The dynamics of spatially coupled food webs

McCann, Kevin S.; Rasmussen, Joseph B.; Umbanhowar, James

doi:10.1111/j.1461-0248.2005.00742.x

Cited by 571 publications

(681 citation statements)

References 62 publications

(125 reference statements)

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“…Consequently, niche specialisation at the population and individual levels resulting from strong interspecific and intraspecific resource competition, respectively, may significantly limit the coupling between benthic and pelagic food-web compartments by generalist fish species . Because of the possible role of top consumers as important regulators of food-web dynamics and stability (Post et al, 2000;McCann, Rasmussen & Umbanhowar, 2005;Rooney et al, 2006), generalist fish should be considered as heterogeneous rather than homogeneous sets of individuals, potentially with both specialised and generalist trophic niches Araú jo et al, 2011). Nevertheless, relatively few trophic studies of generalist fish species have focussed on niche variation and segregation at both the population and individual levels.…”

Section: Introductionmentioning

confidence: 99%

Seasonal and ontogenetic shifts in the diet of Arctic charr Salvelinus alpinus in a subarctic lake

Eloranta

Kahilainen

Jones

2010

Journal of Fish Biology

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Arctic charr (Salvelinus alpinus (L.)) is a cold-adapted salmonid fish with a wide circumpolar distribution. Due to its wide fundamental trophic niche (i.e. diet and habitat use), Arctic charr can be used to study energy flow as well as competitive and predator-prey interactions in subarctic lakes. The objective of this thesis was to evaluate how the trophic niche of Arctic charr in subarctic lakes is influenced by various biotic (e.g. intra-and interspecific resource competition and predation) and abiotic (e.g. seasonality and lake morphometry) factors. Stomach contents and stable isotope analyses indicated marked between-lake and between-individual differences in Arctic charr diet and habitat use. In Saanajärvi, Arctic charr relied mainly on littoral production regardless of season or individual size, probably due to high primary production and lack of sympatric fish species in the littoral zone. In contrast, Arctic charr showed a reduced littoral reliance when the littoral trophic niche was dominated by brown trout, and an increased prevalence of piscivorous foraging when coexisting with planktivorous whitefish and benthivorous grayling. The final results from a total of 17 subarctic lakes indicated that Arctic charr shifted from littoral to a more pelagic trophic niche with increasing lake area and fish species richness. The shift of Arctic charr to a more pelagic piscivorous niche in large lakes was evidently promoted by the existence of small, planktivorous prey fish species and increased interspecific resource competition and/or predation in the littoral zone. The results demonstrate that littoral and pelagic food-web compartments in subarctic lakes can be integrated by generalist Arctic charr, but the energy flow pathways supporting this top consumer can be strongly influenced by prevailing intra-and interspecific interactions as well as by the morphometric characteristics of the lakes. The findings highlight that a comprehensive view of food-web structures is fundamental for predicting the likely responses of fish communities and subarctic lake ecosystems to potential environmental changes. Keywords: Energy flow; individual specialization; lake morphometry; littoral production; resource competition; stable isotope analysis; trophic niche. LIST OF ORIGINAL PUBLICATIONSThe thesis is based on the following original articles, which will be referred to in the text by their Roman numerals I-IV. I did most of the planning for each study and contributed to field work in I, III and IV, and to laboratory analyses in all the studies. I was responsible for the data analysis and wrote the first draft of all the papers. All co-authors made a significant contribution to planning and preparation of the final papers. IV Eloranta A.P., Kahilainen K.K., Amundsen P.-A., Knudsen R., Harrod C. & Jones R.I. 2013. Lake size and fish species richness determine resource use by top consumers in subarctic lakes. Manuscript. INTRODUCTION Food webs in lakesLakes are complex ecosystems, whose functioning is tightly connecte...

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Section: Introductionmentioning

confidence: 99%

Seasonal and ontogenetic shifts in the diet of Arctic charr Salvelinus alpinus in a subarctic lake

Eloranta

Kahilainen

Jones

2010

Journal of Fish Biology

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“…9). Recently, ecologists have begun to recognize that important stabilizing structures likely materialize under nonequilibrium conditions (9)(10)(11)(12)(13)(14)(15)(16). Arguably, one of the main mechanisms for stability under such dynamic conditions is the tendency for complex systems to adapt to changing conditions (11,17).…”

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confidence: 99%

Fluctuations in density of an outbreak species drive diversity cascades in food webs

Eveleigh

McCann

McCarthy

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

185

253

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Patterns in food-web structure have frequently been examined in static food webs, but few studies have attempted to delineate patterns that materialize in food webs under nonequilibrium conditions. Here, using one of nature's classical nonequilibrium systems as the food-web database, we test the major assumptions of recent advances in food-web theory. We show that a complex web of interactions between insect herbivores and their natural enemies displays significant architectural flexibility over a large fluctuation in the natural abundance of the major herbivore, the spruce budworm ( Choristoneura fumiferana ). Importantly, this flexibility operates precisely in the manner predicted by recent foraging-based food-web theories: higher-order mobile generalists respond rapidly in time and space by converging on areas of increasing prey abundance. This “birdfeeder effect” operates such that increasing budworm densities correspond to a cascade of increasing diversity and food-web complexity. Thus, by integrating foraging theory with food-web ecology and analyzing a long-term, natural data set coupled with manipulative field experiments, we are able to show that food-web structure varies in a predictable manner. Furthermore, both recent food-web theory and longstanding foraging theory suggest that this very same food-web flexibility ought to be a potent stabilizing mechanism. Interestingly, we find that this food-web flexibility tends to be greater in heterogeneous than in homogeneous forest plots. Because our results provide a plausible mechanism for boreal forest effects on populations of forest insect pests, they have implications for forest and pest management practices.

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“…However, little work so far has analysed stochastic food web dynamics in association with adaptive behaviour. The only example we know of is given by McCann et al (2005), who introduced white, uncorrelated noise in resource carrying capacities in quad-trophic food webs with diet switching. When a top predator selected between the top consumers in two distinct food webs, increasingly balanced consumption (i.e., stronger coupling between the food webs by the top predator) promoted stability at the level of the entire system .…”

Section: Adaptive Consumer Behaviour In Noisy Environmentsmentioning

confidence: 99%

“…Dynamic coupling of distinct food chains by an actively foraging top predator is regarded as important for community stability (e.g., Abrams, 2000;McCann et al, 2005;Rooney et al, 2008;Teng and McCann, 2004). This means that mobile predators can integrate over disparate energy sources (Vander Zanden and Vadeboncoeur, 2002), and pursue relatively more abundant prey while decoupling from scarce prey (McCann and Rooney, 2009).…”

Section: Introductionmentioning

confidence: 99%

Environmental weakening of trophic interactions drives stability in stochastic food webs

Ruokolainen

McCann

2013

Journal of Theoretical Biology

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A 3-species food web model is analysed, with stochastic variation in parameters. Noise affects either resource growth or consumer intake as a Gaussian function. Noise variance, colour, and the consumers foraging adaptation rate is varied. Environmental characteristics impact on the consumer-resource interaction strength. Noise impact on population variability depends on where it hits in the food web. a r t i c l e i n f o t r a c tThe physiological performance and behaviour of organisms are contingent on environmental conditions. When these conditions vary over time, this can have important consequences for the dynamics of individual populations and entire species communities. While the importance of environmental variation on the structuring and stability of natural food webs is recognised, little work has been done so far to build up a theoretical understanding of these processes. Here we investigate a simple model food web, where a consumer species forages flexibly upon two distinct, inter-competing resource species. Resource productivities or the resource intake rates by the consumer are assumed to depend on environmental conditions in a realistic manner. Fluctuations in these parameters drive variation in the strength of consumer-resource interactions, depending on whether the resource or the consumer is sensitive to environmental noise. The way resources and the consumer respond to changes in environmental conditions stems from the deterministic influence of each stochastic parameter on food web dynamics, which interact with the consumer adaptation process as well as between-resource competition. According to recent empirical reports, the mechanisms behind our results are likely to be relevant in natural systems and thus the model predictions are of potential importance in understanding food web responses to environmental stochasticity in general.

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The dynamics of spatially coupled food webs

Cited by 571 publications

References 62 publications

Seasonal and ontogenetic shifts in the diet of Arctic charr Salvelinus alpinus in a subarctic lake

Seasonal and ontogenetic shifts in the diet of Arctic charr Salvelinus alpinus in a subarctic lake

Fluctuations in density of an outbreak species drive diversity cascades in food webs

Environmental weakening of trophic interactions drives stability in stochastic food webs

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