Collected Evidence: Collected Evidence: Remove and relocate ‘problem’ animals One replicated, before-and-after study in India found that ‘problem’ rhesus monkeys that were translocated, alongside other interventions, survived and remained at the release sites for at least four years. One controlled, before-and-after study in Kenya found that after 16 years, most crop-raiding olive baboons that were translocated from farmland, alongside other interventions, had survived and had similar survival rates compared to non-translocated populations. One before-and-after, site comparison study in the Republic of Congo and Gaboon found that 84% of the ‘problem’ western lowland gorillas that were relocated, alongside other interventions, survived for at least four years. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1422https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1422Tue, 17 Oct 2017 09:04:32 +0100Collected Evidence: Collected Evidence: Relocate primates to non-residential areas We found no evidence for the effects of relocating primates to non-residential areas on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1423https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1423Tue, 17 Oct 2017 09:26:18 +0100Collected Evidence: Collected Evidence: Retain nesting trees/shelter for primates within agricultural fields We found no evidence for the effects of retaining nesting trees/shelter for primates within agricultural fields on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1430https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1430Tue, 17 Oct 2017 09:53:02 +0100Collected Evidence: Collected Evidence: Regularly remove traps and snares around agricultural fields We found no evidence for the effects of regularly removing traps and snares around agricultural fields on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1433https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1433Tue, 17 Oct 2017 10:17:41 +0100Collected Evidence: Collected Evidence: Reduce road widths We found no evidence for the effects of reducing road widths on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1459https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1459Tue, 17 Oct 2017 13:35:36 +0100Collected Evidence: Collected Evidence: Regularly de-activate/remove ground snares One before-and-after study in the Democratic Republic of Congo and Rwanda found that mountain gorilla numbers increased over five years in an area that was patrolled for snares, alongside other interventions. One before-and-after study in the Democratic Republic of Congo, Rwanda and Uganda found that a mountain gorilla population declined in an area where snares were removed regularly, alongside other interventions. One before-and-after study in Ghana found that the number of snares declined in an area where they were regularly removed, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1475https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1475Tue, 17 Oct 2017 17:15:09 +0100Collected Evidence: Collected Evidence: Reduce the size of forestry teams to include employees only (not family members) We found no evidence for the effects of reducing the size of forestry teams to include employees only and not family members on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1499https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1499Tue, 17 Oct 2017 19:53:29 +0100Collected Evidence: Collected Evidence: Restrict the number of people that are allowed access to site We found no evidence for the effects of restricting the number of people that are allowed access to the site on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1504https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1504Tue, 17 Oct 2017 20:04:02 +0100Collected Evidence: Collected Evidence: Run research project and ensure permanent human presence at site Two before-and-after studies in Rwanda, Uganda and Congo found that numbers of mountain gorillas increased over 5-41 years while gorillas were continuously monitored by researchers, alongside other interventions. One review on mountain gorillas in Uganda found that no gorilla was killed over one year while gorillas were continuously monitored by researchers, alongside other interventions. One before-and-after study in Brazil found that most reintroduced golden lion tamarins did not survive over seven years post-release despite being permanently monitored by researchers, alongside other interventions, yet tamarins reproduced succesfully. One before-and-after study in Belize found that numbers of black howler monkeys increased by 138% over 13 years after being permanently monitored by researchers, alongside other interventions. One before-and-after study in the Republic of Congo found that most reintroduced chimpanzees permanently monitored by researchers, alongside other interventions, survived over 3.5 years. One before-and-after study in Kenya found ‘problem’ olive baboon troops still survived over 17 years post-translocation while being permanently monitored by researchers, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1511https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1511Wed, 18 Oct 2017 15:51:12 +0100Collected Evidence: Collected Evidence: Resettle illegal human communities (i.e. in a protected area) to another location One review on mountain gorillas in Uganda found that no more gorillas were killed after illegal settlers were relocated from the area, alongside other interventions. One before-and-after study in the Republic of Congo found that most reintroduced chimpanzees survived over five years after human communities were resettled, from the protected area alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1515https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1515Thu, 19 Oct 2017 09:12:23 +0100Collected Evidence: Collected Evidence: Regularly and continuously provide supplementary food to primates Two studies in China and The Gambia found that after regularly providing supplementary food, along with other interventions, primate populations increased. Two studies in Thailand and Malaysia found that populations declined after regular provision of supplementary food, alongside other interventions. Three studies in Brazil, South Africa, and Indonesia found that the majority of primates survived after being regularly provided supplementary food, along with other interventions. One study in Liberia found that after regular provision of supplementary food, along with other interventions, the majority of introduced chimpanzees survived for at least one year. One controlled study in Madagascar found that after a year of regular food supplimentation, along with other interventions, introduced black-and-white ruffed lemurs showed different diets compared to a resident wild group of the same species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1526https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1526Thu, 19 Oct 2017 09:53:52 +0100Collected Evidence: Collected Evidence: Regularly provide supplementary food to primates during resource scarce periods only One before-and-after study in the Republic of Congo found that the majority of chimpanzees survived for at least five years after supplementary feeding in resource scarce periods, alongside other interventions. One before-and-after study in Kenya found that wild olive baboons survived for at least 17 years after supplementary feeding in drought periods soon after translocation, alongside other interventions. One controlled study in Madagascar found that the diet of black-and-white ruffed lemurs was similar to that of wild individuals after supplementary feeding in resource scarce periods, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1527https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1527Thu, 19 Oct 2017 09:59:24 +0100Collected Evidence: Collected Evidence: Remove alien invasive vegetation where the latter has a clear negative effect on the primate species in question We found no evidence for the effects of removing alien invasive vegetation on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1533https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1533Thu, 19 Oct 2017 13:35:57 +0100Collected Evidence: Collected Evidence: Regularly disinfect clothes, boots etc. One controlled, before-and-after study in Rwanda, Uganda and Congo found that numbers of mountain gorillas increased by 168% over 41 years while being visited by researchers and tourists whose clothes were disinfected, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1547https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1547Thu, 19 Oct 2017 17:33:18 +0100Collected Evidence: Collected Evidence: Remove/treat external/internal parasites to increase reproductive success/survival One before-and-after study in Brazil found that most reintroduced golden lion tamarins treated for parasites, alongside other interventions, did not survive over seven years post-release. Three studies, including two before-and-after studies, in the Republic of Congo and The Gambia found that 70% of reintroduced chimpanzees treated for parasites, alongside other interventions, survived for at least 3.5-5 years and in one case the population increased. One study in Gabon found that 33% of reintroduced mandrills died within one year after release despite being treated for parasites, alongside other interventions. Two site comparison studies in Vietnam found that most reintroduced pygmy slow lorises died or disappeared (lost radio signal soon after release) despite being treated for parasites, alongside other interventions. One before-and-after, site comparison study in the Republic of Congo and Gabon and one before-and-after study in Gabon found that most western lowland gorillas treated for parasites, alongside other interventions, survived over nine months or four years. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1551https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1551Thu, 19 Oct 2017 19:11:32 +0100Collected Evidence: Collected Evidence: Remove human food waste that may potentially serve as food sources for primates to avoid disease transmission and conflict with humans We found no evidence for the effects of removing human wastes that may potentially serve as food sources for primates to avoid disease transmission and conflict with humans, on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1561https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1561Fri, 20 Oct 2017 10:04:19 +0100Collected Evidence: Collected Evidence: Reintroduce primates in groups Two studies in Brazil and Thailand found that populations of introduced primates declined after reintroduction in groups, alongside other interventions, while one study in Belize recorded an increase in populations. Two studies in Madagascar and India found that primate populations persisted 4-55 years after reintroduction in groups, alongside other interventions. Seven studies in Brazil, French Guiana, Madagascar, and South Africa found that a minority of primates survived for at least 15 weeks to seven years after reintroduction in groups, alongside other interventions. Seven studies in Belize, Brazil, French Guiana, Madagascar, and South Africa found that a majority of primates survived after between two and thirty months. One study in Madagascar found that introduced black-and-white ruffed lemurs Varecia variegata had similar diets to individuals in a wild population after reintroduction in groups, alongside other interventions. One study in The Gambia found that a population of introduced chimpanzees increased 25 years after reintroduction in groups, alongside other interventions. Four studies in Guinea, Liberia and the Republic of Congo found that the majority of chimpanzees survived for at least two to five years, after reintroduction in groups, alongside other interventions. Two before-and-after studies in Gabon and the Republic of Congo found that the majority of western gorillas survived for at least nine months to four years, after reintroduction in groups, alongside other interventions. One controlled study in Indonesia found that all Sumatran orangutans survived for at least three months after reintroduction in groups, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1567https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1567Fri, 20 Oct 2017 10:46:09 +0100Collected Evidence: Collected Evidence: Regularly play TV & radio announcements to raise primate conservation awareness One before-and-after study in the Republic of Congo found that most reintroduced central chimpanzees whose release was broadcasted by multiple media means, alongside other interventions, survived over five years post-reintroduction. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1569https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1569Fri, 20 Oct 2017 11:42:52 +0100Collected Evidence: Collected Evidence: Restore habitat corridors We found no evidence for the effects of restoring habitat corridors on primate populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested 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%2F1583https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1583Fri, 20 Oct 2017 13:06:15 +0100Collected Evidence: Collected Evidence: Reintroduce primates as single/multiple individuals One study in Tanzania found that a reintroduced population of chimpanzees increased in size after reintroduction as single/multiple individuals, alongside other interventions. One study in Senegal found that an infant chimpanzee was reunited with its mother after reintroduction, alongside other interventions. Two studies in Brazil and Thailand found that populations of reintroduced primates declined after reintroduction as single/multiple individuals, alongside other interventions. Four studies in French Guiana, Indonesia, Malaysia, and Vietnam found that a minority of primates survived after between two months and one year after reintroduction as single/multiple individuals, alongside other interventions. One study in Vietnam found that half of introduced primates survived after two months. One study in Brazil found that an abandoned infant muriqui was reunited with its mother after reintroduction as single/multiple individuals, alongside other interventions. One study in Indonesia found that Bornean agile gibbons had similar behaviour and diet to wild populations after reintroduction as single/multiple individuals, alongside other interventions. One controlled study in Malaysia found that a reintroduced population of orangutans declined in size after reintroduction, alongside other interventions. One study in Malaysia found that 98% of orangutans survived release after reintroduction, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1589https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1589Fri, 20 Oct 2017 13:18:43 +0100Collected Evidence: Collected Evidence: Reintroduce primates into habitat where the species is absent One study in The Gambia found that a population of reintroduced chimpanzees increased over 25 years after reintroduction into habitat where the species was absent, alongside other interventions. One controlled study in Indonesia found that all Sumatran orangutans survived for at least three months after reintroduction into habitat where the species was absent, alongside other interventions. One before-and-after study in the Republic of Congo found that a majority of reintroduced gorillas survived for at least four years after reintroduction into habitat where the species was absent, alongside other interventions. One study in Thailand found that a reintroduced population of lar gibbons declined over three years following reintroduction into habitat where the species was absent, alongside other interventions. One study in India found that a population of reintroduced rhesus monkeys persisted for at least four years after reintroduction. Six studies (including four before-and-after studies) in Belize, Gabon, Madagascar, Malaysia, South Africa, and Vietnam found that a majority of primates survived for two to thirty months after reintroduction into habitat where the species was absent, alongside other interventions. Two studies in Malaysia and Vietnam found that a minority of primates survived after between three months and 12 years. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1590https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1590Fri, 20 Oct 2017 13:38:29 +0100Collected Evidence: Collected Evidence: Reintroduce primates into habitat where the species is present Four before-and-after studies in Guinea and the Republic of Congo found that the majority of reintroduced chimpanzees survived for at least one to five years after reintroduction into habitat where the species was present, alongside other interventions. One study in Uganda found that a reintroduced chimpanzee repeatedly returned to human settlements after reintroduction intro habitat where the species was present, alongside other interventions, while a study in Senegal found that a reintroduced chimpanzee was reunited with its mother. One study in Malaysia found that a majority of reintroduced orangutans survived reintroduction intro habitat where the species was present, alongside other interventions. One controlled study in Malaysia found that a reintroduced population of orangutans had declined 33 years after reintroduction into habitat where the species was present, alongside other interventions. One study in Belize found that primate population increased five years after reintroduction into habitat where the species was present, alongside other interventions, while one study in Thailand found that primate population declined post-reintroduction. Six studies in Brazil, French Guiana, Indonesia, Madagascar, and South Africa found that a minority of primates survived for at least fifteen weeks to seven years after reintroduction into habitat where the species was present, alongside other interventions. Five studies in Brazil, French Guiana, Gabon, and South Africa found that a majority of primates survived for at least two months to one year. Two controlled studies in Madagascar and Indonesia found that reintroduced primates had similar diets to individuals in wild populations after reintroduction into habitat where the species was present, alongside other interventions. One controlled study in Indonesia found that reintroduced primates showed similar behaviour to wild individuals after reintroduction into habitat where the species was present, alongside other interventions. One study in Brazil found that a reintroduced muriqui rejoined a wild group after reintroduction into habitat where the species was present, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1591https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1591Fri, 20 Oct 2017 13:46:00 +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: Reintroduce primates into habitat with predators Two before-and-after studies in Brazil found that most golden lion tamarins reintroduced into habitat with predators, alongside other interventions, did not survive over one to seven years but reproduced succesfully. Three studies, including two before-and-after studies, in the Congo, The Gambia and Guinea, found that most chimpanzees reintroduced into habitat with predators, alongside other interventions, survived over one to five years or increased population numbers. One before-and-after study in Gabon found that most western lowland gorillas reintroduced into habitat with predators, alongside other interventions, survived over nine months. One before-and-after study in Madagascar found that most black-and-white ruffed lemurs reintroduced into habitat with predators did not survive over five years. One study in Madagascar found that all reintroduced lemurs survived over 30 months after being released into habitat with predators, along with other interventions. One study in Gabon found that most mandrills reintroduced into habitat with predators, alongside other interventions, survived over 30 years. Two before-and-after studies in South Africa found that most vervet monkeys reintroduced into habitat with predators, alongside other interventions, survived over six months. Two studies, including one before-and-after study, in Vietnam and Indonesia found that most lorises reintroduced into habitat with predators, alongside other interventions, were assumed dead within approximately one year after being released. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1593https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1593Fri, 20 Oct 2017 14:16:39 +0100Collected Evidence: Collected Evidence: Rehabilitate injured/orphaned primates One before-and-after study in Brazil found that most reintroduced golden lion tamarins did not survive over seven years, despite being rehabilitated, alongside other interventions. Two before-and-after studies in South Africa found that most reintroduced vervet monkeys survived over six months after being rehabilitated before release, alongside other interventions. Two before-and-after studies in the Republic of Congo found that most reintroduced chimpanzees survived over 3.5–5 years after undergoing pre-release rehabilitation, alongside other interventions. One study in The Gambia found that numbers of reintroduced chimpanzees that underwent pre-release rehabilitation, alongside other interventions, increased by 38% over 25 years. One review on bonobos, chimpanzees and gorillas in 13 African countries found that rehabilitated bonobos living in sanctuaries did not reproduce but the reproductive rate of chimpanzees was 14% and of gorillas was 2%. One controlled study in Indonesia found that Bornean agile gibbons that were rehabilitated before release, alongside other interventions, behaved similarly to wild gibbons. One controlled study in Malaysia found that numbers of reintroduced orangutans decreased by 33% over 33 years, despite orangutans being rehabilitated before release. One controlled study in Indonesia found that most translocated orangutans that were rehabilitated before release, along with other interventions, survived over three months. One before-and-after, site comparison study in the Congo and Gabon found that most western lowland gorillas that were rehabilitated before release, alongside other interventions, survived over four years. One before-and-after study in Gabon found that one out of two western lowland gorillas that were reintroduced died despite being rehabilitated, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1597https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1597Fri, 20 Oct 2017 14:47:02 +0100
What Works 2021 cover

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.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.


Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust