Collected Evidence: Collected Evidence: Maintain traditional water meadows A replicated study from the UK found that northern lapwing and common redshank populations increased on nature reserves managed to maintain water meadows. Two replicated studies from the Netherlands found that there were more waders or birds overall on specially managed meadows or 12.5 ha plots including several management interventions than on conventional fields, but one study found that these differences were present before the management scheme was introduced and the other found no differences between individual fields under different management. A replicated study from the UK found that common snipe decreased on nature reserves managed to maintain water meadows and a replicated before-and-after study from the Netherlands found that wader population trends on specially managed meadows were no different to those on conventionally-managed meadows. A replicated study from the UK found that lapwing populations on three of four water meadow sites managed for conservation did not have high enough productivity to maintain population levels. All three sites were judged deficient in at least one management category.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F229https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F229Tue, 17 Jul 2012 15:37:55 +0100Collected Evidence: Collected Evidence: Plant grass buffer strips/margins around arable or pasture fields Nineteen studies from Finland, the Netherlands, Sweden and the UK (including seven replicated controlled studies of which two were randomized, and three reviews), found that planting grass buffer strips (some margins floristically-enhanced) increased arthropod abundance, species richness and diversity. A review found grass margins benefited bumblebees and some other invertebrates but did not distinguish between the effects of several different margin types. Nine studies from the UK (including seven replicated studies of which two were controlled, and two reviews) found that planting grass buffer strips (some margins floristically-enhanced) benefits birds, resulting in increased numbers, densities, species richness and foraging time. Seven studies from the Netherlands and the UK (all replicated of which four were controlled and two randomized), found that planting grass buffer strips (some margins floristically-enhanced) increased the cover and species richness of plants. A review found grass margins benefited plants but did not distinguish between the effects of several different margin types. Five studies from Finland and the UK (including two replicated, controlled trials and a review), found that planting grass buffer strips benefits small mammals: including increased activity and numbers. Six studies from the Netherlands and the UK (including three replicated, controlled trials) found that planting grass buffer strips had no clear effect on insect numbers, bird numbers or invertebrate pest populations. A replicated site comparison found sown grassy margins were not the best option for conservation of rare arable plants. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F246https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F246Wed, 18 Jul 2012 11:47:21 +0100Collected Evidence: Collected Evidence: Disturb birds using foot patrolsTwo replicated studies from Belgium and Australia found that using foot patrols to disturb birds from fish farms did not reduce the number of birds present or fish consumption.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F249https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F249Wed, 18 Jul 2012 12:05:00 +0100Collected Evidence: Collected Evidence: Use in-water devices to reduce fish loss from ponds A before-and-after study from the USA found a 95% reduction in the number of double-crested cormorant Phalacrocorax auritus at two ponds in a fish farm following the installation of underwater ropes. A replicated study at a fish farm in Australia found that hanging gill nets in ponds did not decrease the number of cormorants swimming in ponds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F254https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F254Wed, 18 Jul 2012 12:54:38 +0100Collected Evidence: Collected Evidence: Plant nectar flower mixture/wildflower strips A total of 80 individual studies have in some way investigated the effects of flowering strips on biodiversity. Sixty-four individual studies show some benefits to one or more wildlife groups. Sixty-five individual studies reported the effects of flower strips on invertebrates. Of these, fifty reported positive effects. Forty-one studies from eight European countries (including five reviews and twenty-three replicated controlled studies, of which one randomized and two site comparisons) found evidence that flower strips had a positive influence on invertebrate numbers with increased abundance, species richness/diversity, or both. Ten studies (nine replicated of which two controlled) found invertebrates visited or foraged on flower strips but did not specify increases/decreases in numbers. Two studies found effects on ground beetles other than changes in numbers. One replicated controlled study showed that ground beetles were more active or had enhanced feeding/reproductive conditions in flower strips. A review found flower strips supported ground beetle species that were rarely found in crops. Fifteen studies reported mixed or negative effects of flower strips on invertebrates. Six studies found no significant effects. Twenty-one studies looked at the effects of flower strips on plants. Sixteen studies from seven European countries (including ten replicated controlled studies of which one randomized) found evidence that flower strips had higher plant cover, number of flowers, diversity, and species richness. One review found flower strips benefited plants but did not specify how. Four studies found negative or no effects of flower strips on the number or diversity of plant species. Five studies described the effects of different margin establishment or management techniques on plants. Seven studies investigated birds and wildflower strips. Four replicated, controlled studies from Switzerland and the UK (two of which were randomized) and one review of European studies found evidence that plots sown with a wildflower or legume seed mix had a positive influence on birds. Flower strips attracted more birds or bird species and the number of birds using flower strips increased over time. Eurasian skylarks preferentially foraged in, and nested in or near, sown weed patches and were less likely to abandon their territories when they included sown weed patches. However one replicated trial in Switzerland found barn owls avoided sown wildflower areas. Two winter recording periods of the same replicated, controlled study in the UK found there were not more bird species or individuals on wildflower plots compared to control margins. All five studies investigating the effects of wildflower strips on small mammals (four replicated studies from Switzerland and one review of studies from north-western Europe) found evidence that small mammals benefit from strips sown with wildflowers or flowers rich in pollen and nectar, with increases in abundance, density and species richness. One replicated study from Switzerland reported that most common vole home ranges and core regions of their territories were found within a wildflower strip. Nineteen studies (of which eight replicated, controlled) reported positive effects on biodiversity of sowing specific plant species including phacelia, and/or other plant species such as borage and red clover. Three replicated studies (two also controlled) found negative impacts or no effects on biodiversity of sowing phacelia. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F442https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F442Thu, 23 Aug 2012 15:37:16 +0100Collected Evidence: Collected Evidence: Leave headlands in fields unsprayed (conservation headlands) Three studies from Europe, two replicated, found that conservation headlands were frequently used by some of all of the bird species studied, or were strongly associated with species. A review from the UK found that grey partridge Perdix perdix populations were far larger on farms with conservation headlands and other interventions in place than other farms. Two replicated studies from Europe found that species were not associated with, or were no more abundant on, conservation headlands, compared with control fields. All four studies, three replicated, that investigated survival found higher grey partridge Perdix perdix chick or adult survival on sites with conservation headlands than control sites. One found that this difference was not significant. Five studies from Europe, four replicated, found larger grey partridge broods on farms with conservation headlands, one study found that differences were not significant. One replicated study from the UK found that fewer broods were found in fields with conservation headlands. Another replicated study from the UK found no relationship between conservation headlands and partridge brood size or young to adult ratio.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F461https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F461Wed, 29 Aug 2012 15:39:20 +0100Collected Evidence: Collected Evidence: Plant new hedges Two studies from France and the UK compared newly planted hedges with control areas. Both (including one replicated trial) found newly planted hedges had higher abundance, species richness or diversity of beetles or spiders than crop fields or field margins. The replicated study also found vascular plant species diversity and grass species richness were higher in newly planted hedges than recently established grass field margins. A review found newly established hedges supported more ground beetles than older hedges. A small-scale study from the UK found that local hawthorn plants exhibited better growth and were more stock proof than those of eight other provenances. A literature review found lower pest outbreaks in areas with new hedges. A replicated study in the UK found that the diversity of arthropods supported by newly planted hedges varied between seven different plant species An unreplicated site comparison study in Germany found that two out of 85 ground beetle species used newly planted hedges as stepping stones for dispersal. Results from the same study found that invertebrates that moved passively (attached to mammals and birds), such as snails, benefited most from the hedge-islands compared to actively moving ground beetles and harvestmen. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F538https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F538Tue, 11 Sep 2012 15:38:22 +0100Collected Evidence: Collected Evidence: Increase crop diversity All four studies (including one replicated, controlled study and one review) from Belgium, Germany, Hungary and unspecified European countries reported a positive effect of crop rotations on ground beetles or plants. Three studies found higher ground beetle species richness and/or abundance and one study found higher plant species richness in rotation fields or on farms with more crops in rotation compared to monoculture fields. A study from Hungary found that fields in monoculture had a more stable and abundant ground beetle community than fields within a rotation.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F560https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F560Tue, 25 Sep 2012 12:08:33 +0100Collected Evidence: Collected Evidence: Plant wild bird seed or cover mixture Thirty individual studies investigated the effects on birds of sowing wild bird seed or cover mixture, 21 studies found positive effects. Fourteen studies from the UK (including one systematic review and nine replicated controlled trials of which four randomized, and three reviews) found that fields sown with wild bird cover mix had higher abundance, density, species diversity and species richness of birds than other farmland habitats. Six studies from the UK (including one review and two replicated studies) found that birds showed a preference for wild bird cover and used it significantly more than other habitats. One review found the grey partridge population increased substantially on farms where conservation measures including cover crops were in place. Nine replicated studies from France and the UK reported mixed or negative effects of wild bird cover on birds compared to other farmland habitats. Six studies found that mixtures including kale or a mixture of kale and/or other species attracted the largest number of bird species or highest bird abundance. Twelve studies from the UK looked at the effects of wild bird cover strips on invertebrates. Seven studies from the UK (including one review and four replicated controlled studies of which two were also randomized) found positive effects. Farmland habitats sown with wild bird cover mix were used more by butterflies, and had a higher abundance or species richness of butterflies and/or bees than other farmland habitats. One review found wild bird cover benefited invertebrates. Four studies (including one review and two replicated trials) reported mixed or negative effects of wild bird cover on invertebrate numbers compared with other farmland habitats. One study found that bees and butterflies showed preferences for particular plant species. Eight studies from the UK looked at plants and wild bird cover. Six studies (including two reviews and two replicated controlled trials) found that planting wild bird cover mix was one of the three best options for conservation of annual herbaceous plant communities, benefited plants and resulted in increased plant diversity and species richness. However two replicated studies (of which one a site comparison) found mixed/negative effects for plant species richness. One replicated trial from the UK found that small mammal activity was higher in wild bird cover than in the crop in winter but not in summer.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F594https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F594Fri, 12 Oct 2012 14:56:56 +0100Collected Evidence: Collected Evidence: Maintain upland heath/moorland Of 15 individual studies from the UK, eight (including three replicated, controlled trials, of which one also randomized) found that appropriate management can help to maintain the conservation value of upland heath or moorland. Of these eight studies, four tested the effectiveness of excluding or reducing grazing. Impacts included increases in the abundance of Scottish primrose and other broadleaved plant species, heather cover and numbers of true bugs, biomass of arthropods associated with the bird diet, number and diversity of moths and benefits to black grouse. Among other treatments, repeated cutting and grazing by goats were found to be effective in controlling the dominance of certain grass species. A review found management under the Environmentally Sensitive Areas scheme had broadly positive effects on moorland birds and a reduction in grazing benefited most bird species and increased heath vegetation and heather cover. A replicated before-and-after study found that moorland management under the Environmentally Sensitive Area scheme maintained the number of plant species in two out of three areas. Three studies (including one before-and-after trial) reported mixed results for invertebrates or birds, where management to maintain upland heath or moorland benefited some but not all species or where the effect depended on the vegetation type. Treatments tested included reducing grazing intensity and grouse moor management (burning and predator control). Four studies (including one controlled site comparison and two reviews) found that reducing the intensity of livestock grazing reduced the abundance of soil organisms including invertebrates, bacteria or fungi. A randomized, replicated before-and-after study found that heather cover declined over nine years on a moorland site managed under the Environmentally Sensitive Areas scheme in which grazing intensity had increased.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F647https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F647Wed, 17 Oct 2012 17:51:16 +0100Collected Evidence: Collected Evidence: Provide supplementary food for birds or mammals A total of 18 individual studies investigated the effects of providing supplementary food. Nine studies from France, Sweden and the UK (six replicated studies, of which five controlled and one also randomized and paired) found that the provision of supplementary food increased farmland bird abundance, breeding population size, density, body mass, hatching, nestling growth and fledging rates, increased overwinter survival of a declining house sparrow population and that fed male hen harriers bred with more females than control birds. Two studies did not separate the effects of several other interventions carried out on the same study site. Four studies from the UK and Finland (three replicated studies, of which one controlled and one randomized) found that farmland songbirds and field voles (field voles on unmown plots only) used supplementary food when provided, including the majority of targeted species such as tree sparrow, yellowhammer and corn bunting. Five replicated studies from the UK (of which two also controlled) found that the provision of supplementary food had no clear effect on farmland bird breeding abundance, European turtle dove reproductive success, territory size or territory density, overwinter survival of three stable house sparrow populations, tree sparrow nest box use, or the abundance of weed seeds on the soil surface. One replicated, controlled study from Sweden found no effect of supplementary food provision on common starling clutch size or nestling weight, and lower fledging rates in nests which received supplementary food compared to nests without supplementary food in one year. Four studies from the UK (two replicated of which one was also randomized and controlled) found that the use of supplementary food by farmland birds varied between species and region, depended upon the time of year and proximity to other feeding stations and natural feeding areas. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F648https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F648Thu, 18 Oct 2012 14:20:34 +0100Collected Evidence: Collected Evidence: Create beetle banks Fourteen reports from eight studies out of a total 24 reports from 12 individual studies (including eight replicated studies of which three controlled and four literature reviews) from Denmark and the UK found that beetle banks provide some benefits to farmland biodiversity. Sixteen reports from eight individual studies looked at invertebrates and beetle banks. Five reports from two replicated studies (of which one controlled) and a review found positive effects on invertebrate densities/numbers, distribution, or higher ground beetle density and species diversity in spring and summer but not winter. Six reports from three replicated studies (of which one randomized and controlled) found that invertebrate numbers varied between specific grass species sown on beetle banks. Two replicated studies (one paired and controlled) found that the effect of beetle banks varied between invertebrate groups or families. Five replicated studies (of which two controlled) found lower or no difference in invertebrate densities or numbers on beetle banks relative to other habitats. One review found lesser marsh grasshopper did not forage on two plant species commonly sown in beetle banks. Six studies looked at birds and beetle banks. Two reviews and one replicated controlled trial found positive effects on bird numbers (in combination with other farmland conservation measures) or evidence that birds used beetle banks. Two studies (one replicated site comparison) found mixed effects on birds. One replicated study found no farmland bird species were associated with beetle banks. One replicated, paired, controlled study and a review looked at the effects of beetle banks on plants and found either lower plant species richness on beetle banks in summer, or that grass margins including beetle banks were generally beneficial to plants but these effects were not pronounced on beetle banks. One controlled study and a review found beetle banks acted as nest sites for harvest mice. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F651https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F651Tue, 23 Oct 2012 16:24:44 +0100Collected Evidence: Collected Evidence: Leave headlands in fields unsprayed (conservation headlands) Twenty-two studies from 14 replicated, controlled experiments (of which two randomized) including two reviews, from a total of 32 studies from 20 experiments (of which 17 replicated, controlled) including three reviews from Finland, Germany, the Netherlands, Sweden and the UK that investigated species richness and diversity of farmland wildlife found that conservation headlands contained higher species richness or diversity of invertebrates or plants than other habitat types. Twelve studies (including a review) from ten replicated experiments (of which eight controlled and three controlled and randomized) found that some or all invertebrates or plants investigated did not have higher species richness or diversity on conservation headlands compared to other habitat types. This included both replicated, controlled studies investigating bee diversity. Two replicated studies from the UK found that unfertilized conservation headlands had more plant species than fertilized conservation headlands. Positive effects of conservation headlands on abundances or behaviours of some or all species investigated were found by 27 studies from 15 replicated experiments (of which 13 controlled) including five reviews out of a total of 36 studies from 20 experiments (17 replicated, controlled) including five reviews from Finland, Germany, the Netherlands, Sweden and the UK that investigated birds (some studies looked at number of visits), mammals (some studies looked at number of visits), invertebrates and plant abundance/cover. One review from the UK found a positive effect on grey partridge populations but did not separate the effects of several other interventions including conservation headlands. Nineteen studies from 13 replicated (12 controlled) experiments and a review from Finland, Germany, the Netherlands and the UK found that some or all species of birds, invertebrates or plants investigated were at similar, or lower, abundances on conservation headlands compared to other management. One review from the UK and a study in Germany found conservation headlands had a positive effect on plants and some, but not all invertebrates, or rare arable weeds but did not specify how. All eight studies from the UK and Sweden that investigated species’ productivity, from three replicated (two controlled) experiments including two reviews found that grey partridge productivity or survival was higher in conservation headlands (or in sites with conservation headlands), compared to other management. One replicated study from the UK found that conservation headlands did not increase the proportion of young grey partridges in the population. A before-and-after study from the UK found that some invertebrates in conservation headlands survived pesticide applications to neighbouring fields. A review found crop margins reduce the effects of spray drift on butterflies. A replicated study from Germany and a review found that conservation headlands appeared to prevent or reduce the establishment and spread of pernicious weeds. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F652https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F652Wed, 31 Oct 2012 09:36:44 +0000Collected Evidence: Collected Evidence: Reduce chemical inputs in grassland management A total of 16 studies (including five reviews) investigated the effects of reducing inputs in permanent grasslands. Six studies from the Netherlands, Switzerland and the UK (including one review and four replicated studies of which one was also controlled and one a randomized and controlled before-and-after trial) found that stopping fertilizer inputs in permanent grassland resulted in an increase in plant species richness, reduced the rate of plant species loss and attracted a higher abundance or species richness of some or all invertebrates studied. One review from the Netherlands found that low fertilizer input grasslands favour common meadow bird species. One review found a study showing that densities of some invertebrates were higher in unfertilized plots compared with those receiving nitrogen inputs. Two replicated, controlled trials from the Czech Republic and the UK (one randomized) found that applying fertilizer to permanent grasslands reduced plant species richness or diversity and that the effects on plant communities were still apparent 16 years after the cessation of fertilizer application. Four studies from Ireland, the Netherlands and the UK (including two replicated trials of which one randomized and one controlled and a review) found that reducing fertilizer inputs on grassland had no clear or rapid effect on plant species richness. A review found no clear effect of reducing fertilizer inputs on the density of soil-dwelling invertebrates. One replicated study found that fertilizer treatment only affected seed production of a small number of meadow plants. One replicated study from the UK found lower invertebrate abundance on plots with reduced fertilizer inputs but the differences were not significant.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F694https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F694Sat, 01 Dec 2012 17:52:25 +0000Collected Evidence: Collected Evidence: Maintain traditional water meadows (includes management for breeding and/or wintering waders/waterfowl) Four studies from Belgium, Germany, the Netherlands and the UK (including two site comparisons of which one also replicated) found that maintaining traditional water meadows resulted in an increased population size or number of territories of northern lapwing, common redshank and black-tailed godwit and increased plant species richness. However one of these studies also found common snipe declined on all sites under management to maintain traditional water meadows, and another of the studies found that differences in numbers of birds were present before meadow bird management. Two studies (a replicated study and a review of European studies) found that managing traditional water meadows by grazing had mixed impacts on wildlife and that the productivity of northern lapwings was too low to sustain populations on three of the four water meadows managed for waders. A randomized, replicated, controlled trial in the Netherlands found that cutting in June maintained relatively stable vegetation and a review found mowing could be used to maintain water meadows but had variable effects on plant species richness. One replicated site comparison from the Netherlands found more birds bred on 12.5 ha plots with management for wading birds (in combination with per-clutch payments), however at the field scale there was no difference in bird abundance or species richness between conventionally managed fields and those managed for birds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F696https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F696Fri, 07 Dec 2012 09:05:54 +0000Collected Evidence: Collected Evidence: Maintain species-rich, semi-natural grassland Of 22 studies (including eleven replicated trials, three reviews and a systematic review) from the Czech Republic, Finland, Germany, Russia, Slovenia, Switzerland and the UK, 13 identified management regimes that maintained species-rich grassland. Four of these studies were replicated, controlled trials (including two randomized). Nine studies (including two randomized, replicated before-and-after trials) from Switzerland and the UK examined the effectiveness of existing or historical agri-environment schemes: seven testing the effectiveness of the Environmentally Sensitive Areas scheme in England and two testing the effectiveness of the Ecological Compensation Areas scheme in Switzerland. All except one reported mixed results, with the schemes broadly maintaining plant species richness, but being less effective, for example, in enhancing species richness, preserving the highest quality sites, or overcoming the effects of past intensive management. One study found six Environmentally Sensitive Areas were of ‘outstanding’ significance for their lowland grassland, containing >40% of the English resource of a grassland type. A replicated site comparison study found that on average 86% of Swiss Ecological Compensation Area litter meadows were of ‘good ecological quality’ compared with only 20% of hay meadow Ecological Compensation Areas. Twelve studies (including a systematic review, six replicated trials of which two also controlled and randomized, and three reviews) from the Czech Republic, Finland, Germany, Slovenia, Switzerland and the UK tested the effects of management treatments on species richness or vegetation quality usually involving combinations of mowing, grazing or no fertilizer but some also tested the effectiveness of mulching or burning. All of these studies identified management treatments which benefited or maintained species richness or vegetation quality. One site comparison from Finland and northwest Russia found that butterfly species richness, diversity and total abundance did not differ significantly between mown meadows and grazed pastures and that grassland age and origin had a greater impact on butterfly communities than present management. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F702https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F702Mon, 28 Jan 2013 11:44:12 +0000Collected Evidence: Collected Evidence: Reduce grazing intensity on grassland (including seasonal removal of livestock) Of 27 individual studies (including 10 replicated, controlled trials, four reviews and one systematic review) from France, Germany, Ireland, the Netherlands and the UK, 15 (including three randomized, replicated, controlled trials) from four countries found benefits to birds, plants or invertebrates in response to reducing grazing intensity on permanent grassland (including seasonal removal of livestock). Of these 15 studies, six (including one randomized, replicated, controlled trial) found that reducing grazing intensity throughout the year increased the abundance and diversity of plants (Tallowin et al. 2005, Marriott et al. 2009), frequency of certain plant species, invertebrate diversity, usage by geese and the number of northern lapwing and common redshank. Six studies (including three replicated controlled trials of which two randomized) found that excluding or delaying summer grazing increased plant species diversity, invertebrate abundance and benefited breeding Eurasian skylark. A review found a study that showed that removing autumn grazing after a silage cut increased the winter abundance of seed-eating birds. A review and a replicated controlled study from the UK found that reduced grazing intensity or seasonal removal of livestock increased the number of invertebrates, plant seed heads and foraging skylark, and that some bird species preferred plots with seasonal removal of livestock. Three studies (including one randomized, replicated, controlled trial) from the Netherlands and the UK found no benefit to plants or invertebrates from reduced grazing intensity. One randomized, replicated controlled trial excluded grazing in autumn/winter and another study excluded grazing in the summer. A further study found that reducing grazing intensity throughout the year did not increase plant diversity. Nine studies from France, Germany and the UK reported mixed results for some or all species or wildlife groups considered (including one randomized, replicated, controlled trial and two reviews and a systematic review). Of these, eight studies found that reduced grazing intensity throughout the year benefited some species but not others, one found that the impact depended on the type of vegetation grazed, and one found benefits to bee and wasp abundance but not species richness. One study found that the response of birds to removal of summer grazing varied between functional groups and depended on time of year. A UK review found that reduced grazing benefited invertebrates, plants, rodents and some but not all birds. A systematic review of the effects of grazing intensity on meadow pasture concluded that intermediate levels of grazing are usually optimal for plants, invertebrates and birds but that trade-offs are likely to exist between the requirements of different taxa.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F704https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F704Tue, 29 Jan 2013 17:33:20 +0000Collected Evidence: Collected Evidence: Use crop rotation in potato farming systemsPests: Nine studies from Canada and the USA, and one review, investigated the effect of crop rotation on pest or pathogen populations in potato. Three studies (including two replicated studies of which one randomised and one controlled) and a review found crop rotation reduced pest populations and crop diseases in at least one year or at least one site. One paired study (including one replicated, randomised, controlled trial) found pest populations increased in crop rotation. Four studies (including one replicated, randomised, controlled trial) found increases and decreases in pest populations depending on rotation crops used and other treatments. One replicated, randomised, controlled study found no effect. Yield: Three out of five studies (all replicated, controlled, two also randomised) from Canada and the USA, found that crop rotation increased crop yield in some years or with certain rotation crops. The two other studies (both replicated, one also randomised and one replicated) found yield increases and decreases depending on rotation crops used. Profit: One replicated, controlled study found that crop rotation increased profit.Insecticides: Two studies (one replicated, controlled) found that fewer insecticide treatments were needed on rotated plots. Crops studied were alfalfa, barley, broccoli, brown mustard, buckwheat, cotton, lupins, maize, oats, pearl millet, peas, potato, rye, sorghum, soybean, sugar beet, timothy grass, wheat and yellow sweet clover.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F719https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F719Thu, 30 May 2013 11:33:50 +0100Collected Evidence: Collected Evidence: Delay mowing or first grazing date on pasture or grasslandNatural enemy abundance: One replicated, randomised, controlled study found fewer predatory spiders with delayed cutting. Three studies from the UK (two of them replicated, randomised and controlled) found no change in insect predator numbers and one replicated study from Sweden found mixed effects between different predator groups. Natural enemy diversity: One replicated study from Sweden found a decrease in ant diversity with delayed cutting and one replicated, randomised, controlled study from the UK found no effect on spider and beetle diversity. Pests: One of two replicated, randomised, controlled studies from the UK and USA found more pest insects in late-cut plots and one found no effect. Insects in general: Four replicated, randomised, controlled studies measured the abundance of insect groups without classifying them as pests or natural enemies. One UK study found lower numbers in late-cut plots, while two found effects varied between groups. Two studies from the UK and USA found no effect on insect numbers. Crops studied were barley, bird’s-foot trefoil, clovers, fescues, rapeseed, ryegrass, other grasses and wheat.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F727https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F727Thu, 30 May 2013 13:34:12 +0100Collected Evidence: Collected Evidence: Create beetle banksNatural enemies in fields: Six studies from Canada, the UK and USA (three replicated, controlled, of which two were also randomised) examined the effects on predator numbers in adjacent crops. A review found that predators increased in adjacent crops, but one study found effects varied with time and another found no effect. Two studies found small or slow movements of predators from banks to crops. One study found greater beetle activity in fields but this did not improve pest predation. Natural enemies on banks: Four studies and a review found more invertebrate predators on beetle banks than in surrounding crops, but one of these found that effects varied with time. Eight studies from the UK and USA (including two randomised, replicated, controlled trials and two reviews) compared numbers of predatory invertebrates on beetle banks with other refuge habitats. Two studies found more natural enemies on beetle banks, but one of these found only seasonal effects. One review found similar or higher numbers of predators on beetle banks and four studies found similar or lower numbers. Pests: A replicated, randomised study and a review found the largest pest reductions in areas closest to a beetle bank or on the beetle bank itself. One review found fewer pests in fields with than without a beetle bank. Economics: One replicated, randomised, controlled trial and a review showed that beetle banks could make economic savings if they prevented pests from reaching a spray threshold or causing 5% yield loss. Beetle bank design: Two studies from the UK found certain grass species held higher numbers of predatory invertebrates than others. Crops studied were barley, field bean, maize, oats, pea, radish, rapeseed, soybean, wheat and pasture.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F729https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F729Thu, 30 May 2013 14:45:59 +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: Engage landowners and other volunteers to manage land for amphibians Two before-and-after studies (including one replicated study) in Estonia and Taiwan found that habitat management with participation of volunteers increased natterjack toad and Taipei frog populations. One controlled study in Mexico found that engaging landowners in aquatic habitat management increased axolotl weight. Six studies in Estonia, the USA and UK found that between eight and 41,000 volunteers were engaged in aquatic and terrestrial habitat restoration programmes for amphibians. Individual programmes restored up to 1,023 ponds or over 11,500 km2 of habitat.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F777https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F777Wed, 21 Aug 2013 14:39:26 +0100Collected Evidence: Collected Evidence: Convert to organic farmingBiodiversity: Four studies in Asia, Europe, and the USA (including two site comparison studies and three replicated trials) found higher numbers, diversity, functional diversity (see background) or activity of soil organisms under organic management. Soil organic carbon: Two replicated trials in Italy and the USA showed that organically managed orchards had higher soil carbon levels compared to conventionally managed orchards. One randomized, replicated trial in the USA found soil carbon was lower under organic management compared to alley cropping. Soil organic matter: One replicated trial in Canada found that soil nutrients were lower in organically managed soils. Yields: One replicated trial in Canada found lower yields in organically managed soils. Two replicated trials in the USA (one also randomized) found that fruit was of a higher quality and more resistant to disease, though smaller or that organic management had mixed effects on yield. SOIL TYPES COVERED: clay, clay loam, fine sandy-loam, loam, sandy loam, sandy-clay loam, silt, silty-clay, silt-loam.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F895https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F895Mon, 30 Sep 2013 11:31:06 +0100Collected Evidence: Collected Evidence: Control traffic and traffic timingBiodiversity: One randomized, replicated study from Poland found higher numbers and bacterial activity under controlled traffic. One replicated site comparison study from Denmark found higher microbial biomass when farm traffic was not controlled Erosion: Five trials from Europe and Australia (including three replicated trials, one controlled before-and after-trial, and one review) found a higher number of pores in the soil, less compaction, reduced runoff and increased water filtration into the soil under controlled traffic. One controlled, replicated trial from India found increased soil crack width when traffic was not controlled. Yield: Two replicated trials from Australia and the USA found increased yield under controlled traffic. SOIL TYPES COVERED: clay, loamy-sand, loamy-silt, sandy loam, silty, silty-clay, silt loam.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F899https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F899Tue, 01 Oct 2013 10:25:04 +0100Collected Evidence: Collected Evidence: Integrated aquaculture systems One replicated, controlled study in the USA reported greater growth of scallops grown next to fish farms. A study in Canada found that blue mussels absorbed waste from a salmon farm. A replicated, controlled study in Scotland reported enhanced algal growth when placed adjacent to fish farms. One study in Spain found no evidence that oyster and mussels were feeding on fish farm waste.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F932https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F932Fri, 25 Oct 2013 13:57:09 +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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