Effects of nonnative species on the stability of riverine fish communities

Tibor Erős,Stefano Larsen,Julian D Olden,Katie Irving,Pablo A Tedesco,Xingli Giam,Ana Filipa Filipe,Claire Jacquet,Albert Ruhi,Marie‐Josée Fortin,Ulrich Brose,Lise Comte,Sapna Sharma

doi:10.1111/ecog.04985

Abstract

Despite the increasing ubiquity of biological invasions worldwide, little is known about the scale‐dependent effects of nonnative species on real‐world ecological dynamics. Here, using an extensive time series dataset of riverine fish communities across different biogeographic regions of the world, we assessed the effects of nonnative species on the temporal variability and synchrony in abundance at different organizational levels (population, metapopulation, community and metacommunity) and spatial scales (stream reach and river basin). At the reach scale, we found that populations of nonnative species were more variable over time than native species, and that this effect scaled up to the community level – significantly destabilizing the dynamics of riverine fish communities. Nonnative species not only contributed to reduced community stability, but also increased variability of native populations. By contrast, we found no effect of nonnative species dominance on local interspecific synchrony among native species. At the basin scale, nonnative metapopulations were again more variable than the native ones. However, neither native metapopulations nor metacommunities showed differences in temporal variability or synchrony as nonnative species dominance increased basin‐wide. This suggests a ‘dilution effect’ where the contribution to regional stability of local native populations from sites displaying low levels of invasion reduced the destabilizing effects of nonnative species. Overall, our results indicate that accounting for the destabilizing effect of nonnative species is critical to understanding native species persistence and community stability.

Highlights

Knowledge of the mechanisms controlling the stability of ecological communities is a long-standing challenge in ecology (MacArthur 1955, May 1972, Pimm 1984) and remains central to inform ecosystem management in a changing world (Tilman et al 2014, Wilcox et al 2017)
The contribution of individual species to community coefficient of variation (CV) was significantly lower for native species, indicating that these species tended to stabilize community dynamics more than nonnative species
We found that population CV, local interspecific synchrony and community CV were all significantly related to alpha diversity when considering the native species pool only (Table 1a–c)

Summary

Introduction

Knowledge of the mechanisms controlling the stability of ecological communities is a long-standing challenge in ecology (MacArthur 1955, May 1972, Pimm 1984) and remains central to inform ecosystem management in a changing world (Tilman et al 2014, Wilcox et al 2017). Studies on stream fish communities suggest, for example, that interactions between native and nonnative species can be more intense in hydrologically less variable streams and rivers (Moyle and Light 1996, Gido et al 2013) or within rivers in hydrologically stable flow periods, because nonnative species are less adapted to variable hydrologic conditions of the recipient habitat (Marchetti and Moyle 2001, Eby et al 2003). This may result in stronger asynchrony among different co-occurring species at the local scale, as well as across metapopulations at regional scales

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Results

Conclusion