Increases in Capture Rates of an Aquatic Snake (Seminatrix pygaea) Using Naturally Baited Minnow Traps: Evidence for Aquatic Funnel Trapping as a Measure of Foraging Activity

摘要

The secretive nature of most snake species can hinder efforts to understand aspects of their ecology and population biology unless systematic capture techniques are employed and potential sampling biases are recognized (Parker and Plummer 1987). For herpetofauna other than snakes (e.g., amphibians, lizards, and turtles) numerous studies of collecting methods and sampling regimes have resulted in standardized methods, with well-elucidated biases (e.g., Dodd 1991; Dunham etal. 1994; Gibbons l990;Heyer et al. 1994; Willson and Dorcas 2004; Willson et al. 2005). Several collection techniques have been used successfully for terrestrial snakes (reviewed in Fitch 1987, 1992), such as terrestrial drift fences with pitfall and funnel traps (Gibbons and Semlitsch 1981), road cruising (Dodd et al. 1989; Mendelson and Jennings 1992; Seigel and Pilgrim 2002), visual encounter surveys (Sun et al. 2001). and artificial cover objects (Fitch 1992; Grant et al. 1992). For capturing snakes in aquatic habitats most studies have relied upon visual encounter surveys, opportunistic captures, or aquatic funnel traps (Casaz.za et al. 2000; Gibbons and Dorcas 2004; Madsen and Shine 2000; Seigel et al. 1995a; Seigel et al. 2000), but the effectiveness and biases of these methods have seldom been examined experimentally (e.g., Willson et al. 2005).