An economic analysis of predator removal approaches for protecting marine turtle nests at Hobe Sound National Wildlife Refuge

Abstract

Hobe Sound National Wildlife Refuge (HSNWR) on Florida's east coast provides undisturbed nesting habitat for three species of threatened or endangered marine turtles. Predation by raccoons and armadillos poses the greatest risk to turtle nests, and predator control has been identified as the most important management tool for enhancing nesting productivity. Recently, estimates of the number of nests that would have been lost in the 2000 nesting and incubation season were made using the results from four control approaches. These approaches were, in order of descending complexity: (1) refuge control enhanced by a one person-month contract with federal control specialists, with that control optimized using a passive tracking methodology for monitoring predators; (2) refuge control enhanced by a one person-month contract with federal control specialists, without predator monitoring; (3) refuge control, but no contract with specialists; (4) no control. In that analysis, approach 1 resulted in the fewest turtles lost to predation. In this paper, we perform a benefit Á/cost analysis to determine if operational efficacy translates into economic efficiency. Approach 1 had by far the best benefit Á/cost ratio for loggerhead turtles, but approach 2 was best for Atlantic green and leatherback turtles. However, almost 90% of the turtles nesting at HSNWR are loggerhead, and this area is vital to loggerhead survival. Thus, approach 1 also had by far the best benefit Á/cost ratio over all turtle species, saving approximately $1.7 million over approach 2, $2.6 million over approach 3 and $8.4 million over approach 4. Given these results, one must ask how can we afford not to control predators, and furthermore, how can we not afford to take the minimal extra steps to maximize control efficacy.

An economic assessment of the potential for predator management to benefit Puerto Rican parrots

“…Engeman et al, 2002). The Puerto Rican parrot is an extremely rare animal, and we have demonstrated that the combined costs for managing multiple predatory threats is more than offset by saving a single parrot in the existing wild populations.…”

Assignment of measurable costs and benefits to wildlife conservation projects

“…In the U.S., the federal Migratory Bird Treaty Act and the Endangered Species Act are sources of legislatively designated values for illegal taking of a variety of species of concern. Engeman et al (2002a) used a civil penalty value for endangered sea turtles in a CBA of conservation methodologies used to protect the turtles. Under the assumption that an individual is aware of the civil penalty for illegal take with some probability of being caught, but takes the animal anyway, then this value represents a stated WTP value.…”

“…produced through different management efforts and has cost information for each management effort, but is unable to value the units then CEA is most appropriate. Economic efficiency is thereby determined by the methodology that produces the greatest return at the least cost (Laycock et al 2011, Caudell et al 2010, Engeman et al 2002a, Cullen et al 2001. Like CEA, CUA is another popular alternative to CBA that is widely used by health economists as a measure of the improvements to health status (Laycock et al 2011, Boardman et al 1996.…”

“…For example, if the goal of the project is to increase the number of birds that have been determined to have a monetary social value, then this value can be used to determine if the costs expended on the project were justified in terms of the total benefits (total value of birds produced or protected) (Engeman et al 2002a(Engeman et al , 2003. Benefit--cost ratios are calculated when the value of units produced is divided by the costs to provide a ratio of monetary value of benefits for every unit of costs.…”

“…Cost--benefit analysis or benefit--cost analysis can be used when the productive units of the conservation project can be assigned a monetary value (Christie et al 2011, Naidoo and Ricketts 2006, Gutman 2002, Engeman et al 2002a. For example, if the goal of the project is to increase the number of birds that have been determined to have a monetary social value, then this value can be used to determine if the costs expended on the project were justified in terms of the total benefits (total value of birds produced or protected) (Engeman et al 2002a(Engeman et al , 2003.…”