Plant traits related to precipitation sensitivity of species and communities in semiarid shortgrass prairie

Authors: WILCOX, KEVIN - University Of Wyoming; Blumenthal, Dana; Kray, Julie; MUELLER, KEVIN - Cleveland State University; Derner, Justin; OCHELTREE, TROY - Colorado State University; Porensky, Lauren

Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2020
Publication Date: 5/15/2021
Citation: Wilcox, K.R., Blumenthal, D.M., Kray, J.A., Mueller, K.E., Derner, J.D., Ocheltree, T.W., Porensky, L.M. 2021. Plant traits related to precipitation sensitivity of species and communities in semiarid shortgrass prairie. New Phytologist. 229(4):2007-2019. https://doi.org/10.1111/nph.17000.
DOI: https://doi.org/10.1111/nph.17000

Interpretive Summary: Understanding how plant communities respond to interannual variation in precipitation is critical to predicting rangeland functions such as forage production. In shortgrass steppe rangeland, we tested whether species and community precipitation responses could be predicted from continuous plant traits. Across 32 plant species, those most sensitive to precipitation had low leaf dry matter content (LDMC) and high specific leaf area (SLA), which together explained 59% of species-level variation. Plant height improved predictions for annual species. Most relationships between continuous traits and species-level sensitivity also scaled to the community-level. These results demonstrate that shortgrass prairie shifts towards faster growing, less stress resistant species in wetter years. Scientists and land managers can use these patterns to predict drought resistance and forage quality responses to both short-term and long-term changes in precipitation.

Technical Abstract: Understanding how plant communities respond to precipitation in water-limited ecosystems is necessary to predict inter-annual variation and trends of ecosystem properties, including forage production, biogeochemical cycling, and biodiversity. In a North American shortgrass prairie, we measured plant abundance, functional traits related to growth rate and drought tolerance, and aboveground net primary productivity (ANPP) to identify: (1) species-level responsiveness to precipitation (i.e., precipitation sensitivity) across functional groups, (2) precipitation sensitivity variation along continuous plant traits, and (3) whether these patterns scaled to the community level. Across 32 plant species, leaf dry matter content (LDMC) and specific leaf area (SLA) explained 59% of precipitation sensitivity. Plant height was related to precipitation sensitivity of annuals but not perennials. Most relationships between continuous traits and precipitation sensitivity scaled to the community-level but were often contingent on the presence/absence of particular species and/or land use patterns at a site. Thus, plant communities in the shortgrass prairie may shift towards faster growing, less stress resistant species in wetter years and/or under chronically increased precipitation. Such trait shifts would also likely influence long-term ecosystem function. The utility of these easily measured leaf traits also helps validate trait-based ecology as a practical discipline.