10.5061/DRYAD.70RXWDBWH
Sarremejane, Romain
0000-0002-4943-1173
University of California, Berkeley
Truchy, Amélie
Swedish University of Agricultural Sciences
McKie, Brendan
Swedish University of Agricultural Sciences
Mykrä, Heikki
Finnish Environment Institute
Johnson, Richard
Swedish University of Agricultural Sciences
Huusko, Ari
Natural Resources Institute Finland
Sponseller, Ryan
Umeå University
Muotka, Timo
University of Oulu
Stochastic processes and ecological connectivity drive stream invertebrate
community responses to short-term drought
Dryad
dataset
2020
mesocosm experiments
hydrological disturbance
community recovery
2020-12-21T00:00:00Z
2020-12-21T00:00:00Z
en
21307 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1. Community responses to and recovery from disturbances depend on local
(e.g. presence of refuges) and regional (connectivity to recolonization
sources) factors. Droughts are becoming more frequent in boreal regions,
and are likely to constitute a severe disturbance for boreal stream
communities where organisms largely lack adaptations to such hydrological
extremes. 2. We conducted an experiment in 24 seminatural stream flumes to
assess the effects of local and regional factors on the responses of
benthic invertebrate communities to a short-term drought. We manipulated
flow (drought vs. constant-flow), spatial arrangement of leaf litter
patches (aggregated vs. evenly distributed) and colonization from regional
species pool (enhanced vs. ambient connectivity) to test the combined
effects of disturbance, connectivity, and resource arrangement on the
structural and functional responses of benthic invertebrate communities.
3. We found that a drought as short as one week reduced invertebrate
richness and abundances, mainly through stochastic extinctions. Such
changes in richness were not reflected in functional diversity. This
suggests that communities were characterized by a high degree of
functional redundancy, which allowed maintenance of functional diversity
despite species losses. Feeding groups responded differently to drought,
with organic matter decomposers responding more than scrapers and
predators. 4. Three weeks was insufficient for a complete invertebrate
community recovery from the drought. However, recovery was greater in
channels subjected to enhanced connectivity, which increased taxonomic
diversity and abundance of certain taxa. Spatial configuration of
resources explained the least variation in our response variables, having
a significant effect only on invertebrate abundance and evenness (both
sampling occasions) and species richness (end of recovery period). 5. Even
a short drought, if occurring late to the season, may not allow
communities to recover before the onset of winter, thus having a
potentially long-lasting effect on stream communities. For boreal
headwaters, extreme dewatering poses a novel disturbance regime that may
trigger substantial and potentially irreversible changes. An improved
understanding of such changes is needed to underpin adaptive management
strategies in these increasingly fragmented and disturbed ecosystems.
18-Dec-2020