Mussels: The forgotten fauna of regulated rivers. A case study of the Caney Fork River

Abstract

During the past century freshwater mussel populations have declined precipitously throughout North America. Much of this loss has resulted from the construction of dams. In the Cumberland River system, 23% (22 species) of the historic mussel fauna is extinct or listed as endangered. Several additional species have either been extirpated from the Cumberland River or exist only in small, non-reproducing populations. Mussels of headwater streams have been severely affected by coal mining and poor land use practices. An intensive survey was conducted in the Caney Fork River, a major tributary to the Cumberland River, to determine the historic and extant mussel fauna. The results indicate that at least 37 species of mussels have been extirpated from the Caney Fork River, mainly as a result of the construction and operation of the Center Hill Dam. Among the species extirpated, two are now extinct, five are endangered and five are candidates for listing as threatened or endangered. Effects associated with this dam include the inundation of 102 km of riverine habitat, the discharge of hypolimnetic water (which limits mussel reproduction) and an alternating pattern of stream bed scouring and dewatering. The recognition of mussel life history requirements during preconstruction could have reduced many of these effects.

Impacts of climate change and land-use scenarios on Margaritifera margaritifera, an environmental indicator and endangered species

“…However, other alterations may also occur downstream of dams, like releases from impoundments which often result in either abnormally high or low flows (Baskaya et al, 2011;Vaughn and Taylor, 1999). Layzer et al (1993) and Hastie et al (2003) concluded that these rapid alterations in high and low flows produce short-term near-flood or neardrought conditions which are incompatible with the maintenance of mussel populations. High water velocities can also alter the sediment dynamics, affecting both adults and juveniles (Sousa et al, in press).…”

A Tale of Two Rivers: Implications of Water Management Practices for Mussel Biodiversity Outcomes During Droughts

“…Such releases need to be planned carefully based on the dynamics of specific rivers and species life history and habitat needs. For example, hypolimnetic water releases that lead to higher water levels and cooler temperatures during summer months can affect mussel gamete development, parasitism rates, and body condition (Galbraith and Vaughn 2009;Galbraith and Vaughn 2011), and even inhibit mussel reproduction (Layzer et al 1993;Peterson et al 2011).…”

Biodiversity Loss in Freshwater Mussels: Importance, Threats, and Solutions

“…The biomass of freshwater mussels can higher than all other benthic macroinvertebrates by an order of magnitude (Layzer et al, 1993), and as a result of their large size and sheer numbers they can significantly influence both the biotic and abiotic conditions around them. Although the critical factors determining the location of mussel beds are still unclear, most researchers agree that water velocity and substrate, most notably where water velocity is low enough to limit shear stress and allow for substrate stability but high enough to prevent siltation, are strongly influential.…”