Interactions among stressors may be weak: Implications for management of freshwater macroinvertebrate communities

Kath, Jarrod and Thomson, James R. and Thompson, Ross and Kefford, Ben and Dyer, Fiona and MacNally, Ralph (2018) Interactions among stressors may be weak: Implications for management of freshwater macroinvertebrate communities. Diversity and Distributions, 24 (7). pp. 939-950. ISSN 1366-9516

Abstract

Aim: Ecological models that do not account for interactions among stressors, if interactions are important, could be inaccurate and lead to inefficient conservation strategies.
Conversely, if interactions are not important (i.e., stressors operate largely independently), then actions concentrating on a stressor-by- stressor basis would be warranted. Here, we investigated whether interactions among multiple stressors affected widely used indices of freshwater macroinvertebrate biodiversity, which are sensitive to environmental change at management-relevant scales (i.e., reaches and catchments).

Location: State of Victoria, south-eastern Australia.

Methods: We used a 7,418-sample dataset for stream macroinvertebrates from 2,165 sites distributed over 237,630 km2 for 20 years. We calculated the interactive effects on stream macroinvertebrates of stressors operating at different scales, namely vegetation loss at the catchment and reach scales and hydrological change and salinization at the local scale. The importance of interactions among multiple stressors was assessed by comparing the cross-validated predictive performance of models with and without multiple stressor interaction terms.

Results: Cross-validated models explained 31%–63% of the variation in the macroinvertebrate responses. The most important stressors were catchment vegetation loss (the proportion of remaining native vegetation cover) and salinity. The inclusion of interaction terms did not increase cross-validated predictive performance, which indicates that there was little evidence that interactions among stressors were important for explaining variation in commonly used freshwater macroinvertebrate condition indices.

Main conclusions: Interactions among vegetation, salinity and hydrological change stressors may not always be of importance for determining patterns of stream macroinvertebrate biodiversity, so that such interactions may not necessarily be critical considerations for catchment and reach scale management, at least if based on these or comparable condition indices. The mitigation of the impacts of vegetation loss, salinization and hydrological change stressors one-by- one probably is sufficient to guide conservation activities and might be advantageous if socio-political contexts make it difficult to address interactions among stressors.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Restricted access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Institute for Agriculture and the Environment
Date Deposited: 25 Jun 2018 06:46
Last Modified: 02 Jul 2018 01:29
Uncontrolled Keywords: additive; antagonistic; freshwater communities; multiple pressures; non-additive; synergistic
Fields of Research : 05 Environmental Sciences > 0501 Ecological Applications > 050101 Ecological Impacts of Climate Change
Socio-Economic Objective: D Environment > 96 Environment > 9605 Ecosystem Assessment and Management > 960506 Ecosystem Assessment and Management of Fresh, Ground and Surface Water Environments
Funding Details:
Identification Number or DOI: 10.1111/ddi.12737
URI: http://eprints.usq.edu.au/id/eprint/34332

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