Collected Evidence: Collected Evidence: Breed reptiles in captivity: Sea turtles Two studies evaluated the effects of breeding sea turtles in captivity. One study was in the Cayman Islands, Costa Rica, Surinam and Ascension Island and one was in Japan. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Reproductive success (2 studies): One replicated, controlled study in the Cayman Islands, Costa Rica, Surinam and Ascension Island found that artificially incubated green turtle eggs that were laid in captivity had lower hatchling success than those laid in the wild and artificially incubated. One study in Japan reported that hatching success of eggs produced by one female black turtle in captivity was 12%. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3745https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3745Tue, 14 Dec 2021 11:14:04 +0000Collected Evidence: Collected Evidence: Breed reptiles in captivity: Snakes – Boas and pythons Twelve studies evaluated the effects of breeding boas and pythons in captivity. Five studies were in the USA, two were in the UK and one was in each of Jersey, Australia, India an unknown location and one was a global review. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (12 STUDIES) Reproductive success (11 studies): Five studies in Jersey, the USA and the UK reported that 1–4 female boas produced litters of 3–34 young, though 2–10 young/litter or 38% of young overall were stillborn. One replicated study in the USA reported that a captive breeding programme for ball pythons produced over 5,000 eggs from nearly 800 clutches, with an average hatching success of 81%. Five studies in an unknown location, the USA, Australia, India and the UK reported that female pythons produced clutches of 4–29 eggs, with hatching success of 40–100% or 0–100%. Survival (5 studies): Five studies in the USA, Australia, India and the UK reported that 2–8 captive-bred python hatchlings survived at least two years or 5–8 months, but seven captive-bred emerald tree boas died within three months of birth. Condition (1 study): One global review reported on one study on Jamaica boas that found that captive breeding had a negative effect on genetic variation compared to wild populations. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3747https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3747Tue, 14 Dec 2021 12:34:08 +0000Collected Evidence: Collected Evidence: Breed reptiles in captivity: Snakes – Colubrids Eighteen studies evaluated the effects of breeding colubrid snakes in captivity. Ten studies were in the USA, two were the UK, two were in unknown locations and one was in each of Costa Rica, Taiwan, India and Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (18 STUDIES) Reproductive success (18 studies): Seventeen studies in the USA, Costa Rica, the UK, Taiwan, Australia, India and unknown locations reported that 1–2 female colubrid snakes produced 1–12 clutches of 3–16 eggs. Ten of those studies reported hatching success of 67–100%, two reported hatching success of 25% and two reported that hatching success varied from 0–75%. Two of the studies reported that at least 18–20 eggs hatched successfully. One study also found that captive-bred offspring produced two clutches of 3–4 eggs and all hatched successfully. One study in the USA reported that three female San Francisco garter snakes produced broods of 9–35 young. Survival (5 studies): Five studies in the USA and the UK found that 2–20 captive-bred snakes survived for at least 1–3 months and 2–3 years in captivity, and that from six broods of 9–35 captive-bred San Francisco garter snakes, six young died within four months of birth. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3748https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3748Tue, 14 Dec 2021 13:03:41 +0000Collected Evidence: Collected Evidence: Breed reptiles in captivity: Lizards Twenty-three studies evaluated the effects of breeding lizards in captivity. Ten studies were in the USA, three were in Australia, two were in the UK and one was in each of Switzerland, an unknown location, the Arabian Peninsula, Mexico, Italy, Spain, Bahamas and Jamaica and the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (23 STUDIES) Abundance (2 studies): One replicated study in Spain reported that a captive-breeding programme for large psammodromus lizards produced 365 juveniles for release over two years. One replicated study in Australia reported that captive populations of Lister’s geckos and Christmas Island blue-tailed skinks at two facilities grew or remained stable over 4–5 years. Reproductive success (22 studies): Eighteen studies (including seven replicated studies) in the USA, Switzerland, an unknown location, the Arabian Peninsula, Mexico, Italy, Spain the UK and Australia reported that captive lizards produced one or more clutches of 2–21 eggs, 3–12 eggs/year or gave birth to 21 live young. Eleven of the studies reported hatching success of 45–96%. Three of the studies reported hatching success of 0–40%, 0–43% or 0–100%. One of the studies reported hatching success of <10%. One of the studies also found that hatching success for Australian painted dragon eggs was similar across all incubation temperatures used, but higher for eggs laid earlier in the season. One of two studies (including one replicated study) in Jamaica and the USA and the Bahamas reported that captive breeding programmes lasting 19 and 24 years produced 73 and five Jamaican iguana hatchlings respectively. The other study reported that over 2.5 years, captive San Salvador rock iguanas produced only a single hatchling. One controlled study in the USA found that captive-reared western fence lizard females housed individually or in pairs produced more clutches with fewer infertile eggs compared to females kept in groups of four or eight. One replicated, before-and-after study in the USA found that curious skinks kept in smaller breeding groups and provided nutrient rich food produced more clutches of eggs than skinks that were kept in larger groups and given regular food. Survival (9 studies): Seven studies (including four replicated studies) in an unknown location, Mexico, Italy, the USA and the UK reported that 4–23 captive-bred lizards, or some individuals, survived for six weeks or at least six months to three years, or that individuals of three species survived to reach adult size. Two studies in the USA reported that one of three and eight of 10 captive-bred lizards died within one day or 18 months. Condition (1 study): One controlled study in the USA reported that giant horned lizard eggs incubated at 26.5°C produced larger hatchlings compared to those incubated at 28°C. BEHAVIOUR (1 STUDY) Use (1 study): One study in the USA reported that captive female Yuman fringe-toed lizards selected an 8:1 sand:water mixture when laying eggs. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3756https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3756Tue, 14 Dec 2021 14:27:51 +0000Collected Evidence: Collected Evidence: Breed reptiles in captivity: Crocodilians Six studies evaluated the effects of breeding crocodilians in captivity. Two studies were in the USA, one was in each of Venezuela, Brazil and China and one was a global review. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (6 STUDIES) Abundance (1 studies): One study in China reported that a captive population of Chinese alligators increased from 10,000 to 15,000 individuals over a 10-year period. Reproductive success (4 studies): Four studies in the USA, Venezuela and Brazil reported that 1–4 captive females crocodilians, including four captive-born broad-snouted caiman, produced clutches of 17–49 eggs, with hatching successes of 35–86% or 6%. Survival (1 studies): One study in Brazil reported that 4% of broad-snouted caiman hatchlings died within one week Condition (1 studies): One global review reported on one study on Chinese alligators that found that captive breeding had a positive effect on genetic variation compared to wild populations. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3757https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3757Tue, 14 Dec 2021 15:32:22 +0000Collected Evidence: Collected Evidence: Alter incubation temperatures to achieve optimal/desired sex ratio: Sea turtles One study evaluated the effects of altering incubation temperatures to achieve optimal/desired sex ratios on sea turtles. This study was in Canada. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Reproductive success (1 study): One replicated study in Canada reported that hatching success of two clutches of artificially incubated green turtle eggs was 8% and 62%. BEHAVIOUR (0 STUDIES) OTHER (1 STUDY): Offspring sex ratio (1 study): One replicated study in Canada found that incubating green turtle eggs at higher temperatures resulted in more females hatchlings. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3761https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3761Tue, 14 Dec 2021 16:09:09 +0000Collected Evidence: Collected Evidence: Alter incubation temperatures to achieve optimal/desired sex ratio: Tortoises, terrapins, side-necked & softshell turtles Eight studies evaluated the effects of altering incubation temperatures to achieve optimal/desired sex ratios on tortoise, terrapin, side-necked and softshell turtle populations. Four studies were in the USA, two were in Columbia and one was in each of Brazil and the Galápagos. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (5 STUDIES) Reproductive success (5 studies): Four studies (including two replicated studies) in the USA, Colombia and the Galápagos found that hatching success of alligator snapping turtle, Magdalena river turtle, western pond turtle and Española giant tortoise eggs varied across the range of temperatures tested. One controlled study in Brazil found that Amazon River turtle nests covered with black plastic sheeting had lower hatching success than uncovered nests. BEHAVIOUR (0 STUDIES) OTHER (8 STUDIES): Offspring sex ratio (8 studies): Seven studies (including three replicated, randomized studies) in the USA, Colombia and the Galápagos found that hatchling sex ratio of turtles and tortoises was affected by incubation temperature, and that warmer temperatures resulted in more female hatchlings. One controlled study in Brazil found that Amazon River turtle nests covered with black plastic sheeting produced more female hatchlings than uncovered nests. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3762https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3762Tue, 14 Dec 2021 16:12:00 +0000Collected Evidence: Collected Evidence: Alter incubation temperatures to achieve optimal/desired sex ratio: Snakes & lizards Four studies evaluated the effects of altering incubation temperatures to achieve optimal/desired sex ratios on snake and lizard populations. Two studies were in each of the USA and China. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Reproductive success (3 studies): Two replicated studies (including one randomized study) in China and the USA found that toad-headed agama hatching success was lowest at the highest incubation temperature tested and southern alligator lizard hatching success was highest at intermediate temperatures.One randomized study in the USA found that survival of garter snake offspring was highest when females were maintained at intermediate temperatures. BEHAVIOUR (0 STUDIES) OTHER (4 STUDIES): Offspring sex ratio (4 studies): Three replicated studies (including two randomized studies) in China and the USA found that hatchling sex ratio of stripe-tailed ratsnakes, toad-headed agamas and southern alligator lizard was not affected by incubation temperature. One randomized study in the USA found that sex ratio of live garter snake offspring was not affected by the temperature females were maintained at. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3763https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3763Tue, 14 Dec 2021 16:36:15 +0000Collected Evidence: Collected Evidence: Alter incubation temperatures to achieve optimal/desired sex ratio: Crocodilians Three studies evaluated the effects of altering incubation temperatures to achieve optimal/desired sex ratios on crocodilian populations. Two studies were in Argentina and one was in China. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Reproductive success (2 studies): Two replicated, randomized study in Argentina found that hatching success of broad-snouted caiman eggs was similar across all temperatures tested. BEHAVIOUR (0 STUDIES) OTHER (3 STUDIES): Offspring sex ratio (3 studies): Two replicated, randomized studies in Argentina found that hatchling sex ratio of broad-snouted caimans was affected by temperature, and that warmer temperatures resulted in fewer females. One replicated study in China found that exposing Chinese alligator eggs to short periods of high temperatures during incubation resulted in fewer female hatchlings. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3764https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3764Tue, 14 Dec 2021 16:44:08 +0000Collected Evidence: Collected Evidence: Alter incubation temperatures to achieve optimal/desired sex ratio: Tuatara Two studies evaluated the effects of altering incubation temperatures to achieve optimal/desired sex ratios on tuatara populations. Both studies were in New Zealand. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (2 STUDIES): Offspring sex ratio (2 studies): Two replicated studies (including one controlled study) in New Zealand found that hatchling sex ratio of tuatara was affected by temperature, and that warmer temperatures resulted in more males. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3765https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3765Tue, 14 Dec 2021 17:00:12 +0000
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What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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