Journal ArticleDOI
Trends in water quality and discharge confound long-term warming effects on river macroinvertebrates
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TLDR
This paper assessed trends among macroinvertebrates in 50 southern English streams in relation to temperature, discharge and water quality over 18 years (1989-2007) and concluded that recent winter-biased warming in southern English chalk-streams has been insufficient to affect invertebrates negatively over a period of improving water quality.Abstract:
1. Climate-change effects on rivers and streams might interact with other pressures, such as pollution, but long-term investigations are scarce. We assessed trends among macroinvertebrates in 50 southern English streams in relation to temperature, discharge and water quality over 18 years (1989–2007).
2. Long-term records, coupled with estimates from inter-site calibrations of 3–4 years, showed that mean stream temperatures in the study area had increased by 2.1–2.9 °C in winter and 1.1–1.5 °C in summer over the 26 year period from 1980 to 2006, with trends in winter strongest.
3. While invertebrate assemblages in surface-fed streams were constant, those in chalk-streams changed significantly during 1989–2007. Invertebrate trends correlated significantly with temperature, but effects were spurious because (i) assemblages gained taxa typical of faster flow or well-oxygenated conditions, contrary to expectations from warming; (ii) more invertebrate families increased in abundance than declined and (iii) concomitant changes in water quality (e.g. declining orthophosphate, ammonia and biochemical oxygen demand), or at some sites changes in discharge, explained more variation in invertebrate abundance and composition than did temperature.
4. These patterns were reconfirmed in both group- and site-specific analyses.
5. We conclude that recent winter-biased warming in southern English chalk-streams has been insufficient to affect invertebrates negatively over a period of improving water quality. This implies that positive management can minimize some climate-change impacts on stream ecosystems. Chalk-stream invertebrates are sensitive, nevertheless, to variations in discharge, and detectable changes could occur if climate change alters flow pattern.
6. Because climatic trends now characterize many inter-annual time-series, we caution other investigators to examine whether putative effects on ecological systems are real or linked spuriously to other causes of change.read more
Citations
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Journal ArticleDOI
Climate change and freshwater ecosystems: impacts across multiple levels of organization
TL;DR: It is proposed that an understanding of the connections between these different levels of organization can help to develop a more coherent theoretical framework based on metabolic scaling, foraging theory and ecological stoichiometry, to predict the ecological consequences of climate change.
Journal ArticleDOI
Incorporating thermal regimes into environmental flows assessments: modifying dam operations to restore freshwater ecosystem integrity
Julian D. Olden,Robert J. Naiman +1 more
TL;DR: In this article, the authors explore the concept of the natural thermal regime, review how dam operations modify thermal regimes, and discuss the ecological implications of thermal alteration for freshwater ecosystems and identify five major challenges for incorporating water temperatures into environmental flow assessments, and describe future research opportunities and some alternative approaches for confronting those challenges.
Journal ArticleDOI
Multiple stressors in freshwater ecosystems
TL;DR: A collection of case studies from the first Freshwater Biological Association Conference on Multiple Stressors in Freshwater Ecosystems (FBA-2007) as mentioned in this paper, which was devoted to the management of multiple stressors in freshwater ecosystems, is a good starting point for this work.
Journal ArticleDOI
Rising stream and river temperatures in the United States
Sujay S. Kaushal,Gene E. Likens,Norbert A. Jaworski,Michael L. Pace,Michael L. Pace,Ashley M Sides,David A. Seekell,Kenneth T. Belt,David H. Secor,Rebecca L. Wingate +9 more
TL;DR: The authors analyzed historical records from 40 sites and found that 20 major streams and rivers have shown statistically significant, long-term warming, and rates of warming were most rapid in, but not confined to, urbanizing areas.
Journal ArticleDOI
Climate change effects on stream and river temperatures across the northwest U.S. from 1980–2009 and implications for salmonid fishes
TL;DR: In this article, the authors collected temperature data from regulated and unregulated streams in the northwest U.S. to describe historical trends from 1980-2009 and assess thermal consistency between these stream categories.
References
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Journal ArticleDOI
Nonpoint pollution of surface waters with phosphorus and nitrogen
Stephen R. Carpenter,Nina F. Caraco,David L. Correll,Robert W. Howarth,Andrew N. Sharpley,Val H. Smith +5 more
TL;DR: In this article, a review of the available scientific information, they are confident that nonpoint pollution of surface waters with P and N could be reduced by reducing surplus nutrient flows in agricultural systems and processes, reducing agricultural and urban runoff by diverse methods, and reducing N emissions from fossil fuel burning, but rates of recovery are highly variable among water bodies.
Journal ArticleDOI
Fingerprints of global warming on wild animals and plants
Terry L. Root,Jeff Price,Kimberly R. Hall,Stephen H. Schneider,Cynthia Rosenzweig,J. Alan Pounds +5 more
TL;DR: A consistent temperature-related shift is revealed in species ranging from molluscs to mammals and from grasses to trees, suggesting that a significant impact of global warming is already discernible in animal and plant populations.
Book ChapterDOI
Regional nitrogen budgets and riverine N & P fluxes for the drainages to the North Atlantic Ocean: Natural and human influences
Robert W. Howarth,Gilles Billen,Dennis P. Swaney,Andrea K. Townsend,Norbert A. Jaworski,Kate Lajtha,John A. Downing,Ragnar Elmgren,Nina F. Caraco,Teresa Jordan,Frank Berendse,Jean Freney,V. N. Kudeyarov,Peter S. Murdoch,Zhao-Liang Z.-L. Zhu +14 more
TL;DR: In this paper, the authors present estimates of total nitrogen and total phosphorus fluxes in rivers to the North Atlantic Ocean from 14 regions in North America, South America, Europe, and Africa which collectively comprise the drainage basins to North Atlantic.
Journal ArticleDOI
Adaptation to natural flow regimes
David A. Lytle,N. LeRoy Poff +1 more
TL;DR: Here, three modes of adaptation are identified that plants and animals use to survive floods and/or droughts and the rate of evolution in response to flow regime alteration remains an open question.
Journal ArticleDOI
Increasing river discharge to the Arctic Ocean
Bruce J. Peterson,Robert M. Holmes,James W. McClelland,Charles J. Vörösmarty,Richard B. Lammers,Alexander I. Shiklomanov,Igor A. Shiklomanov,Stefan Rahmstorf +7 more
TL;DR: Synthesis of river-monitoring data reveals that the average annual discharge of fresh water from the six largest Eurasian rivers to the Arctic Ocean increased by 7% from 1936 to 1999, a large-scale change in freshwater flux.