Collected Evidence: Collected Evidence: Add nutrients to new ponds as larvae food source We found no evidence for the effects of adding nutrients, such as zooplankton, to new ponds on amphibian 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%2F812https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F812Thu, 22 Aug 2013 15:07:50 +0100Collected Evidence: Collected Evidence: Create refuge areas in aquatic habitats We found no evidence for the effects of creating refuge areas in aquatic habitats on amphibian 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%2F813https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F813Thu, 22 Aug 2013 15:08:47 +0100Collected Evidence: Collected Evidence: Add woody debris to ponds We found no evidence for the effects of adding woody debris to ponds on amphibian 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%2F814https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F814Thu, 22 Aug 2013 15:09:29 +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: Add specific plants to aquatic habitats We found no evidence for the effects of adding specific plants, such as emergent vegetation, to aquatic habitats on amphibian 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%2F816https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F816Thu, 22 Aug 2013 15:10:49 +0100Collected Evidence: Collected Evidence: Deepen, de-silt or re-profile ponds Two before-and-after studies in France and Denmark found that pond deepening and enlarging or re-profiling resulted in the establishment of a breeding population of great crested newts or translocated garlic toads. Two studies (including one replicated, controlled study) in the UK and Denmark found that pond deepening and enlarging or dredging increased a population of common frogs or numbers of calling male tree frogs. Four before-and-after studies in Denmark and the UK found that pond deepening, along with other interventions, maintained newt populations and increased populations of European fire-bellied toads or natterjack toads.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F817https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F817Fri, 23 Aug 2013 09:03:23 +0100Collected Evidence: Collected Evidence: Create ponds for great crested newts Three before-and-after studies (including two replicated studies) in Germany and the UK found that naturally colonizing, captive-bred and translocated great crested newts established breeding populations at 57–75% of created ponds or sites. One systematic review in the UK found that there was no conclusive evidence that mitigation, which often included pond creation, resulted in self-sustaining populations. Three replicated, before-and-after studies in the UK found that up to 88% of created ponds were colonized by translocated or by small numbers of naturally colonizing great crested newts. One replicated before-and-after study in the UK found that head-started great crested newts reproduced in 38% of created ponds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F863https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F863Fri, 06 Sep 2013 15:57:48 +0100Collected Evidence: Collected Evidence: Create ponds for green toads Two before-and-after studies (including one controlled study) in Denmark found that pond creation, along with other interventions, significantly increased green toad populations. One replicated, before-and-after study in Sweden found that green toads used 59% and reproduced in 41% of created ponds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F864https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F864Fri, 06 Sep 2013 16:23:40 +0100Collected Evidence: Collected Evidence: Create ponds for frogs Three of five before-and-after studies (including one replicated study) in Australia, Spain, the UK and USA found that translocated, head-started, captive-bred and naturally colonizing frogs established breeding populations in created ponds. Two found that breeding populations were established at one of four sites by translocated frogs, but were not established by captive-bred frogs. One replicated, before-and-after study in Denmark found that frogs colonized created ponds. One before-and-after study in the Netherlands found that pond creation, along with vegetation clearance, increased a breeding population of European tree frogs. An additional three of four replicated, before-and-after studies in Italy, the UK and USA found that naturally colonizing frog species reproduced in 50–75% of created ponds. Two found that translocated frog species reproduced in only 31% of created ponds, or colonized but did not reproduce successfully. One replicated study in the USA found that survival of translocated Oregon spotted frogs increased with increasing age of created ponds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F865https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F865Tue, 10 Sep 2013 14:47:43 +0100Collected Evidence: Collected Evidence: Create ponds for natterjack toads Five before-and-after studies (including three replicated and one controlled study) in the UK and Denmark found that pond creation, along with other interventions, significantly increased natterjack toad populations, or in two cases maintained or increased populations at 75% of sites. One replicated, site comparison study in the UK found that compared to natural ponds, created ponds had lower natterjack toad tadpole mortality from desiccation, but higher mortality from predation by invertebrates.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F866https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F866Tue, 10 Sep 2013 15:47:29 +0100Collected Evidence: Collected Evidence: Create ponds for salamanders (including newts) Three before-and-after studies (including two replicated studies) in France, Germany and the USA found that naturally colonizing alpine newts, captive-bred smooth newts or translocated spotted salamanders established stable breeding populations in 20–100% of created ponds. Two replicated, before-and-after study in France and China found that alpine newts or Chinhai salamanders reproduced in 60–100% of created ponds. One small, replicated, before-and-after study in the USA found that translocated spotted salamanders but not tiger salamanders reproduced in created ponds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F867https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F867Tue, 10 Sep 2013 15:55:04 +0100Collected Evidence: Collected Evidence: Create ponds for toads Four before-and-after studies (including one replicated study) in Germany, the UK and USA found that translocated and naturally colonizing toads established breeding populations in created ponds, or in one case 33% of created ponds. Two before-and-after studies (including one replicated study) in Denmark and Switzerland found that common toads and midwife toads naturally colonized 29–100% of created ponds, whereas captive-bred garlic toads did not colonize. One before-and-after study in Denmark found that creating and restoring ponds, along with head-starting, increased populations of European fire-bellied toads. One replicated, before-and-after study in Switzerland found that midwife toads reproduced in 16% of created ponds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F868https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F868Wed, 11 Sep 2013 08:55:34 +0100Collected Evidence: Collected Evidence: Create ponds for amphibians Twenty-eight studies investigated the colonization of created ponds by amphibians in general (rather than by targeted species, which are discussed below). All of the studies found that amphibians used some or all created ponds. Nine site comparison studies (including seven replicated studies) in Australia, Canada, Spain, the UK and USA compared amphibian numbers in created and natural ponds. Five found that numbers of species or breeding species were similar or higher in created ponds, and numbers of ponds colonized were similar. Four found that species composition differed, and comparisons between abundance of individual species, juvenile productivity and size at metamorphosis differed depending on species. One found that numbers of species were similar or lower depending on the permanence of created water bodies. One found that populations in created ponds were less stable. One review and two replicated, before-and-after studies in Denmark and the USA found that amphibians established stable populations in 50–100% of created ponds. Six replicated studies (including one randomized study) in France, the Netherlands, UK and USA found that amphibians used 64–100% and reproduced in 64–68% of created ponds, or used 8–100% and reproduced in 2–62% depending on species. One review and 15 studies (including 12 replicated studies, one of which was randomized) in Europe and the USA found that created ponds were used or colonized by up to 15 naturally colonizing species, up to 10 species that reproduced, as well as by captive-bred amphibians. Five replicated studies (including three site comparison studies) in Denmark, Estonia, France, Italy and the USA found that pond creation, and restoration in three cases, maintained and increased amphibian populations or increased numbers of species. Seven studies (including one review) in Austria, Denmark, Poland, the Netherlands and USA found that use or colonization of or reproductive success in created ponds was affected by pond age, permanence, vegetation cover, surrounding landscape, distance to existing ponds and presence of fish.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F869https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F869Wed, 11 Sep 2013 09:16:41 +0100Collected Evidence: Collected Evidence: Restore ponds Fifteen studies investigated the effectiveness of pond restoration for amphibians. One replicated, before-and-after study in Denmark found that pond restoration had mixed effects on European tree frog population numbers depending on site. One replicated, controlled, before-and-after study in the UK found that pond restoration did not increase great crested newt populations. Six replicated, before-and-after studies (including one controlled and one site comparison study) in Denmark, Estonia, Italy and the UK found that pond restoration and creation increased numbers of amphibian species, maintained or increased populations, or increased pond occupancy and ponds with breeding success. One found that numbers of species did not increase. Two before-and-after studies (including one replicated study) in Estonia found that pond restoration, along with terrestrial habitat management, maintained or increased populations of natterjack toads. One systematic review in the UK found that there was no conclusive evidence that mitigation, which often included pond restoration, resulted in self-sustaining great crested newt populations. One small, replicated study in the USA found that pond restoration had mixed effects on spotted salamander hatching success depending on restoration method. One replicated, before-and-after study in the UK found that restoration increased the number of ponds used by breeding natterjack toads. One replicated study in Sweden found that following restoration green toads only reproduced in one of 10 ponds. Three before-and-after studies (including one replicated, controlled study) in Denmark and Italy found that restored and created ponds were colonized by 1–7 species, with 6–65% of ponds colonized and 35% used for breeding.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F878https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F878Thu, 12 Sep 2013 15:17:02 +0100Collected Evidence: Collected Evidence: Restore wetland Seventeen studies investigated the effectiveness of wetland restoration for amphibians. Ten site comparison studies (including eight replicated studies) in Canada and the USA compared amphibian numbers in restored and natural wetlands. Eight found that amphibian abundance, numbers of species and species composition were similar. Two found that the number of species or abundance was lower and species composition different in restored wetlands. One found that restored wetlands were used more or less depending on the habitat surrounding natural wetlands. One global review found that in 89% of cases, restored and created wetlands had similar or higher amphibian abundance or numbers of species to natural wetlands. Seven of nine studies (including six site comparison and/or replicated studies) in Canada, Taiwan and the USA found that wetland restoration increased numbers of amphibian species, with breeding populations establishing in some cases. Three found that numbers of species or abundance did not increase with restoration. Two found mixed effects, with restoration maintaining or increasing abundance of individual species. Three replicated studies (including two site comparison studies) in the USA found that numbers of species in restored wetlands were affected by wetland size, proximity to source ponds and seasonality, but not wetland age. Three studies (including two replicated, site comparison studies) in Taiwan and the USA found that restored wetlands were colonized by three to eight amphibian species. One before-and-after study in the USA found that three target species did not recolonize restored wetlands.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F879https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F879Thu, 12 Sep 2013 15:34:57 +0100Collected Evidence: Collected Evidence: Create wetland Fifteen studies investigated the effectiveness of creating wetlands for amphibians. Five site comparison studies (including four replicated studies) in the USA compared created to natural wetlands and found that created wetlands had similar numbers of amphibian species, amphibian abundance or communities depending on depth as natural wetlands. Two of the studies found that created wetlands had fewer amphibian species or lower abundance and different communities compared to natural wetlands. One site comparison study in the USA found that created wetlands had similar numbers of species to adjacent forest. One global review and two site comparison studies (including one replicated study) in the USA combined created and restored wetlands and compared them to natural wetlands and found that numbers of amphibian species and abundance was higher or similar, or higher in 54% of studies and similar in 35% of studies reviewed compared to natural wetlands. Three site comparison studies (including one replicated study) in the USA found that certain amphibian species were only found in created or natural wetlands. One before-and-after study in Australia found that captive-bred green and golden bell frog tadpoles released into a created wetland did not establish a self-sustaining population. Five studies (including two replicated studies) in Kenya and the USA that investigated colonization of created wetlands found that four to 15 amphibian species used or colonized the wetlands. One global review and three studies (including two replicated studies) in the USA found that numbers of amphibian species and amphibian abundance in created wetlands were affected by wetland design, vegetation, water levels, surrounding habitat, fish presence and distance to source wetlands.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F880https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F880Fri, 13 Sep 2013 11:16:59 +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.

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