Non‐native Chinese mystery snail (Bellamya chinensis) supports consumers in urban lake food webs

Abstract

Non‐native species are widely regarded as threats to ecosystem structure and function; however, these species may also provide benefits to ecosystems that have lost former functions to environmental degradation. This study evaluated whether non‐native species provide prey resources or induce trophic cul‐de‐sacs (by diverting basal energy away from higher trophic levels) in developed ecosystems where native prey are in decline. We used stable isotopes of 13C, 15N, and 2H to assess whether non‐native Chinese Mystery snail (Bellamya chinensis) provides a prey resource to consumers, and maintains the integration of benthic resources into food webs of lakes subjected to lakeshore development. Regardless of Bellamya presence, consumers in undeveloped lakes were supported primarily by benthic resources, and lakeshore development dramatically reduced consumer reliance on these resources. This was at least partly due to a reduction in the availability of native snails, a high‐quality prey item, to the dominant littoral consumer, molluscivorous pumpkinseed sunfish (Lepomis gibbosus). In developed lakes with non‐native Bellamya, generalist yellow perch (Perca flavescens) and piscivorous largemouth bass (Micropterus salmoides) consumed benthic resources in proportions similar to undeveloped lakes, and pumpkinseed sunfish consumed Bellamya in higher proportions than in undeveloped lakes. Thus, Bellamya provided a prey substitute in developed lakes where native snail populations were depressed; and Bellamya's influence extended to higher trophic‐level consumers. Our study provides evidence that non‐native species can ameliorate some effects of environmental degradation, and we suggest that future research considers how the effects of non‐native species, either positive or negative, may vary across human‐modified landscapes.

Emerging threats and persistent conservation challenges for freshwater biodiversity

“…Invasive species have inflicted profoundly damaging effects on recipient freshwater ecosystems (Gallardo et al ., ). However, it must not be ignored that some non‐native species can now play important ecological roles in human‐altered environments, such as supporting lake food webs (Twardochleb & Olden, ) and riverine ecosystem functions (Moore & Olden, ). Species have been repeatedly and deliberately introduced outside their native ranges with the aim to support food security, recreation opportunities and ecosystem rehabilitation.…”

Response diversity, nonnative species, and disassembly rules buffer freshwater ecosystem processes from anthropogenic change

“…Our simulations found that ecoregions with more nonnative fishes were more resistant to land development impacts on nutrient excretion. These results provide new evidence of the potential important contribution of nonnative species to ecosystem processes in a changing world (Schlaepfer et al ., ; Gribben et al ., ; Twardochleb & Olden, ).…”

“…By contrast, ecosystem processes in communities with low response diversity and limited redundancy may decline precipitously with degradation. Through contributing to this response diversity, nonnative species likely play an important, yet underappreciated and rarely quantified role in maintaining ecosystem processes in the face of environmental change (Schlaepfer et al, 2011;Bertness & Coverdale, 2013;Lagrue et al, 2014;Twardochleb & Olden, 2016). Second, disassembly rules describing the relationship between the sensitivity of a species (response) and its contribution to ecosystem function (effect) can control the resistance of ecosystems to environmental change (Solan et al, 2004;Bunker et al, 2005;Gross & Cardinale, 2005;McIntyre et al, 2007;Zavaleta et al, 2009).…”

A review of the non-indigenous Chinese mystery snail, Cipangopaludina chinensis (Viviparidae), in North America, with emphasis on occurrence in Canada and the potential impact on indigenous aquatic species

“…The larger shell size likely enables non-indigenous C. chinensis to avoid some predators that otherwise feed on aquatic North American gastropods (e.g. Yellow Perch, Perca flavescens) (Twardochleb & Olden 2016).…”