Pye, Marian C., Vaughan, Ian Phillip ORCID: https://orcid.org/0000-0002-7263-3822 and Ormerod, Stephen James ORCID: https://orcid.org/0000-0002-8174-302X 2012. Episodic acidification affects the breakdown and invertebrate colonisation of oak litter. Freshwater Biology 57 (11) , pp. 2318-2329. 10.1111/fwb.12007 |
Abstract
Summary 1. Although European streams are now recovering chemically from acidification, biological recovery is limited. One hypothesis is that continuing acid episodes restrict acid-sensitive species in recovering locations either through direct toxicity or by affecting ecological processes. Here, we test this hypothesis by assessing the effects of episodic acid exposure on the breakdown and macroinvertebrate colonisation of oak (Quercus robur) litter. 2. Over 83 days, acid episodes of 4 days’ duration were simulated by repeatedly transplanting litter bags of contrasting mesh size between replicate acidic and circumneutral streams around Llyn Brianne (Wales, U.K.). Results were compared against controls from circumneutral streams and circumneutral transplants, while invertebrates colonising litter were compared with adjacent assemblages. 3. Breakdown was retarded significantly by repeated acid exposure in comparison with circumneutral transplants, but only in litter to which invertebrates had access. Overall breakdown was also significantly slower in fine-mesh than in coarse-mesh bags. 4. Plecopteran shredders were the major invertebrate colonists of litter, along with smaller numbers of grazers and predators. However, acid exposure eliminated or suppressed acid-sensitive families, resulting in an overall composition converging on that in acid streams. 5. The rapid loss of sensitive invertebrates from acid-exposed litter supports the hypothesis that acid episodes suppress biological recovery from acidification through direct physiological effects. However, our litter breakdown data indicate that (i) some effects of acid episodes could be mediated through litter processing; and (ii) episodic acidification could disrupt litter breakdown through effects on invertebrate composition or activity. These data suggest that delayed biological recovery from acidification can reflect a combination of direct toxic and indirect ecological effects.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Biosciences |
Subjects: | Q Science > QH Natural history > QH301 Biology |
Uncontrolled Keywords: | acid episodes; ecosystem processes; litter decomposition; macroinvertebrates; streams |
Publisher: | John Wiley & Sons |
ISSN: | 0046-5070 |
Last Modified: | 21 Oct 2022 10:56 |
URI: | https://orca.cardiff.ac.uk/id/eprint/41812 |
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