Novo: Impacts of the invasive species Corbicula fluminea on native freshwater mussels Antigo: Can freshwater bivalves be used as a biofilter

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Interspecific differences in the physiological condition of native freshwater mussels in response to the invasive Asian clam Corbicula fluminea

Publication . Modesto, Vanessa; Ilarri, Martina; Castro, Paulo S.; Carvalho, Francisco; Cavalheri, Thais; Lopes-Lima, Manuel; Teixeira, Amílcar; Ozório, Rodrigo O.A.; Antunes, Carlos; Sousa, Ronaldo

The Asian clam Corbicula fluminea has been widely introduced into aquatic ecosystems and may impact the physiological condition and survival of native freshwater mussels. However, very few studies have evaluated this issue quantitatively. To fill this gap, manipulative field experiments were performed to assess two possible mechanisms of impact on native mussels: (i) interspecific interactions, and (ii) C. fluminea die-offs. We assessed these effects by measuring the physiological condition through the analysis of glycogen content in the foot tissue of the native freshwater mussel species Anodonta anatina, Potomida littoralis, and Unio delphinus. Although with interspecific differences, our results suggest that C. fluminea can impact the physiological condition of native freshwater mussels. Anodonta anatina showed positive significant variations on glycogen content when subjected to high densities of live C. fluminea in contrast to the other native species studied, P. littoralis and U. delphinus, where no significances were observed. On the other hand, these native species do not seem be significantly impacted by the decomposition of C. fluminea resulting from a die-off. Overall, and contrary to our expectations, both experiments showed a positive (or no) effect of C. fluminea on the physiological condition of the three freshwater mussel species.

2023Journal article

Restricted access

Trophic niche overlap between native freshwater mussels (Order: Unionida) and the invasive Corbicula fluminea

Publication . Modesto, Vanessa; Dias, Ester; Ilarri, Martina; Lopes-Lima, Manuel; Teixeira, Amílcar; Varandas, Simone; Castro, Paulo S.; Antunes, Carlos; Sousa, Ronaldo

Freshwater mussels (Order Unionida) are highly threatened. Interspecific competition for food sources with invasive alien species is considered to be one of the factors responsible for their decline because successful invaders are expected to have wider trophic niches and more flexible feeding strategies than their native counterparts. In this study, carbon (δ13C: 13C/12C) and nitrogen (δ15N: 15N/14N) stable isotopes were used to investigate the trophic niche overlap between the native freshwater mussel species, Anodonta anatina, Potomida littoralis, and Unio delphinus, and the invasive bivalve Corbicula fluminea living in sympatry in the Tua basin (south-west Europe). The species presenting the widest trophic niches were C. fluminea and A. anatina, which indicate that they have broader diets than U. delphinus and P. littoralis. Nonetheless, all the species assimilated microphytobenthos, sediment organic matter, and detritus derived from vascular plants, although with interspecific variability in the assimilated proportions of each source. The trophic niche of the invasive species overlapped with the trophic niche of all the native species, with the extent varying between sites and according to the species. From the three native species analysed, Potomida littoralis may be at a higher risk for competition for food with C. fluminea in the Tua basin, if food sources become limited, because this native mussel presented the narrowest trophic niche across sites and the highest probability of overlapping with the trophic niche of C. fluminea. Given the global widespread distribution of C. fluminea, the implementation of management measures devoted to the control or even eradication of this invasive alien species should be a conservation priority given its potential for competition with highly threatened native freshwater mussels.

2021Journal article

Open access