al. 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: Data are available at https://uknowledge.uky.edu/pss_climate_data/. Funding: This work was supported by grants to R. L.M by the United States Department of Energy (08-SC-NICCR-1073; https://www.energy.gov), the United States Department of Agriculture- Agricultural Research Service Forage Animal Production Research Unit (Specific Cooperative Agreement 58-6440-7-135; https://www.ars.usda. gov), and the National Science Foundation Division of Environmental Biology (DEB-1021222; https:// www.nsf.gov/div/index.jsp?div=DEB). The work