Water availability dictates how plant traits predict demographic rates.

Autor: Stears AE; Botany Department and Program in Ecology, University of Wyoming, Laramie, Wyoming, USA., Adler PB; Department of Wildland Resources and the Ecology Center, Utah State University, Logan, Utah, USA., Blumenthal DM; USDA-ARS Rangeland Resources Research Unit, Fort Collins, Colorado, USA., Kray JA; USDA-ARS Rangeland Resources Research Unit, Fort Collins, Colorado, USA., Mueller KE; Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio, USA., Ocheltree TW; Warner College of Natural Resources, Colorado State University, Fort Collins, Colorado, USA., Wilcox KR; Department of Ecosystem Science and Management, University of Wyoming, Laramie, Wyoming, USA., Laughlin DC; Botany Department and Program in Ecology, University of Wyoming, Laramie, Wyoming, USA.
Jazyk: angličtina
Zdroj: Ecology [Ecology] 2022 Nov; Vol. 103 (11), pp. e3799. Date of Electronic Publication: 2022 Jul 27.
DOI: 10.1002/ecy.3799
Abstrakt: A major goal in ecology is to make generalizable predictions of organism responses to environmental variation based on their traits. However, straightforward relationships between traits and fitness are rare and likely to vary with environmental context. Characterizing how traits mediate demographic responses to the environment may enhance the predictions of organism responses to global change. We synthesized 15 years of demographic data and species-level traits in a shortgrass steppe to determine whether the effects of leaf and root traits on growth and survival depended on seasonal water availability. We predicted that (1) species with drought-tolerant traits, such as lower leaf turgor loss point (TLP) and higher leaf and root dry matter content (LDMC and RDMC), would be more likely to survive and grow in drier years due to higher wilting resistance, (2) these traits would not predict fitness in wetter years, and (3) traits that more directly measure physiological mechanisms of water use such as TLP would best predict demographic responses. We found that graminoids with more negative TLP and higher LDMC and RDMC had higher survival rates in drier years. Forbs demonstrated similar yet more variable responses. Graminoids grew larger in wetter years, regardless of traits. However, in both wet and dry years, graminoids with more negative TLP and higher LDMC and RDMC grew larger than less negative TLP and low LDMC and RDMC species. Traits significantly mediated the impact of drought on survival, but not growth, suggesting that survival could be a stronger driver of species' drought response in this system. TLP predicted survival in drier years, but easier to measure LDMC and RDMC were equal or better predictors. These results advance our understanding of the mechanisms by which drought drives population dynamics, and show that abiotic context determines how traits drive fitness.
(© 2022 The Ecological Society of America.)
Databáze: MEDLINE
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