Cost-effective suppression and eradication of invasive predators

Baxter, P. W. J., Sabo, J. L., Wilcox, C., McCarthy, M. A., & Possingham, H. P. (2008) Cost-effective suppression and eradication of invasive predators. Conservation Biology, 22(1), pp. 89-98.

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Introduced predators can have pronounced effects on naïve prey species; thus, predator control is often essential for conservation of threatened native species. Complete eradication of the predator, although desirable, may be elusive in budget-limited situations, whereas predator suppression is more feasible and may still achieve conservation goals. We used a stochastic predator-prey model based on a Lotka-Volterra system to investigate the cost-effectiveness of predator control to achieve prey conservation. We compared five control strategies: immediate eradication, removal of a constant number of predators (fixed-number control), removal of a constant proportion of predators (fixed-rate control), removal of predators that exceed a predetermined threshold (upper-trigger harvest), and removal of predators whenever their population falls below a lower predetermined threshold (lower-trigger harvest). We looked at the performance of these strategies when managers could always remove the full number of predators targeted by each strategy, subject to budget availability. Under this assumption immediate eradication reduced the threat to the prey population the most. We then examined the effect of reduced management success in meeting removal targets, assuming removal is more difficult at low predator densities. In this case there was a pronounced reduction in performance of the immediate eradication, fixed-number, and lower-trigger strategies. Although immediate eradication still yielded the highest expected minimum prey population size, upper-trigger harvest yielded the lowest probability of prey extinction and the greatest return on investment (as measured by improvement in expected minimum population size per amount spent). Upper-trigger harvest was relatively successful because it operated when predator density was highest, which is when predator removal targets can be more easily met and the effect of predators on the prey is most damaging. This suggests that controlling predators only when they are most abundant is the "best" strategy when financial resources are limited and eradication is unlikely. © 2008 Society for Conservation Biology.

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ID Code: 82387
Item Type: Journal Article
Refereed: Yes
Keywords: Introduced species, Management efficiency, Pest eradication, Predator control, Predator-prey model, Process error, Suppression of invasive species, Trigger harvest, invasive species, Lotka-Volterra model, population size, predator, species conservation, stochasticity, article, biological model, cost benefit analysis, economics, environmental protection, pest control, population dynamics, statistics, Conservation of Natural Resources, Cost-Benefit Analysis, Models, Biological, Stochastic Processes
DOI: 10.1111/j.1523-1739.2007.00850.x
ISSN: 08888892 (ISSN)
Divisions: Current > Schools > School of Earth, Environmental & Biological Sciences
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Deposited On: 10 Mar 2015 07:47
Last Modified: 13 Mar 2015 04:46

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