Collected Evidence: Collected Evidence: Physically protect nests from predators using non-electric fencing Two studies from the USA and UK found that fewer nests were predated or failed when predator exclusion fences were erected. Two studies from the USA found that nesting success or fledging success did not differ between areas with fences erected and those without fences; although one found that hatching rates were higher with fences. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F183https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F183Fri, 01 Jun 2012 17:15:36 +0100Collected Evidence: Collected Evidence: Physically protect nests with individual exclosures/barriers or provide shelters for chicks of ground nesting seabirds A before-and-after study from Japan found an increase in fledging rates of little terns Sterna albifrons following the provision of chick shelters and other interventions. Two studies from the USA and Canada found reduced predation of tern chicks following the provision of chick shelters. A small study from the USA found low levels of use of chick shelters, except when predators were present.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F397https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F397Tue, 14 Aug 2012 13:01:08 +0100Collected Evidence: Collected Evidence: Physically protect nests with individual exclosures/barriers or provide shelters for chicks of waders Three of 13 studies from the USA found higher productivity from nests protected by individual barriers than unprotected nests. Two studies from the USA and Sweden found no higher productivity from protected nests. Eight studies from the USA and Europe found higher hatching rates, or survival, or low predation of nests protected by individual barriers, although two of these found that higher hatching rates did not result in higher productivity. Two small studies from North America found no differences in predation or survival rates between protected and unprotected nests. A meta-analysis from the USA found that there were differences in the effectiveness of different exclosure designs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F398https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F398Wed, 15 Aug 2012 14:32:17 +0100Collected Evidence: Collected Evidence: Physically protect nests with individual exclosures/barriers or provide shelters for chicks of storks and ibisesA randomised, replicated and controlled study from Cambodia found that giant ibis Thaumatibis gigantean fledgling rates were higher for nests in protected trees than controls.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F399https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F399Thu, 16 Aug 2012 13:10:41 +0100Collected Evidence: Collected Evidence: Physically protect nests with individual exclosures/barriers or provide shelters for chicks of songbirds Three studies from across the world found increased fledging success for nests in trees protected by individual barriers. A replicated controlled study from the USA also found higher success for ground-nests protected by individual barriers. Two studies from the UK and Japan found lower predation rates on nests protected by individual barriers.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F400https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F400Thu, 16 Aug 2012 13:13:40 +0100Collected Evidence: Collected Evidence: Place feeders close to windows to reduce collisionsA randomised, replicated and controlled experiment in the USA found that placing bird feeders close to windows reduced the number of collisions with the windows and the number of fatal collisions.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F557https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F557Sun, 23 Sep 2012 15:13:35 +0100Collected Evidence: Collected Evidence: Physically exclude vehicles from peatlands One study evaluated the effects on peatland vegetation of physically excluding vehicles from peatlands. The study was in a fen. Vegetation structure (1 study): One replicated, paired, controlled, site comparison study in a floating fen in the USA reported that fencing off airboat trails allowed total and non-woody vegetation biomass to increase, recovering to levels recorded in undisturbed fen. Woody plant biomass did not recover. Overall plant richness/diversity (1 study): The same study reported that fencing off airboat trails allowed overall plant diversity to increase, recovering to levels recorded in undisturbed fen. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1750https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1750Mon, 27 Nov 2017 21:31:38 +0000Collected Evidence: Collected Evidence: Physically exclude pedestrians from peatlands We found no studies that evaluated the effects on peatland vegetation of physically excluding pedestrians from peatlands. ‘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%2F1752https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1752Mon, 27 Nov 2017 21:32:15 +0000Collected Evidence: Collected Evidence: Physically remove problematic plants Three studies evaluated the effects on peatland vegetation of removing problematic plants. All three studies were in fens. Characteristic plants (1 study): One replicated, randomized, controlled study in a fen in Ireland reported that cover of fen-characteristic plants increased after mossy vegetation was removed. Herb cover (3 studies): Three replicated, controlled studies in fens in the Netherlands and Ireland reported mixed effects of moss removal on herb cover after 2–5 years. Results varied between species or between sites, and sometimes depended on other treatments applied to plots (i.e. drainage or isolation from the surrounding bog). Moss cover (3 studies): One replicated, randomized, controlled study in a fen in Ireland reported that removing the moss carpet reduced total bryophyte and Sphagnum moss cover for three years. Two replicated, controlled, before-and-after studies in fens in the Netherlands reported that removing the moss carpet had no effect on moss cover (after 2–5 years) in wet plots, but reduced total moss and Sphagnum cover in drained plots. Overall plant richness/diversity (1 study): One replicated, controlled, before-and-after study in a fen in the Netherlands reported that moss removal increased plant species richness, but only in a drained area. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1768https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1768Mon, 27 Nov 2017 21:41:10 +0000Collected Evidence: Collected Evidence: Place anthropogenic installations (e.g: windfarms) in an area such that they create artificial habitat and reduce the level of fishing activity We found no studies that evaluated the effects of placing anthropogenic installations in an area such that they reduce the level of fishing activity 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%2F2261https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2261Wed, 23 Oct 2019 10:51:55 +0100Collected Evidence: Collected Evidence: Place captive young with captive foster parents Two studies evaluated the effects of placing captive young mammals with captive foster parents. One study was in the USA and one was in Sweden and Norway. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): A replicated, controlled study in the USA found that most captive coyote pups placed with foster parents were successfully reared. A replicated study in Sweden and Norway found that captive grey wolf pups placed with foster parents had higher survival rates than pups that stayed with their biological mother. Condition (1 study): A replicated study in Sweden and Norway found that captive grey wolf pups placed with foster parents weighed less than pups that stayed with their biological mother. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2472https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2472Wed, 03 Jun 2020 17:02:34 +0100Collected Evidence: Collected Evidence: Physically remove invasive or problematic species We found no studies that evaluated the effects of physically removing invasive or other problematic species on marine and freshwater mammal 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%2F2851https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2851Mon, 08 Feb 2021 10:58:53 +0000Collected Evidence: Collected Evidence: Physically exclude vehiclesWe found no studies that evaluated the effects, on vegetation, of physically excluding vehicles from marshes or swamps.   ‘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%2F3020https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3020Wed, 31 Mar 2021 14:40:09 +0100Collected Evidence: Collected Evidence: Physically exclude pedestriansWe found no studies that evaluated the effects, on vegetation, of physically excluding pedestrians from marshes or swamps.   ‘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%2F3023https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3023Wed, 31 Mar 2021 14:43:16 +0100Collected Evidence: Collected Evidence: Physically remove problematic plants: freshwater marshes Five studies evaluated the effects, on vegetation, of physically removing problematic plants from freshwater marshes. Three studies were in the USA, one was in India and one was in France. Two of the studies in the USA were in the same site and shared some plots. VEGETATION COMMUNITY Community composition (1 study): One replicated, randomized, paired, controlled, before-and-after study in the USA found that physically removing all vegetation from a cattail-invaded marsh altered the overall plant community composition, over the following two years. Overall richness/diversity (3 studies): One replicated, randomized, paired, controlled, before-and-after study in the USA found that removing all vegetation from a cattail-invaded marsh increased overall plant species richness 1–2 years later. Two replicated, randomized, paired, controlled, before-and-after studies in wet meadows in the USA found that physically removing vegetation had no significant effect on overall plant species richness or diversity three years later. One of the studies removed all vegetation, whilst the other controlled regrowth of the invasive species (by physical removal along with herbicide application). Characteristic plant richness/diversity (1 study): One controlled, before-and-after study in a temporary marsh in France reported that stripping all vegetation increased the number of habitat-characteristic plant species present in the following two years. VEGETATION ABUNDANCE Overall abundance (3 studies): Three before-and-after studies (two also replicated, randomized, paired, controlled) in freshwater marshes/wet meadows in India and the USA found that physically removing vegetation had no clear or significant effect on overall vegetation cover, nine months or three years later. Two of the studies removed all vegetation, whilst one controlled regrowth of the invasive species (by physical removal along with herbicide application). Herb abundance (2 studies): Of two replicated, randomized, paired, controlled, before-and-after studies in loosestrife-invaded wet meadows in the USA, one reported that removing all vegetation increased the cover of grass-like plants, and reduced the cover of forbs, three years later. The other study found that controlling regrowth of the invasive species – by physical removal and applying herbicide – had no significant effect on cover of grass-like plants or forbs after three years. Algae/phytoplankton abundance (1 study): One before-and-after, site comparison study in India reported that removing all vegetation from a knotgrass-invaded marsh increased the cover of algae nine months later. Individual species abundance (3 studies): Three studies quantified the effect of this action on the abundance of individual plant species, other than the target problematic species. For example, one before-and-after, site comparison study in India reported that removing all vegetation from a knotgrass-invaded marsh increased the cover of some other common herb species nine months later. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3091https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3091Sat, 03 Apr 2021 14:59:31 +0100Collected Evidence: Collected Evidence: Physically remove problematic plants: brackish/salt marshes One study evaluated the effects, on vegetation, of physically removing problematic plants from brackish/salt marshes. The study was in the USA. VEGETATION COMMUNITY   VEGETATION ABUNDANCE Native/non-target abundance (1 study): One replicated, randomized, paired, controlled, before-and-after study in pepperweed invaded marshes in the USA found that physically removing pepperweed from plots sprayed with herbicide increased cover of native plants, over the following two years, compared to spraying with herbicide only. Individual species abundance (1 study): The same study quantified the effect of this action on the cover of individual plant species, other than the target of control (see original paper for data). VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3092https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3092Sat, 03 Apr 2021 14:59:44 +0100Collected Evidence: Collected Evidence: Physically remove problematic plants: freshwater swampsWe found no studies that evaluated the effects, on vegetation, of physically removing problematic plants from freshwater swamps.   ‘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%2F3093https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3093Sat, 03 Apr 2021 15:00:05 +0100Collected Evidence: Collected Evidence: Physically remove problematic plants: brackish/saline swampsWe found no studies that evaluated the effects, on vegetation, of physically removing problematic plants from brackish/saline swamps.   ‘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%2F3094https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3094Sat, 03 Apr 2021 15:00:18 +0100Collected Evidence: Collected Evidence: Physically damage problematic plants: freshwater marshes Five studies evaluated the effects, on vegetation, of physically damaging problematic plants in freshwater marshes. There were two studies in Australia and two in Costa Rica. In each country, the two studies were based in one study area but used different experimental set-ups. The final study was in Mexico. VEGETATION COMMUNITY Overall extent (1 study): One controlled, before-and-after study in a freshwater marsh in Costa Rica reported that crushing (and burning) cattail stands reduced the area of live vegetation present 5–22 months later. Community composition (1 study): One replicated, randomized, paired, controlled study in a marsh in Costa Rica found that plots in which cattail-dominated vegetation was crushed had a different overall plant community composition, over the following 15 months, to plots in which vegetation was not crushed. Overall richness/diversity (3 studies): Two controlled studies (one also replicated, randomized, paired) in one freshwater marsh in Costa Rica reported that in plots where cattail-dominated vegetation was crushed (sometimes along with burning), plant species richness and diversity were not lower than in plots where vegetation was not crushed (or burned). Vegetation was surveyed 2–22 months after intervention. One replicated, randomized, paired, controlled study in a freshwater marsh in Mexico found that disking after cutting grass-invaded vegetation increased overall plant diversity, after 4–8 months, compared to cutting alone. However, disking had no significant effect on plant richness. VEGETATION ABUNDANCE Overall abundance (2 studies): One controlled, before-and-after study in a freshwater marsh in Costa Rica reported that crushing (and burning) cattail stands reduced live vegetation cover 5–22 months later. One replicated, randomized, paired, controlled study in a freshwater marsh in Mexico found that disking after cutting grass-invaded vegetation typically had no significant effect on overall plant density, after 4–8 months, compared to cutting alone. Herb abundance (1 study): One study of a floodplain marsh in Australia simply reported grass/sedge cover for up to four years after crushing mimosa-invaded vegetation (along with other interventions). Native/non-target abundance (2 studies): One replicated, randomized, paired, controlled, before-and-after study in a mimosa-invaded wetland in Australia reported that crushing mimosa stands did not reduce – and often increased – cover of non-mimosa vegetation one year later. One study of a floodplain marsh in Australia simply reported non-target vegetation cover for up to four years after crushing mimosa-invaded vegetation (along with other interventions). Individual species abundance (2 studies): Two studies quantified the effect of this action on the abundance of individual plant species, other than the species being controlled. One replicated, randomized, paired, controlled study in a freshwater marsh in Costa Rica found that plots in which cattail-dominated vegetation was crushed supported a greater abundance of individual plant species other than cattail, over the following 15 months, than plots in which vegetation was not crushed. One replicated, randomized, paired, controlled study in a freshwater marsh in Mexico found that disking after cutting grass-invaded vegetation increased the cover of two of five common native plant species, after 4–8 months, compared to cutting alone. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3095https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3095Sat, 03 Apr 2021 16:05:22 +0100Collected Evidence: Collected Evidence: Physically damage problematic plants: freshwater swamps Two studies evaluated the effects, on vegetation, of physically damaging problematic plants in freshwater swamps. Both studies were in the USA. VEGETATION COMMUNITY Overall richness/diversity (1 study): One controlled study aiming to restore a swamp in the USA found that ploughing a canarygrass-invaded plot after spraying it with herbicide increased overall plant richness and diversity, two growing seasons later, compared to spraying alone. Native/non-target richness/diversity (1 study): The same study found that ploughing a canarygrass-invaded plot after spraying it with herbicide had no significant effect on native plant species richness, two growing seasons later, compared to spraying alone. VEGETATION ABUNDANCE Tree/shrub abundance (2 studies): Two controlled studies in the USA evaluated the effects, on tree/shrub abundance, of physically damaging canarygrass-invaded vegetation. One study found that ploughing a canarygrass-invaded plot after spraying it with herbicide had no significant effect on the density of non-planted tree seedlings, two growing seasons later, compared to spraying alone. The other study found that managed plots (cut, disked and sprayed with herbicide) contained more non-planted tree seedlings than unmanaged plots, after 1–3 years. Native/non-target abundance (1 study): One replicated, controlled study aiming to restore a swamp in the USA found that plots in which canarygrass-invaded vegetation was managed (by disking, along with cutting and applying herbicide) contained at least as much non-canarygrass herb cover, after 1–3 years, to plots in which vegetation was not managed. Individual species abundance (1 study): One controlled study aiming to restore a swamp in the USA reported that ploughing a canarygrass-invaded plot after spraying it with herbicide affected the abundance of some individual plant species – other than the target problematic species – two growing seasons later. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3097https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3097Sat, 03 Apr 2021 16:05:55 +0100Collected Evidence: Collected Evidence: Physically or chemically remove oilWe found no studies that evaluated the effects, on vegetation, of physically or chemically removing oil (but not vegetation) from contaminated marshes or swamps.   ‘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%2F3173https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3173Tue, 06 Apr 2021 13:40:33 +0100Collected Evidence: Collected Evidence: Physically damage seeds of non-woody plants before sowing: freshwater wetlands Three studies evaluated the effects – on emergent, non-woody plants typical of freshwater wetlands – of physically damaging their seeds before sowing. All three studies were in greenhouses or laboratories in the USA. VEGETATION COMMUNITY   VEGETATION ABUNDANCE   VEGETATION STRUCTURE   OTHER Germination/emergence (3 studies): Two replicated, controlled studies (one also randomized) in greenhouses in the USA found that rubbing seeds of herbaceous plants with sandpaper before sowing had no significant effect on their germination rate. One replicated, randomized, paired, controlled study in a laboratory in the USA found that removing the sac-like seed coating before sowing typically increased, and did not reduce, the germination rate of sedges Carex spp. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3376https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3376Mon, 12 Apr 2021 08:22:24 +0100Collected Evidence: Collected Evidence: Physically damage seeds of non-woody plants before sowing: brackish/saline wetlandsWe found no studies that evaluated the effects – on emergent, non-woody plants typical of brackish/saline wetlands – of physically damaging their seeds before sowing.   ‘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%2F3377https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3377Mon, 12 Apr 2021 08:22:39 +0100Collected Evidence: Collected Evidence: Physically damage tree/shrub seeds before sowing: freshwater wetlands One study evaluated the effects – on trees/shrubs typical of freshwater wetlands – of physically damaging their seeds before sowing. The study was in a laboratory in the USA. VEGETATION COMMUNITY   VEGETATION ABUNDANCE   VEGETATION STRUCTURE          OTHER Germination/emergence (1 study): One replicated, controlled study in a laboratory in the USA found that cutting baldcypress Taxodium distichum seeds in half before sowing reduced their germination rate. Growth (1 study): The same study found that cutting baldcypress Taxodium distichum seeds in half before sowing had no significant effect on the height of surviving seedlings, 30 days after germination. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3378https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3378Mon, 12 Apr 2021 08:22:48 +0100Collected Evidence: Collected Evidence: Physically damage tree/shrub seeds before sowing: brackish/saline wetlandsWe found no studies that evaluated the effects – on trees/shrubs typical of brackish/saline wetlands – of physically damaging their seeds before sowing.   ‘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%2F3379https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3379Mon, 12 Apr 2021 08:23:06 +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
For a full list of, and information about, our champions:
All Evidence Champions
About our champions, why and how to become one:
Become an Evidence Champion

This website uses Cookies

We use limited Cookies to run the site and to analyse our traffic (none for site vendors). By using this site, you will be providing your consent to our use of Cookies.

Accept & continue