Collected Evidence: Collected Evidence: Replace honey-hunting with apiculture  One study reported that a programme to enhance take-up of stingless beekeeping in southern Mexico increased the number of managed colonies in the area. Five trials contributed to scientific improvement of stingless beekeeping methods. Two controlled trials showed that either brewer's yeast (one trial) or a mix with 25% pollen collected by honey bees Apis mellifera (one trial) can be used as a pollen substitute to feed Scaptotrigona postica in times of pollen scarcity. A study on the island of Tobago found a wooden hive design with separate, different-shaped honey and brood chambers allowed honey to be extracted without damaging the brood. One trial showed that 50 g of comb with mature pupae is enough to start a new daughter colony of S. mexicana. One trial found brood growth was higher in traditional log hives than in box hives with internal volumes exceeding 14 litres, and recommended smaller box hives. We have captured no clear evidence about whether these activities help conserve bees or enhance native bee populations.    Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F33https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F33Thu, 20 May 2010 06:29:24 +0100Collected Evidence: Collected Evidence: Leave uncut strips of rye grass on silage fields Two reviews and two replicated controlled trials from the UK found that leaving uncut strips of rye grass on silage fields resulted in benefits to birds including increased numbers. One of these studies found that whilst seed-eating birds preferred rye grass cut once only, birds that fed on different food resources such as insect-eaters showed more variable results with some preferring plots cut two or more times. One replicated controlled randomized study from the UK found no difference in ground beetle abundance and diversity between cut and uncut silage field headlands in the first two years of the experiment, but higher species diversity in uncut plots in the third year.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F132https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F132Mon, 14 Nov 2011 22:28:34 +0000Collected Evidence: Collected Evidence: Create scrapes and pools Three studies from Sweden and the UK (including two site comparisons one of which was replicated) found that the creation of scrapes and pools provided habitat for a range of plant, invertebrate or bird species and resulted in increased aquatic macroinvertebrate diversity. One of these studies found constructed pools supported locally or nationally scarce species of plant and water beetle. A study in Sweden found that a combination of large surface area, high shoreline complexity and shallow depth resulted in increased bird, bottom-dwelling invertebrate and aquatic plant diversity. However there were fewer fish species than in natural wetlands. Two replicated studies from Ireland and the UK (one controlled paired study and a site comparison) found that bird visit rates were higher but invertebrate numbers varied in ditch-fed paired ponds compared with dry controls and total macroinvertebrate and beetle richness did not differ between artificial and natural ponds, although communities did differ.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F153https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F153Sat, 14 Jan 2012 15:30:46 +0000Collected Evidence: Collected Evidence: Legally protect habitats Four studies (two replicated) from Europe found population increases following habitat protection, more positive population trends in protected habitats, compared with outside, or with increases amounts of protected habitats. A literature review reported that a large number of cranes (Gruidae) of seven species used nature reserves in China, whilst a replicated, randomised and controlled study from Argentina found that some guilds of birds were found at higher species richnesses in protected forests, some at higher densities, and that some showed no differences. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F158https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F158Tue, 15 May 2012 13:48:22 +0100Collected Evidence: Collected Evidence: Protect bird nests using electric fencing One before-and-after study from the UK found an increase in tern numbers after the erection of an electric fence, whilst a study from the USA found an increase in the number of nests. Five studies from the USA found higher survival or productivity at wader or seabird colonies with electric fencing, compared to areas without fencing, although one study found that hatching rates were no different, whilst nesting success was only higher in one of two years. One study from the USA found lower predation by mammalian predators inside electric fence exclosures, whilst predation by birds was higher. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F188https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F188Wed, 13 Jun 2012 16:59:40 +0100Collected Evidence: Collected Evidence: Create beetle banks A small UK study found that a site with beetle banks had increasing populations of rare or declining species, although several other interventions were used on this site. A literature review from the UK found that grey partridge Perdix perdix populations were far larger on sites with beetle banks and other interventions than on other farms. Two replicated studies from the UK also investigated population-level effects: one found that no bird species were strongly associated with beetle banks; the second found no relationship between beetle banks and grey partridge population density trends. A UK literature review found that two bird species nested in beetle banks and that some species were more likely to forage in them than others. A study in the UK found that one of two species used beetle banks more than expected. The other used them less than other agri-environment options.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F217https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F217Tue, 17 Jul 2012 12:04:26 +0100Collected Evidence: Collected Evidence: Use netting to exclude fish-eating birds Two replicated studies from Germany and the USA found that netting or closely-spaced string barriers reduced losses of fish or deterred fish-eating birds from fish ponds. A review concluded that excluding birds was an effective way to reduce damage. A series of tests in the Netherlands found that netting or nylon lines over ponds did not prevent birds from landing, but did alter behaviour, whilst a before-and-after study from the USA found that fewer great blue herons Ardea Herodias landed at fish ponds with netting, but that they stayed longer. Two replicated studies from Germany and Israel found that some birds became entangled in netting or closely-spaced string barriers over fish ponds. The Israeli study found that dark, small meshed netting entangled fewer birds than other netting types.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F248https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F248Wed, 18 Jul 2012 12:00:45 +0100Collected Evidence: Collected Evidence: Use education programmes and local engagement to help reduce persecution or exploitation of species Five out of six studies from across the world found increases in bird populations or decreases in mortality following education programmes. In all but one case, education was one of several interventions employed. A replicated before-and-after study from Canada also found that there was a significant shift in local peoples’ attitudes to conservation and exploited species following educational programmes. One study from Venezuela found no evidence for decreases in yellow-shouldered parrot Amazona barbadensis poaching following an educational programme in local schools. The authors argue that the benefits would probably be seen later in the project.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F274https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F274Thu, 19 Jul 2012 18:28:35 +0100Collected Evidence: Collected Evidence: Mow or cut natural grasslands Of six studies, two replicated and controlled studies from the USA found higher densities of birds or nests on mown grasslands, compared to unmanaged or burned areas. Two controlled studies from the USA, one replicated, found lower nesting or population densities of some species, on mown grasslands compared to unmown areas. Two replicated and controlled studies found no significant differences in nesting densities or community composition between mown and unmown areas. One study from the USA found that grasshopper sparrow nesting success was higher on mown areas than grazed areas of grassland. A replicated controlled study from the USA found that ducks had similar nesting success on cut and uncut areas.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F338https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F338Sat, 28 Jul 2012 15:41:22 +0100Collected Evidence: Collected Evidence: Manage water level in wetlands Of six studies, one replicated, controlled study from the USA found that bird diversity was affected by maintaining water levels at different levels. A study from the USA found that ducks were more abundant when high water levels were maintained on a wetland site. Geese were more abundant when lower levels were maintained. Three studies from the USA and Canada, two replicated, found that different species showed preferences for different water levels in wetlands. A replicated study from the UK found that great bitterns established territories earlier when deep water levels were maintained, but this had no effect on productivity. A review from Spain found that management successfully maintained water near a greater flamingo nesting area, but the effects of this were not measured.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F355https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F355Sun, 29 Jul 2012 16:49:45 +0100Collected Evidence: Collected Evidence: Create scrapes and pools in wetlands and wet grasslands Of six studies captured, four before-and after studies from the UK and North America found that the use of sites, or the breeding population of birds on sites, increased following the creation of ponds and scrapes or was higher in areas with ditch-fed ponds. A study from the USA found that dabbling ducks used newly-created ponds in large numbers, although other species preferred older ponds. Songbirds did not appear to be affected by pond-creation. A replicated site from the UK found that northern lapwing chicks foraged in newly created wet features and that chick condition was higher in sites with a large number of footdrains.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F359https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F359Sun, 29 Jul 2012 17:26:31 +0100Collected Evidence: Collected Evidence: Restore or create coastal and intertidal wetlands All six studies found, from the USA and UK, found that target bird species used restored or created wetlands. Two found that numbers and/or diversity were at least as high as in natural wetlands, one that numbers were higher than in unrestored sites. Three found that bird numbers on wetlands increased over time. Two studies from the UK found that songbirds and waders decreased following wetland restoration, whilst a study from the USA found that songbirds were more common on unrestored sites than restored wetlands.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F367https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F367Tue, 07 Aug 2012 13:15:07 +0100Collected Evidence: Collected Evidence: Remove vegetation to create nesting areas Two out of six studies found that the number of waders and terns nesting in an area increased following the removal of vegetation, and another found that a tern colony moved to an area prepared by removing vegetation. Two of these studies used multiple interventions at once. One study found a decrease in colony size after several interventions, including vegetation control. A study from the UK found that gulls and terns nested in an area cleared of vegetation and a controlled study from Puerto Rico found that although no terns nested in plots cleared completely of vegetation, more nested in partially-cleared plots than in uncleared plots. A before-and-after study from Canada found that tern nesting success was higher after plots were cleared of vegetation and other interventions were used.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F505https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F505Thu, 06 Sep 2012 14:00:49 +0100Collected Evidence: Collected Evidence: Provide supplementary food for gulls, terns and skuas to increase reproductive success Four studies of three experiments from Europe and Alaska found that providing supplementary food increased fledging success or chick survival in two gull species, although a study from the UK found that this was only true for one island, with abnormally low breeding success. A second island with higher success was not affected by feeding. Two of the experiments fed parent birds and one fed the chicks directly. One study from the Antarctic found no effect of feeding parent skuas on productivity. One study from Alaska found increased chick growth when parents were fed; one study from the Antarctic found no increase in chick growth.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F525https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F525Sat, 08 Sep 2012 13:37:48 +0100Collected Evidence: Collected Evidence: Provide supplementary food for gamebirds to increase adult survival Two European studies found increased numbers of grey partridge Perdix perdix in fed areas, compared to unfed areas. In one study there was no change in the overall population in the study area, in the second there was an increase. One cross-over study from the USA found that northern bobwhites Colinus virginianus had higher overwinter survival in fed areas, one found lower survival and a literature review found no overall effect of feeding.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F544https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F544Sun, 16 Sep 2012 09:01:06 +0100Collected Evidence: Collected Evidence: Provide supplementary food for nectar-feeding songbirds to increase adult survival Two studies from Australia and New Zealand found that ten species of honeyeaters and stitchbirds Notiomystis cincta readily used feeders supplying sugar solutions, with seasonal variations varying between species and stitchbirds spending more time foraging for insects when food was supplied. A series of ex situ trials using southern African birds found that most species tested showed a preference for sucrose solutions over glucose or fructose. One study found that sunbirds and sugarbirds only showed such a preference at low (equimolar) concentrations. Two more studies found that two species showed preferences for sucrose when comparing 20% (by weight) solutions, although a third species did not show this preference. All species rejected solutions with xylose (a natural sugar in nectar) added. A final study found that sucrose preferences only became apparent at equicalorific concentrations high enough for birds to subsist on.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F553https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F553Sat, 22 Sep 2012 20:11:36 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of cranes Four studies of five release programmes from the USA and Russia, from a total of eight programmes, found that released cranes had high survival or bred in the wild. Two studies from two release programmes in the USA found low survival of captive-bred eggs fostered to wild birds, compared with wild eggs, or a failure to increase the wild flock size. A worldwide review found that releases of migratory species only tended to be successful if birds were released into existing flocks, with higher success for non-migratory populations. One study from the USA found that birds released as sub-adults had higher survival than birds cross-fostered to wild birds. One study from the USA found that 73% of all mortalities occurred in the first year after release.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F621https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F621Sun, 14 Oct 2012 14:04:41 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of songbirds A before-and-after study in Mauritius describes the establishment of a population of Mauritius fody Foudia rubra following the release of captive-bred individuals. Four studies of three release programmes on Hawaii found high survival of all three species released (Hawaiian crows Corvus hawaiiensis and two thrushes: omao Myadestes obscurus and puaiohi M. palmeri), with the two thrushes successfully breeding. The authors in one note that many of the released puaiohi dispersed from the release site, meaning that repopulating specific areas may require multiple releases. A replicated, controlled study from the USA found that San Clemente loggerhead shrike Lanius ludovicianus mearnsi pairs with captive-bred females had lower reproductive success than pairs where both parents were wild-bred.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F630https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F630Sun, 14 Oct 2012 23:05:39 +0100Collected Evidence: Collected Evidence: Use holding pens at release sites Three replicated and one small study from three release programmes in Saudi Arabia, the USA and Canada found that released birds had higher survival or were more likely to pair up if kept at release sites in holding pens before release. A replicated study in the USA found lower survival for thick-billed parrots Rhynchopsitta pachyrhyncha released in holding pens, compared to birds released without preparation. A review of northern bald ibis Geronticus eremita conservation found that holding pens successfully prevented most birds from migrating (which resulted in 100% mortality), although some 200 birds ‘escaped’ over 25 years.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F632https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F632Sun, 14 Oct 2012 23:22:45 +0100Collected Evidence: Collected Evidence: Provide 'sacrificial' grasslands to reduce the impact of wild geese on crops All six studies from the UK (including four replicated, controlled trials) found that managing grasslands for geese increased the number grazing there. Two replicated, controlled studies found that fertilized and cut areas were grazed by more white-fronted geese or brent geese than control areas. A replicated, controlled trial found that re-seeded and fertilized wet pasture fields were used by more barnacle geese than control fields, and that fertilized areas were used less than re-seeded ones. A replicated, controlled study found that spring fertilizer application increased the use of grassland fields by pink-footed geese. A replicated study found that plots sown with white clover were preferred by dark-bellied brent geese compared to plots sown with grasses. However, four of the studies found that the birds were moving within a relatively small area (i.e. within the study site) and therefore the grasslands may not reduce conflict with farmers.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F641https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F641Mon, 15 Oct 2012 16:28:48 +0100Collected Evidence: Collected Evidence: Use vaccinations Two controlled studies from Iceland and Norway found higher survival rates in vaccinated salmon compared to unvaccinated control groups. This was post exposure to the disease-causing bacteria, Aeromonas salmonicida spp.achromogenes and Yersinia ruckeri, respectively. Two controlled studies in Australia and Canadia reported higher survival in salmon infected with marine flexibacteriosis and bacterial kidney disease, post vaccination. Two controlled studies in Norway reported similar results for salmon vaccinated against infectious salmon anaemia. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F733https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F733Mon, 03 Jun 2013 14:33:01 +0100Collected Evidence: Collected Evidence: Provide education programmes about amphibians One study in Taiwan found that education programmes about wetlands and amphibians, along with other interventions, doubled a population of Taipei frogs. Three studies (including one replicated study) in Germany, Mexico, Zimbabwe and the USA found that education programmes increased the amphibian knowledge of students, boatmen and their tourists. Two studies (including one replicated study) in Germany and Slovenia found that students who were taught using live amphibians and had previous direct experience, or who participated in outdoor amphibian conservation work, gained greater knowledge, had improved attitudes towards species and retained knowledge better than those than those taught indoors with pictures. Four studies in Mexico, Taiwan, Zimbabwe and the USA found that courses on amphibians and the environment were attended by 119–6,000 participants and amphibian camps by 700 school children.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F776https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F776Wed, 21 Aug 2013 11:04:07 +0100Collected Evidence: Collected Evidence: Use humans to assist migrating amphibians across roads Two studies (including one replicated study) in Italy and the UK found that despite assisting toads across roads during breeding migrations, 64–70% of populations declined over 6–10 years. One study in the UK  found that despite assisting toads across roads during breeding migrations, at 7% of sites over 500 toads were still killed on roads. Five studies in Germany, the UK and Italy found that large numbers of amphibians were moved across roads by patrols. Numbers ranged from 7,532 toads moved before and after breeding to half a million moved during breeding migrations annually. In the UK, there were over 400 patrols and 71 patrols spent an average of 90 person-hours moving toads and had been active for up to 10 years.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F784https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F784Thu, 22 Aug 2013 13:52:12 +0100Collected Evidence: Collected Evidence: Grow cover crops beneath the main crop (living mulches) or between crop rowsBiodiversity: One randomized, replicated study from Spain found that cover crops increased bacterial numbers and activity. Erosion: Two studies from France and the USA showed reduced erosion under cover crops. One controlled study showed that soil stability was highest under a grass cover, and one randomized replicated study found that cover crops reduced soil loss. Soil organic matter: Two controlled trials from India and South Africa (one also randomized and replicated) found that soil organic matter increased under cover crops, and one trial from Germany found no effect on soil organic matter levels. SOIL TYPES COVERED: gravelly-sandy loam, sandy loam, sandy, silty loam.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F897https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F897Mon, 30 Sep 2013 14:24:18 +0100Collected Evidence: Collected Evidence: Retain crop residuesBiodiversity: One replicated study from Mexico found higher microbial biomass when crop residues were retained. Erosion: One review found reduced water runoff, increased water storage and reduced soil erosion. One replicated site comparison from Canada found mixed effects on soil physical properties, including penetration resistance and the size of soil aggregates. One replicated study from the USA found that tillage can have mixed results on soil erosion when crop remains are removed. Soil organic matter: Two randomized, replicated trials from Australia and China found higher soil organic carbon and nitrogen when residues were retained. One trial found this only when fertilizer was also applied. Yield: Two randomized, replicated trials from Australia and China found higher yields when residues were retained. One trial found this only when residue retention was done combination with fertilizer application and no-tillage. Soil types covered: clay, loam, sandy-loam, silt loam.      Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F907https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F907Wed, 02 Oct 2013 11:38:30 +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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