No detectable trophic cascade in a high-Arctic arthropod food web

Visakorpi, Kristiina; Wirta, Helena; Ek, Malin; Schmidt, Niels Martin; Roslin, Tomas

doi:10.1016/j.baae.2015.06.003

Cited by 13 publications

(16 citation statements)

References 31 publications

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“…S3) that birds will at least sometimes consume spiders and lepidopteran parasitoids, spiders will eat other spider species, and both birds and spiders will feed on other predatory taxa (see the complete matrix of trophic interactions detailed in Table S1). Intraspecific predation is common in spiders and has often been observed within the species studied here (Visakorpi et al, 2015; Appendix S1, Fig. S3).…”

Section: A Densely Linked Arctic Food Webmentioning

confidence: 72%

“…Adding to dietary plasticity within the arctic community is the scope for cannibalism among the spiders as a key predator guild. While our current methods fall short of accurately resolving either inter-or intraguild predation among predators (Appendix S1), we know from both field observations (Visakorpi et al, 2015) and stray records obtained in the current study (Appendix S1, Fig. S3) that birds will at least sometimes consume spiders and lepidopteran parasitoids, spiders will eat other spider species, and both birds and spiders will feed on other predatory taxa (see the complete matrix of trophic interactions detailed in Table S1).…”

Section: A Densely Linked Arctic Food Webmentioning

confidence: 96%

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Exposing the structure of an Arctic food web

Wirta

Vesterinen

Hambäck

et al. 2015

Ecology and Evolution

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106

125

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How food webs are structured has major implications for their stability and dynamics. While poorly studied to date, arctic food webs are commonly assumed to be simple in structure, with few links per species. If this is the case, then different parts of the web may be weakly connected to each other, with populations and species united by only a low number of links. We provide the first highly resolved description of trophic link structure for a large part of a high-arctic food web. For this purpose, we apply a combination of recent techniques to describing the links between three predator guilds (insectivorous birds, spiders, and lepidopteran parasitoids) and their two dominant prey orders (Diptera and Lepidoptera). The resultant web shows a dense link structure and no compartmentalization or modularity across the three predator guilds. Thus, both individual predators and predator guilds tap heavily into the prey community of each other, offering versatile scope for indirect interactions across different parts of the web. The current description of a first but single arctic web may serve as a benchmark toward which to gauge future webs resolved by similar techniques. Targeting an unusual breadth of predator guilds, and relying on techniques with a high resolution, it suggests that species in this web are closely connected. Thus, our findings call for similar explorations of link structure across multiple guilds in both arctic and other webs. From an applied perspective, our description of an arctic web suggests new avenues for understanding how arctic food webs are built and function and of how they respond to current climate change. It suggests that to comprehend the community-level consequences of rapid arctic warming, we should turn from analyses of populations, population pairs, and isolated predator–prey interactions to considering the full set of interacting species.

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Section: A Densely Linked Arctic Food Webmentioning

confidence: 72%

Section: A Densely Linked Arctic Food Webmentioning

confidence: 96%

Exposing the structure of an Arctic food web

Wirta

Vesterinen

Hambäck

et al. 2015

Ecology and Evolution

Self Cite

106

125

View full text Add to dashboard Cite

show abstract

“…2) may however also cause resilience/resistance (as impacts onto the interaction web are diluted through its many channels) (Strong 1992; Bartomeus et al 2013). An illustration of this was provided by the experimental study by Visakorpi et al (2015). While predicting pronounced trophic cascades in the presumptively simple food webs of the Arctic, they expected that the removal of predators would enhance herbivory by increasing the number of herbivores, and that an increase in predator species would come with the opposite effect.…”

Section: Tolerance Towards Loss Gain or Change In The Relative Abunmentioning

confidence: 98%

“…While it is clear that in the tundra biome, birds depend on the arthropods, the impact of bird predation on the arctic arthropod community has not yet been thoroughly evaluated (e.g. Appendix B in Visakorpi et al 2015). …”

Section: Arctic Birds Depend On Their Arthropod Preymentioning

confidence: 99%

Interaction webs in arctic ecosystems: Determinants of arctic change?

Schmidt

Hardwick

Gilg

et al. 2017

Ambio

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How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they vary in time, and how they are changing with current environmental change: firstly, the high arctic interaction webs are much more complex than previously envisaged, and with a structure mainly dictated by its arthropod component. Secondly, the dynamics of species within these webs reflect changes in environmental conditions. Thirdly, biotic interactions within a trophic level may affect other trophic levels, in some cases ultimately affecting land–atmosphere feedbacks. Finally, differential responses to environmental change may decouple interacting species. These insights form Zackenberg emphasize that the combination of long-term, ecosystem-based monitoring, and targeted research projects offers the most fruitful basis for understanding and predicting the future of arctic ecosystems.

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“…, Fahimipour and Anderson , Visakorpi et al. ), compared to those typically induced by predators (Shurin et al. ), are not uncommon and provide support to the intuitive hypothesis that omnivory precludes strong trophic cascades.…”

Section: Introductionmentioning

confidence: 60%

Omnivory does not preclude strong trophic cascades

2019

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Omnivory has been cited as an explanation for why trophic cascades are weak in many ecosystems, but empirical support for this prediction is equivocal. Compared to predators that feed only on herbivores, top omnivores—species that feed on both herbivores and primary producers—have been observed generating cascades ranging from strong to moderate, null, and negative. To gain intuition about the sensitivity of cascades to omnivory, we analyzed models describing systems with top omnivores that display either fixed or flexible diets, two foraging strategies that are supported by empirical observations. We identified regions of parameter space, wherein omnivores following a fixed foraging strategy, with herbivores and producers comprising a constant proportion of the diet, non‐intuitively generate stronger cascades than predators that are otherwise demographically identical: (1) high productivity relative to herbivore mortality and (2) small discrepancies in producer vs. herbivore reward create conditions in which cascades are stronger with moderate omnivory. In contrast, flexible omnivores that attempt to optimize per capita growth rates during search never induce cascades that are stronger than the case of predators. Although we focus on simple models, the consistency of these general patterns together with prior empirical evidence suggests that omnivores should not be uniformly ruled out as agents of strong trophic cascades.

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No detectable trophic cascade in a high-Arctic arthropod food web

Cited by 13 publications

References 31 publications

Exposing the structure of an Arctic food web

Exposing the structure of an Arctic food web

Interaction webs in arctic ecosystems: Determinants of arctic change?

Omnivory does not preclude strong trophic cascades

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