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: 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: 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: 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: Add chemicals to the water A replicated laboratory study in the USA found that dosing with the biocides chlorine, potassium and copper killed Asian clams. A controlled, replicated laboratory study and a controlled, replicated field study in the USA found that higher concentrations of chlorine and bromine, delivered at higher temperatures, shortened the time required to kill the Asian clams. A controlled field-based trial in Spanish irrigation systems showed that fat-coated particles called BioBullets could kill 100% of the Asian clams within pipes. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1118https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1118Tue, 13 Oct 2015 14:59:51 +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: Physical removal A study in the USA found that hand pulling and raking water primrose failed to reduce its abundance, whereas hand-pulling from the margins of a pond eradicated a smaller population of water primrose. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1138https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1138Tue, 13 Oct 2015 16:11:51 +0100Collected Evidence: Collected Evidence: Water primrose: Chemical control using herbicides A controlled, replicated laboratory study in the USA found that the herbicide triclopyr TEA applied at concentrations of 0.25% killed 100% of young cultivated water primrose within two months. A before-and-after field study in the UK found that the herbicide glyphosate controlled water primrose, causing 97% mortality when mixed with a non-oil based sticking agent and 100% mortality when combined with TopFilm. A controlled, replicated, randomized study in Venezuela3, found that use of the herbicide halosulfuron-methyl (Sempra) resulted in a significant reduction in water primrose coverage without apparent toxicity to rice plants. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1139https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1139Tue, 13 Oct 2015 16:14:37 +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: Crassula helmsii: Use hydrogen peroxide to control plants One controlled study in the UK using tank trials found that hydrogen peroxide did not control Crassula helmsii.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1281https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1281Tue, 12 Jul 2016 08:42:23 +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 dyes to reduce light levels One replicated, controlled study in the UK found that applying aquatic dye, along with other treatments, did not reduce coverage of Crassula helmsii. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1293https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1293Tue, 12 Jul 2016 09:32:38 +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 +0100Collected Evidence: Collected Evidence: Crassula helmsii: Decontamination to prevent further spread One controlled, replicated container study in the UK found that submerging Crassula helmsii in hot water led to higher mortality than drying out plant fragments or a control.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1308https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1308Tue, 12 Jul 2016 10:57:56 +0100Collected Evidence: Collected Evidence: Crassula helmsii: Use a combination of control measures One before-and-after study at a single pond in the UK found covering Crassula helmsii with carpet, followed by treatment with the herbicide glyphosate, killed 80% of the plant. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1313https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1313Tue, 12 Jul 2016 11:04:35 +0100Collected Evidence: Collected Evidence: Parrot’s feather: Water level drawdown One replicated, randomized, controlled laboratory study in the USA found that water removal to expose plants to drying during the summer led to lower survival of parrot’s feather plants than exposing plants to drying during the winter. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1585https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1585Fri, 20 Oct 2017 13:07:37 +0100Collected Evidence: Collected Evidence: Parrot’s feather: Biological control using plant pathogens One study in South Africa found that parrot’s feather plants survived after being treated with a strain of the bacterium Xanthomonas campestris. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1601https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1601Fri, 20 Oct 2017 15:05:32 +0100Collected Evidence: Collected Evidence: Parrot’s feather: Reduction of trade through legislation and codes of conduct One randomized, before-and-after trial in the Netherlands reported that the implementation of a code of conduct reduced the trade of aquatic plants banned from sale (group that included parrot’s feather Myriophyllum aquaticum). One study in the USA found that parrot’s feather plants were still traded despite a state-wise trade ban. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1604https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1604Fri, 20 Oct 2017 15:14:50 +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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