Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of wildfowl Two studies of reintroduction programmes of ducks in New Zealand found high survival of released birds and population establishment, with one describing successful breeding. One study describes higher success in the second year of the release programme, potentially because there was then a population present in the wild and more intensive predator control. A before-and-after study from Alaska found low survival of released cackling geese Branta hutchinsii, but that the population recovered from 1,000 to 6,000 birds after releases and the control of mammalian predators. A review of a reintroduction programme from Hawaii found that the release of 2,150 Hawaiian geese (nene) Branta sandvicensis had not resulted in the establishment of a self-sustaining population, although some birds bred. Two studies from Canada found very low return rates for released ducks with one finding no evidence for survival of released birds over two years, although there was some evidence that breeding success was higher for released birds than wild ones. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F618https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F618Sun, 14 Oct 2012 13:05:11 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of gamebirds One of five studies from across the world found that releasing gamebirds established a population or bolstered an existing population, although the authors argued that the population of 30–40 western capercaillie Tetrao urogallus (from nearly 400 released) was unlikely to be self-sustaining. A review of a reintroduction programme in Pakistan found some breeding success in released cheer pheasants Catreus wallichii, but that habitat change at the release site then excluded released birds. Three studies from Europe and the USA found that released birds had low survival, low reproductive success and had no impact on the wild population. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F619https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F619Sun, 14 Oct 2012 13:38:41 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of rails One replicated study from Australia found that released Lord Howe Island woodhens Tricholimnas sylvestris successfully bred in the wild, re-establishing a wild population. A replicated study from the UK found high survival of released corncrake Crex crex in the first summer (although no data were available on overwinter survival or breeding). A replicated study in New Zealand found very low survival of North Island weka Gallirallus australis greyi following release, mainly due to predation by invasive mammals. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F620https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F620Sun, 14 Oct 2012 13:58:52 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of cranes Four studies of five release programmes from the USA and Russia, from a total of eight programmes, found that released cranes had high survival or bred in the wild. Two studies from two release programmes in the USA found low survival of captive-bred eggs fostered to wild birds, compared with wild eggs, or a failure to increase the wild flock size. A worldwide review found that releases of migratory species only tended to be successful if birds were released into existing flocks, with higher success for non-migratory populations. One study from the USA found that birds released as sub-adults had higher survival than birds cross-fostered to wild birds. One study from the USA found that 73% of all mortalities occurred in the first year after release. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F621https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F621Sun, 14 Oct 2012 14:04:41 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of bustards Three reviews of a release programme for houbara bustard Chlamydotis undulata macqueenii in Saudi Arabia and a replicated trial as part of the same programme found low initial survival of released birds, but the establishment of a breeding population and an overall success rate of 41%. The programme tested many different release techniques, discussed elsewhere, with releases being most successful if sub-adults were released, able to fly, into a large exclosure. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F622https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F622Sun, 14 Oct 2012 14:23:17 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of wadersA review of black stilt Himantopus novaezelandiae releases in New Zealand found that birds had low survival (13–20%) and many moved away from their release sites so, in consequence, that they could not be managed and were unlikely to interact with stilt populations in the wild. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F623https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F623Sun, 14 Oct 2012 14:32:46 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of storks and ibisesA replicated study and a review of northern bald ibis Geronticus eremita release programmes in Europe and the Middle East found that only one of four had resulted in a wild population being established or supported, with many birds dying or dispersing, rather than forming stable colonies. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F624https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F624Sun, 14 Oct 2012 14:38:18 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of vultures Four studies of two release programmes found that release programmes led to large population increases in Andean condors Vultur gryphus in Colombia and griffon vultures Gyps fulvus in France. A small study in Peru found high survival of released Andean condors Vultur gryphus over 18 months, with all fatalities occurring in the first six months after release. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F625https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F625Sun, 14 Oct 2012 14:40:59 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of raptors Five studies of three release programmes from across the world found the establishment or increase of wild populations of falcons Falco spp. Five studies from the USA found high survival of released raptors (with between one and 204 birds released), whilst two found that released birds behaved normally and hunted successfully. One study from Australia found that a wedge-tailed eagle Aquila audax had to be taken back into captivity after acting aggressively towards humans, whilst another Australian study found that only one of 15 brown goshawks Accipiter fasciatus released was recovered, although the authors do not draw conclusions about survival rates from this. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F626https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F626Sun, 14 Oct 2012 14:54:39 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of owls A study in the USA found that a barn owl Tyto alba population was established following the release of 157 birds in the area over three years. A replicated, controlled study in Canada found that released burrowing owls Athene cunicularia had similar reproductive output, but higher mortality than wild birds, and no released birds returned after migration, although return rates for released birds’ offspring were no different from wild birds. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F627https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F627Sun, 14 Oct 2012 22:47:34 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of pigeonsA single review of a captive-release programme in Mauritius found that that released pink pigeons Nesoenas mayeri had a first year survival of 36%. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F628https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F628Sun, 14 Oct 2012 22:54:33 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of parrots A before-and-after study from Venezuela found that the local population of yellow-shouldered amazons Amazona barbadensis increased significantly following the release of captive-bred birds, along with other interventions. A replicated study in Costa Rica and Peru found high survival and some breeding of scarlet macaw Ara macao after release. Three replicated studies in the USA, Dominican Republic and Puerto Rico found low survival in released birds (4–41% in the first year after release), although the Puerto Rican study also found that released birds bred successfully. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F629https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F629Sun, 14 Oct 2012 22:56:19 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of songbirds A before-and-after study in Mauritius describes the establishment of a population of Mauritius fody Foudia rubra following the release of captive-bred individuals. Four studies of three release programmes on Hawaii found high survival of all three species released (Hawaiian crows Corvus hawaiiensis and two thrushes: omao Myadestes obscurus and puaiohi M. palmeri), with the two thrushes successfully breeding. The authors in one note that many of the released puaiohi dispersed from the release site, meaning that repopulating specific areas may require multiple releases. A replicated, controlled study from the USA found that San Clemente loggerhead shrike Lanius ludovicianus mearnsi pairs with captive-bred females had lower reproductive success than pairs where both parents were wild-bred. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F630https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F630Sun, 14 Oct 2012 23:05:39 +0100Collected Evidence: Collected Evidence: Release birds in groupsA replicated study from New Zealand found that released black stilts Himantopus novaezelandiae were more likely to move long distances after release if they were released in larger groups. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F634https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F634Sun, 14 Oct 2012 23:34:47 +0100Collected Evidence: Collected Evidence: Release birds in ‘coveys’ A replicated study in Saudi Arabia found that houbara bustard Chlamydotis undulata macqueenii survival was low when chicks were released in coveys with flightless females. A review of cackling goose Branta hutchinsii conservation and a replicated study in England found that geese and grey partridge Perdix perdix releases were more successful for birds released in coveys than for young birds released on their own or adults released in pairs. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F635https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F635Sun, 14 Oct 2012 23:35:50 +0100Collected Evidence: Collected Evidence: Release birds as adults or sub-adults, not juveniles Three replicated studies found that malleefowl Leipoa ocellata, houbara bustards Chlamydotis undulata macqueenii and cackling geese Branta hutchinsii released as sub-adults, not juveniles had higher survival rates. A replicated study from New Zealand found lower survival for black stilts Himantopus novaezelandiae released as sub-adults, compared with juveniles. Two replicated studies from Hawaii and Saudi Arabia found lower survival for Hawaiian geese Branta sandvicensis and bustards released as wing-clipped sub-adults, compared with birds released as juveniles. Three replicated studies found no differences in survival between ducks, vultures and ibises released at different ages, but a second study of the vulture release programme found that birds released when more than three years old had lower reproductive success than birds released at an earlier stage. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F636https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F636Sun, 14 Oct 2012 23:39:47 +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: Reintroduce primates into habitat without predators One study in Tanzania found that a population of reintroduced chimpanzees increased over 16 years following reintroduction into habitat without predators. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1592https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1592Fri, 20 Oct 2017 14:15:01 +0100Collected Evidence: Collected Evidence: Release captive-bred bats We found no studies that evaluated the effects of releasing captive-bred bats on bat populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2039https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2039Wed, 05 Dec 2018 18:32:17 +0000Collected Evidence: Collected Evidence: Release captive-bred individuals to re-establish or boost populations in native range Thirty-one studies evaluated the effects of releasing captive-bred mammals to establish or boost populations in their native range. Seven studies were in the USA, three were in Australia and Italy, two studies were in each of Canada, Sweden, Saudi Arabia, the UK, the Netherlands and South Africa and one study was in each of France, Africa, Europe, and North America, Estonia, the USA and Mexico, Poland and China. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (30 STUDIES) Abundance (7 studies): Five of five studies (one replicated) and two reviews in Saudi Arabia, Australia, the USA, South Africa, France, the Netherlands and China found that following release of captive-bred (or in one case captive-reared, or including translocated) animals, populations of mountain gazelles, Corsican red deer, Père David's deer, Eurasian otters and swift foxes increased. The two reviews found that following release of mainly translocated but some captive-bred large carnivores, populations of four of six species increased, and over half of mammal release programmes were considered successful. Reproductive success (5 studies): Four studies (one replicated) in Saudi Arabia, the UK and the Netherlands found that released captive-bred (and in some cases some wild-born translocated) mountain gazelles, dormice and some Eurasian otters reproduced successfully and female Arabian oryx reproduced successfully regardless of prior breeding experience. A controlled study in Italy found that released captive-born Apennine chamois reproduced in similar numbers to wild-caught translocated chamois. Survival (24 studies): Four of three controlled studies (two replicated) and two reviews in Canada, Canada and the USA, Sweden, Italy and across the world found that released captive-bred swift foxes, European otters and mammals from a review of 49 studies had lower post-release survival rates than did wild-born translocated animals. The other study found that released captive-born Apennine chamois survived in similar numbers to wild-caught translocated chamois. Three studies (one replicated) in the USA and Canada found that released captive-born Key Largo woodrats, Vancouver Island marmots and swift fox pups had lower survival rates than wild-born, wild-living animals. One of the studies also found that Vancouver Island marmots released at two years old were more likely to survive than those released as yearlings. Eleven studies (three replicated) in Italy, Sweden, the UK, Estonia, Poland, Saudi Arabia, Australia and the USA found that following the release of captive-bred (and in some cases some wild-born translocated) animals, Arabian oryx, populations of European otters, European mink and mountain gazelle survived for 2-11 years, roe deer and over a third of brush-tailed rock-wallabies, black-footed ferrets and brown hares survived for 0.5-24 months and dormice populations survived three months to over seven years. A review in Australia found that release programmes for macropod species resulted in successful establishment of populations in 61% of cases and that 40% survived over five years, and another review in Australia found that over half of programmes were considered successful. Two studies and a review in the USA, USA and Mexico and South Africa found that over 40% of released captive-bred American black bears were killed or had to be removed, only one of 10 oribi survived over two years and that most black-footed ferret releases were unsuccessful at maintaining a population. BEHAVIOUR (3 STUDIES) Use (3 studies): Two studies in the USA and Australia found that following release, most captive-bred and translocated mountain lions that had been held in captivity prior to release and most released captive-bred brush-tailed rock-wallabies established stable home ranges. A controlled study in Italy found that released captive-born Apennine chamois remained closer to the release site than released wild-caught translocated chamois. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2476https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2476Thu, 04 Jun 2020 10:11:11 +0100Collected Evidence: Collected Evidence: Reintroduce top predators to suppress and reduce the impacts of smaller non-native predator and prey species We found no studies that evaluated the effects on mammals of reintroducing top predators to suppress and reduce the impacts of smaller non-native predator and prey species. 'We found no studies' means that we have not yet found any studies that have directly evaluated this intervention during our systematic journal and report searches. Therefore, we have no evidence to indicate whether or not the intervention has any desirable or harmful effects.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2531https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2531Mon, 08 Jun 2020 16:22:00 +0100Collected Evidence: Collected Evidence: Release accidentally caught (‘bycatch’) reptiles Three studies evaluated the effects on reptile populations of releasing accidentally caught reptiles. One study was in each of the Caribbean Sea, Costa Rica and the Republic of Korea. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One replicated study in the Caribbean Sea found that from a released group of green turtles that included some accidentally caught and some head-started individuals, some survived for at least several months in the wild. One replicated study in the Republic of Korea found that green turtles caught in pound nets all survived for at least two weeks to a year after release. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One controlled study off the Pacific coast of Costa Rica found that the behaviour of longline-caught sea turtles following release was broadly similar to free-swimming turtles. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3624https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3624Thu, 09 Dec 2021 13:37:44 +0000Collected Evidence: Collected Evidence: Release animals that modify landscapes (e.g. ecological engineers) We found no studies that evaluated the effects on reptile populations of releasing animals that modify landscapes (e.g. ecological engineers). ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3710https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3710Mon, 13 Dec 2021 13:55:20 +0000