| 1. |
- Albert, James S., et al.
(författare)
-
Scientists' warning to humanity on the freshwater biodiversity crisis
- 2021
-
Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 50, s. 85-94
-
Tidskriftsartikel (refereegranskat)abstract
- Freshwater ecosystems provide irreplaceable services for both nature and society. The quality and quantity of freshwater affect biogeochemical processes and ecological dynamics that determine biodiversity, ecosystem productivity, and human health and welfare at local, regional and global scales. Freshwater ecosystems and their associated riparian habitats are amongst the most biologically diverse on Earth, and have inestimable economic, health, cultural, scientific and educational values. Yet human impacts to lakes, rivers, streams, wetlands and groundwater are dramatically reducing biodiversity and robbing critical natural resources and services from current and future generations. Freshwater biodiversity is declining rapidly on every continent and in every major river basin on Earth, and this degradation is occurring more rapidly than in terrestrial ecosystems. Currently, about one third of all global freshwater discharges pass through human agricultural, industrial or urban infrastructure. About one fifth of the Earth's arable land is now already equipped for irrigation, including all the most productive lands, and this proportion is projected to surpass one third by midcentury to feed the rapidly expanding populations of humans and commensal species, especially poultry and ruminant livestock. Less than one fifth of the world's preindustrial freshwater wetlands remain, and this proportion is projected to decline to under one tenth by midcentury, with imminent threats from water transfer megaprojects in Brazil and India, and coastal wetland drainage megaprojects in China. The Living Planet Index for freshwater vertebrate populations has declined to just one third that of 1970, and is projected to sink below one fifth by midcentury. A linear model of global economic expansion yields the chilling prediction that human utilization of critical freshwater resources will approach one half of the Earth's total capacity by midcentury. Although the magnitude and growth of the human freshwater footprint are greater than is generally understood by policy makers, the news media, or the general public, slowing and reversing dramatic losses of freshwater species and ecosystems is still possible. We recommend a set of urgent policy actions that promote clean water, conserve watershed services, and restore freshwater ecosystems and their vital services. Effective management of freshwater resources and ecosystems must be ranked amongst humanity's highest priorities.
|
|
| 2. |
- Leadley, Paul, et al.
(författare)
-
Interacting Regional-Scale Regime Shifts for Biodiversity and Ecosystem Services
- 2014
-
Ingår i: BioScience. - : Oxford University Press (OUP). - 0006-3568 .- 1525-3244. ; 64:8, s. 665-679
-
Tidskriftsartikel (refereegranskat)abstract
- Current trajectories of global change may lead to regime shifts at regional scales, driving coupled human-environment systems to highly degraded states in terms of biodiversity, ecosystem services, and human well-being. For business-as-usual socioeconomic development pathways, regime shifts are projected to occur within the next several decades, to be difficult to reverse, and to have regional- to global-scale impacts on human society. We provide an overview of ecosystem, socioeconomic, and biophysical mechanisms mediating regime shifts and illustrate how these interact at regional scales by aggregation, synergy, and spreading processes. We give detailed examples of interactions for terrestrial ecosystems of central South America and for marine and coastal ecosystems of Southeast Asia. This analysis suggests that degradation of biodiversity and, ecosystem services over the twenty-first century could be far greater than was previously predicted. We identify key policy and management opportunities at regional to global scales to avoid these shifts.
|
|
| 3. |
- Pereira, Henrique M., et al.
(författare)
-
Scenarios for Global Biodiversity in the 21st Century
- 2010
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 330:6010, s. 1496-1501
-
Forskningsöversikt (refereegranskat)abstract
- Quantitative scenarios are coming of age as a tool for evaluating the impact of future socioeconomic development pathways on biodiversity and ecosystem services. We analyze global terrestrial, freshwater, and marine biodiversity scenarios using a range of measures including extinctions, changes in species abundance, habitat loss, and distribution shifts, as well as comparing model projections to observations. Scenarios consistently indicate that biodiversity will continue to decline over the 21st century. However, the range of projected changes is much broader than most studies suggest, partly because there are major opportunities to intervene through better policies, but also because of large uncertainties in projections.
|
|
| 4. |
- Rejas, Danny, 1968-, et al.
(författare)
-
The introduced Arapaima gigas in the Bolivian Amazon : Trophic position and isotopic niche overlap with native species
- 2023
-
Ingår i: Ecology of Freshwater Fish. - 0906-6691 .- 1600-0633. ; 32:4, s. 926-937
-
Tidskriftsartikel (refereegranskat)abstract
- Non-native fish species may generate major ecological impacts on native assemblages. This study aims to assess the potential impact of the introduced Arapaima gigas on native fish assemblages in two oxbow lakes of the Bolivian Amazon. Stable isotope data were used to determine trophic position (TP) and isotopic niche overlap, to evaluate potential predation and competition interactions, respectively. Results suggest that A. gigas is more an omnivore than a top predator, as often claimed. Arapaima gigas occupied an intermediate TP between detritivore/herbivore and piscivore fish species and showed broader isotopic niche compared to most native species analysed. The isotopic niche of A. gigas significantly overlapped with most native fish species in one lake (i.e. Lake Mentiroso), while there was low niche overlap in the second (i.e. Lake Miraflores). Given its omnivorous tendencies, the predation impact of A. gigas on other fish species is likely less than currently claimed and likely varies with the food web structure of the ecosystem. More precise data on resource availability and use are necessary to infer whether niche overlap will have negative impacts on native fish species through potential competitive interactions. Increasing our understanding on the processes generating impact of these introductions on resident communities through food web ecology will pave the way for better resource management and conservation efforts.
|
|
