ionMolecular ecology has become one of the key tools in the modern conservationist's kit. Here we review three areas where molecular ecology has been applied to amphibian conservation: genes on landscapes, within - population processes, and genes that matter. We summarize relevant analytical methods, recent important studies from the amphibian literature, and conservation implications for each section. Finally, we include five in - depth examples of how molecular ecology has been successfully applied to specific amphibian systems.
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Amphibian immunity - stress, disease, and climate change
Like all other vertebrate groups, amphibian responses to the environment are mediated through the brain ( hypothalamic ) - pituitary - adrenal/interrenal ( HPA/I ) axis and the sympathetic nervous system. Amphibians are facing historically unprecedented environmental stress due to climate change that will involve unpredictable temperature and rainfall regimes and possible nutritional deficits due to extremes of temperature and drought. At the same time, amphibians in all parts of the world are experiencing unprecedented declines due to the emerging diseases, chytridiomycosis ( caused by Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans ) and ranavirus diseases due to viruses of the genus Ranavirus in the family Iridoviridae. Other pathogens and parasites also afflict amphibians, but here I will limit myself to a review of recent literature linking stress and these emerging diseases ( chytridiomycosis and ranavirus disease ) in order to better predict how environmental stressors and disease will affect global amphibian populations.
Developments in amphibian captive breeding and reintroduction programs
Captive breeding and reintroduction remain high profile but controversial conservation interventions. It is important to understand how such programs develop and respond to strategic conservation initiatives. We analyzed the contribution to conservation made by amphibian captive breeding and reintroduction since the launch of the International Union for Conservation of Nature ( IUCN ) Amphibian Conservation Action Plan ( ACAP ) in 2007. We assembled data on amphibian captive breeding and reintroduction from a variety of sources including the Amphibian Ark database and the IUCN Red List. We also carried out systematic searches of Web of Science, JSTOR, and Google Scholar for relevant literature. Relative to data collected from 1966 to 2006, the number of species involved in captive breeding and reintroduction projects increased by 57% in the 7 years since release of the ACAP. However, there have been relatively few new reintroductions over this period; most programs have focused on securing captive - assurance populations ( i. e. , species taken into captivity as a precaution against extinctions in the wild ) and conservation - related research. There has been a shift to a broader representation of frogs, salamanders, and caecilians within programs and an increasing emphasis on threatened species. There has been a relative increase of species in programs from Central and South America and the Caribbean, where amphibian biodiversity is high. About half of the programs involve zoos and aquaria with a similar proportion represented in specialist facilities run by governmental or nongovernmental agencies. Despite successful reintroduction often being regarded as the ultimate milestone for such programs, the irreversibility of many current threats to amphibians may make this an impractical goal. Instead, research on captive assurance populations may be needed to develop imaginative solutions to enable amphibians to survive alongside current, emerging, and future threats.
