Omnivory and stability of food webs

Namba, Tsunehisa; Tanabe, Kumi; Maeda, Naomi

doi:10.1016/j.ecocom.2008.02.001

Cited by 82 publications

(59 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, in this model the IG prey was more efficient at consuming the basal resource. Adding a fourth species to the model that consumed only the IG prey greatly stabilized the food web dynamics (Namba et al 2008). These two studies show generally, that the presence of a top predator in the system can stabilize otherwise unstable dynamics, provided it feeds preferentially on the more efficient competitor for the basal resource.…”

Section: Broader Food Web Contextmentioning

confidence: 78%

Stability and persistence of food webs with omnivory: Is there a general pattern?

et al. 2012

View full text Add to dashboard Cite

Abstract. The relationship between omnivory and stability has been the subject of a longstanding debate in ecology. Early theory predicted that omnivory would decrease the probability of food webs being stable. While early empirical data appeared to support the prediction that omnivory should be rare, detailed study of food webs later revealed that omnivory is ubiquitous across ecosystems and taxa. Recent years have seen renewed interest in the omnivory-stability debate, and advances in mechanistic non-equilibrium models demonstrated that omnivory can both increase and decrease stability. Current efforts have therefore focused on identifying biological mechanisms that promote the persistence of food webs with omnivory. We synthesize recent evidence that omnivory often stabilizes food webs when it occurs as life-history omnivory, when prey experience reduced predation rates due to refuges or adaptive antipredator defences, and when omnivores interfere with each other or feed adaptively. Empirical research has lagged behind theory and there remains a shortage of studies directly measuring the stability of diverse natural communities that vary in the number and strength of omnivorous interactions. Early microcosm experiments indicated a narrow range of conditions for the persistence of simple omnivorous modules, while studies of omnivory embedded within larger natural networks have demonstrated its stabilizing effects. These new findings alter our view of food web dynamics and show that rather than looking for a simple and general omnivory-stability relationship, we should focus on identifying conditions under which omnivory is a stabilizing feature of more complex natural systems.

show abstract

Section: Broader Food Web Contextmentioning

confidence: 78%

Stability and persistence of food webs with omnivory: Is there a general pattern?

et al. 2012

View full text Add to dashboard Cite

show abstract

“…As a final example, we turn to a parameter space which displays all the hallmarks of chaotic instabilities [16,17]. For fixed parameters, system (2.1) exhibits large-amplitude oscillations, period doubling and chaos over a large region of parameter space as can be seen in the bifurcation diagram (figure 4a) over the range of omnivory strength f and for a fixed value of the trophic …”

Section: Examplesmentioning

confidence: 99%

“…the intermediate consumer) has to endure both direct predation and competition from the top predator [13]. This is borne out in simple dynamic descriptions that suggest that intra-guild predation systems are highly unstable [13] in their restricted admittance of stable coexistence [14,15], large-amplitude limit cycles [14], chaotic dynamics [16,17] and susceptibility to enrichment-induced extinctions [18]. And yet, tri-trophic arrangements including omnivory are ubiquitous features of nearly all ecosystems [5,[19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Adaptive behaviour, tri-trophic food-web stability and damping of chaos

Visser

Mariani

Pigolotti

2011

J. R. Soc. Interface.

View full text Add to dashboard Cite

We examine the effect of adaptive foraging behaviour within a tri-trophic food web with intra-guild predation. The intra-guild prey is allowed to adjust its foraging effort so as to achieve an optimal per capita growth rate in the face of realized feeding, predation risk and foraging cost. Adaptive fitness-seeking behaviour of the intra-guild prey has a stabilizing effect on the tri-trophic food-web dynamics provided that (i) a finite optimal foraging effort exists and (ii) the trophic transfer efficiency from resource to predator via the intra-guild prey is greater than that from the resource directly. The latter condition is a general criterion for the feasibility of intra-guild predation as a trophic mode. Under these conditions, we demonstrate rigorously that adaptive behaviour will always promote stability of community dynamics in the sense that the region of parameter space in which stability is achieved is larger than for the non-adaptive counterpart of the system.

show abstract

“…Simulation studies have shown that weak omnivorous links enhance community stability and persistence by dampening the oscillations between consumers and producers (McCann and Hastings 1997;Emmerson and Yearsley 2004;Namba et al 2008, although see (Tanabe and Namba 2005). Weak omnivorous links can be seen as consumers complementing their main diet with occasional preys located at a different trophic level than their main diet (ex.…”

Section: General Food Web Structurementioning

confidence: 99%

The structure of subtidal food webs in the northern Gulf of St. Lawrence, Canada, as revealed by the analysis of stable isotopes

Nadon

Himmelman

2010

Aquat. Living Resour.

View full text Add to dashboard Cite

-We analyzed stable isotopes of carbon and nitrogen to investigate the trophic structure of the subtidal food web around the Mingan Islands, northern Gulf of St. Lawrence, eastern Canada. All benthic consumers were enriched in 13 C (mean δ 13 C of -17.1% ) compared to particulate organic matter (POM: -23.3% ). Nitrogen stable isotope ratios ranged from 6% to 14% and the organisms studied fell into three distinct trophic groups, primary producers, primary consumers (herbivores), and predators. The sea star Crossaster papposus and the sculpin Myoxocephalus scorpius, known to be top level predators, had slightly higher δ 15 N than other predators. Although the average isotope signature of the sea star Solaster endeca placed it among regular predators, the δ 15 N increased with sea star size and large individuals could be considered as top predators. The relatively small number of organisms located at intermediate trophic levels suggests a low level of omnivory in the Mingan Islands' system, which contrasts with previously described benthic systems that exhibit a continuum between herbivores and predators. Low omnivory, in addition to low diversity, suggests that this ecosystem may be relatively unstable if exposed to natural and/or anthropogenic disturbances such as exploitation and climate change.Key words: Stable isotopes / Food webs / Omnivory / Community structure / Trophic interaction / Gulf of St. Lawrence Résumé -Nous avons analysé les isotopes stables du carbone et de l'azote pour définir la structure trophique du réseau alimentaire infralittoral (zone immergée subtidale) des îles Mingan situées dans la zone nord du golfe du SaintLaurent, côte est du Canada. La quasi-totalité des consommateurs benthiques sont enrichis en carbone 13 C (δ 13 C moyen : −17,1 % ) comparés à la matière organique particulaire (POM : -23,3 % ). Le rapport isotopique stable de l'azote se situe entre 6 % et 14 % et les organismes étudiés se classent en trois groupes trophiques distincts : les producteurs primaires, les consommateurs primaires (herbivores), et les prédateurs. L'étoile de mer, Crossaster papposus, et le poisson chaboisseau à épines courtes, Myoxocephalus scorpius, reconnus comme étant des prédateurs de niveau trophique supérieur, exhibent des rapports δ 15 N supérieurs aux autres prédateurs. Bien que la signature isotopique moyenne de l'étoile de mer, Solaster endeca, la place ici comme prédateur typique, le rapport δ 15 N augmente avec sa taille ; ce qui suggère que les individus de grande taille, chez cette espèce, peuvent être considérés comme des prédateurs de haut niveau. Le petit nombre d'organismes situés à des niveaux trophiques intermédiaires suggère un faible taux « d'omnivorie » dans le système des îles Mingan, ce qui contraste avec ce qui a été décrit précédemment pour d'autres écosystèmes marins (un continuum entre herbivores et prédateurs). Le faible taux « d'omnivorie », additionné à la faible diversité, suggère que cet écosystème peut être relativement instable face à d'éventuelles perturbatio...

show abstract

Omnivory and stability of food webs

Cited by 82 publications

References 76 publications

Stability and persistence of food webs with omnivory: Is there a general pattern?

Stability and persistence of food webs with omnivory: Is there a general pattern?

Adaptive behaviour, tri-trophic food-web stability and damping of chaos

The structure of subtidal food webs in the northern Gulf of St. Lawrence, Canada, as revealed by the analysis of stable isotopes

Contact Info

Product

Resources

About