Stubbington_et_al-2016-Freshwater_Biology.pdf (397.77 kB)
Macroinvertebrate seedbank composition in relation to antecedent duration of drying and multiple wet-dry cycles in a temporary stream
journal contribution
posted on 2016-05-05, 16:07 authored by Rachel Stubbington, J. Gunn, Sally Little, Thomas P. Worrall, Paul WoodPaul WoodThe aquatic invertebrate ‘seedbank’ comprises life stages that remain viable in the bed sediments of temporary freshwaters during dry phases. This seedbank promotes persistence of temporary-stream macroinvertebrates, but how its inhabitants respond to extended dry phases or repeated transitions between wet and dry phases remains unknown.
We rehydrated samples collected from the dry bed of a temperate-zone stream during a supra-seasonal drought, to examine the seedbank assemblage. Samples were first collected in autumn, from 12 sites along the ephemeral (4 sites), intermittent (2) and near-perennial (6) reaches, which had been dry for up to 8 months. Our first hypothesis was that assemblage composition would be related to the dry-phase duration preceding sampling, with longer dry phases reducing abundance and richness.
We revisited the same sites in three subsequent seasons, collecting and rehydrating sediments from all dry sites: five sites in early spring, three in late spring and four in late summer. Unpredictable flow resumption and redrying occurred between sampling dates. Our second hypothesis was that repeated wet-dry cycles would not degrade the assemblage because temporary-stream taxa would be adapted to fluctuating hydrological conditions.
Multiple individuals of only Chironomidae, Oligochaeta and Pisidium were present at sites that experienced the longest dry phases, providing some support for our first hypothesis. An additional 21 taxa were recorded across the remaining (shorter dry phase) sites in autumn, indicating that such sites act as refuges and potential recolonist sources following flow resumptions.
Although several insect orders first recorded in early spring were absent in later seasons, taxon-specific life cycles indicated that these absences were probably seasonal and not due to repeated wet-dry cycles.
We recorded 38 taxa in total, highlighting the seedbank as a dry-phase resistance mechanism for many temporary-stream macroinvertebrates. Our results also suggest that seedbank diversity may be threatened by increases in drought extent and duration.
Funding
Natural England funded collection of hydrological data in the Lathkill Dale through grants to JG. Kevin Bull (Senior Reserve Manager/Group Coordinator, Derbyshire Dales National Nature Reserve) and Shaun Taylor (Reserve Manager, Derbyshire Dales National Nature Reserve) are thanked for their assistance and support.
History
School
- Social Sciences
Department
- Geography and Environment
Published in
Freshwater BiologyCitation
STUBBINGTON, R. ... et al., 2016. Macroinvertebrate seedbank composition in relation to antecedent duration of drying and multiple wet-dry cycles in a temporary stream. Freshwater Biology, DOI: 10.1111/fwb.12770.Publisher
John Wiley & Sons (© the authors)Version
- VoR (Version of Record)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/Publication date
2016ISSN
0046-5070eISSN
1365-2427Publisher version
Language
- en