A case for associational resistance: Apparent support for the stress gradient hypothesis varies with study system. (13th November 2021)

• Record Type: Journal Article
• Authors: Adams, Amy E.; Besozzi, Elizabeth M.; Shahrokhi, Golya; Patten, Michael A.
• Editors: Chase, Jonathan
• Is Part Of: Ecology letters. Volume 25:Number 1(2022)
• Page Start: 202
• Page End: 217
• Publication Date: 2021-11-13
• Subjects: associational resistance -- context‐dependency -- ecological niche -- Hedges' g* -- interspecific -- intraspecific -- meta‐analysis -- negative interactions -- positive interactions -- stress gradient hypothesis; Ecology -- Periodicals; 577
• DOI: 10.1111/ele.13917
• Languages: English
• ISSNs: 1461-023X

Abstract

Abstract: According to the stress gradient hypothesis (SGH), ecological interactions between organisms shift positively as environmental stress increases. In the case of associational resistance, habitat is modified to ameliorate stress, benefitting other organisms. The SGH is contentious due to conflicting evidence and theoretical perspectives, so we adopted a meta‐analytic approach to determine if it is widely supported across a variety of contexts, including different kingdoms, ecosystems, habitats, interactions, stressors, and life history stages. We developed an extensive list of Boolean search criteria to search the published ecological literature and successfully detect studies that both directly tested the hypothesis, and those that were relevant but never mentioned it. We found that the SGH is well supported by studies that feature bacteria, plants, terrestrial ecosystems, interspecific negative interactions, adults, survival instead of growth or reproduction, and drought, fire, and nutrient stress. We conclude that the SGH is indeed a broadly relevant ecological hypothesis that is currently held back by cross‐disciplinary communication barriers. More SGH research is needed beyond the scope of interspecific plant competition, and more SGH research should feature multifactor stress. There remains a need to account for positive interactions in scientific pursuits, such as associational resistance in tests of the SGH. Abstract : According to the Stress Gradient Hypothesis (SGH), ecological interactions between organisms shift positively as environmental stress increases. This hypothesis is contentious due to conflicting evidence, so we adopted a meta‐analytic approach to determine if it is widely supported across a variety of contexts, including different kingdoms, ecosystems, habitats, interactions, stressors, and life history stages. Our findings indicate that the Stress Gradient Hypothesis is well supported in a variety of contexts, not just in the context of botany or competition.