Collected Evidence: Collected Evidence: Scare birds from fish farms One before-and-after study from Israel found that the population of pygmy cormorants in the area increased after birds were scared away from fish farms, possibly due to lower persecution. One of two studies that examined fish stocks found that fewer fish were taken from a farm when heron distress calls were played. The other study, a literature review, found no evidence for the effects of scaring birds on fish stocks. Two replicated studies from Belgium and Australia found that using foot patrols to disturb birds from fish farms did not reduce the number of birds present or fish consumption. Ten of eleven studies from across the world, three controlled, found evidence that playing distress calls or using other acoustic deterrents (some with flashes of light) reduced the number of birds at fish farms, or changed bird behaviours. One of these involved underwater broadcasting. One study found effects were only temporary and five found that birds became habituated to noises. Four studies, one replicated and controlled, two before-and-after, found that acoustic deterrents were not effective in scaring birds. Five of seven studies, one controlled, found evidence that visual deterrents (including inflatable ‘Scarey Man’ scarecrows) reduced the number of birds at fish farms. Three found evidence for habituation to deterrents and three studies found no evidence that visual deterrents were effective. Two studies examined other deterrents, finding that trained raptors were effective but that the effects of helicopters and ultra-light aircraft were either inconclusive or very temporary.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F244https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F244Wed, 18 Jul 2012 11:00:04 +0100Collected Evidence: Collected Evidence: Clean nest boxes to increase occupancy or reproductive success Five studies from Spain and North America found that various songbirds preferentially nested in cleaned nest boxes, compared to used ones. One study from the USA found that eastern bluebirds showed this preference, but most did not switch from a soiled to a cleaned nest box. One study from the USA found that birds showed an avoidance of heavily-soiled boxes and one from Canada found that tree swallows Tachycineta bicolor preferentially selected nests which were sterilised by microwaving. Two studies from the USA found that eastern bluebirds Sialia sialis and house wrens Troglodytes aedon preferentially nested in uncleaned nest boxes, and one study found that prothonotary warblers Protonotaria citrea showed no preference for cleaned or uncleaned boxes. None of the five studies that investigated it found any difference in success or parasitism levels between cleaned and uncleaned nest boxes.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F499https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F499Tue, 04 Sep 2012 16:10:03 +0100Collected Evidence: Collected Evidence: Use chemicals to attract natural enemiesParasitism and predation (by natural enemies): One review and two of five studies from Asia, Europe and North America found that attractive chemicals increased parasitism. Two studies, including one randomised, replicated, controlled trial, found greater parasitism for some but not all chemicals, crops, sites or years and one study found no effect. One study showed that parasites found pests more rapidly. One study found lower egg predation by natural predators. Natural enemies: Five of 13 studies from Africa, Asia, Australasia, Europe and North America found more natural enemies while eight (including seven randomised, replicated, controlled trials) found positive effects varied between enemy groups, sites or study dates. Four of 13 studies (including a meta-analysis) found more natural enemies with some but not all test chemicals. Two of four studies (including a review) found higher chemical doses attracted more enemies, but one study found lower doses were more effective and one found no effect. Pests: Three of nine studies (seven randomised, replicated, controlled) from Asia, Australasia, Europe and North America found fewer pests, although the effect occurred only in the egg stage in one study. Two studies found more pests and four found no effect. Crop damage: One study found reduced damage with some chemicals but not others, and one study found no effect. Yield: One study found higher wheat yields. Crops studied were apple, banana, bean, broccoli, Chinese cabbage, cotton, cowpea, cranberry, grape, grapefruit, hop, maize, oilseed, orange, tomato, turnip and wheat.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F754https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F754Thu, 08 Aug 2013 13:40:59 +0100Collected Evidence: Collected Evidence: Artificially mist habitat to keep it damp One before-and-after study in Tanzania found that installing a sprinkler system to mitigate against a 90% reduction of river flow did not maintain a population of Kihansi spray toads.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F755https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F755Wed, 14 Aug 2013 11:05:17 +0100Collected Evidence: Collected Evidence: Restrict human access to bat caves to reduce the spread of the white-nose syndrome pathogen We found no studies that evaluated the effects of restricting human access to bat caves to reduce the spread of the white-nose syndrome pathogen 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%2F1010https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1010Fri, 20 Dec 2013 17:45:48 +0000Collected Evidence: Collected Evidence: Vaccinate bats against the white-nose syndrome pathogen We found no studies that evaluated the effects of vaccinating bats against the white-nose syndrome pathogen 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%2F1011https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1011Fri, 20 Dec 2013 17:46:43 +0000Collected Evidence: Collected Evidence: Cover the ground with straw after tree planting One replicated, randomized, controlled study in the Czech Republic found that covering the ground with straw, but not bark or fleece, increased the growth rate of planted trees and shrubs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1266https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1266Fri, 10 Jun 2016 08:44:29 +0100Collected Evidence: Collected Evidence: Use weed mats to protect planted trees One replicated, controlled study in Hong Kong found no effect of using weed mats on thick-leaved oak seedling height.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1267https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1267Fri, 10 Jun 2016 08:53:49 +0100Collected Evidence: Collected Evidence: Reduce primate predation by other primate species through exclusion (e.g. fences) or translocation We found no evidence for the effects of reducing primate predation by other primate species through exclusion or translocation 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%2F1522https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1522Thu, 19 Oct 2017 09:32:37 +0100Collected Evidence: Collected Evidence: Guard habituated primate groups to ensure their safety/well-being A controlled, before-and-after study in Rwanda, Uganda, and the Democratic Republic of Congo found that a population of mountain gorillas increased over 41 years after being guarded against poachers, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1523https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1523Thu, 19 Oct 2017 09:34:22 +0100Collected Evidence: Collected Evidence: Clean waste water before it enters the environment One study evaluated the effect, on peatland vegetation, of cleaning waste water before it enters the environment. The study was in a fen. Characteristic plants (1 study): One study in a floating fen in the Netherlands found that after input water began to be cleaned (along with other interventions to reduce pollution), cover of mosses characteristic of low nutrient levels increased. Vegetation structure (1 study): The same study found that after input water began to be cleaned (along with other interventions to reduce pollution), vascular plant biomass decreased. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1778https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1778Tue, 28 Nov 2017 08:13:46 +0000Collected Evidence: Collected Evidence: Divert/replace polluted water source(s) Three studies evaluated the effects, on peatland vegetation, of diverting or replacing polluted water source(s). Two studies were in bogs and one was in a fen. Characteristic plants (1 study): One study in a fen in the Netherlands found that after a nutrient-enriched water source was replaced (along with other interventions to reduce pollution), cover of mosses characteristic of low nutrient levels increased. Vegetation cover (2 studies): Two studies (one before-and-after) in bogs in the UK and Japan reported that after polluting water sources were diverted (sometimes along with other interventions), Sphagnum moss cover increased. Both studies reported mixed effects on herb cover, depending on species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1779https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1779Tue, 28 Nov 2017 08:14:06 +0000Collected Evidence: Collected Evidence: Create new unlit commuting routes using planting We found no studies that evaluated the effects of creating new unlit bat commuting routes using planting 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%2F2034https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2034Wed, 05 Dec 2018 18:26:40 +0000Collected Evidence: Collected Evidence: Restore or create linear habitat features/green corridors We found no studies that evaluated the effects of restoring or creating linear habitat features/green corridors 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%2F2035https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2035Wed, 05 Dec 2018 18:27:44 +0000Collected Evidence: Collected Evidence: Install pole crossings for gliders/flying squirrels Seven studies evaluated the effects on gliders/flying squirrels of installing pole crossings. Six studies were in Australia and one was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): A study in Australia found that arboreal marsupials using artificial road crossing structures did not suffer high predation rates when doing so. BEHAVIOUR (6 STUDIES) Use (6 studies): Six studies (five replicated), in Australia and the USA, found that poles were used for crossing roads by squirrel gliders, sugar gliders and Carolina northern flying squirrels. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2546https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2546Tue, 09 Jun 2020 09:20:33 +0100Collected Evidence: Collected Evidence: Use a smaller mesh size for fishing nets We found no studies that evaluated the effects of using a smaller mesh size for fishing nets 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%2F2802https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2802Thu, 04 Feb 2021 17:11:57 +0000Collected Evidence: Collected Evidence: Use a larger mesh size for fishing trap-nets One study evaluated the effects on freshwater mammals of using a larger mesh size for fishing trap-nets. The study was in the River Indal (Sweden). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Human-wildlife conflict (1 study): One controlled study in the River Indal found that a fishing trap-net with a larger mesh size in the first two sections had fewer grey seals feeding around it and less damage caused by seals. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2803https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2803Thu, 04 Feb 2021 17:13:38 +0000Collected Evidence: Collected Evidence: Use herbicide to maintain or restore disturbance: freshwater marshes One study evaluated the effects, on vegetation, of using herbicide to maintain or restore disturbance in freshwater marshes. The study was in the USA. VEGETATION COMMUNITY Community composition (1 study): One replicated, randomized, controlled, before-and-after study aiming to restore freshwater marshes in the USA found that applying herbicide to trees (along with other interventions) significantly affected the overall plant community composition over the following five years. VEGETATION ABUNDANCE Characteristic plant abundance (1 study): One replicated, randomized, controlled, before-and-after study aiming to restore freshwater marshes in the USA reported that of the 26 plant taxa that became more frequent after applying herbicide to trees (along with other interventions), 16 were obligate wetland taxa. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3058https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3058Fri, 02 Apr 2021 12:13:44 +0100Collected Evidence: Collected Evidence: Use herbicide to maintain or restore disturbance: brackish/salt marshesWe found no studies that evaluated the effects, on vegetation, of using herbicide to maintain or restore disturbance in brackish/salt marshes.   ‘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%2F3059https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3059Fri, 02 Apr 2021 12:13:54 +0100Collected Evidence: Collected Evidence: Add surface mulch before/after planting trees/shrubs: freshwater wetlands One study evaluated the effects, on vegetation, of mulching freshwater wetlands planted with trees/shrubs. The study was in Australia. VEGETATION COMMUNITY   VEGETATION ABUNDANCE Tree/shrub abundance (1 study): One replicated, randomized, paired, controlled study in floodplain swamps in Australia found that mulching with woodchips before planting native shrubs had no significant effect on their overall cover, one year later. Individual species abundance (1 study): The same study found that mulching with woodchips before planting swamp gum Eucalyptus camphora seedlings had no significant effect on swamp gum cover, one year later. Mulching reduced cover of the problematic herb species in one of two swamps, but had no significant effect in the other. VEGETATION STRUCTURE Height (1 study): One replicated, randomized, paired, controlled study in floodplain swamps in Australia found that planted swamp gum Eucalyptus camphora seedlings reached a similar height, after one year, in mulched and unmulched plots. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3314https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3314Sun, 11 Apr 2021 12:06:05 +0100Collected Evidence: Collected Evidence: Add surface mulch before/after planting trees/shrubs: brackish/saline wetlandsWe found no studies that evaluated the effects, on vegetation, of mulching brackish/saline wetlands planted with trees/shrubs.   ‘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%2F3315https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3315Sun, 11 Apr 2021 12:06:27 +0100Collected Evidence: Collected Evidence: Create walls or barriers to exclude pollutants We found no studies that evaluated the effects on reptile populations of creating walls or barriers to exclude pollutants. ‘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%2F3570https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3570Wed, 08 Dec 2021 15:12:06 +0000Collected Evidence: Collected Evidence: Use non-offset hooks Two studies evaluated the effects of using non-offset hooks on reptile populations. One study was off the Pacific coast of Costa Rica and one was in the north-east Atlantic. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, controlled, paired study in the north-east Atlantic Ocean found that mortality of leatherback turtles was similar when caught with non-offset hooks or offset hooks. BEHAVIOUR (0 STUDIES) OTHER (2 STUDIES) Unwanted catch (2 studies): One of two replicated, paired studies (including one controlled study) off the Pacific coast of Costa Rica and in the north-east Atlantic found that non-offset circle hooks caught a similar number of olive ridley and green turtles compared to offset circle hooks in a shallow-set longline fishery. The other study found that non-offset G-style circle hooks caught fewer leatherback and hard-shell turtles compared to offset Gt-style circle hooks or offset J-hooks in a longline swordfish fishery. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3571https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3571Wed, 08 Dec 2021 15:13:12 +0000Collected Evidence: Collected Evidence: Use technology to communicate near real-time catch information to fishers to enable avoidance of unwanted catchicate near real-time catch information to fishers to enable avoidance of unwanted catch One study examined the effects of using technology to communicate near real-time catch information to fishers to enable avoidance of unwanted catch on marine fish populations. The study was in the North Pacific and North Atlantic Oceans.   COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Reduction of unwanted catch (1 study): A review in the North Pacific and North Atlantic Oceans reported that where technology was used to provide near real-time catch information to fishers there were reductions of unwanted catch or discards in two of three cases. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3826https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3826Fri, 27 May 2022 09:38:00 +0100Collected Evidence: Collected Evidence: Employ adaptive management methods to achieve long-term goals We found no studies that evaluated the effects of employing adaptive management methods to achieve long-term goals on marine fish 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%2F3827https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3827Fri, 27 May 2022 09:41:07 +0100
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What Works in Conservation

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

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