(CN) – Researchers warn that future freshwater damming efforts could present significant dangers to aquatic life if allowed to proceed as planned, potentially threatening the habitats of up to 10,000 fish species.
A study, published Monday in Proceedings of the National Academy of Sciences, details how a large team of environmental researchers have charted out the potential consequences of both present and future damming efforts of freshwater sources. Researchers discovered that should dam construction projects currently in the works globally be allowed to continue, nearly 10,000 fish species could find their habitats fundamentally altered.
Much of the danger dam projects can pose to freshwater environments comes from habitat fragmentation, in which the physical presence of dams can interrupt the life cycles of aquatic life by cutting them off from natural migration and spawning routes. Habitat fragmentation makes it difficult for thousands of freshwater fish species to thrive and reproduce in rivers blocked by dams, particularly for fish that do not migrate to the ocean.
The consequences of damming efforts have been well documented in the past. One notable example is found in the recent extinction of the Chinese paddlefish, which found it impossible to survive after its populations were irreparably damaged by dams.
Valerio Barbarossa, first author of the study and environmental researcher at Radboud University and the PBL Netherlands Environmental Assessment Agency, says that while dams can have negative consequences in freshwater environments anywhere in the world, it is in the southern tropics that the most damage could be done.
“But especially in the tropics, where a lot of new hydropower dams are going to be built, impacts will be disproportional. We see for example that the completion of only one dam close to the outlet of the Purari River in Papua New Guinea will decrease habitat connectivity by about 80% on average for freshwater fish there,” Barbarossa said with the release of the study.
Researchers made these conclusions by drawing on data from roughly 40,000 currently existing hydropower dams and another 3,700 planned dams. Using the information from these dams and the roughly 10,000 fish species living near them, researchers created comprehensive maps detailing areas around the world could be or already are suffering from habitat fragmentation.
The researchers hope the findings will help policymakers around the world adopt a broader perspective on dam usage. The study notes that the concept of strategic dam construction, which aims to only maintain dams that offer up the best potential energy gains while presenting the fewest threats to natural ecosystems, holds particular promise. This approach could greatly assist current efforts around the world, such as in the United States and Europe, that are already aiming to combat and reverse the damage caused by habitat fragmentation and could help communities better understand what dams could work and what dams could be problematic.
“In the U.S. and Europe, there are plans for the removal of decommissioned dams to restore the connectivity of the rivers. Some dams have already been removed. Our global maps can help to prioritize locations for restoration measures, such as dam removal and installation of bypasses,” Barbarossa said with the release of the study.
Should these strategies and broader environmental perspectives be embraced, researchers hope global attitudes toward dams and their construction will consider energy benefits only in honest tandem with their potential environmental consequences.
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