Artificial habitats provide refuge for a threatened freshwater mussel in south-western Australia

Context Worldwide modifications of river systems, closely tied to human development, has led to a proliferation of artificial waterbodies. Their associated artificial habitats can support various aquatic taxa, including freshwater mussels, one of the most threatened animal groups worldwide. An endemic threatened species of freshwater mussel (Westralunio carteri) has been sporadically observed in artificial habitats across south-western Australia. However, the viability of these populations remains understudied. Aims This study aimed to compare the abundance and demographic structure of W. carteri across artificial and natural habitats to determine how artificial habitats may support viable populations of W. carteri. Methods Data from 12 habitats, (six artificial and six natural) were analysed to determine density and demographic structure. Key results Four of the six artificial habitats supported large populations with varied demography and evidence of recruitment. Both artificial and natural showed some impaired, non-recruiting populations at risk of extirpation. Overall, mussel demographics differed between artificial and natural habitats, with a broader size range observed in populations from natural habitats (8.0–92.0 mm) than from artificial habitats (23.1–84.7 mm). Conclusions This study provides evidence that W. carteri can successfully colonise and persist in artificial habitats, particularly when conditions are representative of analogous natural refuges. Artificial habitats likely provide a supplementary tool for the conservation of mussel populations experiencing habitat degradation and loss. Implications Artificial habitats can provide viable refuge for W. carteri. However, poor management practices and a lack of environmental protection means artificial habitas are often prone to further impairment, undermining their value as conservation tools.