University of Oulu

Turunen, J., Louhi, P., Mykrä, H., Aroviita, J., Putkonen, E., Huusko, A., Muotka, T. (2018) Combined effects of local habitat, anthropogenic stress, and dispersal on stream ecosystems: a mesocosm experiment. Ecological Applications, 28 (6), 1606-1615.

Combined effects of local habitat, anthropogenic stress, and dispersal on stream ecosystems : a mesocosm experiment

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Author: Turunen, Jarno1,2; Louhi, Pauliina2,3; Mykrä, Heikki1;
Organizations: 1Freshwater Centre, Finnish Environment Institute, PO Box 413, 90014 Oulu, Finland
2Department of Ecology and Genetics, University of Oulu, PO Box 8000, 90014 Oulu, Finland
3Natural Resources Institute Finland (Luke), Paavo Havaksen tie 3, 90014 Oulu, Finland
4Natural Resources Institute Finland (Luke), Manamansalontie 90, 88300 Paltamo, Finland
5Natural Environment Centre, Finnish Environment Institute, PO Box 413, 90014 Oulu, Finland
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, 2018
Publish Date: 2019-03-25


The effects of anthropogenic stressors on community structure and ecosystem functioning can be strongly influenced by local habitat structure and dispersal from source communities. Catchment land uses increase the input of fine sediments into stream channels, clogging the interstitial spaces of benthic habitats. Aquatic macrophytes enhance habitat heterogeneity and mediate important ecosystem functions, being thus a key component of habitat structure in many streams. Therefore, the recovery of macrophytes following in‐stream habitat modification may be prerequisite for successful stream restoration. Restoration success is also affected by dispersal of organisms from the source community, with potentially the strongest responses in relatively isolated headwater sites that receive a limited amount of dispersing individuals. We used a factorial design in a set of stream mesocosms to study the independent and combined effects of an anthropogenic stressor (sand sedimentation), local habitat (macrophytes, i.e., moss transplants), and enhanced dispersal (two levels: high vs. low) on organic matter retention, algal accrual rate, leaf decomposition, and macroinvertebrate community structure. Overall, all responses were simple additive effects with no interactions between treatments. Sand reduced algal accumulation, total invertebrate density, and density of a few individual taxa. Mosses reduced algal accrual rate and algae‐grazing invertebrates, but enhanced organic matter retention and the number of detritus and filter feeders. Mosses also reduced macroinvertebrate diversity by increasing the dominance by a few taxa. Mosses reduced leaf mass loss, possibly because the organic matter retained by mosses provided an additional food source for leaf‐shredding invertebrates and thus reduced shredder aggregation into leaf packs. The effect of mosses on macroinvertebrate communities and ecosystem functioning was distinct irrespective of the level of dispersal, suggesting strong environmental control of community structure. The strong environmental control of macroinvertebrate community composition even under enhanced dispersal suggests that re‐establishing key habitat features, such as natural stream vegetation, could aid ecosystem recovery in boreal streams.

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Series: Ecological applications
ISSN: 1051-0761
ISSN-E: 1939-5582
ISSN-L: 1051-0761
Volume: 28
Issue: 6
Pages: 1606 - 1615
DOI: 10.1002/eap.1762
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
Funding: This work was funded by the Academy of Finland (grant no 263597) and Maa‐ja vesitekniikan tuki ry foundation. This paper is also part of the MARS project (Managing Aquatic ecosystems and water Resources under multiple Stress) funded under the 7th EU Framework Programme, Theme 6 (Environment including Climate Change), contract no. 603378.
Copyright information: © 2018 by the Ecological Society of America.