Collected Evidence: Collected Evidence: Procambarus crayfish control: Encouraging predators Two replicated, controlled studies in Italy found that eels fed on the red swamp crayfish and reduced population size. One replicated, controlled study from France in 2001 found that pike predated red swamp crayfish.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1030https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1030Fri, 03 Jul 2015 15:15:43 +0100Collected Evidence: Collected Evidence: Skunk cabbage: Physical removal A study in Switzerland found that annual physical removal of recently established skunk cabbage plants over five years removed the entire stock. A study in the Netherlands found that manual removal of mature skunk cabbage plants was effective for a small outbreak of a small-growing plant. A study in Germany reported that after the first four years of a twice yearly full removal programme of skunk cabbage, a large number of plants still needed to be removed each year. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1101https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1101Tue, 13 Oct 2015 14:11:52 +0100Collected Evidence: Collected Evidence: Adopt community-based management to protect forests Two studies from Ethiopia and Nepal (including one replicated, before-and-after, site comparison) found that forest cover increased more in community-managed forests than in forests not managed by local communities. One replicated, site comparison study in Colombia found that deforestation rates in community-managed forests did not differ from deforestation rates in forests that were not managed by local communities, or in uninhabited national parks.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1152https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1152Wed, 18 May 2016 14:58:54 +0100Collected Evidence: Collected Evidence: Shorten livestock grazing period or control grazing season in forests One replicated, controlled study in Spain found that shortening the livestock grazing period increased the abundance and size of regenerating oak trees. One paired-sites study in Australia found no effect of shortening the livestock grazing period on native plant species richness. One replicated study in the UK found that the number of tree seedlings was higher following summer compared to winter grazing.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1208https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1208Thu, 19 May 2016 14:33:45 +0100Collected Evidence: Collected Evidence: Use shelterwood harvest instead of clearcutting Three replicated, controlled studies in Sweden and the USA found that shelterwood harvesting resulted in higher plant diversity, lower grass cover and higher density of tree species compared with clearcutting.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1214https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1214Fri, 20 May 2016 13:48:37 +0100Collected Evidence: Collected Evidence: Use partial retention harvesting instead of clearcutting Three studies (including one replicated, randomized, controlled study) in Canada found that using partial retention harvesting instead of clearcutting decreased the density of young trees.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1215https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1215Fri, 20 May 2016 13:59:21 +0100Collected Evidence: Collected Evidence: Legal protection of forests Two site comparison studies in Nigeria and Iran found that legal protection of forest increased tree species richness and diversity and the density of young trees. One replicated, paired site study in Mexico found no effect of forest protection on seed density and diversity of trees and shrubs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1233https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1233Mon, 23 May 2016 11:25:48 +0100Collected Evidence: Collected Evidence: Sow tree seeds after wildfire Three studies (including one replicated, randomized, controlled study) in the USA examined the effect of sowing herbaceous plant seeds in burnt forest areas. One found it decreased the number and cover of native species and one found it decreased the density of tree seedlings. All three found no effect of seeding on total plant cover or species richness.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1236https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1236Fri, 03 Jun 2016 08:34:24 +0100Collected Evidence: Collected Evidence: Enhance soil compaction Three studies (including two replicated, randomized, controlled) in Canada and the USA found that soil compaction decreased tree regeneration height and density. Two of the studies found it increased understory plant cover and density, while one found it decreased understory plant species richness.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1253https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1253Fri, 03 Jun 2016 14:05:56 +0100Collected Evidence: Collected Evidence: Log/remove trees within forests: effects on non-vascular plants Two of three studies (including one replicated, paired sites study) in Australia, Norway and Sweden found logging trees in forests decreased epiphytic plant abundance and fern fertility. One found mixed effects depending on species.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1270https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1270Fri, 10 Jun 2016 09:37:49 +0100Collected Evidence: Collected Evidence: Use vegetation removal together with mechanical disturbance to the soil Two studies (including one replicated, randomized, controlled study) in Portugal and France found that vegetation removal together with mechanical disturbance of the soil increased the cover and diversity of understory plants. One of the studies found it also decreased understory shrub cover. One replicated, randomized, controlled study in France found that vegetation removal together with mechanical disturbance of the soil increased the density of young trees.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1274https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1274Tue, 28 Jun 2016 10:55:55 +0100Collected Evidence: Collected Evidence: Limit vessel speeds Three studies evaluated the effects of limiting vessel speeds on reptiles. One study was in each of Australia, Costa Rica and the USA. COMMUNITY RESPONSE (0 STUDIES)   POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One replicated, site comparison study in Costa Rica found that in waterways with enforced speed limits, fewer spectacled caiman were found dead with boat-related injuries compared to waterways with no speed limits. One replicated study in the USA found that vessels travelling at lower speeds caused fewer catastrophic injuries to artificial loggerhead turtle shells, though vessels with jet motors caused no catastrophic injuries at any speed tested. Condition (1 study): One replicated, site comparison study in Costa Rica found that in waterways with enforced speed limits, fewer spectacled caiman were found with boat-related injuries compared to waterways with no speed limits. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One replicated study in Australia found that green turtles were more likely to flee from vessels travelling at lower speeds. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3531https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3531Tue, 07 Dec 2021 15:40:57 +0000Collected Evidence: Collected Evidence: Establish temporary fishery closures Three studies evaluated the effects of establishing temporary fishery closures on reptile populations. Two studies were in the USA and one was in Brazil. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Abundance (1 study): One site comparison study in Brazil found that areas where a fishing agreement was implemented that involved seasonal fishing restrictions along with a wider set of measures had more river turtles than areas that did not implement the agreement.  Survival (2 studies): One replicated, before-and-after study in the USA found that during seasonal closures of shrimp trawling there were fewer lethal strandings of loggerhead and Kemp’s ridley turtles. One study in the USA found that following the re-opening of a swordfish long-line fishery with turtle catch limits in place, loggerhead turtle bycatch reached the annual catch limit in two of three years, and when the limit was reached the fishery was closed for the rest of the year. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3545https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3545Tue, 07 Dec 2021 17:27:09 +0000Collected Evidence: Collected Evidence: Deploy fishing gear at different depths Three studies evaluated the effects of deploying fishing gear at different depths on reptile populations. One study was in each of Canada, off the coast of Mexico and the Atlantic. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, randomized, paired study in Canada found that no turtles died in floated nets, but some died in submerged nets. Condition (1 study): One replicated, randomized, paired study in Canada found that turtles caught in floated nets were less at risk of drowning than those caught in submerged nets. BEHAVIOUR (0 STUDIES) OTHER (3 STUDIES) Unwanted catch (3 studies): Two of three studies (including two replicated studies) in Canada, Mexico and the Atlantic found that bottom-set fishing nets with fewer buoys caught fewer sea turtles than standard nets or that fewer loggerhead turtles were caught when longline hooks were set below 22 m deep, but the number of leatherback turtles caught was unaffected by hook depth. The other study found that floated and submerged nets caught a similar number of turtle species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3547https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3547Wed, 08 Dec 2021 09:29:51 +0000Collected Evidence: Collected Evidence: Install exclusion devices on fishing gear: Sea turtles Three studies evaluated the effects of installing exclusion devices on fishing gear on sea turtle populations. One study was in the Gulf of Mexico (USA), one was in the Mid-Atlantic (USA) and one was off the coast of Western Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, before-and-after study in the Gulf of Mexico found that when exclusion grids with escape holes were used in a shrimp trawl fishery there were fewer lethal strandings of loggerhead turtles compared to when grids were not used. BEHAVIOUR (1 STUDY) Use (1 study): One controlled study in the Mid-Atlantic found that when exclusion devices were used on scallop dredges there were fewer interactions with sea turtles than when no devices were used. OTHER (1 STUDY) Unwanted catch (1 study): One replicated study off the coast of Western Australia found that exclusion grids with escape hatches prevented sea turtles entering trawl nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3584https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3584Wed, 08 Dec 2021 15:30:20 +0000Collected Evidence: Collected Evidence: Install escape devices on fishing gear: Tortoises, terrapins, side-necked & softshell turtles Three studies evaluated the effects of installing escape devices on fishing gear on tortoise, terrapin, side-necked & softshell turtle populations. One study was in each of Australia, the USA and Canada. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated, randomized, paired, controlled study in the USA found that a lower percentage of turtles died in hoop nets with escape devices than in unmodified nets. BEHAVIOUR (0 STUDIES) OTHER (3 STUDIES) Unwanted catch (3 Studies): One replicated, controlled study in Australia found that most short-necked turtles escaped from a carp trap with an escape ring. One replicated, randomized, controlled, paired study in the USA found that hoop nets with escape devices caught fewer turtles than unmodified nets. One replicated, randomized, paired, controlled study in Canada found that more painted turtles escaped from fyke nets with an escape device than from unmodified nets after being placed in the net. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3602https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3602Thu, 09 Dec 2021 09:55:00 +0000Collected Evidence: Collected Evidence: Install escape devices on fishing gear: Snakes & lizards Three studies evaluated the effects of installing escape devices on fishing gear on snake and lizard populations. All three studies were in the Gulf of Carpentaria (Australia). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (3 STUDIES) Unwanted catch (3 Studies): One of two paired, controlled studies (including one randomized and one replicated study) in the Gulf of Carpentaria found that trawl nets with escape devices caught a similar number of sea snakes compared to unmodified nets. The other study found that trawl nets with an escape device caught fewer sea snakes compared to unmodified nets. One replicated, paired, controlled study in the Gulf of Carpentaria found that the placement of escape devices trawl nets affected the number of sea snakes caught compared to unmodified nets. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3603https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3603Thu, 09 Dec 2021 10:08:51 +0000Collected Evidence: Collected Evidence: Release accidentally caught (‘bycatch’) reptiles Three studies evaluated the effects on reptile populations of releasing accidentally caught reptiles. One study was in each of the Caribbean Sea, Costa Rica and the Republic of Korea. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One replicated study in the Caribbean Sea found that from a released group of green turtles that included some accidentally caught and some head-started individuals, some survived for at least several months in the wild. One replicated study in the Republic of Korea found that green turtles caught in pound nets all survived for at least two weeks to a year after release. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One controlled study off the Pacific coast of Costa Rica found that the behaviour of longline-caught sea turtles following release was broadly similar to free-swimming turtles. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3624https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3624Thu, 09 Dec 2021 13:37:44 +0000Collected Evidence: Collected Evidence: Change the colour (spectral composition) of lighting Three studies evaluated the effects of changing the colour (spectral composition) of lighting on reptile populations. Two studies were in the USA and one was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (3 STUDIES) Behaviour change (3 studies): Two replicated, controlled studies (including one randomized study) in the USA and Australia found that yellow-tinted incandescent lighting did not affect the seaward orientation of loggerhead turtle hatchlings, whereas four other types of lighting did, and that hatchlings were disoriented in fewer trials by red lighting than by amber lighting. One replicated, controlled study in the USA found in laboratory trials that filtering out high wavelengths did not prevent loggerhead or green turtles crawling towards light sources. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3628https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3628Thu, 09 Dec 2021 13:43:25 +0000Collected Evidence: Collected Evidence: Use selective logging Three studies evaluated the effects of using selective logging in forests on reptile populations. One study was in each of Brazil, the USA and Mexico. COMMUNITY RESPONSE (1 STUDY) Richness/diversity (1 study): One replicated, site comparison study in Mexico found that areas with low intensity selective logging tended to have similar reptile species richness compared to areas with high intensity selective logging. POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): One of two replicated, randomized, controlled studies (including one before-and-after study) in Brazil and the USA found that selective logging intensity had mixed effects on the abundance of three lizard species. The other study found that areas with selective logging had similar reptile abundance compared to areas with combined clearcutting and thinning. BEHAVIOUR (0 STUDIES) Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3637https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3637Thu, 09 Dec 2021 14:57:16 +0000Collected Evidence: Collected Evidence: Restore or maintain beaches (‘beach nourishment’) Three studies evaluated the effects of restoring or maintaining beaches on reptile populations. All three studies were in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Abundance (1 study): One replicated, site comparison study in the USA found that gopher tortoise densities were higher and numbers occupying burrows similar on constructed sand dunes compared to natural dunes. Reproductive success (2 studies): Two controlled, before-and-after studies in the USA found that one year after adding sand to beaches, nesting activity decreased more for loggerhead turtles, and loggerhead and green turtles compared to on unmodified beaches. Two years after nourishment, both studies found that loggerhead nesting activity had increased, and in one study nesting had returned to pre-nourishment levels. BEHAVIOUR (2 STUDIES) Use (1 study): One replicated, site comparison study in the USA found that burrows on a constructed dune were discovered by gopher tortoises after three months. Behaviour change (1 study): One controlled, before-and-after study in the USA found that one year after adding sand to beaches, loggerhead turtles made more non-nesting crawls than on unmodified beaches, but the difference was smaller two years after nourishment. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3669https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3669Fri, 10 Dec 2021 11:30:32 +0000Collected Evidence: Collected Evidence: Restore island ecosystems Three studies evaluated the effects of restoring island ecosystems on reptile populations. One study was in each of the Seychelles, the USA and the US Virgin Islands. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Occupancy/range (1 study): One study in the US Virgin Islands found that following translocation to a restored island, St. Croix ground lizards expanded their range during the fifth to seventh year after release. Reproductive success (2 studies): One study in the Seychelles found that following a range of interventions carried out to restore an island ecosystem, the number of hawksbill and green turtle nests increased. One replicated study in the USA found that during and after an island was rebuilt, diamondback terrapins continued to nest on the island. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3736https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3736Tue, 14 Dec 2021 10:00:08 +0000Collected Evidence: Collected Evidence: Alter incubation temperatures to achieve optimal/desired sex ratio: Crocodilians Three studies evaluated the effects of altering incubation temperatures to achieve optimal/desired sex ratios on crocodilian populations. Two studies were in Argentina and one was in China. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Reproductive success (2 studies): Two replicated, randomized study in Argentina found that hatching success of broad-snouted caiman eggs was similar across all temperatures tested. BEHAVIOUR (0 STUDIES) OTHER (3 STUDIES): Offspring sex ratio (3 studies): Two replicated, randomized studies in Argentina found that hatchling sex ratio of broad-snouted caimans was affected by temperature, and that warmer temperatures resulted in fewer females. One replicated study in China found that exposing Chinese alligator eggs to short periods of high temperatures during incubation resulted in fewer female hatchlings. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3764https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3764Tue, 14 Dec 2021 16:44:08 +0000Collected Evidence: Collected Evidence: Release captive-bred reptiles into the wild: Sea turtles Three studies evaluated the effects of releasing captive-bred sea turtles into the wild. Two studies were in the Gulf of Mexico and one was in the Caribbean. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Reproductive success (1 study): One replicated study in the Caribbean found that eight of over 30,000 captive-bred green turtles released into the wild (around 15,000 reared to one year or more in captivity) were observed nesting and two produced clutches of >100 eggs with hatching success of 63% and 88%. Survival (3 studies): Three replicated studies in the Gulf of Mexico and the Caribbean reported that following releases of captive-bred Kemp's ridley turtles and green turtles into the wild, 120–606 of 22,000–30,000 turtles survived for 1–19 years after release. Condition (1 study): One replicated study in the Gulf of Mexico found that captive-bred Kemp's ridley turtles released into the wild grew by 19–59 cm over 1–9 years. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3768https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3768Tue, 14 Dec 2021 17:46:32 +0000Collected Evidence: Collected Evidence: Bring threatened wild populations into captivity Three studies evaluated the effects on reptile populations of bringing threatened wild populations into captivity. One study was in each of New Zealand, Myanmar and Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Abundance (2 studies): One of two replicated studies in Myanmar and Australia found that after bringing Burmese start tortoises into captivity the populations increased from 175 individuals to over 7,000 in 12 years. The other study found that Lister’s gecko and blue-tailed skink populations remained stable or grew over 4–5 years in captivity. Reproductive success (2 studies): Two replicated studies in New Zealand and Myanmar found that after bringing tuatara and Burmese start tortoises into captivity, 44% of tuatara eggs hatched successfully in 16 years, and the number of hatchlings produced by Burmese start tortoises increased from 168 to over 2,000 in eight years Survival (1 studies): One replicated study in New Zealand found that varying proportions of wild tuatara brought into captivity survived for 16 years. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3791https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3791Wed, 15 Dec 2021 16:40:22 +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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