Research priorities for freshwater mussel conservation assessment

Abstract

Freshwater mussels are declining globally, and effective conservation requires prioritizing research and actions to identify and mitigate threats impacting mussel species. Conservation priorities vary widely, ranging from preventing imminent extinction to maintaining abundant populations. Here, we develop a portfolio of priority research topics for freshwater mussel conservation assessment. To address these topics, we group research priorities into two categories: intrinsic or extrinsic factors. Intrinsic factors are indicators of organismal or population status, while extrinsic factors encompass environmental variables and threats. An understanding of intrinsic factors is useful in monitoring, and of extrinsic factors are important to understand ongoing and potential impacts on conservation status. This dual approach can guide conservation status assessments prior to the establishment of priority species and implementation of conservation management actions.

Freshwater conservation assessments in (semi-)arid regions: Testing river intermittence and buffer strategies using freshwater mussels (Bivalvia, Unionida) in Morocco

“…Despite all of this, freshwater mussels are globally threatened and many populations are in pronounced decline (Strayer et al, 2004;Graf and Cummings, 2007;Lopes-Lima et al, 2014b, 2018. Recent efforts have been implemented to better understand and conserve this group (Lopes-Lima et al, 2014a, 2014b, 2018, but there is still much to be done (see Ferreira-Rodríguez et al, 2019). Freshwater mussels are considered "permanent refugial organisms" , meaning they have limited dispersal abilities even under flow conditions, and are restricted to areas where water availability is permanent across many years.…”

Captive breeding of Margaritifera auricularia (Spengler, 1793) and its conservation importance

“…Such actions include the restoration of river dynamics and hydromorphology, an increase of floodplain habitats, improving water quality, and assisting the recovery of microhabitats by ensuring well-oxygenated substrates and a decrease of suspended solids (Dudgeon et al, 2006;Strayer et al, 2019). Remedial actions should remove the likely cause(s) for species decline (Bolland et al, 2010), so the management of fish host populations should also be included as a key management action in order to restore the reproductive potential of freshwater mussels in their natural habitats (Ferreira-Rodríguez et al, 2019).…”

“…from increased fine sediment deposition, excessive nutrient input, heavy metal accumulation, herbicides and fungicides used in agriculture), overexploitation (including exploitation of fish hosts), introduction of invasive alien species (IAS), and climate change (for a review see Lopes-Lima et al, 2017). Despite their threatened conservation status there is still a noticeable scarcity of information on their complex biology (Geist, 2010(Geist, , 2011Geist & Auerswald, 2007;Howard & Coffey, 2006;Lopes-Lima et al, 2014), particularly on their reproductive biology and on the fish-mussel relationship (Modesto et al, 2018), which may impair the implementation of effective conservation efforts (Ferreira-Rodríguez et al, 2019).…”

Simple nonlethal identification criteria for two endangered freshwater pearl mussels, Margaritifera laevis and Margaritifera togakushiensis, in Hokkaido, northern Japan

“…Recent studies have shown that one of the most important problems for mussel conservation is recruitment cessation. Mussel populations without recently born juveniles will become extinct in the near future, even though the current size of the populations might be relatively large (Ferreira‐Rodríguez et al, ; Geist, ; Österling, Greenberg, & Arvidsson, ). Thus, long‐term monitoring targeting a wide age class of mussels is required.…”