Collected Evidence: Collected Evidence: Provide buffer strips alongside water courses (rivers and streams) Three studies (including one replicated site comparison) from the Netherlands and the UK reported that the provision of riparian buffer strips had a positive influence on plant, invertebrate and bird diversity or abundance, and supported vegetation associated with habitats preferred by water voles. Two replicated site comparison studies from France and Ireland found that the provision of riparian buffer strips on farms did not result in an increase in the number of plant species when compared to farms without buffer strips. One replicated site comparison study found ground beetle diversity was higher in grazed riparian zones and narrow fenced strips than in wide riparian buffer strips. However the ground beetle assemblages in wide riparian buffer strips were more distinct from the adjacent pasture field assemblages than either the grazed riparian zones or narrow fenced strips. Collected, 01 Nov 2011 21:03:36 +0000Collected Evidence: Collected Evidence: Raise water levels in ditches or grassland Seven studies from Denmark, the Netherlands and the UK (two replicated controlled studies and two before-and-after studies) found that raising water levels in ditches or grassland was associated with increased bird numbers, breeding bird numbers, plant species that favour wet conditions, and invertebrate numbers or biomass in agricultural landscapes. Two replicated studies from the Netherlands and the UK found that raising water levels resulted in a net loss of plant species and did not affect lapwing foraging rate. A review found three studies reporting that re-wetting soils on old arable fields is not an effective method of reducing nutrient levels and restoring species-rich grassland. A replicated study from the UK found that unflooded pastures contained a high biomass of soil macroinvertebrates of importance to breeding wading birds. A controlled, randomized study from the Netherlands found that raising the water level resulted in a more rapid establishment of species typical of wet grassland, than vegetation management. A review of agri-environment schemes from the UK found studies that suggested more expensive agri-environment scheme options for wetland habitats, such as controlling water levels, were more effective at providing good habitat for wading birds than easier-to-implement options. Collected, 01 Nov 2011 21:14:13 +0000Collected Evidence: Collected Evidence: Control weeds without damaging other plants in conservation areas Two studies looked at the effects of controlling weeds on the surrounding vegetation. One study from the UK found that new populations of rare arable plants established following the control of perennial weeds in a nature conservation area. A replicated, controlled and randomized study in the UK found that using grass-specific herbicide reduced grass diversity and resulted in increases in broadleaved plants. Eleven studies investigated different methods of controlling plants. A review found that specific management regimes can reduce the abundance of pernicious weeds in nature conservation areas. Four replicated controlled studies (one also randomized) from Denmark and Germany found cutting and infection with fungal pathogens were effective methods for controlling creeping thistle and one replicated, randomized, controlled trial from the UK found long-term control was achieved by lenient grazing. A replicated, controlled and randomized study in Germany found weevils could be used to infect creeping thistle with systemic rust. One study found a non-native beetle was unsuitable for controlling creeping thistle because it had poor survival in the UK climate. A replicated controlled study found that spraying a high concentration of herbicide killed less than half of broad-leaved dock plants. A replicated, controlled, randomized study found black grass was eliminated with a December treatment of grass-specific herbicide. A small replicated study found that Hebridean sheep grazed more purple moor grass than Swaledale sheep. Two replicated controlled laboratory and grassland studies found negative impacts of the herbicide asulam on green dock beetles.  Collected, 01 Nov 2011 21:27:23 +0000Collected 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, 01 Nov 2011 21:30:53 +0000Collected 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, 14 Nov 2011 22:28:34 +0000Collected Evidence: Collected Evidence: Manage ditches to benefit wildlife Five out of a total eight studies from the Netherlands and the UK (including one replicated, controlled paired study and three replicated site comparisons) looking at the effects of managing ditches on biodiversity, found that this intervention resulted in increased invertebrate biomass or abundance, plant species richness, emergent plant cover, amphibian diversity and abundance, bird visit rates and higher numbers of some bird species or positive impacts on some birds in plots with ditches managed under agri-environment schemes. One replicated controlled and paired study from the Netherlands found higher plant diversity on ditch banks along unsprayed edges of winter wheat compared to those sprayed with pesticides. Three studies from the Netherlands and the UK (including two replicated site comparisons) found that ditch management had negative or no clear effects on some farmland bird species or plants.  Collected, 17 Nov 2011 21:35:00 +0000Collected Evidence: Collected Evidence: Plant crops in spring rather than autumn A total of nine studies from Denmark, Sweden and the UK looked at the effects of sowing crops in spring or autumn on farmland wildlife. Five studies (including one replicated controlled trial, and a review) found that planting crops in spring rather than autumn resulted in higher numbers of farmland birds, weed diversity or weed density and one arable weed species produced more fruit on spring-sown crops. A review found one study from the UK showing that four out of five species of arable weed produced more fruits on autumn-sown crops. A second review found one study showing that there were more invertebrates in winter wheat than spring wheat. A replicated study from the UK found that winter and spring sown crops were used for different broods by Eurasian skylarks. A replicated site comparison found arthropod abundance was higher in autumn barley in early summer and spring barley in late summer. A replicated, controlled study in Sweden, found that northern lapwings nested on spring-sown crops more than expected based on their availability, but hatching success on spring crops was lower than on autumn crops. Collected, 18 Nov 2011 15:36:26 +0000Collected Evidence: Collected Evidence: Raise mowing height on grasslands to benefit farmland wildlife A replicated controlled study and a review from the UK found that raised mowing heights provided benefits to Eurasian skylark including increased productivity. A review found raised cutting heights were less damaging to amphibians and invertebrates. A randomized, replicated, controlled trial from the UK found that raising mowing height on grasslands had no effect on numbers of foraging birds or invertebrates. One replicated controlled study found no difference in invertebrate abundance. One replicated study from the UK found that northern lapwing and common starling chicks had greater foraging success in shorter grass. Collected, 18 Nov 2011 15:43:43 +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, 14 Jan 2012 13:48:09 +0000Collected Evidence: Collected Evidence: Exclude livestock from semi-natural habitat (including woodland) Seven studies (including four replicated controlled trials of which one also randomized, and a review) from Ireland, Poland and the UK looked at the effects of excluding livestock from semi-natural habitats. Three studies (including one replicated controlled and randomized study) from Ireland and the UK found that excluding livestock benefited plants and invertebrates. Three studies (one replicated controlled and one replicated paired sites comparison) from Ireland and the UK found that excluding grazing did not benefit plants or birds. Two studies (one replicated and controlled, one review) from Poland and the UK found that the impact of excluding grazing as a tool in habitat restoration was neutral or mixed.    Collected, 14 Jan 2012 15:15:55 +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, 14 Jan 2012 15:30:46 +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, 14 Jan 2012 15:38:54 +0000Collected Evidence: Collected Evidence: Provide nest boxes for birds Two studies (including one before and after study) from the Netherlands and the UK found that following the provision of nest boxes there was an increase in the number of Eurasian kestrel clutches and breeding tree sparrows. One replicated study from Switzerland found the number of Eurasian wryneck broods in nest boxes declined over five years whilst the number of Eurasian hoopoe broods increased. Eight studies from Finland, the Netherlands, Sweden, Switzerland and the UK (six were replicated) found that nest boxes in agricultural habitats were occupied by Eurasian kestrel, long-eared owl, common starling, tits Parus spp., tree sparrow, stock dove and jackdaw, and Eurasian wryneck and Eurasian hoopoe. Whilst two studies from the UK (a replicated, paired site study and a controlled study) found that carrion crows did not nest in artificial trees and tree sparrows showed a preference for nest boxes in wetland habitat, compared to those in farmland sites. Two replicated studies from Sweden found that nest success within boxes was related to the amount of pasture available and nest boxes positioned higher above the ground had higher occupancy, numbers of eggs and numbers of hatched young.  Collected, 14 Jan 2012 15:49:39 +0000Collected 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, 11 Sep 2012 15:38:22 +0100Collected 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, 11 Sep 2012 15:57:52 +0100Collected Evidence: Collected Evidence: Create skylark plots All four studies from the UK and Switzerland (two replicated and controlled, and one review) investigating the effect of skylark plots on Eurasian skylarks, found a positive effect, reporting increases in skylark population size, breeding density, duration or success or a lower likelihood of skylarks abandoning their territory relative to fields without plots. A replicated study from Denmark found that skylarks used undrilled patches within cereal fields more than expected by an even distribution across the landscape. Four studies reported the effect of undrilled patches on wildlife other than skylarks. Three studies from the UK (including two replicated studies, of which one also controlled and a review) found benefits to plants and invertebrates. Whilst two studies (both replicated, one also controlled) from the UK found no significant differences in the number of some invertebrates or seed-eating songbirds between skylark plots and conventional crop fields. One replicated study from the UK investigated different skylark plot establishment techniques. Plots that were undrilled had greater vegetation cover and height than plots established by spraying out with herbicide. Collected, 11 Sep 2012 16:08:32 +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, 25 Sep 2012 12:08:33 +0100Collected Evidence: Collected Evidence: Convert or revert arable land to permanent grassland All seven individual studies (including four replicated studies, of which two also controlled and a review) looking at the effects of reverting arable land to grassland found no clear benefit to wildlife. The studies monitored UK birds in winter and summer, wading birds in Denmark, grey partridges, brown hares in the UK, and plants in the Czech Republic. One of the studies, a controlled before-and-after study from the UK, showed that grey partridge numbers fell significantly following the reversion of arable fields to grassland.  Collected, 25 Sep 2012 12:33:31 +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, 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, 04 Oct 2012 11:08:34 +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, 15 Oct 2012 16:28:48 +0100Collected 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, 07 Dec 2012 09:05:54 +0000Collected Evidence: Collected Evidence: Employ areas of semi-natural habitat for rough grazing (includes salt marsh, lowland heath, bog, fen) A series of site comparison studies from the UK found that areas of heathland that had been re-seeded with grass to improve livestock grazing were avoided by nesting whimbrels but were the main early spring feeding areas for them. There was no difference in whimbrel chick survival between areas of heathland re-seeded with grass and those that had not. Two replicated studies from the UK found higher butterfly abundance and species richness and a higher frequency of occurrence of songbirds and invertebrate-feeding birds on areas of grazed semi-natural upland grassland than grazed improved pasture. However members of the crow family showed the opposite trend. A review found excluding cattle from fenland reduced the number of plant species, and that low-medium grazing levels could have positive effects on fenland biodiversity but may need to be accompanied by additional management such as mowing. One study from the UK found northern lapwing nest survival and clutch size were greater on ungrazed than grazed marshes. A replicated site comparison from the UK found the proportion of young grey partridges was negatively associated with rough grazing (in combination with several other interventions). Collected, 07 Dec 2012 15:57:06 +0000Collected Evidence: Collected Evidence: Use mowing techniques to reduce mortality Eight studies investigated the effects of different mowing techniques on wildlife. Seven studies (including four replicated trials of which one randomized, and one controlled and three reviews) from Germany, Ireland, Switzerland and the UK found that using specific mowing techniques can reduce mortality or injury in birds, mammals, amphibians or invertebrates. A review found the UK corncrake population increased around the same period that Corncrake Friendly Mowing schemes were introduced. One replicated trial found that changing the mowing pattern reduced the number of corncrake chicks killed. Sixty-eight percent of chicks escaped mowing when fields were mown from the centre outwards, compared to 45% during conventional mowing from the field edge inwards. Six studies looked at the effects of using different mowing machinery. Two studies (one review, one randomized, replicated trial) found bar mowers and one report found double chop mowers caused less damage or lower mortality among amphibians and/or invertebrates than other types of mowing machinery. A review found evidence that twice as many small mammals were killed by rotary disc mowers with conditioners compared to double blade mowers. Two studies found that using a mechanical processor or conditioner killed or injured more invertebrates than without a conditioner, however one replicated controlled study found mower-conditioners resulted in higher Eurasian skylark nest survival than using a tedder. A review of studies found that skylark chick survival was four times higher when wider mowing machinery was used, whilst a replicated controlled trial found skylark nest survival was highest when swather mowers and forage harvesters were used.    Collected, 09 Dec 2012 10:30:37 +0000Collected Evidence: Collected Evidence: Control predatory mammals and birds (foxes, crows, stoats and weasels) A total of nine individual studies from France and the UK (including five replicated controlled studies and a systematic review) looked at the effects of removing predators on birds. Three studies found controlling predatory mammals or birds (sometimes alongside other interventions) increased the abundance or population size of some birds. One of these studies from the UK found numbers of nationally declining songbirds increased on a site where predators were controlled, but there was no overall difference in bird abundance, species richness or diversity between predator control and no-control sites. Five studies (two replicated and controlled, two before-and-after trials) from the UK found some evidence for increased productivity, nest or reproductive success or survival of birds following bird or mammal predator control (sometimes alongside other interventions). A randomized, replicated, controlled study found hen harrier breeding success was no different between areas with and without hooded crow removal. A global systematic review including evidence from European farmland found that reproductive success of birds increased with predator removal.  Collected, 20 Dec 2012 13:08:22 +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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