Intraspecific genetic diversity provides the evolutionary potential to adapt to changing environments and ‘hotspots’ of high intraspecific diversity are recognized as key targets for conservation. In south‐western Australia, intraspecific genetic diversity for mesic taxa is not uniformly distributed. Many species comprise highly divergent lineages with unique haplotypes resulting from contraction to refugia during historical arid cycles. Sampling strategies in studies of the region’s unique and ancient freshwater fauna have often focused on broad distributional range, making it difficult to determine boundaries between lineages and the location of genetic hotspots. This study explored the spatial distribution of intraspecific genetic diversity in the threatened freshwater mussel, Westralunio carteri. Mitochondrial DNA sequences for 164 specimens, sampled from all basins within the distribution of the species, were used to describe lineage boundaries and the location of hotspots, and to reconstruct historical demographics. There was strong evidence for three subregions of genetic diversity based on the largely non‐overlapping distributions of three evolutionarily significant units. Spatial and demographic analyses suggest that these evolutionarily significant units persisted through past arid cycles in separate refugia. The majority of haplotypes were unique to a single location, indicating limited connectivity among populations in recent times. Hotspots were identified throughout the region. Most notably, a significant hotspot in the south‐western corner probably arose through the overlap of lineages in historical refugia. Conservation assessments often focus on the species as a whole, even though sublineages, hotspots and the threats faced are not evenly distributed across the species range. This paper highlights that effective conservation of spatially structured taxa requires targeted management of multiple genetic units. Given the importance of formal taxonomic description for conservation listings, further investigation of the potential for species delimitation within W. carteri is required.
Freshwater mussels provide important benefits to aquatic ecosystems by filtering water, bioturbating sediments, and cycling and transforming nutrients. The global decline in mussel diversity, distribution and abundance has led to concerns that ecological functioning in freshwater systems will be diminished. Mussels from the order Unionoida have an obligate larval stage that parasitizes a fish host, developing into a juvenile while being dispersed throughout the ecosystem. Barriers that obstruct fish movement can lead to localized extinctions of fish and mussels. In many cases, fishways have successfully restored habitat connectivity for fish; however, mussel recolonization is rarely assessed. This paper provides evidence for recolonization by Carter's freshwater mussel (Westralunio carteri, Iredale 1934) in habitats upstream of a weir following fishway installation. Mussels were present at all sites both above and below the weir, although they were far more abundant downstream. A lack of larger size classes upstream highlights the historical lack of recruitment in that area. Recent recruitment post‐fishway installation suggests that the population will eventually recover above the weir. The return of mussels above the weir is likely to benefit the ecosystem owing to the key role mussels play in aquatic habitats. Fishways may therefore be an important tool for the restoration of mussels, and broader ecological functioning.
et al., Freshwater tributaries provide refuge and recolonization opportunities for mussels following salinity reversal, Science of the Total Environment,
The five global Mediterranean‐climate regions are experiencing alarming rates of freshwater biodiversity loss. Although freshwater mussels are recognized as important functional components in aquatic ecosystems, and are among the most threatened faunal groups globally, there has been no synthesis of the plight of this group within these regions. Data from the International Union for Conservation of Nature (IUCN) Red List were reviewed to compare the conservation status, threats, and conservation actions needed for freshwater mussel species occurring in Mediterranean‐climate regions (med‐mussels) with those of other freshwater mussel species globally. The first comprehensive catalogue of med‐mussel species was compiled using existing taxonomic literature. There are 41 med‐mussel species, 30 of which occur in the Mediterranean basin. Many regions have just a single species, and regions where multiple species occur generally only have between one and four species per river basin. Med‐mussel species are almost twice as likely to be ‘Imperilled’, are affected by 2.4 times more threats, and require 3.5 times more conservation actions than non‐med mussels. In many cases, the exact threats have not been identified. In combination with low species richness, this level of imperilment means that Mediterranean‐climate regions are at risk of losing the benefits that mussels provide to broader ecosystem functioning. The conservation of med‐mussels can be improved by increasing our knowledge of species distributions, including the identification of cryptic species and significant management units, through population genetic work. In addition, recognizing the potential of ‘novel’ habitats and refuge areas could augment the management of this important functional group.
1. Like other Mediterranean regions, south-western Australia is predicted to experience an increase in temperature and drought conditions as a result of climate change, leading to altered species distributions. This study provides the first assessment of the effectiveness of the reserve system in Australia for conserving native freshwater fish by considering the congruence between protected areas and potential climate refugia in a global biodiversity hotspot.2. Using species distribution modelling, exposure to climate change was predicted for 13 native fish taxa, and priority areas (refugia) for fish conservation were identified by overlapping the present and future suitable climate envelopes of these taxa. Areas with climate refugia for >70% of the native freshwater fish fauna were recognized as 'coldspots'.3. Two taxa were predicted to lose all suitable climate in the region by 2080, and five other taxa were predicted to lose >80% of their area of suitable climate. A 'coldspot' was identified consisting of a core area where >80% of taxa were predicted to persist and a larger surrounding area where >70% of taxa were predicted to persist. 4. Although 93% of the core area of the coldspot is at present contained within the established protected areas network, only 26% of the surrounding area is contained within reserve boundaries. Future conservation actions, including the design and implementation of the protected area network, should take this coldspot into consideration.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.