Amphibians and conservation breeding programmes: do all threatened amphibians belong on the ark?
Biodivers. Conserv. (2015). DOI 10.1007/s10531-015-0966-9
Amphibians are facing an extinction crisis, and conservation breeding programmes are a tool used to prevent imminent species extinctions. Compared to mammals and birds, amphibians are considered ideal candidates for these programmes due to their small body size and low space requirements, high fecundity, applicability of reproductive technologies, short generation time, lack of parental care, hard wired behaviour, low maintenance requirements, relative cost effectiveness of such programmes, the success of several amphibian conservation breeding programmes and because captive husbandry capacity exists. Superficially, these reasons appear sound and conservation breeding has improved the conservation status of several amphibian species, however it is impossible to make generalisations about the biology or geo-political context of an entire class. Many threatened amphibian species fail to meet criteria that are commonly cited as reasons why amphibians are suitable for conservation breeding programmes. There are also limitations associated with maintaining populations of amphibians in the zoo and private sectors, and these could potentially undermine the success of conservation breeding programmes and reintroductions. We recommend that species that have been assessed as high priorities for ex situ conservation action are subsequently individually reassessed to determine their suitability for inclusion in conservation breeding programmes. The limitations and risks of maintaining ex situ populations of amphibians need to be considered from the outset and, where possible, mitigated. This should improve programme success rates and ensure that the limited funds dedicated to ex situ amphibian conservation are allocated to projects which have the greatest chance of success.
The moor frog (Rana arvalis), for example, exhibits a high degree of local adaptation to varying pH levels in breeding ponds across its large range (Rasanen et al. 2003a). The cost of mismatched adaptive traits and environmental pH is high (Andrén et al. 1989), therefore any conservation breeding initiative for this species would need to ensure that source and recipient habitats have similar pH values, or exploit the rapid evolutionary rate of this trait (Andrén et al. 1989; Rasanen et al. 2003a, b; Merila et al. 2004) to allow captive populations to track changes in their eventual release sites.