来源： Scalera 2007
The bullfrog, a native of the midwestern and eastern United States, was first introduced into California in 1896 (Jennings & Hayes 1985, in Cook & Jennings 2007). American bullfrogs rapidly became established over a wide geographic area in the west (Clarkson & deVos 1986). Winter floods may increase the mortality of bullfrogs in south California streams (Doubledee et al. 2003).
威胁濒危物种: The bullfrog has displaced the endangered California red-legged frog (Rana aurora draytonii) in some locations (Scalera 2007). Model simulations created by Doubledee Muller and Nisbet (2003) indicate that winter floods, which strongly increase mortality of bullfrogs but not California red-legged frogs (Rana aurora draytonii), facilitate coexistence in south Californian streams if they occur more than once every 5 years. In other words, in areas where flooding occurs once every five years or more introduced bullfrogs may be able to live in harmony with red-legged frogs in California. This would of course not apply to all environments and streams with little flooding would still be at risk of invasion by L. catesbeianus.
捕食: The bullfrog has long been implicated as a competitor of and predator on native western ranid frogs (Kiesecker & Blaustein 1997, Kupferberg 1997, Licht 1974, Moyle 1973, Nussbaum et al. 1983, in Cook & Jennings 2007). Bullfrogs have also been documented consuming red-legged frogs (Rana draytonii) at the tadpole, metamorph, and adult life stages (Doubledee et al. 2003; Lawler et al. 1999; Cook, 2002; Cook and Jennings 2001, D. G. Cook Unpub. Data, in Cook and Jennings 2007). According to Cook and Jennings (2007) the effect of bullfrog predation on the red-legged frog depends on the sizes of the individuals involved in the interaction. The much larger body size of the bullfrog suggests it could have a significant impact, especially if it were to become numerically superior (Pearl et al. 2004, in Cook & Jennings 2007).
最后修改 ： 13/01/2010 1:07:03 p.m.