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Published on: March 12, 2013
Testing the stress-gradient hypothesis with aquatic detritivorous invertebrates: insights for biodiversity-ecosystem
V Fugère1, P Andino1, R Espinosa1
1Department of Biology, McGill University, 1205 Ave. Docteur Penfield, Montreal, Quebec H3A 1B1, CanadaPontificia Universidad Católica del Ecuador, Facultad de Ciencias Exactas y Naturales, Laboratorio de Entomología, Quito, EcuadorInstitut de Recherche pour le Développement (IRD), UMR AMAP, CIRAD, TA A51/PS2, 34398 Montpellier Cedex 5, FranceFreshwater Biological Section, Biology Department, University of Copenhagen, Helsingørsgade 51, DK-3400 Hillerød, DenmarkInstitut de Recherche pour le Développement (IRD), UR 072, LEGS-CNRS, UPR 9034, CNRS 91198 Gif-sur Yvette Cedex, France and Université Paris-Sud 11, 91405 Orsay Cedex, France.
The stress-gradient hypothesis (SGH) suggests interactions shift from negative to positive with increasing environmental stress. This study tested SGH in aquatic invertebrates, finding interactions changed but patterns varied, highlighting stressor importance in biodiversity-ecosystem function research.
Area of Science:
- Ecology
- Aquatic Ecology
- Community Ecology
Background:
- The stress-gradient hypothesis (SGH) proposes environmental stress alters species interactions, shifting them from negative to positive as stress increases.
- While widely applied in plant ecology, SGH's relevance to animal communities remains underexplored.
- Understanding these shifts is crucial for biodiversity-ecosystem function (B-EF) relationships.
Purpose of the Study:
- To investigate the applicability of the SGH to aquatic detritivorous invertebrate communities.
- To determine if species interactions change along a resource quality stress gradient.
- To assess the influence of environmental stressors on B-EF relationships in aquatic systems.
Main Methods:
- A litter decomposition experiment was designed using aquatic detritivores.
- Litter quality was manipulated by offering leaves from plant species with varying specific leaf area and decomposition rates.
- Species interactions and responses were measured along this resource quality gradient.
Main Results:
- A shift from negative to neutral species interactions was observed with increasing resource quality stress, aligning with the SGH.
- Re-analysis of existing data revealed diverse interaction patterns among aquatic detritivores along stress gradients.
- The general pattern predicted by SGH may not universally apply to animal systems.
Conclusions:
- Aquatic detritivore interactions demonstrably change along environmental stress gradients.
- The study underscores the necessity of explicitly integrating environmental stressors into B-EF research.
- While SGH's core pattern may not fit all animal systems, its principles offer valuable insights into community dynamics.
