which damage and kill the canes

Frog mutations and genetic defects have increased since the 1990s. These often include missing legs or extra legs. Various causes have been identified or hypothesized, including an increase in ultraviolet radiation affecting the spawn on the surface of ponds, chemical contamination from pesticides and fertilizers, and parasites such as the trematode Ribeiroia ondatrae. Probably all these are involved in a complex way as stressors, environmental factors contributing to rates of disease, and vulnerability to attack by parasites. Malformations impair mobility and the individuals may not survive to adulthood. An increase in the number of frogs eaten by birds may actually increase the likelihood of parasitism of other frogs, because the trematode's complex lifecycle includes the ramshorn snail and several intermediate hosts such as birds.[163][164]

In a few cases, captive breeding programs have been established and have largely been successful.[165][166] In 2007, the application of certain probiotic bacteria was reported to protect amphibians from chytridiomycosis.[167] One current project, the Panama Amphibian Rescue and Conservation Project, has subsequently been developed to rescue species at risk of this disease in eastern Panama, and to develop field applications for probiotic therapy.[168][169] The World Association of Zoos and Aquariums named 2008 as the "Year of the Frog" in order to draw attention to the conservation issues faced by them.[170]

The cane toad (Bufo marinus) is a very adaptable species native to South and Central America. In the 1930s, it was introduced into Puerto Rico, and later various other islands in the Pacific and Caribbean region, as a biological pest control agent.[171] In 1935, 3000 toads were liberated in the sugar cane fields of Queensland, Australia, in an attempt to control cane beetles such as Dermolepida albohirtum, the larvae of which damage and kill the canes. Initial results in many of these countries were positive, but it later became apparent that the toads upset the ecological balance in their new environments. They bred freely, competed with native species of frogs, ate bees and other harmless native invertebrates, had few predators in their adopted habitats, and poisoned pets, carnivorous birds, and mammals. In many of these countries, they are now regarded both as pests and invasive species, and scientists are looking for a biological method to control them