In the 12 years since Dudgeon et al. (2006) reviewed major pressures on freshwater ecosystems, the biodiversity crisis in the world's lakes, reservoirs, rivers, streams and wetlands has deepened. While lakes, reservoirs and rivers cover only 2.3% of the Earth's surface, these ecosystems host at least 9.5% of the Earth's described animal species. Furthermore, using the World Wide Fund for Nature's Living Planet Index, freshwater population declines (83% between 1970 and 2014) continue to outpace contemporaneous declines in marine or terrestrial systems. The Anthropocene has brought multiple new and varied threats that disproportionately impact freshwater systems. We document 12 emerging threats to freshwater biodiversity that are either entirely new since 2006 or have since intensified: (i) changing climates; (ii) e-commerce and invasions; (iii) infectious diseases; (iv) harmful algal blooms; (v) expanding hydropower; (vi) emerging contaminants; (vii) engineered nanomaterials; (viii) microplastic pollution; (ix) light and noise; (x) freshwater salinisation; (xi) declining calcium; and (xii) cumulative stressors. Effects are evidenced for amphibians, fishes, invertebrates, microbes, plants, turtles and waterbirds, with potential for ecosystem-level changes through bottom-up and top-down processes. In our highly uncertain future, the net effects of these threats raise serious concerns for freshwater ecosystems. However, we also highlight opportunities for conservation gains as a result of novel management tools (e.g. environmental flows, environmental DNA) and specific conservation-oriented actions (e.g. dam removal, habitat protection policies, managed relocation of species) that have been met with varying levels of success. Moving forward, we advocate hybrid approaches that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap between the aspirations of conservation biologists and the accelerating rate of species endangerment.
1.Carleton Univ, Dept Biol, Fish Ecol & Conservat Physiol Lab, Ottawa, ON K1S 5B6, Canada 2.Michigan State Univ, Ctr Syst Integrat & Sustainabil, Dept Fisheries & Wildlife & Ecol Evolutionary Bio, E Lansing, MI 48824 USA 3.Univ Saskatchewan, Sch Environm & Sustainabil, Saskatoon, SK S7N 5C8, Canada 4.Univ Calif Santa Barbara, Dept Ecol Evolut & Marine Biol, Santa Barbara, CA 93117 USA 5.Federat Univ Australia, Sch Life & Hlth Sci, Univ Dr, Mt Helen 3350, Australia 6.Univ Colorado, Ecol & Evolutionary Biol, Boulder, CO 80309 USA 7.McMaster Univ, Dept Biol, Hamilton, ON L8S 4K1, Canada 8.McMaster Univ, Sch Geog & Earth Sci, Hamilton, ON L8S 4K1, Canada 9.Mt Allison Univ, Dept Chem & Biochem, Sackville, NB E4L 1G8, Canada 10.Univ Washington, Sch Aquat & Fishery Sci, Seattle, WA 98195 USA 11.Cardiff Univ, Water Res Inst, Cardiff CF10 3AX, S Glam, Wales 12.Cardiff Univ, Sch Biosci, Cardiff CF10 3AX, S Glam, Wales 13.Queens Univ, Paleoecol Environm Assessment & Res Lab, Dept Biol, Kingston, ON K7L 3N6, Canada 14.Leibniz Inst Freshwater Ecol & Inland Fisheries I, D-12587 Berlin, Germany 15.Carleton Univ, Inst Environm Sci, Ottawa, ON K1S 5B6, Canada 16.Univ Hong Kong, Sch Biol Sci, Hong Kong, Peoples R China 17.Austrian Sci Fund FWF, A-1090 Vienna, Austria
Recommended Citation:
Reid, Andrea J.,Carlson, Andrew K.,Creed, Irena F.,et al. Emerging threats and persistent conservation challenges for freshwater biodiversity[J]. BIOLOGICAL REVIEWS,2019-01-01,94(3):849-873