Predicting reintroduction costs for wildlife populations under anthropogenic stress

Abstract

1. In conservation decision-making, it is important to have information not only on the likely effectiveness of conservation actions, but also on the corresponding costs. Reintroduction of wildlife is a commonly applied 'last resort' conservation measure. However, a quantitative approach to predict the costs of reintroduction for sustaining a wildlife population under the influence of time-varying anthropogenic stress is lacking.2. Here, we fill this gap by quantifying the costs of reintroduction as a function of exposure to an environmental stressor and the size of the wildlife population to be maintained. Our approach combines quantitative stressor-response relationships for vital rates (reproduction and survival) with a wildlife demographic model to compute the impacts of the stressor on the size of the target population. Subsequently, cost estimates are obtained by quantifying the number of captive-reared individuals needed per year in order to maintain a user-defined population size, given the exposure to the stressor of concern. We applied our approach to calculate the reintroduction costs required to restore a minimum viable population (MVP) of peregrine falcons (Falco peregrinus) in California over the period 1970-1994, when the population was exposed to the toxicant dichlorodiphenyldichloroethylene.3. Assuming a gradual yearly increase of 150% in the availability of captive-reared young, 1,753 captive-reared young were required to restore and maintain a MVP of 238 adults. The corresponding reintroduction costs were in total ~$3,023,000.Assuming lower reintroduction efforts (in terms of the availability of captivereared young), the projected reintroduction costs decreased by ~33%. However, the population then reached the minimum viable size only 9 years later, thus reflecting a trade-off between costs and population viability. 4. Synthesis and applications. The approach presented in this study ensures an adequate prediction of the costs of maintaining a wildlife population at a user-defined size through reintroduction. It can be applied to any wildlife population in order to obtain the number of individuals and corresponding costs required to sustain a Additional supporting information may be found online in the Supporting Information section. How to cite this article: Hilbers JP, Huijbregts MAJ, Schipper AM. Predicting reintroduction costs for wildlife populations under anthropogenic stress.

Restoring declining species through translocations: A test case using flightless grasshoppers in an urban setting

“…Despite some challenges, our findings showed that insect translocations are viable, even in small urban spaces of revegetated areas, with a fraction of the time and resources required for vertebrate translocation initiatives that need substantial investment over extended periods (Gedir et al, 2004). For example, a translocation project for the black‐footed rock‐wallaby ( Petrogale lateralis ) cost AU$3.86 million over 11 years (Hilbers et al, 2020; Ireland et al, 2018) predicted a cost of ~US$3 million to reintroduce 1753 captive‐reared peregrine falcons ( Falco peregrinus ) in California to restore and maintain a minimum viable population; a project reintroducing the green and golden bell frog ( Litoria aurea ) tadpoles had an approximate overall cost of AU$190 K for more than 4 years (Daly et al, 2008). In contrast, our translocations cost <AU$1 K in non‐labour costs, with around AUS$20 K for surveying, collecting and monitoring.…”

Incorporating human dimensions is associated with better wildlife translocation outcomes

“…As biodiversity continues to decline, there is an urgent need to integrate well-established biological and environmental schema with a deeper understanding of the social and human dimensions that will help to avoid unaffordable failures. A single wildlife restoration failure can result in a species' extinction 4,11 , as well as the loss of millions of dollars and the sowing of distrust between communities and conservation institutions. Therefore, analyses to understand even marginal gains in translocation success can be impactful for future conservation efforts.…”

“…Conversely, reintroduced populations of brush-tailed bettongs (Bettongia penicilliata) in Australia and red wolves (Canis rufus) in the United States swiftly declined to unsustainable levels 9,10 . Translocation programs require considerable time and resources, and their failure can lead to distrust between stakeholders, the loss of resources, and even the extinction or extirpation of entire populations or species 4,11 . Thus, understanding why some efforts succeed where others fail is key to designing future wildlife translocation programs and allocating scarce conservation resources.…”

Renewed coexistence: learning from steering group stakeholders on a beaver reintroduction project in England

“…Any similar reintroduction should consider efficient resource use, with P18 stating the Trial could be 'streamlined' (see theme 6). Costs of reintroduction can be high (Hilbers et al 2019). This may include financial risks for project leads.…”