Collected Evidence: Collected Evidence: Clean birds following oil spills Three studies from South Africa and Australia found high survival of rehabilitated penguins and plovers or similar survival to un-oiled birds. However a large study from the USA and Canada found that rehabilitated common guillemots Uria aalge had significantly lower survival than untreated birds. Three studies from South Africa and Australia found that rehabilitated birds bred, with one finding that rehabilitated birds had similar breeding success to un-oiled birds. However, this study found that birds rehabilitated after a second spill were less likely to breed, whilst two other studies found that rehabilitated birds had lower success than un-oiled birds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F448https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F448Thu, 23 Aug 2012 16:12:49 +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: Chase crop raiding primates using dogs We found no evidence for the effects of using dogs to chase crop raiding primates away 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%2F1444https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1444Tue, 17 Oct 2017 11:19:39 +0100Collected Evidence: Collected Evidence: Clear open patches in the forest We found no evidence for the effects of clearing open patches in the forest 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%2F1490https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1490Tue, 17 Oct 2017 19:37:34 +0100Collected Evidence: Collected Evidence: Change type of livestock Two replicated, before-and-after studies and one controlled study in Spain and the UK found changing the type of livestock led to mixed effects on shrub cover. However, in two of these studies changing the type of livestock reduced the cover of herbaceous species. One replicated, controlled, before-and-after study in the UK found that grazing with both cattle and sheep, as opposed to grazing with sheep, reduced cover of purple moor grass, but had no effect on four other plant species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1608https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1608Sun, 22 Oct 2017 10:05:25 +0100Collected Evidence: Collected Evidence: Change type of livestock We found no studies that evaluated the effects, on peatland vegetation, of changing livestock type. ‘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%2F1736https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1736Mon, 27 Nov 2017 21:21:54 +0000Collected 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: Change timing of forestry operations We found no studies that evaluated the effects of changing the timing of forestry 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%2F1984https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1984Tue, 04 Dec 2018 19:26:55 +0000Collected Evidence: Collected Evidence: Clean the hull, anchor and chain of commercial and recreational vessels We found no studies that evaluated the effects of cleaning the hull, anchor and chain of commercial and recreational vessels 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%2F2166https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2166Tue, 22 Oct 2019 12:16:33 +0100Collected Evidence: Collected Evidence: Clean anthropogenic platforms, structures or equipment We found no studies that evaluated the effects of cleaning anthropogenic platforms, structures or equipment 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%2F2167https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2167Tue, 22 Oct 2019 12:17:14 +0100Collected Evidence: Collected Evidence: Change type of livestock Two studies evaluated the effect of changing type of livestock on mammals. One study was in the UK and one was in the Netherlands. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): One replicated, randomized, paired sites, controlled, before-and-after study in the UK found that sheep and cattle grazing increased field vole abundance relative to sheep-only grazing. One replicated, randomized, paired sites study in the Netherlands found that cattle grazing increased vole abundance relative to horse grazing. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2412https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2412Fri, 29 May 2020 13:34:08 +0100Collected Evidence: Collected Evidence: Change timing of maintenance work at road/railway bridges and culverts We found no studies that evaluated the effects of changing the timing of maintenance work at road/railway bridges and culverts 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%2F2940https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2940Fri, 12 Feb 2021 17:47:15 +0000Collected Evidence: Collected Evidence: Change type of livestock grazing: freshwater marshesWe found no studies that evaluated the effects, on vegetation, of allowing different types of livestock to graze freshwater 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%2F2978https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2978Thu, 25 Mar 2021 15:05:08 +0000Collected Evidence: Collected Evidence: Change type of livestock grazing: brackish/salt marshes Three studies evaluated the effects, on vegetation, of allowing different types of livestock to graze brackish/salt marshes. There was overlap in the sites used in the studies, which all compared cattle and horse grazing on one salt marsh in the Netherlands. VEGETATION COMMUNITY Community types (1 study): One replicated, randomized, paired, controlled, before-and-after study on a salt marsh in the Netherlands found that plots experienced similar changes in the area of a couch-grass-dominated community, over four years, whether grazed by cattle or horses. Community composition (1 study): One replicated, randomized, paired, controlled, before-and-after study on a salt marsh in the Netherlands found that plots grazed by cattle and plots grazed by horses experienced a similar turnover of plant species over six years, and had a similar overall plant community composition after six years. Overall richness/diversity (2 studies): Two replicated, randomized, paired, controlled studies on one salt marsh in the Netherlands found that plots grazed by cattle and plots grazed by horses had similar plant species richness after 1–6 years. One of the studies also reported similar increases in species richness over six years, whether plots were grazed by cattle or horses. VEGETATION ABUNDANCE Individual species abundance (1 study): One replicated, randomized, paired, controlled, before-and-after study on a salt marsh in the Netherlands3 found that plots grazed by cattle and plots grazed by horses experienced similar changes in the cover of two salt marsh herb species, over six years. VEGETATION STRUCTURE Height (2 studies): Of two replicated, paired, controlled studies on one salt marsh in the Netherlands, one found that horses maintained shorter late-summer vegetation than cattle after two years of grazing. The other study found that horses and cattle maintained late-summer vegetation of a similar height, over four years. The first study also examined variation in height between vegetation patches, and found no significant difference between horse- and cattle-grazed plots. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2979https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2979Thu, 25 Mar 2021 15:05:17 +0000Collected Evidence: Collected Evidence: Change type of livestock grazing: freshwater swampsWe found no studies that evaluated the effects, on vegetation, of allowing different types of livestock to graze 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%2F2980https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2980Thu, 25 Mar 2021 15:05:27 +0000Collected Evidence: Collected Evidence: Change type of livestock grazing: brackish/saline swampsWe found no studies that evaluated the effects, on vegetation, of allowing different types of livestock to graze 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%2F2981https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2981Thu, 25 Mar 2021 15:05:33 +0000Collected Evidence: Collected Evidence: Clean waste water before it enters the environmentWe found no studies that evaluated the effects, on marsh or swamp vegetation, of cleaning waste water before releasing it into the environment.   ‘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%2F3142https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3142Mon, 05 Apr 2021 14:26:28 +0100Collected Evidence: Collected Evidence: Chill seeds of non-woody plants before sowing: freshwater wetlands Six studies evaluated the effects – on emergent, non-woody plants typical of freshwater wetlands – of chilling their seeds before sowing. All six studies were in the USA. Five of the studies were in laboratories or greenhouses. VEGETATION COMMUNITY   VEGETATION ABUNDANCE   VEGETATION STRUCTURE   OTHER Germination/emergence (6 studies): All six replicated, controlled studies in the USA found that chilling (at 1–10°C) seeds of herbaceous plants before sowing either increased or had no significant effect on their germination rate. Within studies, the direction and/or size of the effect depended on factors such as the duration of chilling, species, conditions (light/temperature) after sowing, and sowing site (restored vs natural meadows). One replicated, randomized, controlled study in the USA found that freezing sawgrass Cladium jamaicense seeds before sowing reduced their germination rate. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3367https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3367Mon, 12 Apr 2021 07:33:28 +0100Collected Evidence: Collected Evidence: Chill 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 chilling 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%2F3368https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3368Mon, 12 Apr 2021 07:33:39 +0100Collected Evidence: Collected Evidence: Chill tree/shrub seeds before sowing: freshwater wetlandsWe found no studies that evaluated the effects – on trees/shrubs typical of freshwater wetlands – of chilling 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%2F3369https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3369Mon, 12 Apr 2021 07:33:49 +0100Collected Evidence: Collected Evidence: Chill tree/shrub seeds before sowing: brackish/saline wetlandsWe found no studies that evaluated the effects – on trees/shrubs typical of brackish/saline wetlands – of chilling 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%2F3370https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3370Mon, 12 Apr 2021 07:33:57 +0100Collected Evidence: Collected Evidence: Classify conservation status of individual sitesWe found no studies that evaluated the effects, on vegetation or human behaviour, of classifying the conservation status of individual 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%2F3395https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3395Mon, 12 Apr 2021 12:11:48 +0100Collected Evidence: Collected Evidence: Change turbine colour to reduce insect attraction We found no studies that evaluated the effects of changing turbine colour to reduce attraction to 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%2F3844https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3844Tue, 05 Jul 2022 11:07:53 +0100Collected Evidence: Collected Evidence: Clear or open patches in forests Fourteen studies evaluated the effects on butterflies and moths of clearing or opening patches in forests. Five studies were in the UK, two were in each of Finland and Japan one was in each of Sweden, the USA and Canada and the Czech Republic, and one was a review across Europe. COMMUNITY RESPONSE (6 STUDIES) Community composition (1 study): One replicated, site comparison study in the UK found that wider woodland rides (and coppiced woodland) contained more unique species of macro-moth than standard width rides or mature forest. Richness/diversity (6 studies): Three replicated studies (including one controlled study, one site comparison study and one paired sites, controlled study) in the UK, Japan and the Czech Republic found that cleared patches in forests had a greater species richness of butterflies but a lower species richness of moths than unmanaged patches, coppiced woodland or closed canopy forest. One of these studies also found that the species richness of butterflies declined over the first three years after clearing. One of two replicated, site comparison studies in the UK and Canada found that larger, but not smaller, cleared patches supported a higher species richness of butterflies than undisturbed forest. The other study found that both wider and standard width rides had a similar species richness of macro-moths to mature forest. One replicated, site comparison study in Japan found that cleared forest patches had a similar species richness of butterflies to semi-natural grassland, although six species were only observed in cleared patches, compared to 15 species only observed in grassland. POPULATION RESPONSE (10 STUDIES) Abundance (10 studies): Five studies (including one replicated, controlled, before-and-after study, one replicated, controlled study and one replicated, site comparison study and two before-and-after studies) in the UK, Finland, Sweden and Japan found that cleared patches in forests, which were also managed with coppicing and grazing, had a higher abundance of butterflies generally, and chequered blue, woodland brown, high brown fritillary and small pearl-bordered fritillary specifically, than before management, or than unmanaged or coppiced areas. One of these studies also found that the abundance of butterflies declined over the first three years after clearing. One of two replicated, site comparison studies in the UK and Canada found that larger, but not smaller, cleared patches had a higher abundance of butterflies than undisturbed forest. The other study found that wider rides had a lower abundance of macro-moths than standard width rides or mature forest. One replicated, site comparison study in the UK found that patches cleared 2–4 years ago had a greater abundance of heath fritillary than patches cleared 7–11 years ago or patches in their first year after clearance. One study in Finland reported that, in an area with selected clearance of pines, a translocated population of baton blue butterflies increased in number over two years. One review across Europe reported that clearing small patches in forests benefitted 19 out of 67 butterfly species of conservation concern. Survival (1 study): One study in Finland reported that, in an area with selected clearance of pines, a translocated population of baton blue survived for at least two years. BEHAVIOUR (2 STUDY) Use (2 studies): One paired sites study in the USA found that orange sulphur butterflies, but not pine whites, flew into areas with selective clearance of pines more often than other areas. One replicated, before-and-after, site comparison study in the UK reported that in cleared patches in forests, which were also managed with cutting, grazing and ride widening, pearl-bordered fritillary and Duke of Burgundy breeding sites increased compared to before management. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3938https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3938Sat, 13 Aug 2022 14:56:39 +0100Collected Evidence: Collected Evidence: Change type of livestock grazing Four studies evaluated the effects on butterflies and moths of changing the type of livestock grazing. One study was in each of the UK, Sweden, China and France. COMMUNITY RESPONSE (2 STUDIES) Richness/diversity (2 studies): Two replicated studies (including one paired, site comparison study and one randomized, controlled study) in Sweden and France found that semi-natural grasslands grazed by cattle or horses had a greater species richness of butterflies and burnet moths than grasslands grazed by sheep. POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): One of two replicated, randomized, controlled studies (including one paired study) in China and France found that semi-natural grasslands grazed by cattle had a higher abundance of butterflies and burnet moths than grasslands grazed by sheep. The other study found that meadow steppe grazed by cattle, goats or sheep for 1–5 years had a similar abundance of butterflies and moths. BEHAVIOUR (1 STUDY) Use (1 study): One replicated, site comparison study in the UK found that a similar proportion of fen meadows were occupied by marsh fritillary caterpillars whether they were managed by cattle, horse or sheep grazing. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3963https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3963Sun, 14 Aug 2022 10:38:00 +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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