Collected Evidence: Collected Evidence: Rear and manage populations of solitary beesSeveral species of solitary bee in the family Megachilidae are reared and managed commercially as pollinators, mostly for the forage crop alfalfa, or fruit trees. These species readily nest in drilled wooden blocks, or stacked grooved boards of wood or polystyrene. Parasites and pathogens can be problematic and a number of control methods have been developed. Rearing methods have been investigated for two other species not yet commercially managed and one replicated trial shows that temperature regimes are important to survival. If rearing for conservation purposes is to be attempted, we would recommend a systematic review of these methods. Three management trials with megachilids not commercially managed in the USA or Poland, and a review of studies of managed species, found that local populations can increase up to six-fold in one year under management if conditions are good and plentiful floral resources are provided. Two replicated trials have reared solitary bees on artificial diets. One found high larval mortality in Osmia cornuta reared on artificial pollen-based diets, including honey bee-collected pollen. The other found Megachile rotundata could be reared on an artificial diet based on honey bee-collected pollen, but bees reared on synthetic pollen substitutes either died or had low pre-pupal weight.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F54https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F54Thu, 20 May 2010 18:24:45 +0100Collected Evidence: Collected Evidence: Re-plant native forest We have found no evidence on the impact of reforestation on wild bee communities or 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%2F35https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F35Thu, 20 May 2010 18:51:39 +0100Collected Evidence: Collected Evidence: Rear declining bumblebees in captivityWe have captured 22 trials from 13 countries documenting captive rearing of bumblebee colonies by confining mated queens alone (eight trials), with one or more bumblebee workers (seven trials), honey bee workers (one trial), male bumblebee pupae (three trials) or following anaesthetisation with CO2 (four trials). One trial found that over four years of artificial rearing, Bombus terrestris queens gradually decreased in weight. Three trials have tried to rear North American bumblebees now declining or thought to be declining. Two induced spring queens of the half-black bumblebee B. vagans to rear adults in captivity, one trial induced queen yellow-banded bumblebees B. terricola (attempted in all three trials) and red-belted bumblebees B. rufocinctus (only attempted in one trial) to rear adults in captivity. All three trials tried to rear the yellow bumblebee B. fervidus and in all cases the queens laid eggs but the larvae died before becoming adults. One trial found the same pattern for the rusty-patched bumblebee and the American bumblebee B. pensylvanicus. One study reports rearing the large garden bumblebee B. ruderatus, a Biodiversity Action Plan species in the UK. Two trials have reported laboratory rearing of a pocket-making bumblebee, the Neotropical B. atratus. Three replicated trials demonstrated that the pollen diet of captively reared bumblebees influences reproductive success. In one trial, buff-tailed bumblebee B. terrestris colonies fed on freshly frozen pollen produced larger queens that survived better and produced larger colonies themselves than colonies fed on dried, frozen pollen. Two replicated trials demonstrated that B. terrestris workers can produce more offspring when fed types of pollen with a higher protein content. Two replicated experiments showed that an artificial light regime of eight hours light, 16 hours darkness, can reduce the time taken for artificially reared queen B. terrestris to lay eggs, relative to rearing in constant darkness. We have captured two replicated trials examining the effect of different artificial hibernation regimes in B. terrestris. One showed that hibernation of queens at 4-5°C for 45 days enhanced egg-laying and colony formation rates, but hibernated queens produced smaller colonies than non-hibernated queens. The second showed that queens should weigh more than 0.6 g (wet weight) and be hibernated for four months or less to have a good chance of surviving.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F50https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F50Thu, 20 May 2010 20:22:36 +0100Collected Evidence: Collected Evidence: Re-wet moorland We have captured no evidence for the effects of re-wetting moorland on farmland wildlife. '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%2F103https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F103Mon, 24 Oct 2011 21:57:49 +0100Collected Evidence: Collected Evidence: Raise water levels in ditches or grassland Seven studies from Denmark, the Netherlands and the UK (two replicated controlled studies and two before-and-after studies) found that raising water levels in ditches or grassland was associated with increased bird numbers, breeding bird numbers, plant species that favour wet conditions, and invertebrate numbers or biomass in agricultural landscapes. Two replicated studies from the Netherlands and the UK found that raising water levels resulted in a net loss of plant species and did not affect lapwing foraging rate. A review found three studies reporting that re-wetting soils on old arable fields is not an effective method of reducing nutrient levels and restoring species-rich grassland. A replicated study from the UK found that unflooded pastures contained a high biomass of soil macroinvertebrates of importance to breeding wading birds. A controlled, randomized study from the Netherlands found that raising the water level resulted in a more rapid establishment of species typical of wet grassland, than vegetation management. A review of agri-environment schemes from the UK found studies that suggested more expensive agri-environment scheme options for wetland habitats, such as controlling water levels, were more effective at providing good habitat for wading birds than easier-to-implement options. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F121https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F121Tue, 01 Nov 2011 21:14:13 +0000Collected Evidence: Collected Evidence: Re-seed grasslands One of two studies, both from the UK and investigating grazing by geese Branta spp., found that geese grazed at higher densities on grasslands that were re-seeded, compared to control or fertilised areas. One study found that areas sown with clover were grazed at higher densities than those sown with grass seed.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F352https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F352Sun, 29 Jul 2012 15:46:04 +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: Red-eared terrapin: Biological control using native predators No evidence was captured on the use of predators to control invasive terrapin 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%2F1056https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1056Tue, 13 Oct 2015 11:58:10 +0100Collected Evidence: Collected Evidence: Red-eared terrapin: Draining invaded waterbodies No evidence was captured on the impact of draining invaded waterbodies on reduction of red-eared terrapin 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%2F1057https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1057Tue, 13 Oct 2015 12:00:49 +0100Collected Evidence: Collected Evidence: Red-eared terrapin: Search and removal using sniffer dogs No evidence was captured on the success of use of sniffer dogs in removing red-eared terrapins. '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%2F1058https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1058Tue, 13 Oct 2015 12:02:19 +0100Collected Evidence: Collected Evidence: Red-eared terrapin: Application of a biocide One replicated, controlled laboratory study in the USA, found that application of glyphosate to the eggs of red-eared terrapins reduced hatching success to 73%, but only at the highest experimental concentration of glyphosate and a surface active agent.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1059https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1059Tue, 13 Oct 2015 12:05:40 +0100Collected Evidence: Collected Evidence: Red-eared terrapin: Public education No evidence was captured on the impact of education programmes on reduction of red-eared terrapin 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%2F1060https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1060Tue, 13 Oct 2015 12:06:51 +0100Collected Evidence: Collected Evidence: Re-route paths, control access or close paths We found no evidence for the effects of re-routing paths, controlling access or closing paths on forests. '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%2F1171https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1171Thu, 19 May 2016 09:43:03 +0100Collected Evidence: Collected Evidence: Recharge groundwater to restore wetland forest We found no evidence for the effects of recharging groundwater to restore wetland forest. '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%2F1185https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1185Thu, 19 May 2016 11:43:01 +0100Collected Evidence: Collected Evidence: Re-use old roads rather than building new roads We found no evidence for the effects of re-using old roads rather than building new roads on primate 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%2F1463https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1463Tue, 17 Oct 2017 13:55:46 +0100Collected Evidence: Collected Evidence: Re-route vehicles around protected areas We found no evidence for the effects of re-routing vehicles containing invasive species around protected areas on primate 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%2F1464https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1464Tue, 17 Oct 2017 14:01:59 +0100Collected Evidence: Collected Evidence: Re-route paths to reduce habitat disturbance One before-and-after trial in Australia found that closing paths did not alter shrub cover, but did increase the number of plant species in an alpine shrubland. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1619https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1619Sun, 22 Oct 2017 10:35:44 +0100Collected Evidence: Collected Evidence: Rake to control grass A randomized, replicated, controlled, paired study in the USA found that cover of both invasive and native grasses, as well as forbs was lower in areas that were raked than in areas that were not raked, but that the number of annual plants species did not differ. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1640https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1640Sun, 22 Oct 2017 13:13:04 +0100Collected Evidence: Collected Evidence: Recycle or repurpose fluids used in the drilling process We found no studies that evaluated the effects of recycling or repurposing fluids used in the drilling process on subtidal benthic invertebrate populations.   ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this intervention during our systematic journal and report searches. Therefore, we have no evidence to indicate whether or not the intervention has any desirable or harmful effects.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2069https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2069Mon, 21 Oct 2019 13:51:26 +0100Collected Evidence: Collected Evidence: Recover lost fishing gear We found no studies that evaluated the effects of recovering lost fishing gear on subtidal benthic invertebrate populations.   ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this intervention during our systematic journal and report searches. Therefore, we have no evidence to indicate whether or not the intervention has any desirable or harmful effects.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2206https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2206Tue, 22 Oct 2019 13:16:34 +0100Collected Evidence: Collected Evidence: Recover lost or discarded fishing gear We found no studies that evaluated the effects of recovering lost or discarded fishing gear on marine and freshwater mammal populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2F2886https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2886Mon, 08 Feb 2021 11:49:11 +0000Collected Evidence: Collected Evidence: Recover lost or discarded fishing gear We found no studies that evaluated the effects on reptile populations of recovering lost or discarded fishing gear. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2F3567https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3567Wed, 08 Dec 2021 15:04:44 +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 +0000Collected Evidence: Collected Evidence: Re-plant native trees in logged areas One study evaluated the effects on butterflies and moths of replanting native trees in logged areas. The study was in Ghana. COMMUNITY RESPONSE (1 STUDY) Richness/diversity (1 study): One site comparison study in Ghana found that nine years after an area was replanted with native trees after logging it had similar species richness but lower diversity for two of three metrics compared to naturally regenerating secondary forest. POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3874https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3874Mon, 18 Jul 2022 16:03:37 +0100Collected Evidence: Collected Evidence: Rear declining species in captivity Twenty-two studies evaluated the effects of rearing declining species of butterfly and moth in captivity. Seven studies were in each of the UK and South Africa, two were in the USA, one was in each of the UK and France, Spain, Belgium, Poland and Israel, and one was a review. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (22 STUDIES) Abundance (6 studies): Three studies in the UK and the USA reported that populations of large copper, large white and monarch butterflies were successfully reared in captivity for 12 generations or >25 years. One study in the UK reported that a captive population of marsh fritillary increased in size over two years. One study in Poland reported that all captive-reared scarce large blue caterpillars died within 35 days. One review reported that attempts to rear caterpillars of four species of large blue had mixed success. Reproductive success (5 studies): One controlled study in the UK reported that female large copper laid more eggs, and these eggs had a higher hatching success, in a cage kept in a greenhouse than in a cage kept outside. One study in South Africa reported that a Dickson’s copper butterfly laid eggs in captivity in the presence of black cocktail ants from the site where she emerged but not from 10 km away. One study in the UK found that female large white from a population kept in captivity for >25 years laid more eggs than females from a population in its third generation in captivity. One study in the UK reported that Fisher’s estuarine moths successfully bred in captivity. One study in South Africa reported that wild-caught, gravid scarce mountain copper butterflies laid eggs but none hatched. Survival (14 studies): Five of six studies (including one replicated, controlled study, four controlled studies and one site comparison study) in the UK, the UK and France, Spain, Belgium and Poland found that large copper, large blue, mountain Alcon blue, cranberry fritillary and scarce large blue caterpillars had higher survival rates when reared on plants or in ant nests at a lower than higher density, in ant nests without queens or with winged females present than with queens or without winged females, when reared at 20 °C than 25 °C, and when reared with ants collected from sites where parasitic butterfly species occur than from sites where parasites do not occur. The sixth study found that mountain Alcon blue caterpillars had a similar survival rate in ant nests with or without queens present. Two of these studies, and one replicated, randomized, paired, controlled study in the USA, found that the survival of large blue, mountain Alcon blue and monarch caterpillars differed when reared in ant nests of different species or on different species of milkweed. Two site comparison studies in the UK and the USA found that large copper and Puget blue eggs had a similar survival rate to the caterpillar and adult stage whether they were laid in captivity or collected from the wild and reared in captivity. One of these studies also found that Puget blue caterpillars kept in refrigerators while overwintering had a lower survival than caterpillars kept in environmental chambers or outside. Three of four studies in South Africa and the UK reported that some wild-collected Brenton blue butterfly, Karkloof blue butterfly and Fishers’ estuarine moth eggs hatched, survived as caterpillars for three months or to adulthood, bred in captivity and the resulting captive population survived for at least eight generations. The other study reported that wild-collected Brenton blue butterfly eggs hatched in captivity and those caterpillars reared with only Pyllanthus incurvatus leaves died whereas all caterpillars also given Indigofera erecta leaves survived to the fourth instar of development. One study in South Africa reported that wild-caught final instar Cape Peninsula butterfly caterpillars reared in an artificial pugnacious ant nest successfully pupated and became adults, but captive-hatched first instar Cape Peninsula and Riley’s skolly butterfly caterpillars placed next to a nest did not survive to pupation. Condition (5 studies): Two studies (including one controlled study) in the UK and the USA found that adult large white from a population kept in captivity for >25 years were heavier, and had smaller wings, than individuals from a population in its third generation in captivity, and captive-reared Puget blue adults were smaller than wild-caught butterflies. One of these studies also found that Puget blue caterpillars raised in environmental chambers or outdoor enclosures reached a similar size as adults. One replicated, controlled study in Spain found that mountain Alcon blue caterpillars reared in ant colonies with winged females were lighter than caterpillars reared in colonies without winged females. One replicated, controlled study in Israel found that spring webworm caterpillars fed vegetation from cattle-grazed pasture had a similar growth rate to caterpillars fed vegetation from an ungrazed paddock. One study in South Africa reported that Brenton blue butterfly caterpillars reared on Indigofera erecta leaves with no ants became dwarf adults, but those reared on whole Indigofera plants with an ant colony became full-sized adults. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3916https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3916Wed, 10 Aug 2022 18:16:38 +0100
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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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