Collected Evidence: Collected Evidence: Protect individual nests of ground-nesting birds Two replicated, randomized, controlled studies from Sweden found providing nest exclosures offered some benefits to ground-nesting birds. One study found that protected nests had higher average daily survival rates than unprotected nests for both common redshank and northern lapwing, however, this study also reported higher predation of adult redshank on protected nests. One study found that the average hatching rate for southern dunlin was higher for protected rather than unprotected nests. This study also found no difference in the number of fledglings, breeding adults or new recruits during two periods with and without nest protection.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F108https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F108Mon, 24 Oct 2011 22:04:47 +0100Collected Evidence: Collected Evidence: Protect nests from livestock to reduce trampling A before-and-after study from the Chatham Islands, New Zealand found that the population of Chatham Island oystercatcher increased following several interventions including the erection of fencing around individual nests. A replicated, controlled study in Sweden found that no southern dunlin nests were trampled when protected by cages; some unprotected nests were destroyed.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F237https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F237Tue, 17 Jul 2012 16:44:30 +0100Collected Evidence: Collected Evidence: Provide ‘sacrificial’ grasslands to reduce the impact of wild geese on cropsTwo studies in the UK found that managing grasslands for geese increased the number grazing there. However, both found that the birds were moving within a relatively small area (i.e. within the study sites) and therefore the grasslands may not reduce conflict with farmers.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F280https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F280Tue, 24 Jul 2012 12:48:14 +0100Collected Evidence: Collected Evidence: Protect nest trees before burning We found no evidence for the effects of protecting nest trees of bird populations before burning. '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%2F325https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F325Thu, 26 Jul 2012 16:48:25 +0100Collected Evidence: Collected Evidence: Protect nests from antsA randomised, replicated and controlled study from the USA found higher fledging success from white-eyed vireo Vireo griseus nests protected from ants with a physical barrier and a chemical repellent, compared to control nests.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F410https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F410Thu, 16 Aug 2012 15:15:18 +0100Collected Evidence: Collected Evidence: Protect nest sites from competitors Two replicated studies from the USA found that red-cockaded woodpecker Picoides borealis populations increased in five forests after several interventions, including the installation of restrictor plates around nesting holes, were implemented. A study from Puerto Rico found evidence for lower competition between Puerto Rican parrots Amazona vittata and pearly-eyed thrashers Margarops fuscatus after modifications were made to nest boxes. A replicated, controlled study from the USA found weak evidence for the effects of exclusion devices on house sparrows Passer domesticus nesting in nest boxes and a study from the USA found that fitting restrictor plates to red-cockaded woodpecker holes reduced the number that were enlarged.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F426https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F426Fri, 17 Aug 2012 17:45:26 +0100Collected Evidence: Collected Evidence: Provide 'sacrificial' grasslands to reduce the impact of wild geese on crops All six studies from the UK (including four replicated, controlled trials) found that managing grasslands for geese increased the number grazing there. Two replicated, controlled studies found that fertilized and cut areas were grazed by more white-fronted geese or brent geese than control areas. A replicated, controlled trial found that re-seeded and fertilized wet pasture fields were used by more barnacle geese than control fields, and that fertilized areas were used less than re-seeded ones. A replicated, controlled study found that spring fertilizer application increased the use of grassland fields by pink-footed geese. A replicated study found that plots sown with white clover were preferred by dark-bellied brent geese compared to plots sown with grasses. However, four of the studies found that the birds were moving within a relatively small area (i.e. within the study site) and therefore the grasslands may not reduce conflict with farmers.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F641https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F641Mon, 15 Oct 2012 16:28:48 +0100Collected Evidence: Collected Evidence: Provide additional sleeping platforms/nesting sites for primates One before-and-after study in Brazil found that a translocated lion tamarin population declined after artificial nest boxes were provided, alongside other interventions. One before-and-after study in Brazil found that a majority of reintroduced golden lion tamarins died seven years after artificial nest boxes were provided, alongside other interventions. One before-and-after study in Gabon found that a majority of juvenile western lowland gorillas survived for at least seven years after nesting platforms were provided, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1530https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1530Thu, 19 Oct 2017 10:22:21 +0100Collected Evidence: Collected Evidence: Protect or prepare vegetation before planting (other interventions) We found no studies that evaluated the effects of protecting or preparing peatland vegetation before planting (other than by adding root-associated fungi). ‘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%2F1842https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1842Tue, 28 Nov 2017 08:56:10 +0000Collected Evidence: Collected Evidence: Protect roost trees during forest operations We found no studies that evaluated the effects of protecting roost trees during forest operations 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%2F1982https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1982Tue, 04 Dec 2018 19:24:09 +0000Collected Evidence: Collected Evidence: Provide additional moorings to reduce anchoring We found no studies that evaluated the effects of providing additional moorings to reduce anchoring on subtidal benthic invertebrate populations.   ‘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%2F2091https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2091Mon, 21 Oct 2019 15:21:08 +0100Collected Evidence: Collected Evidence: Protect mammals close to development areas (e.g. by fencing) We found no studies that evaluated the effects of protecting mammals close to development areas (e.g. by fencing). '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%2F2324https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2324Wed, 20 May 2020 11:54:59 +0100Collected Evidence: Collected Evidence: Protect spawning fish from capture Four studies examined the effects of protecting spawning fish on marine fish populations. Two studies were in the North Atlantic Ocean (Canada, UK) and one study was in each of the Philippine Sea (Palau) and the Tasman Sea (Australia).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Abundance (1 study): One before-and-after, site comparison study in the Atlantic Ocean found no increase in the biomass of the spawning stock of Atlantic cod in the nine years following implementation of a seasonal fishery closure to protect spawning cod, compared to fished areas. Survival (1 study): One before-and-after, site comparison study in the Atlantic Ocean found no change in Atlantic cod survival in the nine years after a seasonal fishery closure to protect spawning cod was implemented, compared to fished areas. Condition (1 study): One before-and-after, site comparison study in the Atlantic Ocean found no change in the length composition of Atlantic cod in the nine years following a seasonal fishery closure to protect spawning cod, compared to fished areas. BEHAVIOUR (2 STUDIES) Use (2 studies): One site comparison study and one study in the Northeast Atlantic Ocean and Tasman Sea reported that spawning and/or nursery areas closed seasonally or permanently to fishing were used by tagged adult Atlantic cod for nearly a third of time during spawning, and by school sharks less than one year old for up to 80% of time, but by school sharks between one and two years old for 18% of time, compared to areas outside. OTHER (2 STUDIES) Commercial catch abundance (2 studies): One before-and-after, site comparison study in the Atlantic Ocean found no change over nine years in commercial catches of Atlantic cod following a seasonal fishery closure to protect spawning cod compared to fished areas. One replicated, controlled study in the Philippine Sea found that during seasonal closure of a grouper fishery to protect spawning individuals, the commercial catch numbers of other fish groups (herbivores) increased, indicating they were being targeted more by spear fishers compared to the open season. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2938https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2938Thu, 11 Feb 2021 16:13:52 +0000Collected Evidence: Collected Evidence: Protect specific habitat structures We found no studies that evaluated the effects of protecting specific habitat structures on reptile 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%2F3665https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3665Fri, 10 Dec 2021 11:00:46 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using artificial nest covers: Sea turtles Fifteen studies evaluated the effects of protecting nests and nesting sites from predation using artificial nest covers on sea turtle populations. Six studies were in the USA, two were in each of Turkey and Australia, and one was in each of Greece, Qatar, Indonesia, Cape Verde and Costa Rica. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (15 STUDIES) Reproductive success (15 studies): Eight of 14 studies (including 10 replicated, controlled studies) in the USA, Turkey, Qatar, Indonesia, Cape Verde, Australia and Costa Rica found that sea turtle, loggerhead, hawksbill and artificial sea turtle nests with artificial covers were predated less frequently than nests with no covers. Three studies found that covering sea turtle nests had mixed effects on predation, depending on predator species or year. One study found that loggerhead turtle nests with artificial covers were predated more frequently than nests with no covers. One study found that olive ridley turtle nests with and without artificial covers were all predated. The other study found that predation attempts of green and hawksbill turtle nests with artificial covers were similar compared to nests with no cover, but that predation success was affected by the cover design. Three studies also found that sea turtle and loggerhead turtle nests with artificial covers had higher hatching success than nests with no covers. One study also found that loggerhead turtle nests with artificial covers had similar hatching and emergence success compared to nests with no covers. One replicated, controlled study in Greece found that covering loggerhead turtle nests had mixed effects on hatching success compared to nests with no covers. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3686https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3686Fri, 10 Dec 2021 16:10:02 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using artificial nest covers: Tortoises, terrapins, side-necked & softshell turtles Seven studies evaluated the effects of protecting nests and nesting sites from predation using artificial nest covers on tortoise, terrapin, side-necked and softshell turtle populations. Five studies were in the USA and one was in each of the Galápagos and Canada. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (7 STUDIES) Reproductive success (7 studies): Two replicated studies (including one controlled study) in the Galápagos and the USA found that Galápagos giant tortoise nests surrounded by rock-walled corrals and bog turtle nests covered with cages were predated less frequently than unprotected nests. Two replicated studies (including one randomized, controlled study) in Canada and the USA found that nests of painted and snapping turtles and bog turtles covered with cages had similar hatching success compared to nests left uncovered. One of two replicated controlled studies (including one randomized study) in Canada and the USA found that painted and snapping turtle nests protected by three different cage types were predated a similar amount. The other study found mixed effects of different cage designs on predation rate of artificial nests at a diamondback terrapin nesting site. One replicated, before-and-after study in the USA found that diamondback terrapin nests covered by a nest box with an electrified wire were predated less frequently than nests under a box with no wire. One before-and-after study in the USA found that over half of eggs from bog turtle nests covered with cages in an area grazed by cattle hatched successfully. One replicated, controlled study in the USA found that diamondback terrapin nests covered with cages had hatching success of 55–93%, and 83–100% of uncaged nests were predated. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3687https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3687Fri, 10 Dec 2021 17:08:55 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using artificial nest covers: Snakes & lizards We found no studies that evaluated the effects of protecting nests and nesting sites from predation using artificial nest covers on snake and lizard 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%2F3688https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3688Fri, 10 Dec 2021 17:26:23 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using artificial nest covers: Crocodilians We found no studies that evaluated the effects of protecting nests and nesting sites from predation using artificial nest covers on crocodilian 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%2F3689https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3689Fri, 10 Dec 2021 17:28:19 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using artificial nest covers: Tuatara We found no studies that evaluated the effects of protecting nests and nesting sites from predation using artificial nest covers on tuatara 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%2F3690https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3690Fri, 10 Dec 2021 17:29:54 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation by camouflaging nests Two studies evaluated the effects of protecting nests and nesting sites from predation by camouflaging nests on reptile populations. One study was in the USA and one was in Costa Rica. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Reproductive success (2 studies): One replicated, controlled study in the USA found that Ouachita map turtle nests that were disguised by sweeping with a broom were predated at a similar rate as unswept nests. One before-and-after, site comparison study in Costa Rica found that camouflaged (details of method not provided) olive ridley turtle nests had similar hatching and emergence success compared to nests moved to a hatchery. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3691https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3691Fri, 10 Dec 2021 17:31:50 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using visual deterrents One study evaluated the effects of protecting nests and nesting sites from predation using visual deterrents on reptile populations. This study was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Reproductive success (1 study): One replicated, controlled study in Australia found that a similar number of loggerhead turtle nests marked with red flags were predated compared to those marked only with wooden stakes. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3692https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3692Fri, 10 Dec 2021 17:37:45 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation by creating new nesting sites One study evaluated the effects of protecting nests and nesting sites from predation by creating new nesting sites on reptile populations. This study was in Spain. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Reproductive success (1 study): One replicated, controlled study in Spain found that predation rate of artificial Hermann’s tortoise nests in newly created nesting sites was similar to the predation rate in natural nesting sites. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3693https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3693Fri, 10 Dec 2021 17:39:17 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using chemical deterrents Four studies evaluated the effects of protecting nests and nesting sites from predation using chemical deterrents on reptile populations. Two studies were in the USA and one was in each of Spain and Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (4 STUDIES) Reproductive success (4 studies): Three of four controlled studies (including three replicated studies) in Spain, the USA and Australia found that a similar number of artificial Hermann’s tortoise nests, diamondback terrapin nests and loggerhead turtle nests that had chemical deterrents, pepper powder or chilli powder applied were predated compared to nests with no deterrent. The other study found that fewer loggerhead turtle nets that had habanero pepper powder applied to the surface were predated than nests with no pepper powder, or nest with pepper powder below the surface. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3694https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3694Fri, 10 Dec 2021 18:08:18 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using conditioned taste aversion One study evaluated the effects of protecting nests and nesting sites from predation using conditioned taste aversion on reptile populations. This study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Reproductive success (1 study): One replicated, randomized, controlled, before-and-after study in the USA found that a similar number of loggerhead turtle nests were predated in areas of the beach where artificial nests containing unpalatable eggs were deployed (to condition taste aversion) compared to areas with no artificial nests with unpalatable eggs. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3695https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3695Fri, 10 Dec 2021 18:18:32 +0000Collected Evidence: Collected Evidence: Protect or restore brownfield or ex-industrial sites We found no studies that evaluated the effects of protecting or restoring brownfield or ex-industrial sites on butterflies and moths. ‘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%2F3835https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3835Mon, 04 Jul 2022 15:24:10 +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