Context-specific effects of the identity of detrital mixtures on invertebrate communities
Article first published online: 17 SEP 2013
© 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
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Ecology and Evolution
Volume 3, Issue 11, pages 3986–3999, October 2013
How to Cite
Ecology and Evolution 2013; 3(11): 3986–3999
- Issue published online: 9 OCT 2013
- Article first published online: 17 SEP 2013
- Manuscript Accepted: 16 AUG 2013
- Manuscript Revised: 15 AUG 2013
- Manuscript Received: 22 APR 2013
- Hermon Slade Foundation. Grant Number: HSF 07/12
- Australian Research Council Discovery. Grant Numbers: DP0558122, DP1093444
- environmental context;
- leaf litter;
- organic enrichment;
- spatial subsidy
Many aquatic ecosystems are sustained by detrital subsidies of leaf litter derived from exogenous sources. Although numerous studies have examined the effects of litter species richness and identity on decomposition processes, it remains unclear how these effects extend to associated invertebrate communities or how these effects vary spatially according to local environmental context. Using field enrichment experiments, we assessed how the species richness, assemblage composition, and supply of detrital litter resources interact to affect benthic communities of three temperate Australian estuarine mudflats. Our experiments utilized eight litter sources that are presently experiencing human-mediated changes in their supply to estuarine mudflats. Contrary to predictions, we did not detect effects of the species richness of detrital mixtures on benthic communities. Macroinvertebrate community structure and, in particular, abundance were, instead, influenced by the assemblage composition of detrital mixtures. At two of the three sites, plots receiving the most labile detrital mix, containing the ephemeral algae Chaetomorpha and Ulva, supported the fewest macroinvertebrates of all the experimental enrichments. The large effect of detrital mix identity on macroinvertebrate communities is of concern given present trends of proliferation of macroalgae at the expense of more refractory seagrasses and marsh grasses. As such environmental degradation continues, it will be important to more fully understand under what environmental contexts such compositional changes in detrital resources will have the most detrimental effects on important prey resources for commercially important fish and wading shorebirds.