Optimal allocation of conservation effort among subpopulations of a threatened species: How important is patch quality?

Chauvenet, Aliénor L. M.; Baxter, Peter; McDonald‐Madden, Eve; Possingham, Hugh P.

doi:10.1890/08-1749.1

Cited by 20 publications

(16 citation statements)

References 26 publications

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“…Until sufficient money is made available, conservationists will continue to be faced with the dilemma of devoting more resources to save a few species versus spreading resources too thinly to achieve success with any species [58]. Similarly, when focusing on a single population, spreading resources too thinly over a large area may reduce the likelihood of saving even a small area [59], [60]. Conservationists even face trade-offs about whether to divert limited resources away from direct conservation activities in order to perform rigorous cost benefit analyses of their effectiveness [1].…”

Section: Discussionmentioning

confidence: 99%

Extreme Conservation Leads to Recovery of the Virunga Mountain Gorillas

et al. 2011

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As wildlife populations are declining, conservationists are under increasing pressure to measure the effectiveness of different management strategies. Conventional conservation measures such as law enforcement and community development projects are typically designed to minimize negative human influences upon a species and its ecosystem. In contrast, we define “extreme” conservation as efforts targeted to deliberately increase positive human influences, including veterinary care and close monitoring of individual animals. Here we compare the impact of both conservation approaches upon the population growth rate of the critically endangered Virunga mountain gorillas (Gorilla beringei beringei), which increased by 50% since their nadir in 1981, from approximately 250 to nearly 400 gorillas. Using demographic data from 1967–2008, we show an annual decline of 0.7%±0.059% for unhabituated gorillas that received intensive levels of conventional conservation approaches, versus an increase 4.1%±0.088% for habituated gorillas that also received extreme conservation measures. Each group of habituated gorillas is now continuously guarded by a separate team of field staff during daylight hours and receives veterinary treatment for snares, respiratory disease, and other life-threatening conditions. These results suggest that conventional conservation efforts prevented a severe decline of the overall population, but additional extreme measures were needed to achieve positive growth. Demographic stochasticity and socioecological factors had minimal impact on variability in the growth rates. Veterinary interventions could account for up to 40% of the difference in growth rates between habituated versus unhabituated gorillas, with the remaining difference likely arising from greater protection against poachers. Thus, by increasing protection and facilitating veterinary treatment, the daily monitoring of each habituated group contributed to most of the difference in growth rates. Our results argue for wider consideration of extreme measures and offer a startling view of the enormous resources that may be needed to conserve some endangered species.

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Section: Discussionmentioning

confidence: 99%

Extreme Conservation Leads to Recovery of the Virunga Mountain Gorillas

et al. 2011

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“…Post-release survival to reproductive age is crucial to the establishment and persistence of reintroduced populations (Armstrong & Seddon, 2008;Parlato & Armstrong, 2013). Post-release survival of individuals frequently varies among multiple release sites depending on factors such as food availability or predation pressure (Chauvenet et al, 2010). In a metapopulation context, establishment can be more difficult at some release sites than others depending on available resources and threats.…”

Section: Introductionmentioning

confidence: 99%

“…Chauvenet et al, 2010;Collazo et al, 2013;Helmstedt & Possingham, 2016;, few have evaluated how variation in release site characteristics can be exploited to reduce post-release effects and increase establishment success in metapopulation restoration efforts. Chauvenet et al, 2010;Collazo et al, 2013;Helmstedt & Possingham, 2016;, few have evaluated how variation in release site characteristics can be exploited to reduce post-release effects and increase establishment success in metapopulation restoration efforts.…”

Section: Introductionmentioning

confidence: 99%

Optimizing release strategies: a stepping‐stone approach to reintroduction

Lloyd¹,

Hostetter

Jackson³

et al. 2018

Animal Conservation

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Evaluation of alternative management strategies enables informed decisions to accelerate species recovery. For reintroductions, post-release survival to reproductive age is a key parameter influencing population growth. Here, we trial a 'stepping-stone' method to maximize the success of captive-bred animals when the availability of more suitable wild-born release candidates is limited. Our approach makes use of relatively safe and established wild populations to prepare captive-bred individuals for eventual translocation to a final release destination, thus building resilience through establishment of multiple populations over time. We developed a novel multievent model integrating encounter history and biotelemetry data to evaluate reintroduction strategies for the critically endangered Vancouver Island marmot Marmota vancouverensis. We compared post-release survival of 176 individuals (52 wild-born, 47 captive-bred marmots released directly to destinations, and 77 captive-bred marmots released with a stepping-stone approach). Survival estimates to prime breeding-age (PBA), were then used to quantify expected success of potential release strategies. Our analysis indicates that post-release survival varies by source population and release method, as well as age, season, year, and years since release. Conditional on an objective of maximizing survival to PBA, our results suggest that using wild-born marmots for translocations as often as possible, and stepping-stone captive-bred marmots prior to final release, will result in the best outcomes. There was a 0.86 probability that survival to PBA was greater for captive-bred marmots released as yearlings using a stepping-stone approach (survival to PBA mode = 0.13, 95% CRI = 0.05-0.30) than for captive-bred animals that were directly released to destination sites as one-year-olds (survival to PBA mode = 0.04, 95% CRI = 0.01-0.24). Consequently, the stepping-stone approach yields much higher population establishment or growth potential than previous release strategies that used captive-bred marmots. Optimizing the combination of release candidates, sites and timing can thereby increase the effectiveness of reintroductions.

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“…Examples include finance, education, construction, transportation, ecology, telecommunication, etc. (see Phillips and Bana e Costa (2007); Paxson and Schady (2002); Karlaftis et al (2007); Chauvenet et al (2010); Lin et al (2009)). Phillips and Bana e Costa (2007) describe five characteristics of the decision dilemma in such problems: (1) benefits are typically expressed by multiple objectives often in conflict; (2) decision makers cannot know every detail about a large number of given alternatives to make informed decisions; (3) individually optimal decisions rarely lead to the collectively best use of the available resources; (4) involved stakeholders cause dispute and competition; (5) those who disagree with the decisions overemphasize their own opinions in implementation.…”

Section: Introductionmentioning

confidence: 99%

Risk-adjusted budget allocation models with application in homeland security

Homem-de-Mello

Mehrotra

2011

IIE Transactions

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This paper presents and studies models for multi-criterion budget allocation problems under uncertainty. The proposed models incorporate uncertainties in decision maker's weights using a robust weighted sum approach. The risk averseness of the decision maker in satisfying random risk related constraints is ensured by using stochastic dominance. A sample average approximation approach together with a cutting surface method is used to solve this model. An analysis for the computation of statistical lower and upper bounds is also given. We use the proposed models to study the budget allocation to ten urban areas in the United States under the Urban Areas Security Initiative (UASI). Here the decision maker considers property losses, fatalities, air departures, and average daily bridge traffic as separate criteria. The properties of the proposed modeling and solution methodology are discussed using a RAND Corporation proposed allocation policy and the current government budget allocation as two benchmarks. The budget results are discussed under several parameter scenarios.

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Optimal allocation of conservation effort among subpopulations of a threatened species: How important is patch quality?

Cited by 20 publications

References 26 publications

Extreme Conservation Leads to Recovery of the Virunga Mountain Gorillas

Extreme Conservation Leads to Recovery of the Virunga Mountain Gorillas

Optimizing release strategies: a stepping‐stone approach to reintroduction

Risk-adjusted budget allocation models with application in homeland security

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