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

Abstract

1. 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.2. In this study, carbon (δ 13 C: 13 C/ 12 C) and nitrogen (δ 15 N: 15 N/ 14 N) 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).3. 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. 4. 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.Ester Dias has equal contribution as first author.

Identifying potential drivers of distribution patterns of invasive Corbicula fluminea relative to native freshwater mussels (Unionidae) across spatial scales

“…Whereas all models were improvements over the null model, the best supported one included the full set of abiotic and biotic factors, suggesting that native mussels and Corbicula occupy similar stream habitats. This is contrary to our expectations that native mussels and Corbicula would limit each other's distribution as predicted by limiting similarity hypothesis (Macarthur & Levins, 1967) and previous works showing negative interactions (Ferreira‐Rodríguez, Fandiño, et al, 2018; Ferreira‐Rodríguez, Sousa, et al, 2018; Modesto et al, 2019, 2021; Vaughn & Spooner, 2006a). Thus, suggesting that niche requirements in these contemporary river habitats may not be limiting to either group or other mechanisms, such as positive interactions, may be at play (Silknetter et al, 2020).…”

“…Freshwater habitats of the Anthropocene are characterized by excessive nutrient loads due to difficulties managing non‐point source pollution inputs (e.g., fertilizer runoff) and may affect species interactions (Strayer, 2014). Studies of the trophic niche of Corbicula often conclude that it is highly flexible and overlaps with the trophic niche of native mussel species, but the extent varies with ecological context (Atkinson et al, 2010; Modesto et al, 2021), and such flexibility can facilitate invasion success (Moyle & Light, 1996; Olsson et al, 2009). We anticipated that nutrient loading would increase quality (increased nutrient content) and quantity of particulate food sources, alleviating competition for food resources between Corbicula and mussels, thereby allowing co‐occurrence.…”

Effects of the Filter-Feeding Benthic Bivalve Corbicula fluminea on Plankton Community and Water Quality in Aquatic Ecosystems: A Mesocosm Study

“…Contrary to our initial hypothesis, C. fluminea did not reduce TN and TP levels in the water, but led to an increase in NO 3 − -N concentrations. C. fluminea can feed on phytoplankton and suspended particulate matter from the water column [53][54][55]. Their ability to reduce suspended particulate matter and phytoplankton biomass in the water column has long been recorded [56][57][58][59][60].…”

Joint species distribution models unveil co‐occurrences between freshwater mussels and their fish hosts

“…Occurrence records for mussel and fish species in the Douro River basin were obtained in three annual campaigns in June 2017, 2018, and 2019 and complemented with data from primary literature and technical reports (e.g., Dias et al, 2020; Modesto et al, 2021). During the field surveys, fish and mussel assemblages were sampled at the same sites and simultaneously.…”