Collected Evidence: Collected Evidence: Procambarus crayfish control: Trapping combined with encouragement of predators A before-and-after study in Switzerland found that introducing predators, combined with trapping significantly reduced red swamp crayfish populations in a pond. A second replicated, controlled study from Italy demonstrated that trapping and predation in combination was more effective at reducing red swamp crayfish populations than predation alone.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1031https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1031Fri, 03 Jul 2015 15:16:05 +0100Collected Evidence: Collected Evidence: American bullfrog control: Direct removal of juveniles One replicated study in Belgium found double fyke nets were effective in catching bullfrog tadpoles in small shallow ponds. One before-and-after study in France found a significant reduction in the number of recorded adults and juveniles following the removal of juveniles by trapping, when carried out as part of a combination treatment.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1046https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1046Fri, 03 Jul 2015 15:20:59 +0100Collected Evidence: Collected Evidence: Brown and black bullheads: Application of a biocide A study in the UK reported that use of a piscicide containing rotenone achieved eradication of black bullhead. A study in the USA found that rotenone successfully eradicated black bullhead, but one of two ponds required two separate doses.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1050https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1050Wed, 07 Oct 2015 10:41:27 +0100Collected Evidence: Collected Evidence: Adopt certification One replicated, site comparison study in Ethiopia found that the risk of deforestation was lower in certified than uncertified forests. One controlled, before-and-after trial in Gabon found that when logging intensity was taken into account although tree damage did not differ, changes in above-ground biomass were smaller in certified than in uncertified forests.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1150https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1150Tue, 17 May 2016 16:23:09 +0100Collected Evidence: Collected Evidence: Improve soil quality after tree planting (excluding applying fertilizer) One of two randomized, replicated, controlled studies in Australia found that different soil enhancers had mixed effects on tree seedling survival and height, but no effect on tree seedling health. The other found that combinations of soil enhancers did not increase seedling survival, height, diameter or health.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1153https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1153Wed, 18 May 2016 15:12:35 +0100Collected Evidence: Collected Evidence: Reduce the intensity of livestock grazing in forests One replicated study in the UK found that reducing grazing intensity increased the number of tree saplings. One replicated, randomized, controlled study in Greece found that reducing grazing intensity increased understory biomass.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1207https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1207Thu, 19 May 2016 14:24:40 +0100Collected Evidence: Collected Evidence: Remove burned trees One replicated, controlled study in Israel1 found that removing burned trees increased total plant species richness. One replicated, controlled study in Spain2 found that removal increased the cover and species richness of some plant species.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1237https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1237Fri, 03 Jun 2016 08:52:10 +0100Collected Evidence: Collected Evidence: Plant a mixture of tree species to enhance diversity One replicated, randomized, controlled study in Brazil found that planting various tree species increased species richness, but had no effect on the density of new trees. One replicated, controlled study in Greece found that planting native tree species increased total plant species richness, diversity and cover.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1243https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1243Fri, 03 Jun 2016 10:43:27 +0100Collected Evidence: Collected Evidence: Remove or disturb leaf litter to enhance germination One replicated, controlled study in Costa Rica found that leaf litter removal decreased the density of new tree seedlings. One replicated, controlled study in Poland found leaf litter removal increased understory plant species richness but decreased their cover.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1246https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1246Fri, 03 Jun 2016 11:07:50 +0100Collected Evidence: Collected Evidence: Use soil disturbance to enhance germination (excluding scarification or ploughing) Two replicated, controlled studies from Canada and Finland found that disturbance of the forest floor decreased understory vegetation cover.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1252https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1252Fri, 03 Jun 2016 13:50:07 +0100Collected Evidence: Collected Evidence: Manage woody debris before tree planting One replicated, randomized, controlled study in Canada found that removal of woody debris increased the survival rate of planted trees. One replicated, controlled study in the USA found mixed effects of removing, chopping and burning woody debris on the size of planted trees.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1257https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1257Mon, 06 Jun 2016 09:39:53 +0100Collected Evidence: Collected Evidence: Add organic matter after tree planting Two replicated, randomized, controlled studies in the USA found that adding leaf litter or wood-chips before restoration planting increased seedling biomass, but decreased seedling emergence and survival.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1258https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1258Mon, 06 Jun 2016 10:36:39 +0100Collected Evidence: Collected Evidence: Add lime to the soil after tree planting One of two replicated, randomized, controlled studies in the USA found that adding lime before restoration planting decreased the survival of pine seedlings. The other study found no effect of adding lime on planted oak seedling growth.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1259https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1259Mon, 06 Jun 2016 10:42:49 +0100Collected Evidence: Collected Evidence: Use tree guards or shelters to protect planted trees One replicated, randomized, controlled study in the USA found that using light but not dark coloured plastic tree shelters increased the survival rate of planted tree seedlings. One replicated, controlled study in Hong Kong found that tree guards increased tree height after 37 but not 44 months.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1268https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1268Fri, 10 Jun 2016 09:07:23 +0100Collected Evidence: Collected Evidence: Log/remove trees within forests: effects on young trees One replicated controlled study in Canada found that logging trees in forests increased the density of young trees. One replicated controlled study in Costa Rica found mixed effects on the density of young trees.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1272https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1272Mon, 13 Jun 2016 09:18:50 +0100Collected Evidence: Collected Evidence: Temporarily move reptiles away from short-term threats Two studies evaluated the effects of temporarily moving reptiles away from short-term threats on their populations. One study was in France and one was in Spain. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (1 study): One replicated, randomized, controlled, before-and-after study in Spain found that after temporarily relocating Hermann’s tortoises during vegetation management, a similar number were observed compared to before management began. Survival (1 study): One replicated study in France found that at least 25% of temporarily relocated and released Hermann’s tortoises survived for 4–5 years after re-release. The study also found that 5% of individuals died while in temporary captivity. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3735https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3735Tue, 14 Dec 2021 09:58:47 +0000Collected Evidence: Collected Evidence: Breed reptiles in captivity: Sea turtles Two studies evaluated the effects of breeding sea turtles in captivity. One study was in the Cayman Islands, Costa Rica, Surinam and Ascension Island and one was in Japan. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Reproductive success (2 studies): One replicated, controlled study in the Cayman Islands, Costa Rica, Surinam and Ascension Island found that artificially incubated green turtle eggs that were laid in captivity had lower hatchling success than those laid in the wild and artificially incubated. One study in Japan reported that hatching success of eggs produced by one female black turtle in captivity was 12%. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3745https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3745Tue, 14 Dec 2021 11:14:04 +0000Collected Evidence: Collected Evidence: Create or restore waterways Two studies evaluated the effects of creating or restoring waterways on reptile populations. Both studies were in the USA. COMMUNITY RESPONSE (1 STUDY) Community composition (1 study): One site comparison study in the USA found that restored and pristine streams had similar turtle community composition. POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): One site comparison study in the USA found that restored and pristine streams had a similar abundance of turtles. One replicated, site comparison study in the USA found that creating new waterways by redirecting flows during forest restoration had mixed effects of reptile abundance. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3754https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3754Tue, 14 Dec 2021 13:37:31 +0000Collected Evidence: Collected Evidence: Alter incubation temperatures to achieve optimal/desired sex ratio: Tuatara Two studies evaluated the effects of altering incubation temperatures to achieve optimal/desired sex ratios on tuatara populations. Both studies were in New Zealand. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (2 STUDIES): Offspring sex ratio (2 studies): Two replicated studies (including one controlled study) in New Zealand found that hatchling sex ratio of tuatara was affected by temperature, and that warmer temperatures resulted in more males. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3765https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3765Tue, 14 Dec 2021 17:00:12 +0000Collected Evidence: Collected Evidence: Release captive-bred reptiles into the wild: Tuatara Two studies evaluated the effects of releasing captive-bred tuatara into the wild. One study was in New Zealand and one was a global review. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Abundance (1 study): One global review found that when using recruitment to the adult population as a measure of success, 32% of reptile translocations/releases (releases of captive individuals were 7% of total projects) were successful. Condition (1 study): One study in New Zealand found that tuatara reared close to the release site had higher growth, but similar body condition compared to individuals reared in a warmer climate. BEHAVIOUR (1 STUDY) Behaviour change (1 studies): One study in New Zealand found that tuatara reared close to the release site had similar home range sizes and post-release dispersal compared to individuals reared in a warmer climate. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3773https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3773Wed, 15 Dec 2021 12:02:09 +0000Collected Evidence: Collected Evidence: Use holding pens or enclosures at release site prior to release of captive-bred reptiles Two studies evaluated the effects on reptile populations of using holding pens or enclosures at release sites prior to release of captive-bred reptiles. Both studies were in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): Two controlled studies (including one replicated study) in the USA found that survival of captive-bred smooth green snakes and desert tortoises held in pens before release was similar over 3–5 months or 2–3 years compared to individuals released directly. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One controlled study in the USA found that movement of smooth green snakes held in pens before release was similar compared to snakes that were released directly. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3774https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3774Wed, 15 Dec 2021 12:04:46 +0000Collected Evidence: Collected Evidence: Head-start wild-caught reptiles for release: Tuatara Two studies evaluated the effects of head-starting wild-caught tuatara for release. Both studies were in New Zealand. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One study in New Zealand reported that 67–70% of head-started tuatara survived over monitoring periods of 9–11 months. One study in New Zealand found that 56% of head-started tuatara were recaptured over six years following release. Condition (1 studies): One study in New Zealand reported that head-started tuatara increased in weight by around 100 g during the five years following release. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3779https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3779Wed, 15 Dec 2021 13:42:27 +0000Collected Evidence: Collected Evidence: Relocate nests/eggs to a hatchery: Tortoises, terrapins, side-necked & softshell turtles Two studies evaluated the effects on tortoise, terrapin, side-necked and softshell turtle populations of relocating nests/eggs to a hatchery. One study was in Costa Rica and Venezuela. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Reproductive success (2 studies): One replicated, controlled study in Venezuela found that yellow-headed sideneck turtle eggs relocated to a hatchery had higher hatching success than both natural nests and artificially incubated eggs. One study in Costa Rica reported that 80% of Nicaraguan slider eggs in a hatchery hatched successfully. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3787https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3787Wed, 15 Dec 2021 16:31:59 +0000Collected Evidence: Collected Evidence: Relocate nests/eggs for artificial incubation: Tuatara Two studies evaluated the effects of relocating nests/eggs for artificial incubation on tuatara populations. Both studies were in New Zealand. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Reproductive success (2 studies): One of two replicated studies (including one controlled study) in New Zealand reported that hatching success of tuatara eggs relocated for artificial incubation was 86–100%. The other study reported hatching success of 44%. Condition (1 study): One replicated, controlled study in New Zealand found that 10 months after hatching, artificially incubated tuatara were larger that those from natural nests. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3800https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3800Wed, 15 Dec 2021 19:27:29 +0000Collected Evidence: Collected Evidence: Recover eggs from injured or dead reptiles Two studies evaluated the effects of recovering eggs from injured or dead reptiles on their populations. One study was in each of the USA and Columbia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Reproductive success (2 studies): One replicated, controlled study in Columbia found that eggs recovered from harvested Magdalena river turtles had similar hatching success compared to both relocated and natural turtle nests. One replicated study in the USA found that 64% of eggs recovered from road-killed red-eared sliders hatched successfully. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3801https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3801Wed, 15 Dec 2021 19:33:27 +0000
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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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