Non‐random food‐web assembly at habitat edges increases connectivity and functional redundancy

Peralta, Guadalupe; Frost, Carol M.; Didham, Raphaël K.; Rand, Tatyana A.; Tylianakis, Jason M.

doi:10.1002/ecy.1656

Cited by 17 publications

(12 citation statements)

References 56 publications

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“…Weighted metrics are often preferred as descriptors of network structure because the additional information that they incorporate better encompasses the complexities of species interactions (Banašek‐Richter et al., ; Bersier et al., ). Many studies use weighted metrics based on the assumption that these are less biased when networks are under‐sampled (e.g., Gagic et al., ; Peralta, Frost, Didham, Rand, & Tylianakis, ). However, as shown here and elsewhere (e.g., Costa et al., ; Fründ et al., ), this may not always be the case.…”

Section: Discussionmentioning

confidence: 99%

The effect of network size and sampling completeness in depauperate networks

Henriksen

Chapple

Chown

et al. 2018

Journal of Animal Ecology

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The accurate estimation of interaction network structure is essential for understanding network stability and function. A growing number of studies evaluate under‐sampling as the degree of sampling completeness (proportional richness observed). How the relationship between network structural metrics and sampling completeness varies across networks of different sizes remains unclear, but this relationship has implications for the within‐ and between‐system comparability of network structure. Here, we test the combined effects of network size and sampling completeness on the structure of spatially distinct networks (i.e., subwebs) in a host–parasitoid model system to better understand the within‐system variability in metric bias. Richness estimates were used to quantify a gradient of sampling completeness of species and interactions across randomly subsampled subwebs. The combined impacts of network size and sampling completeness on the estimated values of twelve unweighted and weighted network metrics were tested. The robustness of network metrics to under‐sampling was strongly related to network size, and sampling completeness of interactions were generally a better predictor of metric bias than sampling completeness of species. Weighted metrics often performed better than unweighted metrics at low sampling completeness; however, this was mainly evident at large rather than small subweb size. These outcomes highlight the significance of under‐sampling for the comparability of both unweighted and weighted network metrics when networks are small and vary in size. This has implications for within‐system comparability of species‐poor networks and, more generally, reveals problems with under‐sampling ecological networks that may otherwise be difficult to detect in species‐rich networks. To mitigate the impacts of under‐sampling, more careful considerations of system‐specific variation in metric bias are needed.

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Section: Discussionmentioning

confidence: 99%

The effect of network size and sampling completeness in depauperate networks

Henriksen

Chapple

Chown

et al. 2018

Journal of Animal Ecology

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“…Ecological networks provide a means of understanding how management practices or perturbations can percolate through ecological communities (Harvey et al 2017) by outlining the characteristics of key species necessary for community functioning in, for example, fragmented landscapes (Hagen et al 2012;Grass et al 2018;Emer et al 2018). Broadening the approach to other multi-habitat landscapes and increasing the spatial scale of network studies captures more species and interactions (Galiana et al 2018), with habitat diversity generating novel architectures (Pillai et al 2011;Peralta et al 2017). Species dynamically link networks in different adjacent habitats (McCann et al 2005;Frost et al 2016), and identifying key species could illuminate how ecological communities might respond to alterations in landscape structure and habitat diversity (Montoya et al 2012;Evans et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Reshaping our understanding of species’ roles in landscape‐scale networks

et al. 2019

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In network ecology, landscape‐scale processes are often overlooked, yet there is increasing evidence that species and interactions spill over between habitats, calling for further study of interhabitat dependencies. Here, we investigate how species connect a mosaic of habitats based on the spatial variation of their mutualistic and antagonistic interactions using two multilayer networks, combining pollination, herbivory and parasitism in the UK and New Zealand. Developing novel methods of network analysis for landscape‐scale ecological networks, we discovered that few plant and pollinator species acted as connectors or hubs, both within and among habitats, whereas herbivores and parasitoids typically have more peripheral network roles. Insect species’ roles depend on factors other than just the abundance of taxa in the lower trophic level, exemplified by larger Hymenoptera connecting networks of different habitats and insects relying on different resources across different habitats. Our findings provide a broader perspective for landscape‐scale management and ecological community conservation.

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“…These generalist filter‐feeding invertebrates can undergo strong rewiring between states, persist in their centrality role in the network of fluxes by interacting with nodes belonging to different modules that permit to switch (Figure ). A similar relationship between trophic performances and system organization is found in forest soils: Therein, generalist invertebrates show a highly redundant network position at habitat edges and this allows extensive rewiring of interaction networks based on a nonrandom, apparently adaptive, dynamics (Peralta, Frost, Didham, Rand, & Tylianakis, ). In the course of green‐blue transitions in GoN plankton community (D'Alelio, Libralato, et al, ), Appendicularia can feed in the main energetic module of the food web, including either surface or deep unicellular nodes, based on their relative availability: To this respect, Appendicularia may behave as “couplers” sensu Rooney et al () (Figure c).…”

Section: Discussionmentioning

confidence: 66%

Rewiring and indirect effects underpin modularity reshuffling in a marine food web under environmental shifts

D’Alelio

Mele

Libralato

et al. 2019

Ecology and Evolution

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Species are characterized by physiological and behavioral plasticity, which is part of their response to environmental shifts. Nonetheless, the collective response of ecological communities to environmental shifts cannot be predicted from the simple sum of individual species responses, since co‐existing species are deeply entangled in interaction networks, such as food webs. For these reasons, the relation between environmental forcing and the structure of food webs is an open problem in ecology. To this respect, one of the main problems in community ecology is defining the role each species plays in shaping community structure, such as by promoting the subdivision of food webs in modules—that is, aggregates composed of species that more frequently interact—which are reported as community stabilizers.In this study, we investigated the relationship between species roles and network modularity under environmental shifts in a highly resolved food web, that is, a “weighted” ecological network reproducing carbon flows among marine planktonic species. Measuring network properties and estimating weighted modularity, we show that species have distinct roles, which differentially affect modularity and mediate structural modifications, such as modules reconfiguration, induced by environmental shifts.Specifically, short‐term environmental changes impact the abundance of planktonic primary producers; this affects their consumers’ behavior and cascades into the overall rearrangement of trophic links. Food web re‐adjustments are both direct, through the rewiring of trophic‐interaction networks, and indirect, with the reconfiguration of trophic cascades. Through such “systemic behavior,” that is, the way the food web acts as a whole, defined by the interactions among its parts, the planktonic food web undergoes a substantial rewiring while keeping almost the same global flow to upper trophic levels, and energetic hierarchy is maintained despite environmental shifts. This behavior suggests the potentially high resilience of plankton networks, such as food webs, to dramatic environmental changes, such as those provoked by global change.

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Non‐random food‐web assembly at habitat edges increases connectivity and functional redundancy

Cited by 17 publications

References 56 publications

The effect of network size and sampling completeness in depauperate networks

The effect of network size and sampling completeness in depauperate networks

Reshaping our understanding of species’ roles in landscape‐scale networks

Rewiring and indirect effects underpin modularity reshuffling in a marine food web under environmental shifts

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