Meta-Analysis of the Effects of Predation on Animal Prey Abundance: Evidence from UK Vertebrates

Holt, Alison R.; Davies, Zoe G.; Tyler, Claire; Staddon, Samantha

doi:10.1371/journal.pone.0002400

Cited by 64 publications

(75 citation statements)

References 45 publications

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“…Certainly there are many case studies where changes in predator numbers have apparently little effect on bird populations (Newton 1998;Holt et al 2008). Some of these may represent special circumstances when predation genuinely has little effects on population, and include when prey have actually permanently escaped direct predation; when other factors limit the size of the breeding population; and when a prey is particularly vulnerable so potentially shielding other prey from high anti-predation costs.…”

Section: Under What Circumstances Do We Apparently Not Find Any Predamentioning

confidence: 99%

“…But others have shown that predator numbers or predator presence do not change prey numbers (e.g. Bolton et al 2007;Holt et al 2008;Amar et al 2010). Almost all of the emphasis in these published studies is on measuring how many individuals are directly killed by a predator: if some proportion of the prey population is killed by a predator, or prey population declines are recorded because of the predator killing prey, then a predator is regarded as being important in influencing the prey's population dynamics (Holt et al 2008;Smith et al 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Bolton et al 2007;Holt et al 2008;Amar et al 2010). Almost all of the emphasis in these published studies is on measuring how many individuals are directly killed by a predator: if some proportion of the prey population is killed by a predator, or prey population declines are recorded because of the predator killing prey, then a predator is regarded as being important in influencing the prey's population dynamics (Holt et al 2008;Smith et al 2010). Yet predators actually killing prey may often be only a minor part of the effect of predation in populations (Brown et al 1999;Sih 1987;Creel and Christianson 2008;see Cresswell 2008 for a review of this idea).…”

Section: Introductionmentioning

confidence: 99%

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Predation in bird populations

Cresswell

2010

J Ornithol

237

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One of the classic ecological questions is how predators affect population size. This is often assessed by measuring how many individuals are killed by a predator, yet such direct effects may only be a relatively minor part of population dynamics. Predators frequently affect prey populations indirectly, with the fear of predation resulting in costly behavioural compensation leading to potentially large population and community effects. Large observable lethal effects may then just represent the most easily observed "special" cases of the effects of predation on populations, with the costs of non-lethal effects being ubiquitous and usually dominant. This review explores these two ideas: that cases where there are no population effects due to predation, and cases where lethal effects dominate, are unusual and involve special circumstances. First, systems where predation effects appear not to arise include complete avoidance of predators by prey; when other environmental factors limit populations so that predation is not additive to mortality; when there are other more vulnerable prey for a predator; when predators interact; because the relationship of perceived predation risk with predator abundance is usually a non-linear function, and simply because non-lethal effects have not been considered. Second, lethal effects tend to dominate over non-lethal effects when there is a high cost of compensating for predation risk associated with either resource constraint or a particularly vulnerable niche or life history stage (e.g. the nest stage generally for birds); when prey are the most popular prey of a predator or linear trophic chains operate; when there is evolutionary lag such as introduced predators and naïve prey populations; and when there are several predator species hunting the same prey in diverse ways. The presence of predators may or may not affect the size of a bird population at any particular life history stage, although in most cases it will through non-lethal effects and occasionally through lethal effects.But the presence of predators will always affect intra-and interspecific competition and so will always affect population dynamics. Studies that wish to fully demonstrate that predation has no effect on bird populations must show that lethal effects and the costs of non-lethal compensation by the prey do not significantly change its density and so the level of competition.3

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Section: Under What Circumstances Do We Apparently Not Find Any Predamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Predation in bird populations

Cresswell

2010

J Ornithol

237

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“…Culling predators, for example, can result in demographic improvements for vulnerable bird species such as increased nest success . These improvements, however, can depend on the maintenance of a low-density predator population (Payton et al 1997) and the strategy has shown a mixed and often low success rate for livestock protection (Conner et al 1998;Berger 2006), or conserving bird populations (Cote and Sutherland 1997;Holt et al 2008). Where the ethics of culling native predators are questioned (Witmer et al 2000;Ziegltrum 2008), translocation is often considered a humane alternative (Massei et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Diversionary feeding: an effective management strategy for conservation conflict?

et al. 2015

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Human population growth has led to increased contact between people and wildlife, with adverse impacts for both, such as damage to economic crops and wildlife persecution. Diversionary feeding, where food is used to draw animals away from problem activities or locations, is sometimes proposed as a socially acceptable conservation action, but little information exists on its success or what influences its efficacy. Here, we review literature on diversionary feeding and evaluate factors contributing to its success or failure. Success varied greatly among studies and successful uptake of diversionary food did not consistently produce outcomes that met stakeholder objectives. Studies often failed to report results in sufficient detail to allow a quantitative evaluation of efficiency. Of 30 trials presented in 21 studies, 13 enabled assessment of outcomes related to the ultimate objective of reducing conflict (related to threatened prey density, crop yield or nuisance reports) and only five of these were considered successful by the researchers conducting the study. A grand mean increase of 15 % in respective measures of success at the outcome stage was found across all studies. Although diversionary feeding is considered expensive, cost-effectiveness analyses were rarely conducted. Only a third of studies reported information on costs and benefits that could be used to inform future management actions. We propose a decision-making framework that incorporates ecological knowledge, financial costs and evidence from previous studies to aid the planning and implementation of diversionary feeding in an adaptive format. Future studies of diversionary feeding should clearly report objectives, results, costs and effort to allow the return-on-investment to be calculated for different levels of management effort.

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“…Many familiar processes, such as endocytic vesicle formation, correspond to the latter topology, where the cytoplasmic protein dynamin encircles the constricting neck and "pushes" the membranes toward the fission point. By contrast, ESCRT protein assemblies work from inside membrane necks to "pull" the constricting membranes toward themselves ( 4,5).…”

mentioning

confidence: 99%