TY - JOUR
T1 - Detrimental effects of a novel flow regime on the functional trajectory of an aquatic invertebrate metacommunity
AU - Ruhi, Albert
AU - Dong, Xiaoli
AU - McDaniel, Courtney H.
AU - Batzer, Darold P.
AU - Sabo, John L.
N1 - Funding Information:
The authors thank the National Park Service (Task Agreement No. P12AC11207) and the Hatch Program, as well as the Chattahoochee Coldwater Fishery Foundation, for graciously contributing the long-term data and many volunteer hours to complete this project. We also thank Tarik Gouhier for his advice on wavelet analysis, Ian Carroll and Kelly Hondula for their help on coding and data visualization, Nuria Pla for her help with Figure, and Jessica Gephart and four anonymous reviewers for their comments on earlier versions of the manuscript. Support for this work was provided by the NSF DEB 1457567 (to JLS and AR) and NSF CBET 1204478 (to JLS). Albert Ruhi was also supported by the National Socio-Environmental Synthesis Center (SESYNC), under funding received from the National Science Foundation DBI-1052875.
Funding Information:
The authors thank the National Park Service (Task Agreement No. P12AC11207) and the Hatch Program, as well as the Chattahoochee Coldwater Fishery Foundation, for graciously contributing the long-term data and many volunteer hours to complete this project. We also thank Tarik Gouhier for his advice on wavelet analysis, Ian Carroll and Kelly Hondula for their help on coding and data visualization, Nuria Pla for her help with Figure 1, and Jessica Gephart and four anonymous reviewers for their comments on earlier versions of the manuscript. Support for this work was provided by the NSF DEB 1457567 (to JLS and AR) and NSF CBET 1204478 (to JLS). Albert Ruhi was also supported by the National Socio-Environmental Synthesis Center (SESYNC), under funding received from the National Science Foundation DBI-1052875.
Publisher Copyright:
© 2018 John Wiley & Sons Ltd
PY - 2018/8
Y1 - 2018/8
N2 - Novel flow regimes resulting from dam operations and overallocation of freshwater resources are an emerging consequence of global change. Yet, anticipating how freshwater biodiversity will respond to surging flow regime alteration requires overcoming two challenges in environmental flow science: shifting from local to riverscape-level understanding of biodiversity dynamics, and from static to time-varying characterizations of the flow regime. Here, we used time-series methods (wavelets and multivariate autoregressive models) to quantify flow-regime alteration and to link time-varying flow regimes to the dynamics of multiple local communities potentially connected by dispersal (i.e., a metacommunity). We studied the Chattahoochee River below Buford dam (Georgia, U.S.A.), and asked how flow regime alteration by a large hydropower dam may control the long-term functional trajectory of the downstream invertebrate metacommunity. We found that seasonal variation in hydropeaking synchronized temporal fluctuations in trait abundance among the flow-altered sites. Three biological trait states describing adaptation to fast flows benefitted from flow management for hydropower, but did not compensate for declines in 16 “loser” traits. Accordingly, metacommunity-wide functional diversity responded negatively to hydropeaking intensity, and stochastic simulations showed that the risk of functional diversity collapse within the next 4 years would decrease by 17% if hydropeaking was ameliorated, or by 9% if it was applied every other season. Finally, an analysis of 97 reference and 23 dam-affected river sites across the U.S. Southeast suggested that flow variation at extraneous, human-relevant scales (12-hr, 24-hr, 1-week) is relatively common in rivers affected by hydropower dams. This study advances the notion that novel flow regimes are widespread, and simplify the functional structure of riverine communities by filtering out taxa with nonadaptive traits and by spatially synchronizing their dynamics. This is relevant in the light of ongoing and future hydrologic alteration due to climate non-stationarity and the new wave of dams planned globally.
AB - Novel flow regimes resulting from dam operations and overallocation of freshwater resources are an emerging consequence of global change. Yet, anticipating how freshwater biodiversity will respond to surging flow regime alteration requires overcoming two challenges in environmental flow science: shifting from local to riverscape-level understanding of biodiversity dynamics, and from static to time-varying characterizations of the flow regime. Here, we used time-series methods (wavelets and multivariate autoregressive models) to quantify flow-regime alteration and to link time-varying flow regimes to the dynamics of multiple local communities potentially connected by dispersal (i.e., a metacommunity). We studied the Chattahoochee River below Buford dam (Georgia, U.S.A.), and asked how flow regime alteration by a large hydropower dam may control the long-term functional trajectory of the downstream invertebrate metacommunity. We found that seasonal variation in hydropeaking synchronized temporal fluctuations in trait abundance among the flow-altered sites. Three biological trait states describing adaptation to fast flows benefitted from flow management for hydropower, but did not compensate for declines in 16 “loser” traits. Accordingly, metacommunity-wide functional diversity responded negatively to hydropeaking intensity, and stochastic simulations showed that the risk of functional diversity collapse within the next 4 years would decrease by 17% if hydropeaking was ameliorated, or by 9% if it was applied every other season. Finally, an analysis of 97 reference and 23 dam-affected river sites across the U.S. Southeast suggested that flow variation at extraneous, human-relevant scales (12-hr, 24-hr, 1-week) is relatively common in rivers affected by hydropower dams. This study advances the notion that novel flow regimes are widespread, and simplify the functional structure of riverine communities by filtering out taxa with nonadaptive traits and by spatially synchronizing their dynamics. This is relevant in the light of ongoing and future hydrologic alteration due to climate non-stationarity and the new wave of dams planned globally.
KW - Biological traits
KW - hydrologic alteration
KW - invertebrates
KW - time-series methods
UR - http://www.scopus.com/inward/record.url?scp=85046745128&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85046745128&partnerID=8YFLogxK
U2 - 10.1111/gcb.14133
DO - 10.1111/gcb.14133
M3 - Article
C2 - 29665147
AN - SCOPUS:85046745128
SN - 1354-1013
VL - 24
SP - 3749
EP - 3765
JO - Global change biology
JF - Global change biology
IS - 8
ER -