Trophic redundancy reduces vulnerability to extinction cascades

Sanders, Dirk; Thébault, Élisa; Kehoe, Rachel; Veen, F. J. Frank van

doi:10.1073/pnas.1716825115

Cited by 120 publications

(96 citation statements)

References 37 publications

(48 reference statements)

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“…Generalist consumers can average variability in their resources (akin to the portfolio effect of Tilman et al (1998)) by rapidly responding to resource variability in space and time by shifting away from low-density resources and towards high density resources, impeding that variability from emanating throughout food webs (Valdovinos, Ramos-Jiliberto, Garay-Narváez, Urbani, & Dunne, 2010). This switching ability also increases trophic redundancy, which can prevent secondary extinctions (Borrvall, Ebenman, & Jonsson, 2000; Sanders, Thébault, Kehoe, & Frank van Veen, 2018). If a broad suite of organisms can make rapid, smart foraging responses to environmental change, they may accentuate the stabilizing effect of a single generalist module.…”

Section: Discussionmentioning

confidence: 99%

Multiple species drive flexible lake food webs with warming

Bartley

et al. 2018

Preprint

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Climate change is rewiring the food webs that determine the fate of diverse ecosystems. Mobile generalist consumers are responding to climate change by rapidly shifting their behaviour and foraging, driving food webs to flex. Although these responsive generalists form a key stabilizing module in food web structure, the extent to which they are present throughout whole food webs is largely unknown. Here, we show that multiple species comprising key trophic roles drive flexible lake food webs with warming. By examining lakes that span a 7°C air temperature gradient, we found significant reductions in nearshore derived carbon and nearshore habitat use with increased temperature in three of four fish species. We also found evidence that the response of lake trout to increased temperatures may reduce their biomass and cascade to release their preferred prey, the pelagic forage fish cisco. Our results suggest that climate warming will shift lake food webs toward increased reliance on offshore habitats and resources. We argue that species across trophic levels broadly couple lake macrohabitats, suggesting that potentially stabilizing responsive consumers are present throughout food webs. However, climate change appears to limit their ability to responsively forage, critically undermining a repeated stabilizing mechanism in food webs.

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Section: Discussionmentioning

confidence: 99%

Multiple species drive flexible lake food webs with warming

Bartley

et al. 2018

Preprint

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“…The isotopic niche breadth had no significant difference along the mixing period. Some studies have highlighted the importance of niche variation and trophic redundancy for the overall community stability across different ecosystems (Ojwang, Ojuok, Mbabazi, & Kaufman, 2010;Sanders, Thébault, Kehoe, & van Veen, 2018;Schwartz-Narbonne et al, 2019). Therefore, the highly conserved niche with low level of trophic redundancy (high MNND values) in the mixing period can enhance ecosystem resilience from the stratification periods.…”

Section: Body Size and Trophic Structure Variations Of Zooplankton mentioning

confidence: 99%

Responses of zooplankton body size and community trophic structure to temperature change in a subtropical reservoir

Gao

Chen

Govaert

et al. 2019

Ecology and Evolution

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Understanding the effects of global warming on trait variation and trophic structure is a crucial challenge in the 21st century. However, there is a lack of general patterns that can be used to predict trait variation and community trophic structure under the ongoing environmental change. We investigated the responses of body size and community trophic structure of zooplankton to climate related factors (e.g., temperature). Isotopic niche breadth was applied to investigate the community trophic structure across a 1‐year study from a subtropical reservoir (Tingxi Reservoir) in southeastern China. Body size and community isotopic niche breadth of zooplankton were larger during water mixing than stratification periods and correlated significantly with water temperature change along the time series. The contributions of intra‐ and intertaxonomic components to body size and community trophic structure variation showed significant relationships with the temperature change going from the mixing to stratification periods. Water temperature imposed direct effect on body size, while direct and indirect effect on the community trophic structure of zooplankton occurred through trophic redundancy along time series. Water temperature and community properties (e.g., body size, trophic redundancy, or trophic interaction) showed complex interactions and integrated to influence community trophic structure of zooplankton. Our results can expand the knowledge of how elevated temperature will alter individual trait and community trophic structure under future climate change.

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“…This aspect of stability, often described as "robustness," is important both from the perspective of managing anthropogenic change and in terms of understanding the fundamental stability of ecological communities. Since empirically testing how whole communities respond to extinctions can be difficult or impossible (although see Sanders, Thébault, Kehoe, and Frank van Veen (2018)), a number of studies have attempted to determine the properties that make ecological communities robust through simulation (Dunne & Williams, 2009;Säterberg, Sellman, & Ebenman, 2013). However, incorporating the acknowledged flexibility of ecological networks is a perennial challenge for such studies (Montoya, Pimm, & Solé, 2006).…”

Section: Introductionmentioning

confidence: 99%

Interaction modifications lead to greater robustness than pairwise non‐trophic effects in food webs

Terry

Morris

Bonsall

2019

Journal of Animal Ecology

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Considerable emphasis has been placed recently on the importance of incorporating non‐trophic effects into our understanding of ecological networks. Interaction modifications are well‐established as generating strong non‐trophic impacts by modulating the strength of interspecific interactions.For simplicity and comparison with direct interactions within a network context, the consequences of interaction modifications have often been described as direct pairwise interactions. The consequences of this assumption have not been examined in non‐equilibrium settings where unexpected consequences of interaction modifications are most likely.To test the distinct dynamic nature of these “higher‐order” effects, we directly compare, using dynamic simulations, the robustness to extinctions under perturbation of systems where interaction modifications are either explicitly modelled or represented by corresponding equivalent pairwise non‐trophic interactions.Full, multi‐species representations of interaction modifications resulted in a greater robustness to extinctions compared to equivalent pairwise effects. Explanations for this increased stability despite apparent greater dynamic complexity can be found in additional routes for dynamic feedbacks. Furthermore, interaction modifications changed the relative vulnerability of species to extinction from those trophically connected close to the perturbed species towards those receiving a large number of modifications.Future empirical and theoretical research into non‐trophic effects should distinguish interaction modifications from direct pairwise effects in order to maximize information about the system dynamics. Interaction modifications have the potential to shift expectations of species vulnerability based exclusively on trophic networks.

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Trophic redundancy reduces vulnerability to extinction cascades

Cited by 120 publications

References 37 publications

Multiple species drive flexible lake food webs with warming

Multiple species drive flexible lake food webs with warming

Responses of zooplankton body size and community trophic structure to temperature change in a subtropical reservoir

Interaction modifications lead to greater robustness than pairwise non‐trophic effects in food webs

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