Emerging threats and persistent conservation challenges for freshwater biodiversity
- Reid, Andrea, Carlson, Andrew, Creed, Irena, Eliason, Erika, Gell, Peter, Johnson, Pieter, Kidd, Karen, MacCormack, Tyson, Olden, Julian, Ormerod, Steve, Smol, John, Taylor, William, Tockner, Klement, Vermaire, Jesse, Dudgeon, David, Cooke, Steven
- Authors: Reid, Andrea , Carlson, Andrew , Creed, Irena , Eliason, Erika , Gell, Peter , Johnson, Pieter , Kidd, Karen , MacCormack, Tyson , Olden, Julian , Ormerod, Steve , Smol, John , Taylor, William , Tockner, Klement , Vermaire, Jesse , Dudgeon, David , Cooke, Steven
- Date: 2019
- Type: Text , Journal article
- Relation: Biological Reviews Vol. 94, no. 3 (2019), p. 849-873
- Full Text: false
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- Description: 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.
Biogeochemical responses to holocene catchment-lake dynamics in the Tasmanian World Heritage Area, Australia
- Mariani, Michela, Beck, Kristen, Fletcher, Michael-Shawn, Gell, Peter, Saunders, Krystyna, Gadd, Patricia, Chisari, Robert
- Authors: Mariani, Michela , Beck, Kristen , Fletcher, Michael-Shawn , Gell, Peter , Saunders, Krystyna , Gadd, Patricia , Chisari, Robert
- Date: 2018
- Type: Text , Journal article
- Relation: Journal of Geophysical Research: Biogeosciences Vol. 123, no. 5 (2018), p. 1610-1624
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- Reviewed:
- Description: Environmental changes such as climate, land use, and fire activity affect terrestrial and aquatic ecosystems at multiple scales of space and time. Due to the nature of the interactions between terrestrial and aquatic dynamics, an integrated study using multiple proxies is critical for a better understanding of climate- and fire-driven impacts on environmental change. Here we present a synthesis of biological and geochemical data (pollen, spores, diatoms, micro X-ray fluorescence scanning, CN content, and stable isotopes) from Dove Lake, Tasmania, allowing us to disentangle long-term terrestrial-aquatic dynamics through the last 12 kyear. We found that aquatic dynamics at Dove Lake are tightly linked to vegetation shifts dictated by regional hydroclimatic variability in western Tasmania. A major shift in the diatom composition was detected at ca. 6 ka, and it was likely mediated by changes in regional terrestrial vegetation, charcoal, and iron accumulation. High rainforest abundance prior ca. 6 ka is linked to increased terrestrially derived organic matter delivery into the lake, higher dystrophy, anoxic bottom conditions, and lower light penetration depths. The shift to a landscape with a higher proportion of sclerophyll species following the intensification of El Niño-Southern Oscillation since ca. 6 ka corresponds to a decline in terrestrial organic matter input into Dove Lake, lower dystrophy levels, higher oxygen availability, and higher light availability for algae and littoral macrophytes. This record provides new insights on terrestrial-aquatic dynamics that could contribute to the conservation management plans in the Tasmanian World Heritage Area and in temperate high-altitude dystrophic systems elsewhere.
- Authors: Mariani, Michela , Beck, Kristen , Fletcher, Michael-Shawn , Gell, Peter , Saunders, Krystyna , Gadd, Patricia , Chisari, Robert
- Date: 2018
- Type: Text , Journal article
- Relation: Journal of Geophysical Research: Biogeosciences Vol. 123, no. 5 (2018), p. 1610-1624
- Full Text:
- Reviewed:
- Description: Environmental changes such as climate, land use, and fire activity affect terrestrial and aquatic ecosystems at multiple scales of space and time. Due to the nature of the interactions between terrestrial and aquatic dynamics, an integrated study using multiple proxies is critical for a better understanding of climate- and fire-driven impacts on environmental change. Here we present a synthesis of biological and geochemical data (pollen, spores, diatoms, micro X-ray fluorescence scanning, CN content, and stable isotopes) from Dove Lake, Tasmania, allowing us to disentangle long-term terrestrial-aquatic dynamics through the last 12 kyear. We found that aquatic dynamics at Dove Lake are tightly linked to vegetation shifts dictated by regional hydroclimatic variability in western Tasmania. A major shift in the diatom composition was detected at ca. 6 ka, and it was likely mediated by changes in regional terrestrial vegetation, charcoal, and iron accumulation. High rainforest abundance prior ca. 6 ka is linked to increased terrestrially derived organic matter delivery into the lake, higher dystrophy, anoxic bottom conditions, and lower light penetration depths. The shift to a landscape with a higher proportion of sclerophyll species following the intensification of El Niño-Southern Oscillation since ca. 6 ka corresponds to a decline in terrestrial organic matter input into Dove Lake, lower dystrophy levels, higher oxygen availability, and higher light availability for algae and littoral macrophytes. This record provides new insights on terrestrial-aquatic dynamics that could contribute to the conservation management plans in the Tasmanian World Heritage Area and in temperate high-altitude dystrophic systems elsewhere.
Tracking a century of change in trophic structure and dynamics in a floodplain wetland: Integrating palaeoecological and palaeoisotopic evidence
- Kattel, Giri, Gell, Peter, Perga, Marie-Elodie, Jeppesen, Erik, Grundell, Rosie, Weller, Sandra, Zawadzki, Atun, Barry, Linda
- Authors: Kattel, Giri , Gell, Peter , Perga, Marie-Elodie , Jeppesen, Erik , Grundell, Rosie , Weller, Sandra , Zawadzki, Atun , Barry, Linda
- Date: 2015
- Type: Text , Journal article
- Relation: Freshwater Biology Vol. 60, no. 4 (2015), p. 711-723
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- Description: The palaeoecological assessment, and the use of stable isotopes of carbon in subfossils of herbivores and omnivores, represents a novel approach to understand transitions in past food-web structure and the dynamics of lake ecosystems in response to natural perturbations and human impacts. Combined with records of subfossil assemblages of cladocerans and chironomids, it may be possible to decipher whether changes are attributable to external forces or internally derived system shifts. A sediment record taken from the shallow (2.3 m depth) Kings Billabong in the River Murray floodplain (Australia) was analysed to explore changes in trophic dynamics over the past century. The palaeoecological assessment revealed that littoral assemblages of cladocerans and benthic diatoms were gradually replaced by planktonic (planktonic and facultative planktonic) assemblages after river regulation in the 1920s. The stable isotopic composition of carbon (
- Authors: Kattel, Giri , Gell, Peter , Perga, Marie-Elodie , Jeppesen, Erik , Grundell, Rosie , Weller, Sandra , Zawadzki, Atun , Barry, Linda
- Date: 2015
- Type: Text , Journal article
- Relation: Freshwater Biology Vol. 60, no. 4 (2015), p. 711-723
- Full Text:
- Reviewed:
- Description: The palaeoecological assessment, and the use of stable isotopes of carbon in subfossils of herbivores and omnivores, represents a novel approach to understand transitions in past food-web structure and the dynamics of lake ecosystems in response to natural perturbations and human impacts. Combined with records of subfossil assemblages of cladocerans and chironomids, it may be possible to decipher whether changes are attributable to external forces or internally derived system shifts. A sediment record taken from the shallow (2.3 m depth) Kings Billabong in the River Murray floodplain (Australia) was analysed to explore changes in trophic dynamics over the past century. The palaeoecological assessment revealed that littoral assemblages of cladocerans and benthic diatoms were gradually replaced by planktonic (planktonic and facultative planktonic) assemblages after river regulation in the 1920s. The stable isotopic composition of carbon (
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