Collected Evidence: Collected Evidence: Remove problematic vegetation A before-and-after study from Japan found higher numbers of long-billed plovers Charadrius placidus after the removal of invasive black locust Robinia pseudoacacia. A study from Australia found lower mortality of Gould’s petrels Pterodroma leucoptera leucoptera following the removal of most of an island’s (native) bird-lime tree Pisonia umbellifera population, whilst a study from New Zealand found that Chatham Island oystercatchers Haematopus chathamensis could nest in preferable areas following invasive marram grass Ammophila arenaria control. A site comparison from the USA found lower densities of several birds in areas with (native) velvet mesquite Prosopis juliflora control.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F432https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F432Wed, 22 Aug 2012 14:43:46 +0100Collected Evidence: Collected Evidence: Remove tree canopy to reduce pond shading One before-and-after study in Denmark found that translocated garlic toads established breeding populations following pond restoration that included canopy removal. One before-and-after study in the USA found that canopy removal did not increase hatching success of spotted salamanders.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F758https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F758Wed, 14 Aug 2013 14:36:22 +0100Collected Evidence: Collected Evidence: Remove the chytrid fungus from ponds One before-and-after study in Mallorca found that pond drying and fungicidal treatment of resident midwife toads reduced levels of infection but did not eradicate chytridiomycosis.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F766https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F766Fri, 16 Aug 2013 16:11:48 +0100Collected Evidence: Collected Evidence: Remove specific aquatic plantsTwo studies investigating the effects of removing specific aquatic plants are discussed in ‘Threat: Invasive alien and other problematic species – Control invasive plants’.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F815https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F815Thu, 22 Aug 2013 15:10:05 +0100Collected Evidence: Collected Evidence: Remove turbine lighting to reduce bat and insect attraction We found no studies that evaluated the effects of removing turbine lighting to reduce bat and insect attraction 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%2F969https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F969Fri, 20 Dec 2013 12:15:27 +0000Collected Evidence: Collected Evidence: Remove residential or commercial development We found no studies that evaluated the effects of removing residential or commercial development on shrublands. '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%2F1542https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1542Thu, 19 Oct 2017 16:43:11 +0100Collected Evidence: Collected Evidence: Remove trees/crops to restore shrubland structure We found no studies that evaluated the effects of removing trees/crops to restore shrubland structure on shrublands. '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%2F1683https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1683Mon, 23 Oct 2017 09:22:11 +0100Collected Evidence: Collected Evidence: Remove trees, leaf litter and topsoil We found no studies that evaluated the effects of removing trees, leaf litter and soil surface on shrublands. '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%2F1684https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1684Mon, 23 Oct 2017 09:23:24 +0100Collected Evidence: Collected Evidence: Remove residential or commercial development from peatlands We found no studies that evaluated the effects, on peatland vegetation, of removing residential or commercial development 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%2F1719https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1719Mon, 13 Nov 2017 15:15:53 +0000Collected Evidence: Collected Evidence: Remove pollutants from waste gases before they enter the environment One study evaluated the effects, on peatland vegetation, of removing pollutants from waste gases before release into the environment. The study was in bogs. Plant richness/diversity (1 study): One before-and-after study in bogs in Estonia reported that following installation of dust filters in industrial plants (along with a general reduction in emissions), the number of Sphagnum moss species increased but the total number of plant species decreased. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1789https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1789Tue, 28 Nov 2017 08:18:07 +0000Collected Evidence: Collected Evidence: Remove trees and shrubs to recreate open areas of land Two studies evaluated the effects on mammals of removing trees and shrubs to recreate open areas of land. Both studies were in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Abundance (1 study): A controlled study in the USA found that where Ashe juniper trees were removed, there were higher abundances of three rodent species. BEHAVIOUR (1 STUDY) Use (1 study): A before-and-after, site comparison study in the USA found that removing trees increased use of areas by Rocky Mountain bighorn sheep. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2483https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2483Thu, 04 Jun 2020 11:42:33 +0100Collected Evidence: Collected Evidence: Remove topsoil that has had fertilizer added to mimic low nutrient soil We found no studies that evaluated the effects on mammals of removing topsoil that has had fertilizer added to mimic low nutrient soil. '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%2F2544https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2544Tue, 09 Jun 2020 09:01:30 +0100Collected Evidence: Collected Evidence: Remove roadkill regularly to reduce kill rate of predators/scavengers We found no studies that evaluated the effects of removing roadkill regularly to reduce the kill rate of predators/scavengers. ‘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%2F2601https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2601Thu, 11 Jun 2020 15:32:32 +0100Collected Evidence: Collected Evidence: Remove residential or commercial developmentWe found no studies that evaluated the effects, on vegetation, of removing residential or commercial development to restore/create 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%2F2946https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2946Mon, 01 Mar 2021 16:14:22 +0000Collected Evidence: Collected Evidence: Remove plant litter: freshwater marshes One study evaluated the effects, on vegetation, of removing plant litter from freshwater marshes. The study was in the USA. VEGETATION COMMUNITY Community composition (1 study): One replicated, paired, controlled study in rewetted marshes in the USA found that plots cleared of plant litter contained a plant community characteristic of wetter conditions than uncleared plots after one growing season – but not after two. Overall richness/diversity (1 study): The same study found that plots cleared of plant litter contained a similar number of wetland plant species to uncleared plots, after 1–2 growing seasons. VEGETATION ABUNDANCE                                                          Overall abundance (1 study): One replicated, paired, controlled study in rewetted marshes in the USA found that plots cleared of plant litter had greater cover of wetland plants than uncleared plots after one growing season – but not after two. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3062https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3062Fri, 02 Apr 2021 12:40:27 +0100Collected Evidence: Collected Evidence: Remove plant litter: brackish/salt marshesWe found no studies that evaluated the effects, on vegetation, of removing plant litter from 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%2F3063https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3063Fri, 02 Apr 2021 13:01:21 +0100Collected Evidence: Collected Evidence: Remove plant litter: freshwater swampsWe found no studies that evaluated the effects, on vegetation, of removing plant litter 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%2F3064https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3064Fri, 02 Apr 2021 13:01:38 +0100Collected Evidence: Collected Evidence: Remove pollutants from waste gases before they enter the environmentWe found no studies that evaluated the effects, on vegetation in marshes or swamps, of removing pollutants from waste gases before releasing them 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%2F3179https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3179Tue, 06 Apr 2021 16:11:49 +0100Collected Evidence: Collected Evidence: Remove surface soil/sediment: freshwater marshes Six studies evaluated the effects, on vegetation, of removing surface soil/sediment to restore or create freshwater marshes. Four studies were in the USA. One study was in the Netherlands. One study was in Japan. VEGETATION COMMUNITY                              Community composition (3 studies): Two replicated, site comparison studies in the USA reported that freshwater marshes being restored by removing excess soil/sediment (along with other interventions) typically contained a different overall plant community, after 1–12 years, to both degraded and natural marshes nearby. One replicated study of dune slacks in the Netherlands simply reported changes in the overall plant community composition over four years after stripping topsoil (along with other interventions). Overall richness/diversity (4 studies): One replicated, site comparison study of dune slacks in the Netherlands reported that overall plant species richness was greater in restored slacks (topsoil stripped five years previously, along with other interventions) than in mature unmanaged slacks. One replicated, site comparison study in the USA reported that freshwater marshes being restored by removing topsoil (along with other interventions) contained fewer wetland plant species, after 1–12 years, than nearby natural marshes. Two studies (including one site comparison) in freshwater marshes in the USA and Japan reported that the effect of removing topsoil on overall plant species richness depended on the amount removed. Characteristic plant richness/diversity (2 studies): One replicated, site comparison study of a floodplain marsh in Japan found that where stripped plots were colonized by plants within two growing seasons, they contained more wetland-characteristic species than an adjacent unstripped area. One replicated study of dune slacks in the Netherlands simply reported the number of characteristic plant species present over five years after stripping topsoil (along with other interventions). VEGETATION ABUNDANCE Overall abundance (3 studies): Three studies (two replicated) in the Netherlands, the USA and Japan simply quantified the overall abundance of vegetation that colonized – within five years – freshwater wetlands stripped of topsoil (sometimes along with other interventions). Characteristic plant abundance (2 studies): Two studies (one replicated) in freshwater marshes in the USA and Japan simply quantified the abundance of wetland-characteristic plant species that colonized – within five years – areas stripped of topsoil. Individual species abundance (5 studies): Five studies quantified the effect of this action on the abundance of individual plant species. For example, one replicated, site comparison study in the USA found that pothole wetlands restored by removing excess sediment (sometimes along with planting herbs) had lower hybrid cattail Typha x glauca cover than unrestored wetlands after 2–7 years, and similar hybrid cattail cover to nearby natural wetlands. One replicated study of dune slacks in the Netherlands simply quantified the cover of individual species present over five years after stripping topsoil (along with other interventions). Only two species had >1% cover in any slack. VEGETATION STRUCTURE Overall structure (1 study): One study in a freshwater marsh in the USA reported that the effect of removing topsoil on the abundance of tall vegetation depended on the amount removed. Visual obstruction (1 study): One replicated, site comparison study of pothole wetlands in the USA found that the effect of removing excess sediment (sometimes along with planting herbs) on horizontal vegetation cover, 2–7 years later, depended on the elevation/vegetation zone. Height (1 study): One site comparison study in the USA reported that sedge tussocks were shorter in a wet meadow restored by removing excess sediment (along with other interventions, including planting sedges) than in nearby natural meadows, after 11–14 years. Diameter/perimeter/area (1 study): One site comparison study in the USA reported that sedge tussocks had a smaller perimeter in a wet meadow restored by removing excess sediment (along with other interventions, including planting sedges) than in natural meadows, after 11–14 years. Basal area (1 study): One site comparison study in the USA reported that the basal area of sedge tussocks was smaller in a wet meadow restored by removing excess sediment (along with other interventions, including planting sedges) than in nearby natural meadows, after 11–14 years. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3221https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3221Fri, 09 Apr 2021 13:07:41 +0100Collected Evidence: Collected Evidence: Remove surface soil/sediment: brackish/salt marshes One study evaluated the effects, on vegetation, of removing surface soil/sediment to restore or create brackish/salt marshes. The study was in the Netherlands. VEGETATION COMMUNITY                              Overall richness/diversity (1 study): One study in the Netherlands reported that 23 plant species colonized over two years after stripping topsoil from coastal farmland. VEGETATION ABUNDANCE Individual species abundance (1 study): One study in the Netherlands reported the frequency of plant species that colonized over two years after stripping topsoil from coastal farmland. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3222https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3222Fri, 09 Apr 2021 13:08:28 +0100Collected Evidence: Collected Evidence: Remove surface soil/sediment: freshwater swampsWe found no studies that evaluated the effects, on vegetation, of removing surface soil/sediment to restore or create 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%2F3223https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3223Fri, 09 Apr 2021 13:08:44 +0100Collected Evidence: Collected Evidence: Remove surface soil/sediment: brackish/saline swampsWe found no studies that evaluated the effects, on vegetation, of removing surface soil/sediment to restore or create 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%2F3224https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3224Fri, 09 Apr 2021 13:08:54 +0100Collected Evidence: Collected Evidence: Remove surface soil/sediment (before planting)We found no studies that evaluated the effects, on vegetation, of removing surface soil/sediment before planting emergent marsh/swamp plants.   ‘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%2F3290https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3290Sat, 10 Apr 2021 20:04:01 +0100Collected Evidence: Collected Evidence: Remove topsoil or turf before seeding/planting Six studies examined the effects of removing topsoil or turf before seeding/planting on grassland vegetation. Three studies were in the UK, two studies were in the USA and one was in France. VEGETATION COMMUNITY (3 STUDIES) Community composition (1 study): One replicated, randomized, controlled study in France found that removing topsoil before sowing seeds increased plant community similarity to that of intact steppe. Overall richness/diversity (1 study): One replicated, randomized, controlled study in France found that removing topsoil before sowing seeds increased plant species richness. Sown/planted species richness/diversity (1 study): One replicated, controlled study in the UK found that removing topsoil before sowing seeds increased the species richness of sown plants. Grass richness/diversity (1 study): One replicated, randomized, paired, controlled study in the UK found that removing turf before sowing seeds increased grass species richness in most cases compared to disturbing the soil before sowing. Forb richness/diversity (1 study): One replicated, randomized, paired, controlled study in the UK found that removing turf before sowing seeds increased forb species richness in most cases compared to disturbing the soil before sowing. VEGETATION ABUNDANCE (2 STUDIES) Overall abundance (1 study): One replicated, randomized, controlled study in France found that removing topsoil before sowing seeds did not alter overall vegetation cover. Sown/planted species abundance (1 study): One replicated, randomized, controlled study in the UK found that removing topsoil before planting seedlings led to higher cover of planted species. Individual species abundance (1 study): One replicated, randomized, controlled study in the UK found that removing topsoil before planting seedlings led to lower cover of common knapweed. VEGETATION STRUCTURE (0 STUDIES) OTHER (2 STUDIES) Survival (2 studies): Two replicated, controlled studies (one paired and one randomized) in the USA found that removing topsoil before planting California oatgrass or sowing and planting purple needlegrass increased the survival of seedlings and plants. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3415https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3415Fri, 25 Jun 2021 16:09:07 +0100Collected Evidence: Collected Evidence: Remove tree canopy to reduce pond or waterway shading One study evaluated the effects on butterflies and moths of removing tree canopy to reduce pond or waterway shading. This study was in the USA. COMMUNITY RESPONSE (0 STUDIES)   POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, randomized, paired, controlled study in the USA1 found that removing trees to reduce stream shading reduced the survival of Appalachian brown caterpillars and pupae, but did not affect egg survival. BEHAVIOUR (0 STUDIES)  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3952https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3952Sat, 13 Aug 2022 15:22:29 +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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