University of Oulu

Truchy, A, Sarremejane, R, Muotka, T, et al. Habitat patchiness, ecological connectivity and the uneven recovery of boreal stream ecosystems from an experimental drought. Glob Change Biol. 2020; 26: 3455– 3472.

Habitat patchiness, ecological connectivity and the uneven recovery of boreal stream ecosystems from an experimental drought

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Author: Truchy, Amélie1; Sarremejane, Romain2,3; Muotka, Timo2,4;
Organizations: 1Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
2Department of Ecology and Genetics, University of Oulu, Oulu, Finland
3School of Science & Technology, Nottingham Trent University, Nottingham, UK
4Finnish Environment Institute, Freshwater Centre, Oulu, Finland
5School of Natural Resources, University of Nebraska – Lincoln, Lincoln, NE, USA
6Natural Resources Institute Finland (Luke), Paltamo, Finland
7Department of Ecology and Environmental Sciences, Umeå University, Umeå, Sweden
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.3 MB)
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Language: English
Published: John Wiley & Sons, 2020
Publish Date: 2020-06-15


Ongoing climate change is increasing the occurrence and intensity of drought episodes worldwide, including in boreal regions not previously regarded as drought prone, and where the impacts of drought remain poorly understood. Ecological connectivity is one factor that might influence community structure and ecosystem functioning post‐drought, by facilitating the recovery of sensitive species via dispersal at both local (e.g. a nearby habitat patch) and regional (from other systems within the same region) scales. In an outdoor mesocosm experiment, we investigated how impacts of drought on boreal stream ecosystems are altered by the spatial arrangement of local habitat patches within stream channels, and variation in ecological connectivity with a regional species pool. We measured basal ecosystem processes underlying carbon and nutrient cycling: (a) algal biomass accrual; (b) microbial respiration; and (c) decomposition of organic matter, and sampled communities of aquatic fungi and benthic invertebrates. An 8‐day drought event had strong impacts on both community structure and ecosystem functioning, including algal accrual, leaf decomposition and microbial respiration, with many of these impacts persisting even after water levels had been restored for 3.5 weeks. Enhanced connectivity with the regional species pool and increased aggregation of habitat patches also affected multiple response variables, especially those associated with microbes, and in some cases reduced the effects of drought to a small extent. This indicates that spatial processes might play a role in the resilience of communities and ecosystem functioning, given enough time. These effects were however insufficient to facilitate significant recovery in algal growth before seasonal dieback began in autumn. The limited resilience of ecosystem functioning in our experiment suggests that even short‐term droughts can have extended consequences for stream ecosystems in the world‘s vast boreal region, and especially on the ecosystem processes and services mediated by algal biofilms.

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Series: Global change biology
ISSN: 1354-1013
ISSN-E: 1365-2486
ISSN-L: 1354-1013
Volume: 26
Issue: 6
Pages: 3455 - 3472
DOI: 10.1111/gcb.15063
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: This work was supported by grants from the Swedish Environmental Protection Agency and the Swedish Agency for Marine and Water Management to R.K.J. and B.G.M. (project WATERS, Dnr 10/179) and the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS) to B.G.M. (project DESTRESS, Dnr 2014-886). Additional funding was supplied from a PhD student grant from the Department of Aquatic Sciences and Assessment (SLU, Uppsala) to A.T., and from the University of Oulu Graduate School (UniOGS) to R.S., the Academy of Finland (AKVA research program) to T.M. and the Natural Resources Institute Finland (Luke) to A.H.
Dataset Reference: Supporting information:
Copyright information: © 2020 The Authors. Global Change Biology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.