Combining food web theory and population dynamics to assess the impact of invasive species

Abstract

The impacts of invasive species on resident communities are driven by a tangle of ecological interactions difficult to quantify empirically. Combining a niche model with a population dynamic model, both allometrically parametrized, may represent a consistent framework to investigate invasive species impacts on resident communities in a food web context when empirical data are scarce. We used this framework to assess the ecological consequences of an invasive apex predator (Silurus glanis) in peri-Alpine lake food webs. Both increases and decreases of resident species abundances were highlighted and differed when accounting for different S. glanis body sizes. Complementarily, the prominence of indirect effects, such as trophic cascades, suggested that common approaches may only capture a restricted fraction of invasion consequences through direct predation or competition. By leveraging widely available biodiversity data, our approach may provide relevant insights for a comprehensive assessment and management of invasive species impacts on aquatic ecosystems.

Species traits and community structure can drive large-scale spatial propagation of effects in ecosystems

“…Quantifying the biotic effects of species and their spatial signature are paramount to understanding and predicting spatial ecological dynamics within (Morris et al ., 2005) and across habitats (Frost et al ., 2016). The propagation of direct and indirect effects is also particularly relevant for understanding the effects of invasive species (Vagnon et al ., 2022), changing species distributions and disease spread in ecosystems (Tompkins et al ., 2011). Here we used tools from network theory and statistical physics to show that the spatial structure of biotic interactions and dispersal can be used to approximate the spread of direct and indirect effects.…”

Les grands lacs

“…Surtout présent dans le « Petit-Lac » (partie proche de Genève, représentant environ 6 % de la surface totale), des captures dans les autres zones du lac sont de moins en moins anecdotiques (Vagnon et al, 2022b). Il exerce principalement une prédation sur des proies littorales (l'écrevisse Orconectes limosus, le gardon Rutilus rutilus et la perche Perca fluviatilis), mais est aussi susceptible d'utiliser d'autres ressources comme le corégone (Coregonus lavaretus) en fonction des stades de vie de ce dernier (Vagnon et al, 2022c). Pour le moment, les impacts de ce poisson se cantonnent au niveau des usages pour la pêche amateur et de la perception du lac.…”

On the limits to invasion prediction using coexistence outcomes

“…As an alternative, the majority of experimental work has focused on performing simultaneous assemblages (Friedman et al, 2017, Gould et al, 2018). Therefore, it has become central to understand the extent to which the outcomes (e.g., individual survival, community persistence, competitor exclusion) from such simultaneous processes can be translated into analogous outcomes (e.g., invader colonization, invader-resident augmentation, resident replacement) expected from sequential processes (Case, 1990, Fukami, 2015, Hubbell, 1997, Vagnon et al, 2022).…”

“…Similarly, in the field, it becomes easier to record coexistence (or co-occurrence) outcomes rather than invasion outcomes (Barner et al, 2018). Therefore, it has become central to understand the extent to which the outcomes (e.g., individual survival, community persistence, competitor exclusion) of coexistence dynamics can be used to predict analogous outcomes (e.g., invader colonization, invader-resident augmentation, resident replacement) expected from invasion dynamics (Case, 1990, Fukami, 2015, Hubbell, 1997, Vagnon et al, 2022).…”