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: Red-eared terrapin: Direct removal of adults A replicated field study in Spain found that Aranzadi turtle traps were effective in trapping red-eared terrapins from a river but did not eradicate the population. A study in the British Virgin Islands found that using sein nets to trap adults and juveniles was not successful in eradicating the population.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1055https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1055Tue, 13 Oct 2015 11:56:26 +0100Collected Evidence: Collected Evidence: Ponto-Caspian gammarids: Control movement of gammarids A replicated, controlled laboratory study in the USA found that movements of invasive freshwater shrimp slowed down or stopped when they were placed in water that had been exposed to different species of predatory fish, compared to those not exposed to fish. A replicated laboratory study in the UK found carbonating the water stunned invasive killer shrimp.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1088https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1088Tue, 13 Oct 2015 13:28:18 +0100Collected Evidence: Collected Evidence: Ponto-Caspian gammarids: Change salinity of the waterOne of two replicated laboratory studies (one controlled) in Canada and the UK found that increasing the salinity level of water killed the majority of invasive shrimp within five hours. One found that increased salinity did not kill invasive killer shrimp.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1091https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1091Tue, 13 Oct 2015 13:36:28 +0100Collected Evidence: Collected Evidence: Skunk cabbage: Chemical control using herbicides A study in the UK found that two herbicides, glyphosate and 2, 4-D Amine, both killed all skunk cabbage plants in test areas. However, another study in the UK found that although using 2,4-D amine at 9 litres/ha, successfully eradicated skunk cabbage, using glyphosate was unsuccessful at eradicating skunk cabbage, with only limited reduction in growth of the plants. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1102https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1102Tue, 13 Oct 2015 14:18:08 +0100Collected Evidence: Collected Evidence: Asian clams: Mechanical removal A replicated, controlled, before-and after trial in North America found that suction dredging reduced Asian clam densities within the sediment by 96% over two weeks and that the reduction persisted for a year. A replicated, controlled, before-and-after field trial in Ireland found that three types of dredges were equally effective at removing Asian clams, resulting in a biomass reduction ranging from 74% to >95%, and an density reduction ranging from 65% to 95%. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1120https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1120Tue, 13 Oct 2015 15:07:16 +0100Collected Evidence: Collected Evidence: Floating pennywort: Physical removal A study in Western Australia found that following a two-week program of physical removal of floating pennywort, the rate of growth exceeded the rate of removal. A study in the UK, found that removal using a mechanical digger and monthly picking by hand greatly reduced the cover of floating pennywort but did not completely eradicate it. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1126https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1126Tue, 13 Oct 2015 15:33:08 +0100Collected Evidence: Collected Evidence: Water primrose: Biological control using co-evolved, host specific herbivores A controlled, replicated field study in China, found a flea beetle caused heavy feeding destruction when added to field cages containing prostrate water primrose seedlings, and was specific to the prostrate water primrose and Indian toothcup. A replicated, before-and-after field study in the USA found that introduction of flea beetles to a pond significantly reduced the abundance of large-flower primrose-willow. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1135https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1135Tue, 13 Oct 2015 16:03:06 +0100Collected Evidence: Collected Evidence: Water primrose: Combination treatment using herbicides and physical removal A study in California, USA1, found that application of glyphosate and a surface active agent called Cygnet-Plus followed by removal by mechanical means achieved a 75% kill rate of water primrose. A study in Australia2, found that a combination of herbicide application, physical removal, and other actions such as promotion of native plants and mulching, reduced the coverage of Peruvian primrose-willow by 85-90%. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1140https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1140Tue, 13 Oct 2015 16:22:24 +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: Crassula helmsii: Use hot foam to control plants One replicated, controlled study in the UK found that treatment with hot foam, along with other treatments, did not reduce cover of Crassula helmsii. One before-and-after study in the UK found that applying hot foam partially destroyed C. helmsii.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1286https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1286Tue, 12 Jul 2016 08:56:05 +0100Collected Evidence: Collected Evidence: Crassula helmsii: Use grazing to control plants One of two replicated, controlled studies in the UK found that excluding grazing reduced the abundance and coverage of Crassula helmsii. The other study found no difference in cover of C. helmsii between ungrazed and grazed plots. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1301https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1301Tue, 12 Jul 2016 10:48:03 +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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