Freshwater tributaries provide refuge and recolonization opportunities for mussels following salinity reversal

Abstract

et al., Freshwater tributaries provide refuge and recolonization opportunities for mussels following salinity reversal, Science of the Total Environment,

Freshwater mussels in Mediterranean‐climate regions: Species richness, conservation status, threats, and Conservation Actions Needed

“…Recent phylogeographical work found support for the separation of W. carteri into distinct western and southern lineages, with the potential of a subspecies in the south‐western corner of the distribution (Klunzinger et al, 2020). The extent of occurrence for W. carteri is estimated to have declined by 49% in the last three generations, and it now appears to be restricted to freshwater lakes, rivers, and streams, within 50–100 km of the coast (Klunzinger et al, 2015; Benson et al, 2019). Where they still occur, population densities can be high (with ≥20–50 individuals per m 2 ; Benson et al, 2018; Ma, 2018).…”

“…Mussel dispersal is largely determined by the availability and mobility of glochidial hosts, but many freshwater fishes in med‐regions are themselves highly imperilled (Ellender et al, 2017). Although there are some recent examples of natural recolonization by med‐mussels, these have been at scales of hundreds of metres, and recovery over larger distances is yet to be observed (Benson et al, 2018; Benson et al, 2019). In combination, these factors indicate that all mussel populations in med‐regions may be more imperilled than current assessments suggest.…”

“…For example, many catchments in the salinized landscape of SWA are scattered with artificial water points, constructed for agriculture and fire management (Beatty et al, 2017). These water points might act as freshwater refuges around salinized rivers and provide a source population for future recolonization in river systems should salinity be reversed (sensu Benson et al, 2019). Mussels are known to occur in these habitats (https://rivers.dwer.wa.gov.au/species/westralunio-carteri/); however, it is not known whether colonization occurred naturally or was assisted, or whether the populations found there are self‐sustaining.…”

“…Mussels have a suite of biological characteristics that make them vulnerable to environmental change (Lydeard et al, 2004; Lopes‐Lima et al, 2018b; Ferreira‐Rodríguez et al, 2019). Adults are largely immobile, often with narrow environmental tolerances for salinity (Blakeslee et al, 2013; Klunzinger et al, 2015; Benson et al, 2019), desiccation (Gough, Gascho Landis & Stoeckel, 2012; Sousa et al, 2018a), and flow conditions (Sheldon & Walker, 1989; Strayer, 1999). Many mussel species are long‐lived (sometimes >100 years), slow growing, and late to mature, so populations are unlikely to recover quickly from disturbance (Strayer et al, 2004; Benson et al, 2018; Benson et al, 2019).…”

“…Adults are largely immobile, often with narrow environmental tolerances for salinity (Blakeslee et al, 2013; Klunzinger et al, 2015; Benson et al, 2019), desiccation (Gough, Gascho Landis & Stoeckel, 2012; Sousa et al, 2018a), and flow conditions (Sheldon & Walker, 1989; Strayer, 1999). Many mussel species are long‐lived (sometimes >100 years), slow growing, and late to mature, so populations are unlikely to recover quickly from disturbance (Strayer et al, 2004; Benson et al, 2018; Benson et al, 2019). Larval mussels (glochidia) generally require a host fish for development and dispersal (Strayer et al, 2004; Modesto et al, 2018), and the loss of suitable fish species and barriers to fish movement (e.g.…”