Collected Evidence: Collected Evidence: Leave field margins unsprayed within the crop (conservation headlands)Two replicated controlled trials in England showed that conservation headlands do not attract more foraging bumblebees than conventional crop fields. One replicated trial found fewer bees on conservation headlands than in naturally regenerated, uncropped field margins in England.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F29https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F29Thu, 20 May 2010 13:15:26 +0100Collected Evidence: Collected Evidence: Keep pure breeding populations of native honey bee subspeciesOne replicated trial in Switzerland found that pure breeding populations of the European black honey bee Apis mellifera mellifera contained a significant proportion (28%) of hybrids with an introduced subspecies Apis mellifera carnica.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F43https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F43Thu, 20 May 2010 14:49:31 +0100Collected Evidence: Collected Evidence: Leave arable field margins uncropped with natural regenerationFour replicated trials in the UK have found more bumblebees (and more bee species in two trials) foraging on uncropped field margins than on cropped margins. One small unreplicated trial found similar bee species richness on a naturally regenerated margin as on margins sown with wildflowers. A small replicated trial found that neither abundance nor diversity of bumblebees were higher on naturally regenerated margins than on cropped margins. Two trials note that the value of naturally regenerated uncropped field margins is based on thistle species considered to be pernicious weeds requiring control. Two trials found that the value of naturally regenerated uncropped field margins for bees was not consistent from year to year. We have captured no evidence on the effects of field margin management on solitary bees.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F20https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F20Thu, 20 May 2010 16:57:57 +0100Collected Evidence: Collected Evidence: Leave cultivated, uncropped margins or plots (includes 'lapwing plots') Nineteen individual studies looked at the effect of uncropped, cultivated margins or plots on wildlife. Seventeen studies from the UK and northwest Europe (six reviews and seven replicated studies of which two were site comparisons, one a before-and-after trial and one was controlled and randomized) found that leaving uncropped, cultivated margins or plots on farmland provides benefits to some or all target farmland bird species, plants, invertebrates, and mammals. These wildlife benefits included increased species richness of plants, bumblebees, species richness and abundance of spiders, abundance of ground-dwelling invertebrates and ground beetles, increased stone curlew breeding population size, northern lapwing hatching success, Eurasian skylark nesting success and the establishment, abundance or species richness of rare arable plant species. A replicated study found northern lapwing, Eurasian skylark, grey partridge and yellow wagtail bred in lapwing plots. Two studies (a replicated study and a review) from the UK found that leaving uncropped, cultivated margins or plots on farmland had no effect on 11 out of 12 farmland bird species or ground beetles. A replicated site comparison study in the UK found fewer seed-eating birds on fallow plots for ground-nesting birds in two out of three regions. One review from the UK found evidence that pernicious weeds were more commonly found on uncropped cultivated margins than conservation or conventional headlands. A replicated site comparison from the UK found the proportion of young grey partridges in the population was lower in areas with a high proportion of uncropped cultivated margins and plots. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F562https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F562Tue, 25 Sep 2012 14:57:25 +0100Collected Evidence: Collected Evidence: Isolate colonies of beneficial antsNatural enemies: One replicated, controlled study from Australia found predatory ants occupied more cashew trees when colonies were kept isolated. Pest damage and yield: The same study found lower pest damage to cashews and higher yields. The crop studied was cashew.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F773https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F773Tue, 20 Aug 2013 15:54:13 +0100Collected Evidence: Collected Evidence: Leave coarse woody debris in forests Two replicated, controlled studies in the USA found that there was no significant difference in abundance in clearcuts with woody debris retained or removed for eight of nine amphibian species, but that the overall response (population, physiological and behavioural) of amphibians was more negative where woody debris was retained. Two replicated, controlled studies in the USA and Indonesia found that the removal of coarse woody debris from standing forest did not decrease amphibian diversity or overall amphibian abundance, but did reduce species richness in one study. One replicated, controlled study in the USA found that migrating amphibians used clearcuts where woody debris was retained more than where it was removed. One replicated, site comparison study in the USA found that within clearcut forest, survival of juvenile amphibians was significantly higher in piles of woody debris than in open areas, and was similar in wood piles to unharvested forest.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F843https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F843Fri, 30 Aug 2013 15:15:04 +0100Collected Evidence: Collected Evidence: Leave bat roosts and roost entrances unlit Five studies evaluated the effects of leaving bat roosts and roost entrances unlit on bat populations. Two studies were in the UK, and one study was in each of Canada, Hungary and Sweden. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (1 study): One replicated, controlled study in Canada found that numbers of big brown bats and little brown bats roosting in buildings increased when roosts were left unlit and decreased when roosts were illuminated with artificial lights. Condition (1 study): One replicated, controlled study in Hungary found that juvenile bats had a higher body mass and greater forearm length at unlit roosts than at roosts with artificial lighting. BEHAVIOUR (4 STUDIES)      Use (1 study): One replicated, before-and-after study in Sweden found that all of 13 unlit churches continued to be used by brown long-eared bat colonies over 25 years, but bat colonies abandoned their roosts at 14 of 23 churches that were either partly or fully lit with floodlights. Behaviour change (3 studies): Three controlled studies (including two replicated studies) in the UK and Hungary found that more bats emerged, and bats emerged earlier and foraged for shorter periods, when roosts were left unlit than when they had artificial lighting. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1017https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1017Fri, 20 Dec 2013 17:54:28 +0000Collected Evidence: Collected Evidence: Keep safety distance to habituated animals One before-and-after study in the Democratic Republic of Congo found that most reintroduced chimpanzees survived over five years after being followed from a distance of 5–100 m, alongside other interventions. One controlled study in Malaysia found that the number of reintroduced orangutans declined by 33% over 31 years despite visitors being required to keep a safety distance to the animals, alongside other interventions. One before-and-after study in Rwanda, Uganda and Congo found that numbers of mountain gorillas increased by 168% over 41 years while being observed from a safety distance, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1538https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1538Thu, 19 Oct 2017 14:38:23 +0100Collected Evidence: Collected Evidence: Irrigate peatland (without planting) Two studies evaluated the effects of irrigation (without planting) on peatland vegetation. One study was in a bog and one was in a fen. Vegetation cover (2 studies): One replicated, paired, controlled, before-and-after study in a bog in Canada found that irrigation increased the number of Sphagnum moss shoots present after one growing season, but had no effect after two. One before-and-after study in Germany reported that an irrigated fen was colonized by wetland- and fen-characteristic herbs, whilst cover of dryland grasses decreased. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1859https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1859Mon, 11 Dec 2017 15:05:17 +0000Collected Evidence: Collected Evidence: Keep domestic cats indoors at night We found no studies that evaluated the effects of keeping domestic cats indoors at night on bat 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%2F2003https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2003Wed, 05 Dec 2018 15:28:13 +0000Collected Evidence: Collected Evidence: Leave a fallow period during fish/shellfish farming Three studies examined the effects of leaving a fallow period during fish farming on subtidal benthic invertebrate populations. Two studies were in the Tasman Sea (Australia), and one in the North Pacific Ocean (USA).   COMMUNITY RESPONSE (3 STUDIES) Overall community composition (2 study): Two replicated, before-and-after, site comparison study in the Tasman Sea found that after a fallow period invertebrate community composition became similar to that occurring before the fish were added but remained different to communities at sites without fish farms. Worm community composition (1 study): One replicated, before-and-after, site comparison study in the North Pacific Ocean found that after a fallow period polychaete worm community composition changed but remained different to communities at sites without fish farms. Worm richness/diversity (1 study): One replicated, before-and-after, site comparison study in the North Pacific Ocean found that after a fallow period polychaete worm diversity did not change and remained lower compared to sites without fish farms. POPULATION RESPONSE (2 STUDIES) Worm abundance (2 studies): Two replicated, before-and-after, site comparison studies in the Tasman Sea and the North Pacific Ocean found that following a fallow period, abundances of pollution-indicator polychaete worms decreased, but remained higher compared to sites without fish farms. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2191https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2191Tue, 22 Oct 2019 13:02:17 +0100Collected Evidence: Collected Evidence: Landscape or artificially enhance the seabed (natural habitats) Three studies examined the effects of landscaping or artificially enhancing the seabed on subtidal benthic invertebrates. One study was in the North Sea (UK), one in the Westerschelde estuary (Netherlands), and one in the Persian Gulf (Kuwait).   COMMUNITY RESPONSE (3 STUDIES) Overall community composition (2 studies): One controlled, before-and after study in the North Sea found that following addition of gravels, invertebrate community composition became more similar to natural seabed communities. One before-and-after, site comparison study in the Westerschelde estuary found no change in invertebrate community composition following addition of sedimentary dredge material. Overall richness/diversity (3 studies): One controlled, before-and after study in the North Sea and one site comparison study in the Persian Gulf found that invertebrate species richness increased following addition of gravels or coral and limestone rubbles, and one also found that richness became similar to natural seabed. One before-and-after, site comparison study in the Westerschelde estuary found no change in species richness following addition of sedimentary dredged material. POPULATION RESPONSE (3 STUDIES) Overall abundance (3 studies): One controlled, before-and after study in the North Sea and one site comparison study in the Persian Gulf found that invertebrate abundance and biomass increased following addition of gravels or coral and limestone rubbles, and one also found that abundance became similar to natural seabed. One before-and-after, site comparison study in the Westerschelde estuary found no change in invertebrate abundance and biomass following addition of sedimentary dredge material. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2253https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2253Wed, 23 Oct 2019 09:56:38 +0100Collected Evidence: Collected Evidence: Keep cats indoors or in outside runs to reduce predation of wild mammals One study evaluated the effects on potential prey mammals of keeping cats indoors or in outside runs. This study was in the UK. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Survival (1 study): One replicated study in the UK found that keeping domestic cats indoors at night reduced the number of dead or injured mammals that were brought home. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2326https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2326Thu, 21 May 2020 09:53:43 +0100Collected Evidence: Collected Evidence: Keep dogs indoors or in outside enclosures to reduce threats to wild mammals We found no studies that evaluated the effects on mammals of keeping dogs indoors or in outside enclosures to reduce threats to wild mammals. ‘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%2F2334https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2334Thu, 21 May 2020 13:18:55 +0100Collected Evidence: Collected Evidence: Keep domestic cats and dogs well-fed to reduce predation of wild mammals We found no studies that evaluated the effects on mammals of keeping domestic cats and dogs well-fed to reduce predation of wild mammals. ‘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%2F2335https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2335Thu, 21 May 2020 13:21:00 +0100Collected Evidence: Collected Evidence: Issue enforcement notices to deter use of non bear-proof garbage dumpsters to reduce human-wildlife conflict One study evaluated the effects of issuing enforcement notices to deter use of non bear-proof garbage dumpsters to reduce human-wildlife conflict. This study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Human-wildlife conflict (1 study): A replicated, controlled, before-and-after study in the USA found that issuing enforcement notices requiring appropriate dumpster use did not reduce garbage accessibility to black bears. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2345https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2345Fri, 22 May 2020 13:17:38 +0100Collected Evidence: Collected Evidence: Leave areas of uncut ryegrass in silage field We found no studies that evaluated the effects on mammals of leaving areas of uncut ryegrass in silage field. ‘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%2F2400https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2400Thu, 28 May 2020 10:59:29 +0100Collected Evidence: Collected Evidence: Leave cut vegetation in field to provide cover One study evaluated the effects on mammals of leaving cut vegetation in field to provide cover. This study was in the USA KEY COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Abundance (1 study): A controlled, before-and-after study in the USA found that increasing cover, by adding cut vegetation (hay), did not increase rodent abundance. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2401https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2401Thu, 28 May 2020 11:01:45 +0100Collected Evidence: Collected Evidence: Keep livestock in enclosures to reduce predation by mammals to reduce human-wildlife conflict One study evaluated the effects of keeping livestock in enclosures to reduce predation by mammals to reduce human-wildlife conflict. This study was in Portugal. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Human-wildlife conflict (1 study): A replicated study in Portugal found fewer wolf attacks on cattle on farms where cattle were confined for at least some of the time compared to those with free-ranging cattle. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2438https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2438Tue, 02 Jun 2020 09:42:50 +0100Collected Evidence: Collected Evidence: Leave headlands in fields unsprayed Two studies evaluated the effects on mammals of leaving headlands in fields unsprayed. One study was in the UK and one was in the Netherlands. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (2 STUDIES) Use (2 studies): Two replicated studies (one also controlled) in the UK and the Netherlands, found that crop edge headlands that were not sprayed with pesticides were used more by mice than were sprayed crop edges. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2540https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2540Mon, 08 Jun 2020 17:43:19 +0100Collected Evidence: Collected Evidence: Leave coarse woody debris in forests Three studies evaluated the effects on mammals of leaving coarse woody debris in forests. One study was in Canada, one was in the USA and one was in Malaysia. COMMUNITY RESPONSE (1 STUDY) Richness/diversity (1 study): A replicated, site comparison study, in Malaysia found more small mammal species groups in felled forest areas with woody debris than without. POPULATION RESPONSE (3 STUDIES) Abundance (3 studies): One out of three replicated studies (two controlled, one site comparison, one before-and-after) in Canada, the USA and Malaysia found that retaining or adding coarse woody debris did not increase numbers or frequency of records of small mammals. The other study found that two of three shrew species were more numerous in areas with increased volumes of coarse woody debris than areas without coarse woody debris. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2647https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2647Fri, 12 Jun 2020 17:38:11 +0100Collected Evidence: Collected Evidence: Issue high fines and penalties for non-compliance with fisheries regulations We found no studies that evaluated the effects of issuing high fines and penalties for non-compliance with fisheries regulations on marine fish 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%2F2772https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2772Wed, 03 Feb 2021 11:19:38 +0000Collected Evidence: Collected Evidence: Leave anthropogenic structures in place after decommissioning We found no studies that evaluated the effects of leaving anthropogenic structures in place after decommissioning 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%2F2922https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2922Mon, 08 Feb 2021 16:37:41 +0000Collected Evidence: Collected Evidence: Keep domestic cats indoors at times when reptiles are most active We found no studies that evaluated the effects on reptile populations of keeping domestic cats indoors at times when reptiles are most active. ‘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%2F3684https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3684Fri, 10 Dec 2021 15:51:52 +0000Collected Evidence: Collected Evidence: Leash or restrict domestic dog movements in reptile habitats We found no studies that evaluated the effects on reptile populations of leashing or restricting domestic dog movements in reptile habitats. ‘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%2F3685https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3685Fri, 10 Dec 2021 16:07:49 +0000
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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