Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Use artificial fertilization in captive breeding Three replicated studies (including two randomized studies) in Australia and the USA found that the success of artificial fertilization depended on the type and number of doses of hormones used to stimulate egg production. One replicated study in Australia found that 55% of eggs were fertilized artificially, but soon died. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F834https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F834Wed, 28 Aug 2013 15:57:47 +0100Collected Evidence: Collected Evidence: Captive breeding frogs Thirty-three studies investigated the success of breeding frogs in captivity. Twenty-three of 33 studies, three of which were reviews and 30 replicated studies, across the world found that amphibians produced egg in captivity, in four cases by captive-bred females. Seven found mixed results, with some species of frogs or 17–50% of captive populations reproducing successfully in captivity, but with other species difficult to maintain or raise to adults. One found that frogs did not breed successfully in captivity and another that all breeding frogs died. Seventeen of the studies found that captive-bred frogs were raised successfully to hatching, tadpoles, froglets or adults in captivity. One found that froglet survival was low and another that three species were not successfully raised to adulthood. Four replicated studies (including one small study) in,Canada, Fiji, Hong Kong and Italy found that 30–88% of eggs hatched or survival to metamorphosis was 75%, as froglets was 17–51% or to adults was 50–90% in captivity. One review and four replicated studies (including two small studies) in Germany, Italy and the USA found that reproductive success of frogs in captivity depended on temperature or a simulated wet and dry season, but not on whether frogs were housed in high or low maintenance facilities. Three replicated studies (including one small study) in Germany, Australia and Canada found that egg or tadpole development in captivity was affected by parental care, density or temperature. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F835https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F835Thu, 29 Aug 2013 09:25:18 +0100Collected Evidence: Collected Evidence: Captive breeding harlequin toads (Atelopus species) One review and three of five replicated studies (including one small study) in Colombia, Ecuador, Germany and the USA found that harlequin toads reproduced in captivity. One found that eggs were only produced in captivity by simulating a dry and wet season and one found that successful breeding was difficult. One found that captive-bred harlequin toads were raised successfully to metamorphosis in captivity. Two found that most toads died before or after hatching. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F836https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F836Thu, 29 Aug 2013 13:54:34 +0100Collected Evidence: Collected Evidence: Captive breeding Mallorcan midwife toads Two replicated studies in the UK found that Mallorcan midwife toads produced eggs that were raised to metamorphs or toadlets successfully in captivity. One found that clutches dropped by males were not successfully maintained artificially. One replicated study in the UK found that survival to metamorphosis was 85%. One randomized, replicated, controlled study in the UK found that toads bred in captivity for nine or more generations had slower tadpole development, reduction in one predator defence trait and decreased genetic diversity. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F837https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F837Thu, 29 Aug 2013 14:21:37 +0100Collected Evidence: Collected Evidence: Captive breeding salamanders (including newts) Four of six replicated studies (including four small studies) in Japan, Germany, the UK and USA found that eggs were produced successfully in captivity, in one case by one captive-bred female. Two found that production of eggs depended on tank habitat or was more successful in semi-natural compared to laboratory conditions. Captive-bred salamanders were raised to yearlings or a small number of larvae or adults in captivity. One review found that four salamander species bred successfully in captivity, but slimy salamanders produced eggs that did not hatch. One replicated study in Japan found that 60% of Japanese giant salamander eggs survived to hatching in captivity. Two replicated studies (including one small study) in Mexico and the USA found that larval development, body condition and survival of captive-bred amphibians were affected by water temperature, density and whether they were raised under laboratory or semi-natural conditions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F838https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F838Thu, 29 Aug 2013 14:43:51 +0100Collected Evidence: Collected Evidence: Captive breeding toads Ten replicated studies (including three small studies) in Germany, Italy, Spain, the UK and USA found that toads produced eggs in captivity, in one case by second generation captive females. Eight found that captive-bred toads were raised successfully to tadpoles, toadlets or adults in captivity. Two found that most toads died after hatching or after metamorphosis. Two reviews found mixed results with four species of toad or 21% of captive populations of Puerto Rican crested toad breeding successfully in captivity. Four replicated studies in Germany, Spain and the USA found that reproductive success of captive toads was affected by tank humidity or was higher in outdoor enclosures than indoor tanks. One replicated study in Germany found that survival of European red-bellied toad eggs, tadpoles and juveniles was higher in captivity than the wild. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F848https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F848Thu, 05 Sep 2013 12:44:56 +0100Collected Evidence: Collected Evidence: Release captive-bred frogs Four of five studies (including one replicated study and one review) in Europe, Hong Kong and the USA found that captive-bred frogs released as tadpoles, juveniles or adults established populations or stable breeding populations at 88-100% of sites, and in some cases colonized new sites. One study found that stable breeding populations were not established. One before-and-after study in Spain found that released captive-bred, captive-reared and translocated frogs established breeding populations at 79% of sites. Three replicated studies in Australia and the USA found that a high proportion of captive-bred frogs released as eggs survived to metamorphosis, some released as tadpoles survived at least the first few months or few released as froglets survived. Three studies (including two replicated studies) in Australia, Italy and the UK and a review in the USA found that captive-bred frogs reproduced at all or 31–33% of release sites, or that there was very limited breeding by released frogs. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F870https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F870Wed, 11 Sep 2013 14:52:42 +0100Collected Evidence: Collected Evidence: Release captive-bred amphibians One review found that 41% of release programmes of captive-bred or head-started amphibians showed evidence of breeding in the wild for multiple generations, 29% showed some evidence of breeding and 12% evidence of survival following release. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F871https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F871Wed, 11 Sep 2013 15:54:35 +0100Collected Evidence: Collected Evidence: Release captive-bred green and golden bell frogs One review and two before-and-after studies in Australia found that captive-bred green and golden bell frogs released mainly as tadpoles did not established breeding populations, or only established stable breeding populations following one of four release programmes. One study in Australia found that a small proportion of captive-bred green and golden bell frog released as tadpoles survived at least 13 months after release. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F872https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F872Wed, 11 Sep 2013 16:03:45 +0100Collected Evidence: Collected Evidence: Release captive-bred Mallorcan midwife toads Three studies (including one replicated study and one review) in Mallorca found that captive-bred midwife toads released as tadpoles, toadlets or adults established breeding populations at 38%, 80% or 100% of sites. One randomized, replicated, controlled study in the UK found that predator defences were maintained, but genetic diversity reduced in a captive-bred reintroduced population. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F873https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F873Thu, 12 Sep 2013 10:43:06 +0100Collected Evidence: Collected Evidence: Release captive-bred salamanders (including newts) One before-and-after study in Germany found that captive-bred great crested newts and smooth newts released as larvae, juveniles and adults established stable breeding populations. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F874https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F874Thu, 12 Sep 2013 10:48:40 +0100Collected Evidence: Collected Evidence: Release captive-bred toads Two of three studies (including two replicated studies) in Denmark, Sweden and the USA found that captive-bred toads released as tadpoles, juveniles or metamorphs established populations, in one case at 70% of sites. One of the studies found that populations were not established from captive-bred and head-started toads. Two studies in Puerto Rico found that survival of released captive-bred Puerto Rican crested toads was low and that 25% were predated within two days of release. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F875https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F875Thu, 12 Sep 2013 10:51:57 +0100Collected Evidence: Collected Evidence: Freeze sperm or eggs for future use Nine replicated studies (including three controlled studies) in Austria, Australia, Russia, the UK and USA found that following freezing frog and toad sperm viability depended on species and/or cryoprotectant used. One found that although sperm viability was low following freezing, it could be frozen for up to 58 weeks. Five of the studies and one additional replicated study in Australia found that following freezing, viability of sperm and in one case eggs, also depended on storage temperature, storage method, freezing or thawing rate. Seven replicated studies (including three controlled studies) in Austria, Australia, the UK and USA found that frog and toad sperm viability was greatest following freezing with the cryoprotectant dimethyl sulfoxide, glycerol, sucrose or dimethyl formamide. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F876https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F876Thu, 12 Sep 2013 11:09:04 +0100Collected Evidence: Collected Evidence: Head-start amphibians for release Twenty-two studies head-started amphibians from eggs and monitored them after release. Six of 10 studies (including five replicated studies) in Denmark, Spain, the UK and USA and a global review found that released head-started tadpoles, metamorphs or juveniles established breeding frog populations or increased populations of frogs or toads. Two found mixed results with breeding populations established in 12 of 17 studies reviewed or at two of four sites. Two found that head-started metamorphs or adults did not prevent a frog population decline or establish a breeding toad population. For five of the studies, release of captive-bred individuals, translocation or habitat management were also carried out. Nine of 10 studies (including nine replicated studies) in Australia, Canada, Europe and the USA found that head-started amphibians released as tadpoles, metamorphs or adults metamorphosed successfully, tended to survive the first season, winter or year or bred successfully. One found adult survival was 1–17% over four years and one found limited breeding following the release of adults. Four replicated studies in Australia, the UK and USA found that frog survival to metamorphosis and size at metamorphosis was greater and time to metamorphosis shorter in head-started compared to wild animals. One replicated study in Canada found that young head-started leopard frogs were smaller than those in the wild. One replicated study in Australia found that corroboree frog tadpoles released earlier had higher survival, but metamorphosed two weeks later than those released a month later. Three studies (including one replicated study) in the USA only provided results for head-starting in captivity. Two found that Houston toad eggs could be captive-reared to tadpoles, but only one successfully reared adults. Three studies (including two replicated studies) in Canada and the USA found that during head-starting, amphibian growth rate, size, stress levels and survival was affected by the amount of protein provided, housing density or enclosure location. One found that mass, stress levels and survival were not affected by the amount of food or habitat complexity. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F881https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F881Fri, 13 Sep 2013 13:02:34 +0100Collected Evidence: Collected Evidence: Use hormone treatment to induce sperm and egg release during captive breeding One review and nine of 10 replicated studies (including two randomized, controlled studies) in Austria, Australia, China, Latvia, Russia and the USA found that hormone treatment of male amphibians stimulated or increased sperm production (Mansour, Lahnsteiner & Patzner 2010, Silla 2011) or resulted in successful breeding in captivity. One found that hormone treatment of males and females did not result in breeding. Four found that the amount and viability of sperm produced was affected by the type, amount or number of doses of hormone. One review and nine of 14 replicated studies (including six randomized and/or controlled studies) in Australia, Canada, China, Ecuador, Latvia and the USA found that hormone treatment of female amphibians had mixed results, with 30–71% of females producing viable eggs following treatment, or with egg production depending on the combination, amount or number of doses of hormones. Three found that hormone treatment stimulated egg production or successful breeding in captivity. Two found that hormone treatment did not stimulate or increase egg production. Five replicated studies (including one controlled study) in Canada, Latvia and the USA found that eggs induced by hormone treatment were raised successfully to tadpoles, toadlets or froglets in captivity. Two replicated studies, one of which was small, in Ecuador and the USA found that most toads died before or soon after hatching. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F883https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F883Fri, 13 Sep 2013 15:54:08 +0100