Predation preference of signal crayfish (Pacifastacus leniusculus) on native and invasive bivalve species

Abstract

Predatory, non‐native fauna can influence biodiversity and trophic dynamics in invaded ecosystems. Signal crayfish (Pacifastacus leniusculus) are a highly successful invader, which have altered freshwater benthic communities, including bivalve populations. Bivalves are a keystone freshwater group in global in decline, partly due to invasion by alien bivalve and crayfish species. However, little is known about the predatory impacts of invasive crayfish within co‐occurring native and invasive bivalve populations. Mesocosm predation choice experiments considered relative signal crayfish predation rates between paired native (Anodonta anatina and Unio tumidus) and invasive (Dreissena polymorpha, D. bugensis, and Corbicula fluminea) bivalves, and between paired invasive bivalves. All bivalves were actively predated, but there was no consistent difference in the biomass of invasive versus native bivalves consumed. However, the effects of consumption were consistently different; 18.2% of invasive bivalves were lethally predated, with 100% of surviving individuals remaining undamaged, whereas 1.1% of native bivalves were lethally predated, but 100% of surviving individuals received nonlethal damage in the form of shell chipping, which could reduce long‐term bivalve fitness in natural environments. In experiments considering paired invasive species, D. polymorpha was more resistant to predation when compared to other invasive taxa tested. The majority of field research considering aquatic invasions considers purely lethal predation effects inferred from invertebrate presence/absence. These experiments demonstrate the need to better understand both the processes and impacts of predation by invasive species, which may include substantial nonlethal effects on the fitness and life history of endangered taxa.

The signal crayfish Pacifastacus leniusculus (Dana, 1852) (Crustacea, Decapoda) is threatening the near future of Margaritifera margaritifera Linnaeus, 1758 (Bivalvia, Unionoida) in the Negro River (NW Zamora, Spain)

“…The signal crayfish is the most common invasive aquatic species in Spain in the rivers of Castilla and León. Its negative effect on freshwater pearl mussels through predation has been observed in several rivers of the Duero River basin (Meira et al 2019 and elsewhere in Europe (Machida andAkiyama 2013, Sanders andMills 2022). Predation on FPM induces changes in their siphon-opening behavior, thus affecting their respiration, feeding and larval spawning, and eventually involves extraction of the FPM specimens from the substrate and lethal chewing.…”

Coexistence of Native and Invasive Freshwater Turtles: The Llobregat Delta (NE Iberian Peninsula) as a Case Study

“…It is currently considered one of the 100 most dangerous invasive species worldwide [74]. The invasive species causes predation [75][76][77], competition [78][79][80], hybridization [81][82][83] and disease transmission [84][85][86] against native species, with the consequent loss of biodiversity of native ecosystems [87][88][89][90].…”

Biological invasions in rivers and associated ecosystems: New insights, challenges, and methodological advancements

“…In this regard “Before‐After‐Control‐Impact” studies are particularly valuable as they enable a more realized extent of the factors associated with invasion to be evaluated (e.g., Guareschi et al, 2021; Mathers et al, 2020b). Second, the range of methodological techniques showcased by the papers highlights that tackling the challenges of biological invasions requires a combination of methods ranging from controlled experiments which may provide explicit evidence for small scale processes (e.g., Coughlan et al, 2022; Sanders & Mills, 2022), through to modelling approaches to gain a broadscale view of invasion dynamics (Larson et al, 2022; Maimela et al, 2022). Field studies which aim to investigate site specific / regional patterns provide in‐situ validation of theories and enable incorporation of potentially interacting and confounding factors to be considered (e.g., Blackman et al, 2022; Bolpagni & Dalla Vecchia, 2022; Mathers et al, 2022; Salgado et al, 2022).…”