Western freshwater mussel populations are dying. According to the Xerces Society for Invertebrate Conservation, a non-profit organization dedicated to the conservation of invertebrate species, freshwater mussels are under threat from dam construction, pollution, the effects of climate change and other changes to their aquatic habitat. In an article titled “Extinction risk for freshwater mussels in western North America“, co-authors Emilie Blevens and Sarina Jepsen said that freshwater mussel species diversity “has declined by 35% in western watersheds by area, and among the most historically diverse watersheds, nearly half now harbor fewer species/clades”.
In a blog post titled “The merit of musselswrites Blevens, “for biologists and the many people who recognize the inherent value of biodiversity and rare species, the conservation of freshwater mussels and the preservation of their habitat is easy to understand. They are animals that share our rivers and enrich our natural and cultural bonds. »
Blevens argued that habitat conservation and restoration efforts should prioritize reducing water pollution, investing in remediation technologies and encouraging a reduction in water use. industrial, agricultural and residential.
The threat of mussel bed mass mortality has increased in freshwater species such as the western ridged mussel (Gonidea angulata), which has heightened conservation concerns. In another post,Work from the bottom up (of the river) to conserve the Western Ridged Musselwrote Blevens, “The stakes are high, and yet there is still an opportunity to provide meaningful protection to the western ridged mussel. Listing an animal under the Endangered Species Act saved more than 200 species of plants and animals from extinction, she said, a result that hopefully , will be shared by Western ridged mussels.
A publication of the Xerces Company, “Pacific Northwest Freshwater Musselssaid molluscs are extremely “sensitive to changes in their environment” and act like a “canary in the coal mine” when it comes to the health of aquatic ecosystems. Since molluscs are slow moving and very sensitive to changes in their environment, they are a useful monitor of habitat conditions. Mussels can only live in “permanent bodies of water”, including lakes, ponds and rivers. They generally need a stable environment, as too much variability in factors such as water flow or drying out can make it difficult for juvenile molluscs to establish.
Mussels play an important role in maintaining aquatic ecosystems. They filter materials in the water like algae and sediment, providing food for seabed organisms and controlling nutrient levels. Mussels act in the same way as garden earthworms, promoting species diversity and the availability of organic matter. They also provide benefits to humans – freshwater mussels filter out pharmaceuticals and bacterial populations like E.coli out of water bodies.
Freshwater mussels are also an essential food source for many predators, including river otters, raccoons, gulls and some fish. While healthy mussel populations can survive a standard amount of predation, fragmented or declining populations could be wiped out.
“Freshwater mussels are one of the most endangered groups of animals on Earth,” according to the Xerces company. Of nearly 300 species of North American freshwater mussels, 35 have gone extinct over the past century. The US Endangered Species Act lists 25% of freshwater mussel species as endangered or threatened, and each US state lists 75% of species as threatened, endangered, or of special concern.
The decline in freshwater mussel populations, the publication says, is the “result of continent-wide degradation of aquatic ecosystems.” Over the past 150 years, mussel populations, like all western freshwater ecosystems, have been negatively impacted by trends such as urbanization, logging, and agriculture. More recently, climate change has exacerbated ecosystem instability, and it will continue to do so.
A conservation booklet from the Xerces Society titled “Conserving the Gems of Our Waters” aims to provide “best management practices for protecting native western freshwater mussels” during projects such as restoration or construction of rivers. Efforts to restore habitats for salmon and other species in the Northwest have overshadowed the need to preserve freshwater mussel populations, the publication says. If mussels are not included in considerations for aquatic projects, the authors say, such projects may not protect or even actively harm mussel populations, which “can take decades to recover, if at all.”
The booklet gives several tips to potential aquatic project planners. They should be aware that mussel populations will remain on a job site year-round, as they are largely immobile. If a mussel population is driven out or destroyed, it is unlikely to recover for decades – and the more mussel beds are lost, the lower the chance of recovery. According to the authors, best practices for managing freshwater mussels are best instituted a year or more in advance of any project. Freshwater mussels have different habitat requirements than other species, and general protective measures may not adequately protect mussels from harm.
Loss of freshwater mussels can lead to loss of living history. “Freshwater mussel beds, like old-growth forests, can provide a lesson in persistence,” Blevens said. “The bed of mussels that you or I observe in a river is probably the same bed, with perhaps even some of the same individuals, that our parents or grandparents would have encountered if they were standing (or swimming) from the same point decades ago, yet at the current rate of decline, our children, and their children too, may not be able to experience Western ridged mussels.