Demographic and genetic factors in the recovery or demise of ex situ populations following a severe bottleneck in fifteen species of Hawaiian tree snails

dc.contributor.author Price, Melissa
dc.contributor.author Sischo, David
dc.contributor.author Pascua, Mark-Anthony
dc.contributor.author Hadfield, Michael
dc.date.accessioned 2020-04-09T01:44:07Z
dc.date.available 2020-04-09T01:44:07Z
dc.date.issued 2015-11-12
dc.description.abstract Wild populations of endangered Hawaiian tree snails have declined precipitously over the last century due to introduced predators and other human impacts. Life history traits, such as very low fecundity (<5 offspring per year across taxa) and maturity at approximately four years of age have made recovery difficult. Conservation efforts such as in situ predator-free enclosures may increase survival to maturity by protecting offspring from predation, but no long-term data existed prior to this study demonstrating the demographic and genetic parameters necessary to maintain populations within those enclosures. We evaluated over 20 years of evidence for the dynamics of survival and extinction in captive ex situ populations of Hawaiian tree snails established from wild-collected individuals. From 1991 to 2006, small numbers of snails (<15) from fifteen species were collected from the wild to initiate captive-reared populations as a hedge against extinction. This small number of founders resulted in a severe bottleneck in each of the captive-reared populations.We identified key demographic parameters that predicted population recovery from this bottleneck. Species with captive populations that produced between two and four offspring per adult per year and had 20–50% of those offspring survive to maturity recovered to numbers above 100 individuals, and maintained viable populations following a decline that occurred between 2009 and 2014. Those populations that had less than two offspring per adult per year and less than 20% survival to maturity did not reach 100 individuals in captivity, and many of these populations died out during the recent decline. We suggest that small reductions in fitness may contribute to extirpation in taxa with inherently low fecundity, by keeping populations below a threshold number essential to long-term recovery. Future ex situ populations should be founded with no less than 15 adults, and maintained in conditions closely approximating the temperature and humidity of source locations to optimize fitness. Permanent translocations of wild populations for conservation purposes will be more likely to succeed with greater than 100 adults, and should be limited to locations with a similar climate to source locations. en_US
dc.format.extent 20 en_US
dc.identifier.citation Price et al. (2015), Demographic and genetic factors in the recovery or demise of ex situ populations following a severe bottleneck in fifteen species of Hawaiian tree snails. PeerJ 3:e1406; DOI 10.7717/peerj.1406 en_US
dc.identifier.doi 10.7717/peerj.1406
dc.identifier.uri http://hdl.handle.net/10125/67645
dc.language.iso en-US en_US
dc.rights CC0 1.0 Universal *
dc.rights.uri http://creativecommons.org/publicdomain/zero/1.0/ *
dc.subject Endangered species en_US
dc.subject Captive-rearing en_US
dc.subject Population genetics en_US
dc.subject Extinction en_US
dc.subject Achatinellinae en_US
dc.subject Self-fertilization en_US
dc.title Demographic and genetic factors in the recovery or demise of ex situ populations following a severe bottleneck in fifteen species of Hawaiian tree snails en_US
dc.type Article en_US
dc.type.dcmi Text en_US
prism.publicationname PeerJ en_US
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