Avaliação de métodos de captura do teiú (Salvator merianae) no Arquipélago de Fernando de Noronha, Pernambuco.

Abstract

Tegu (Salvator merianae), the largest lizard in South America, is an invasive species in the Fernando de Noronha Archipelago, State of Pernambuco, Brazil. Its management in this insular environment is extremely important, due to the predation and competition of this species with the local, endemic and/or threatened fauna; the possibility of pathogen transmission, and the dispersion of invasive plant seeds. The objective of this research was to evaluate and compare the best capture strategy to the management of tegu in the Fernando de Noronha Archipelago. For this purpose, the area of Ponta das Caracas, uninhabited by humans, was chosen, using two types of traps (10 funnel type made of PVC tube and 10 Tomahawk type live trap) interspersed in a 200m² forest fragment with an interval of 50m between and two types of baits (chicken pieces and sachets of wet cat food) to compare the traps and the most efficient bait in capturing tegu. The capture effort was 400 traps per day, totalling 2800h of fieldwork, enough to reduce tegu captures to zero at the end of the experiment. In all, 60 tegus were captured, 47 individuals (78.3%) were captured in Tomahawk-type traps, and 13 individuals (21.7%) in PVC tube-type funnel traps. Regarding the use of baits, 35 individuals (58.3%) were captured in traps with chicken bait and 25 individuals (41.7%) in traps using wet cat food. Following capture, physicochemical containment, biometrics, and sexing of tegu were carried out to assess and monitor the species pattern on the island. There was no statistically significant association between the type of trap used (funnel made of PVC pipe and Tomahawk) or between the type of bait used (chicken pieces and wet cat food) (χ2 = 2.36; p = 0.12). However, the capture success was higher in the Tomahawk trap, regardless of the bait used. This research was the first to compare capture methods for this species on the island of Fernando de Noronha, making it possible to assess the cost of hours and the sample capture effort needed to implement a comprehensive management program for tegu in this archipelago and thus indicate measures of management to improve the conservation of the island's biodiversity.