TitleInteractions between global and local stressors of ecosystems determine management effectiveness in cumulative impact mapping
Publication TypeJournal Article
Year of Publication2014
AuthorsBrown CJ, Saunders MI, Possingham HP, Richardson AJ
Volume20
Pagination538-546
Date PublishedMay
Type of ArticleArticle
ISBN Number1366-9516
Accession NumberBIOSIS:PREV201400381932
Keywords(protected species)], 00512, General biology - Conservation and resource management, 04500,, 07502, Ecology:, 07506, Ecology:, 07512, Ecology: environmental biology -, 10515, Biophysics - Biocybernetics, additive effects model, Angiospermae, Spermatophyta, Plantae, Angiosperms, Monocots, Plants,, Australasia, Australasian region, environmental biology - General and methods, environmental biology - Plant, Environmental Sciences), global-local stressor interaction, impact mapping, index, Marine Ecology (Ecology,, mathematical and computer techniques, mathematical and computer techniques/cumulative, mathematical and computer techniques/interactive impact, Mathematical biology and statistical methods, Models and Simulations (Computational Biology), Monocotyledones [25202], nutrient input, synergistic interaction, antagonistic interaction,, Oceanography, Spermatophytes, Vascular Plants, Wildlife Management (Conservation), [seagrass
AbstractAimCumulative impact maps are used to identify the spatial distribution of multiple human impacts to species and ecosystems. Impacts can be caused by local stressors which can be managed, such as eutrophication, and by global stressors that cannot be managed, such as climate change. Cumulative impact maps typically assume that there are no interactive effects between stressors on biodiversity. However, the benefits of managing the ecosystem are affected by interactions between stressors. Our aim was to determine whether the assumption of no interactions in impact maps leads to incorrect identification of sites for management.LocationGeneral, Australasia.MethodsWe used the additive effects model to incorporate the effects of interactions into an interactive impact map. Seagrass meadows in Australasia threatened by a local stressor, nutrient inputs, and a global stressor, warming, were used as a case study. The reduction in the impact index was quantified for reductions in the nutrient stressor. We examined the outcomes for three scenarios: no interactions, antagonistic interactions or synergistic interactions.ResultsCumulative impact maps imply that reducing a local stressor will give equivalent reductions in the impact index everywhere, regardless of spatial variability in a global stressor. We show that reductions in the impact index were greatest in refuges from warming if there was an antagonistic interaction between stressors, and greatest in areas of high warming stress if there was a synergistic interaction. Reducing the nutrient stressor in refuges from warming always reduced the impact index, regardless of the interaction.Main conclusionsInteractions between local and global stressors should be considered when using cumulative impact maps to identify sites where management of a local stressor will provide the greatest impact reduction. If the interaction type is unknown, impact maps can be used to identify refuges from global stressors, as sites for management.