Bernice Constantin

Monitoring predators to optimize their management for marine turtle nest protection

Abstract The fundamental conservation focus for Hobe Sound National Wildlife Refuge (HSNWR), Florida is to provide protected nesting habitat for three threatened or endangered marine turtle species. Turtle nesting and hatching spans from early spring to fall each year. Left unchecked, nest predation by raccoons and armadillos would destroy most turtle nests. Predators are removed to protect nests, primarily with a one person-month contract using control specialists. We maximized the efficiency of predator removal by using a passive tracking index to: (1) optimize the timing and strategy for predator removal, (2) minimize labor by identifying areas where predator removal would have maximal effect, (3) examine beach invasion patterns of predators, (4) assess efficacy of removal efforts, (5) provide anticipatory information for future turtle nesting seasons, and (6) serve as a detection method for invasion by additional species known to depredate turtle nests. An overall nest predation rate of 28% resulted, whereas the rate for the previous year was 42% when the same level of contracted predator removal was applied, but without monitoring predators. One year before that, predator removal was done without contracts with specialists and predation was 48%. Up to 95% of the nests were destroyed in the years prior to predator removal. Using 2000 data on numbers of nests, clutch sizes, and emergence rates, we estimated the number of hatchlings that would have been lost assuming that the predation rates observed from four predator removal scenarios at HSNWR would have occurred in 2000. Historical predation of 95% would have resulted in 120,597 hatchlings lost in 2000. Predator removal as part of regular refuge operations would have reduced this number to 62,481. Addition of a contract with control specialists would have further reduced the number lost to 53,778. Addition of temporal and spatial monitoring for predator removal reduced losses to 36,637.

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 Floridas 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–cost analysis to determine if operational efficacy translates into economic efficiency. Approach 1 had by far the best benefit–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–cost ratio over all turtle species, saving approximately

Dramatic reduction in predation on marine turtle nests through improved predator monitoring and management

1.7 million over approach 2,

Prevalence and economic value of feral swine damage to native habitat in three Florida state parks

2.6 million over approach 3 and

Monitoring changes in feral swine abundance and spatial distribution

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

We describe improvements to monitoring/ indexing methodology for predators of marine turtle nests on the east coast of Florida, and the resulting marine turtle conservation implications from integrating the methodology into predator management. A strip transect from dune line to the shore improved an already successful design for monitoring raccoons, and was also sensitive for armadillos. The data were integrated into predator management operations to effectively and efficiently remove the species responsible for turtle nest predation. Tracking plot data also served to validate predator patterns of behavior relative to turtle nesting and improve prospects for preventive predator management strategies. Perhaps the most important finding is that predation at a beach historically suffering nearly complete losses (95%) of marine turtle nests had nest predation reduced to nominal levels (9.4%). For 2002 this predation level represents an estimated 69,000 additional hatchling turtles produced over historical predation rates, and 16,700 additional hatchlings over the previous lowest predation rate.

Rapid assessment for a new invasive species threat: the case of the Gambian giant pouched rat in Florida

SUMMARY Feral swine (Sus scrofa) adversely affect the environment in many of the places where they have been introduced. Such is the case in Florida, but quantification and economic evaluation of the damage can provide objective bases for developing strategies to protect habitats. Swine damage to native wet pine-flatwoods at three state parks in Florida was monitored from winter 2002 to winter 2003. Economic valuations of damage were based on the US dollar amounts that wetland regulators have allowed permit applicants to spend in attempts to replace lost resources. The parks had different swine management histories and the damage patterns differed among them over time. Swine were intensively removed in 2000 from the first park, and it initially had the lowest habitat damage at 1.3%, but as a result of natural and artificial population growth this damage rose to 5.4% by the conclusion of the study, and was valued at US

Damage reduction estimates and benefit-cost ratios for feral swine control from the last remnant of a basin marsh system in Florida

19 193‐36 498 ha � 1 . The second park had no history of swine harvest and, over the monitoring period, damage escalated from 2.6%‐6.4%, with an associated value of US

Methyl anthranilate aerosol for dispersing birds from the flight lines at Homestead Air Reserve Station

22 747‐43 257 ha � 1 . Swine were managed as game animals in the third park prior to its inclusion into the state parks system in 2000. Within this park, the proportion of area damaged decreased from 4.3%‐1.5%, valued at US

An ideal combination for marine turtle conservation: exceptional nesting season, with low nest predation resulting from effective low-cost predator management

5 331‐10 138 ha � 1 . This