Collected Evidence: Collected Evidence: Plant more than one crop per field (intercropping) Three replicated, controlled and randomized studies from the Netherlands, Poland and the UK found that intercropping cabbage with French beans or clover resulted in increased ground beetle abundance. A trial from Switzerland found increased earthworm abundance in a maize plot immediately followed by a rye grass crop. A review found ground beetle numbers were enhanced by intercropping relative to single crops.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F124https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F124Tue, 01 Nov 2011 21:30:53 +0000Collected Evidence: Collected Evidence: Increase the proportion of semi-natural habitat in the farmed landscapeFive studies monitored the effects of the Swiss Ecological Compensation Areas scheme at a landscape scale, including three replicated site comparisons. Of these, one found an increase in numbers of birds of some species. Two found no effect on the number of bird species or population densities of farmland birds. Three studies found mixed effects, with some species or groups of species increasing and others decreasing.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F145https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F145Sat, 14 Jan 2012 13:48:09 +0000Collected Evidence: Collected Evidence: Provide owl nest boxes (Tawny owl, Barn owl) Two studies from the UK (a before-and-after study and a controlled study) found that the provision of owl nest boxes in farm buildings maintained barn owl nesting and roosting activity and resulted in an increase in population density. A study from the Netherlands found that the barn owl population increased with increased availability of nest boxes. A replicated, controlled study in Hungary found that juvenile barn owls fledged from nest boxes were significantly less likely to be recovered alive than those reared in church towers. A replicated study from the UK investigating barn owl nest site use, found that the number of occupied nest sites and the proportion breeding decreased from 2001 to 2009, but were unaffected by the number of boxes.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F154https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F154Sat, 14 Jan 2012 15:38:54 +0000Collected Evidence: Collected Evidence: Use traditional breeds of livestock Two UK studies (one replicated) and a review reported differences in quantities of plant species grazed, vegetation structure and invertebrate assemblages between areas grazed with different breeds of sheep or cattle. A small, replicated study found that Hebridean sheep grazed more purple moor grass than Swaledale sheep, but the resulting density of purple moor grass and heather did not differ. A UK study found that at reduced grazing pressure, traditional and commercial cattle breeds created different sward structures and associated invertebrate assemblages. One replicated trial from France, Germany and the UK found grazing by traditional rather than commercial livestock breeds had no clear effect on the number of plant species or the abundance of butterflies, grasshoppers, birds, hares, or ground-dwelling arthropods in general. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F539https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F539Tue, 11 Sep 2012 15:57:52 +0100Collected Evidence: Collected Evidence: Plant cereals in wide-spaced rows One replicated, controlled randomized study and four reports from the same replicated, controlled study in the UK investigated the effects of planting cereals in wide-spaced rows on birds, invertebrates and plants. Both studies found no or inconsistent differences in plant and invertebrate abundance and/or species richness between wide-spaced row and control fields. The replicated controlled study found higher undesirable weed cover, and one study found no significant difference in weed cover in fields with wide-spaced rows compared to control fields. One study found significantly lower invertebrate abundances and fewer Eurasian skylark nests in wide-spaced row fields than control fields or fields with undrilled patches. However it also found an increase in the body condition of nestlings over the breeding season in wide-spaced row fields compared with control fields.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F564https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F564Wed, 26 Sep 2012 16:47:40 +0100Collected Evidence: Collected Evidence: Connect areas of natural or semi-natural habitat All four studies (including one site comparison and two replicated trials) from the Czech Republic, Germany and the Netherlands investigating the effects of habitat corridors or restoring areas of natural or semi-natural habitat between existing patches found some degree of colonization of these areas by invertebrates or mammals. However for invertebrates one unreplicated site comparison reported that the colonization process was slow (Gruttke 1994), and three studies found that the extent of colonization varied between invertebrate taxa. One small, replicated study from the Czech Republic investigated colonization of two bio-corridors by small mammal species. It found more small mammal species in the bio-corridors than in an adjacent forest or arable fields. All three studies from Germany and the Netherlands looking at the effects on invertebrates found mixed results. One replicated study found more species of some wasps (cavity-nesting wasps and caterpillar-hunting wasps) in grass strips connected to forest edges than in isolated strips. An unreplicated study found that the abundance of three ground beetle species substantially increased in an arable field undergoing restoration to heathland but that typical heathland species failed to colonize over the 12 year period. One study found that two out of 85 ground beetle species used a meadow and hedge-island strip extending from semi-natural habitats into arable farmland. In the same study the habitat strip did not function well for ground beetles and harvestmen but was colonized by snails and spiders. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F579https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F579Thu, 04 Oct 2012 11:08:34 +0100Collected Evidence: Collected Evidence: Alter the timing of insecticide useNatural enemies: One controlled study from the UK reported more natural enemies when insecticides were sprayed earlier rather than later in the growing season. Pests: Two of four studies from Mozambique, the UK and the USA found fewer pests or less disease damage when insecticides were applied early rather than late. Effects on a disease-carrying pest varied with insecticide type. Two studies (one a randomised, replicated, controlled test) found no effect on pests or pest damage. Yield: Four studies (including one randomised, replicated, controlled test) from Mozambique, the Philippines, the UK and the USA measured yields. Two studies found mixed effects and one study found no effect on yield when insecticides were applied early. One study found higher yields when insecticides were applied at times of suspected crop susceptibility.Profit and costs: One controlled study from the Philippines found higher profits and similar costs when insecticides were only applied at times of suspected crop susceptibility. Crops studied were aubergine, barley, maize, pear and stringbean.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F723https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F723Thu, 30 May 2013 12:36:53 +0100Collected Evidence: Collected Evidence: Plant new hedgesFive studies in Slovakia, Kenya and Thailand measured the effects of planting grass or shrub hedgerows on soil animals and soil fertility. All five found hedgerows to maintain or improve soil fertility and soil animal activity. Of these, three replicated studies found reduced soil erosion and higher soil organic matter levels. Another replicated trial found a higher diversity of soil animals near to the hedgerows. One of the replicated studies and one review found that adding woody species to the hedgerows improved many factors contributing to soil fertility. SOIL TYPES COVERED: Alluvial, clay, sandy-loam.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F744https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F744Tue, 04 Jun 2013 16:25:36 +0100Collected Evidence: Collected Evidence: Exclude domestic animals or wild hogs by fencing Three replicated, site comparison studies in the USA found that excluding livestock from streams or ponds did not increase numbers of amphibian species or overall abundance, but did increase larval abundance and abundance of green frog metamorphs. Two studies found that the abundance of green frogs and/or American toads was higher with grazing. One randomized, replicated, controlled, before-and-after study in the USA found that excluding cattle from ponds did not increase numbers of eggs or larval survival of Columbia spotted frogs. One before-and-after study in the UK found that pond restoration that included livestock exclusion increased pond use by breeding natterjack toads. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F746https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F746Wed, 17 Jul 2013 10:35:16 +0100Collected Evidence: Collected Evidence: Add lime to water bodies to reduce acidification One before-and-after study in the UK found that adding limestone to ponds resulted in establishment of one of three translocated populations of natterjack toads. One replicated, site comparison study in the UK found that species-specific habitat management that included adding limestone to ponds increased natterjack toad populations. One before-and-after study in the UK found that adding limestone to ponds temporarily increased breeding by natterjack toads. Three before-and-after studies (including one controlled, replicated study) in the Netherlands and UK found that adding limestone increased larval and/or egg survival of moor frogs and common frogs and resulted in metamorphosis of natterjack toads at two of three sites. Two before-and-after studies (including one controlled study) in the UK found that adding limestone to ponds resulted in high tadpole mortality and pond abandonment by natterjack toads and higher numbers of abnormal common frog eggs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F748https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F748Thu, 18 Jul 2013 15:41:50 +0100Collected Evidence: Collected Evidence: Use antifungal skin bacteria or peptides to reduce chytridiomycosis infection Three of four randomized, replicated, controlled studies in the USA found that adding antifungal bacteria to the skin of salamanders or frogs exposed to the chytrid fungus did not reduce chytridiomycosis infection rate or death. One found that adding antifungal bacteria to frogs prevented infection and death. One randomized, replicated, controlled study in the USA found that adding antifungal skin bacteria to soil significantly reduced chytridiomycosis infection rate of red-backed salamanders. One randomized, replicated, controlled study in Switzerland found that treatment with antimicrobial skin peptides before or after infection with chytridiomycosis did not significantly increase survival of common toads. Three randomized, replicated, controlled studies in the USA found that adding antifungal skin bacteria to chytrid infected amphibians reduced weight loss.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F764https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F764Fri, 16 Aug 2013 15:10:05 +0100Collected Evidence: Collected Evidence: Use temperature treatment to reduce chytridiomycosis infection Four of five studies (including four replicated, controlled studies) in Australia, Switzerland and the USA found that increasing enclosure or water temperature to 30–37°C for over 16 hours cured frogs and toads of chytridiomycosis. One found that heat treatment at 30–35°C for 36 hours did not cure northern leopard frogs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F770https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F770Mon, 19 Aug 2013 16:15:16 +0100Collected Evidence: Collected Evidence: Use herbicides to control mid-storey or ground vegetation Three studies (including two randomized, replicated, controlled studies) in the USA found that understory removal using herbicide had no effect or some negative effects on amphibian abundance. One replicated, site comparison study in Canada found that following logging American toad abundance was similar and wood frogs lower in stands with herbicide treatment and planting compared to stands left to regenerate naturally.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F778https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F778Wed, 21 Aug 2013 15:38:27 +0100Collected Evidence: Collected Evidence: Legal protection of species Three reviews (including one systematic review) in the Netherlands and UK (Bosman et al. 2011, Spitzen-van der Sluijs et al. 2011, Lewis 2012) found that legal protection of amphibian species was not effective at protecting populations during development. Two reviews in the UK (Edgar et al. 2005, Lewis 2012) found that the number of great crested newt mitigation licences issued over 10 years increased to over 600 in England and Wales.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F779https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F779Thu, 22 Aug 2013 11:46:02 +0100Collected Evidence: Collected Evidence: Pay farmers to cover the costs of conservation measures Three studies (including one replicated study) in Denmark, Sweden and Taiwan found that payments to farmers created amphibian breeding habitat or increased frog or toad populations. However, a second study in Taiwan found that payments did not maintain green tree frog habitat. One replicated, site comparison study in the Netherlands found that ditches managed under agri-environment schemes had higher numbers of amphibian species and higher abundance than those managed conventionally.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F818https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F818Fri, 23 Aug 2013 09:47:58 +0100Collected Evidence: Collected Evidence: Remove or control fish by drying out ponds One before-and-after study in the USA found that draining ponds to eliminate fish increased numbers of amphibian species. One replicated, before-and-after study in Estonia found that pond restoration, which sometimes included drying to eliminate fish, and pond creation increased numbers of species and breeding populations of common spadefoot toads and great crested newts compared to no management. Three studies (including one review) in the UK and USA found that pond drying to eliminate fish, along with other management activities in some cases, increased breeding success of frog or newt species.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F826https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F826Wed, 28 Aug 2013 11:56:43 +0100Collected Evidence: Collected Evidence: Raise awareness amongst the general public through campaigns and public information Two studies (including one replicated, before-and-after study) in Estonia and the UK found that raising public awareness, along with other interventions, increased numbers of natterjack toads and created 1,023 ponds for amphibians. One before-and-after study in Mexico found that raising awareness in tourists, increased their knowledge of axolotls. One study in Taiwan found that holding press conferences to publicize frog conservation had no effect on a green tree frog project. Two studies in Panama and the UK found that awareness campaigns reached over 50,000 members of the public each year or trained 1,016 people at 57 events over four years.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F831https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F831Wed, 28 Aug 2013 15:05:54 +0100Collected Evidence: Collected Evidence: Regulate water levels Two studies (including one replicated, site comparison study) in the UK found that habitat management that included maintaining pond water levels increased natterjack toad populations or maintained newt populations. One replicated, controlled study in Brazil found that keeping rice fields flooded after harvest changed amphibian species composition, but not numbers of species or abundance. One replicated, controlled study in the USA found that draining ponds, particularly in the summer, significantly increased abundance and numbers of amphibian species. One before-and-after study in the USA found that maintaining pond water levels enabled successful breeding by dusky gopher frogs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F833https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F833Wed, 28 Aug 2013 15:19:57 +0100Collected Evidence: Collected Evidence: Harvest groups of trees instead of clearcutting Three studies (including two randomized, replicated, controlled, before-and-after studies) in the USA found that compared to clearcutting, harvesting trees in small groups did not result in higher amphibian or salamander abundance. A meta-analysis of 24 studies in North America found that partial harvest, which included harvesting groups or individual trees, thinning and shelterwood harvesting, resulted in smaller reductions in salamander populations than clearcutting Two studies (including one randomized, replicated, controlled, before-and-after study) in the USA found that compared to no harvesting, harvesting trees in small groups significantly decreased salamander abundance and changed species composition. One randomized, replicated, controlled, before-and-after study in the USA found that compared to unharvested plots, the proportion of female salamanders carrying eggs were similar and proportion of eggs per female and juveniles similar or lower in harvested plots that included harvest of groups of trees.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F844https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F844Fri, 30 Aug 2013 15:47:36 +0100Collected Evidence: Collected Evidence: Use shelterwood harvesting instead of clearcutting Three studies (including two randomized, replicated, controlled, before-and-after studies) in the USA found that compared to clearcutting, shelterwood harvesting resulted in higher, similar or initially higher and then similar salamander abundance. A meta-analysis of 24 studies in North America found that partial harvest, which included shelterwood harvesting with three other types, resulted in smaller reductions in salamander populations than clearcutting Two of three studies (including two randomized, replicated, controlled, before-and-after studies) in the USA found that compared to no harvesting, shelterwood harvesting decreased salamander abundance and changed species composition. One found that shelterwood harvesting did not affect salamander abundance. One randomized, replicated, controlled, before-and-after study in the USA found that compared to unharvested plots, the proportion of female salamanders carrying eggs, eggs per female or proportion of juveniles were similar or lower in harvested plots that included shelterwood harvested plots, depending on species and time since harvest.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F851https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F851Thu, 05 Sep 2013 14:42:48 +0100Collected Evidence: Collected Evidence: Translocate natterjack toads Three studies (including one review) in France and the UK found that translocated natterjack toad eggs, tadpoles, juveniles or adults established breeding populations at one site or in 30–70% of cases, some of which also released head-started or captive-bred animals or included habitat management. The review found that re-establishing toads on dune or saltmarsh habitat was more successful than on heathland. One replicated study in the UK found that natterjack toad populations increased at sites established by translocations, particularly with replicated translocations of wild rather than captive-bred toads. Two replicated, before-and-after studies in Estonia and the UK found that translocating natterjack toad eggs or tadpoles resulted in breeding at 8–70% of sites, some of which had been restored.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F859https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F859Fri, 06 Sep 2013 13:48:11 +0100Collected Evidence: Collected Evidence: Create ponds for salamanders (including newts) Three before-and-after studies (including two replicated studies) in France, Germany and the USA found that naturally colonizing alpine newts, captive-bred smooth newts or translocated spotted salamanders established stable breeding populations in 20–100% of created ponds. Two replicated, before-and-after study in France and China found that alpine newts or Chinhai salamanders reproduced in 60–100% of created ponds. One small, replicated, before-and-after study in the USA found that translocated spotted salamanders but not tiger salamanders reproduced in created ponds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F867https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F867Tue, 10 Sep 2013 15:55:04 +0100Collected Evidence: Collected Evidence: Release captive-bred toads Two of three studies (including two replicated studies) in Denmark, Sweden and the USA found that captive-bred toads released as tadpoles, juveniles or metamorphs established populations, in one case at 70% of sites. One of the studies found that populations were not established from captive-bred and head-started toads. Two studies in Puerto Rico found that survival of released captive-bred Puerto Rican crested toads was low and that 25% were predated within two days of release.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F875https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F875Thu, 12 Sep 2013 10:51:57 +0100Collected Evidence: Collected Evidence: Create artificial water sources Five studies evaluated the effects of creating artificial water sources for bats on bat populations. One study was in each of the USA, Germany, South Africa, Israel and Mexico. COMMUNITY RESPONSE (1 STUDY) Richness/diversity (1 study): One replicated, paired sites study in South Africa found a similar number of bat species over farm ponds and in grassland/crops, trees, vineyards or orchards. POPULATION RESPONSE (5 STUDIES) Abundance (5 studies): Five replicated studies (including four site comparisons and one paired sites study) in Israel, the USA, Germany, South Africa and Mexico found that bat activity (relative abundance) was similar or higher over reservoirs and waste water treatment pools, heliponds and drainage ditches, retention ponds and farm/cattle ponds compared to over natural wetlands, nearby vineyards, surrounding forest or grassland/crops, trees and orchards. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F959https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F959Fri, 20 Dec 2013 10:14:31 +0000Collected 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 +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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