Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Restore heathlandOne small trial of early-stage lowland heath restoration activity did not have an adverse effect on bumblebee diversity at one site in southeast England. Two replicated trials in Dorset indicated that long-term restoration of dry lowland heath can restore a bee community similar to that on ancient heaths. One of these studies showed that the community of conopid flies parasitizing bumblebees remained impoverished 15 years after heathland restoration began. We found no evidence on interventions to conserve bees on upland heath or moorland. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F9https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F9Thu, 20 May 2010 03:20:44 +0100Collected Evidence: Collected Evidence: Restore species-rich grassland vegetationOne replicated controlled trial in Scotland showed that species-rich grassland managed under agri-environment schemes attracted more nest-searching queen bumblebees but fewer foraging queens in the spring than unmanaged grassland. Three small trials, two in the UK and one in Germany, found that restored species-rich grasslands had similar flower-visiting insect communities (dominated by bees and/or flies) to paired ancient species-rich grasslands. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F8https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F8Thu, 20 May 2010 07:08:34 +0100Collected Evidence: Collected Evidence: Sow uncropped arable field margins with a native wild flower seed mixFive replicated trials in the UK showed that uncropped field margins sown with wild flowers and subsequently mown support a higher abundance (and in three trials higher species richness) of foraging bumblebees than cropped field edges (all five trials), grassy margins (four trials) or naturally regenerated uncropped margins (three trials). One small trial recorded the same number of bee species on wildflower sown and naturally regenerated strips. Two trials demonstrated that perennial leguminous herbs in the seed mixtures are important forage sources for bumblebees, particularly for long-tongued species. One small replicated trial showed that common long-tongued bumblebee species (Bombus pascuorum and B. hortorum) strongly preferred plots of perennial wildflower seed mix over a mix of annual forage plants. We have captured no evidence on the effects of field margin management on solitary bees. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F19https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F19Thu, 20 May 2010 07:11:24 +0100Collected Evidence: Collected Evidence: Increase the use of clover leys on farmlandWe have captured no evidence that increasing the use of clover leys can enhance wild bee populations. One replicated trial in Germany showed that fields planted with a white clover grass mixture do not attract solitary bees to nest preferentially on site. A trial in Switzerland showed that if white clover is mowed during flowering, injuries and mortality of bees can be reduced by avoiding the use of a processor attached to the mower. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F16https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F16Thu, 20 May 2010 08:48:02 +0100Collected Evidence: Collected Evidence: Provide grass strips at field margins for beesThree replicated controlled trials in the UK have monitored wild bees on uncropped grassy field margins. Evidence of the effects on bees is mixed. One trial showed that 6 m wide grassy field margins enhanced the abundance, but not diversity, of wild bees at the field boundary. One trial showed that 6 m wide grassy field margins enhanced the abundance and diversity of bumblebees within the margin. A third, smaller scale trial showed neither abundance nor diversity of bumblebees was higher on sown grassy margins than on cropped margins. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F14https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F14Thu, 20 May 2010 10:42:47 +0100Collected Evidence: Collected Evidence: Reduce grazing intensity on pasturesOne replicated trial has shown that reducing the intensity of summer cattle grazing can increase the abundance, but not the species richness of cavity-nesting bees and wasps. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F23https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F23Thu, 20 May 2010 12:44:56 +0100Collected Evidence: Collected Evidence: Connect areas of natural or semi-natural habitat for bees We found no evidence of the effects on wild bee communities of connecting patches of natural or semi-natural habitat. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F10https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F10Thu, 20 May 2010 14:39:05 +0100Collected Evidence: Collected Evidence: Increase the proportion of natural or semi-natural habitat in the farmed landscape We found no evidence demonstrating the effects of restoring natural or semi-natural habitat on bee diversity or abundance in neighbouring farms. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F6https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F6Thu, 20 May 2010 15:31:52 +0100Collected Evidence: Collected Evidence: Introduce agri-environment schemes to benefit wild beesFour replicated trials in Europe have shown enhanced diversity and/or abundance of foraging wild bees on land managed under various European agri-environment schemes, relative to conventionally-managed fields or field margins. These schemes were the Swiss Ecological Compensation Areas (one replicated trial), the German organic arable farming option (one replicated trial), the Dutch botanical and meadow bird agreements (one replicated trial, very low numbers of bee species) and the Scottish Rural Stewardship Scheme (one replicated trial, also included nest-searching queen bumblebees). Four replicated trials in Europe found that the number of bees and/or bee species is not enhanced on land managed under agri-environment schemes, including meadow bird agreements in wet grassland in the Netherlands, measures to protect steppe-living birds and compensation measures around a National Park in Spain, and 6 m wide grass field margin strips in England (one replicated trial for each). On a wider landscape scale, two replicated trials in the UK have found bumblebee populations were not enhanced on farmland managed under agri-environment schemes. One trial compared the reproductive success of colonies of the buff-tailed bumblebee Bombus terrestris, the other compared queen bumblebee numbers in spring in conventionally managed field margins, on farms with and without agri-environment schemes. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F24https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F24Thu, 20 May 2010 16:11:07 +0100Collected Evidence: Collected Evidence: Leave arable field margins uncropped with natural regenerationFour replicated trials in the UK have found more bumblebees (and more bee species in two trials) foraging on uncropped field margins than on cropped margins. One small unreplicated trial found similar bee species richness on a naturally regenerated margin as on margins sown with wildflowers. A small replicated trial found that neither abundance nor diversity of bumblebees were higher on naturally regenerated margins than on cropped margins. Two trials note that the value of naturally regenerated uncropped field margins is based on thistle species considered to be pernicious weeds requiring control. Two trials found that the value of naturally regenerated uncropped field margins for bees was not consistent from year to year. We have captured no evidence on the effects of field margin management on solitary bees. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F20https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F20Thu, 20 May 2010 16:57:57 +0100Collected Evidence: Collected Evidence: Increase the diversity of nectar and pollen plants in the landscape for beesOne large replicated controlled trial showed that the average abundance of long-tongued bumblebees on field margins was positively correlated with the number of pollen and nectar agri-environment agreements in a 10 km grid square. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F21https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F21Thu, 20 May 2010 18:33:50 +0100Collected Evidence: Collected Evidence: Increase areas of rough grassland for bumblebee nestingOne replicated controlled trial on lowland farms in Scotland showed that grassy field margins attracted nest-searching queen bumblebees in spring at higher densities than cropped field margins, managed or unmanaged grasslands or hedgerows. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F12https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F12Thu, 20 May 2010 18:37:48 +0100Collected Evidence: Collected Evidence: Reduce the intensity of farmland meadow managementFour replicated trials in Europe have compared farmland meadows managed extensively with conventionally farmed meadows or silage fields. Two found enhanced numbers and diversity of wild bees on meadows with a delayed first cut and little agrochemical use. Two found no difference in bee diversity or abundance between conventional meadows and meadows with reduced fertilizer use or cutting intensity. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F22https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F22Thu, 20 May 2010 19:27:37 +0100Collected Evidence: Collected Evidence: Create patches of bare ground for ground-nesting beesOne replicated controlled trial in Germany and four small trials (three replicated, one not) have shown that artificially exposed areas of bare soil can be successfully colonised by ground-nesting solitary bees and wasps in the first or second year. We have captured no evidence for the effect of creating areas of bare ground on bee populations or communities on a larger scale. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F13https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F13Thu, 20 May 2010 19:29:53 +0100Collected Evidence: Collected Evidence: Reduce tillageEvidence on whether reduced tillage or no tillage benefits ground-nesting bees is mixed. Two replicated trials on squash Cucurbita spp. farms in the USA had contrasting results. One showed no difference in the abundance of bees between tilled and untilled farms, the other found three times more squash bees Peponapis pruinosa on no-till farms than on conventional farms. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F11https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F11Thu, 20 May 2010 19:41:46 +0100Collected Evidence: Collected Evidence: Protect existing natural or semi-natural habitat to prevent conversion to agriculture We have captured no evidence for the effects of protecting areas of natural or semi-natural habitat on bee populations or communities. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F5https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F5Thu, 20 May 2010 19:58:47 +0100Collected Evidence: Collected Evidence: Plant dedicated floral resources on farmlandFourteen trials in Europe and North America have recorded substantial numbers of wild bees foraging on perennial or annual sown flowering plants in the agricultural environment. Ten trials (eight replicated) have monitored bees foraging on patches sown with a high proportion of phacelia Phacelia tanacetifolia on farmland and all but one found substantial numbers of foraging wild (non-Apis) bees, particularly bumblebees Bombus spp. Six of these trials recorded the number of foraging bee species, which ranged from eight to 35. One replicated trial shows that phacelia is not very attractive to wild bees in Greece. One replicated controlled trial in the UK showed that planted perennial leguminous herbs, including clovers, were more attractive to bumblebees in landscapes with a greater proportion of arable farming. Four replicated trials have quantified the wider response of wild bee populations to planted flower patches by measuring reproductive success, numbers of nesting bees or numbers foraging in the surrounding landscape. One trial showed that planted patches of bigleaf lupine Lupinus polyphyllus in commercial apple orchards in Novia Scotia, Canada, significantly enhanced the reproductive success of blue orchard mason bees Osmia lignaria. One trial in the Netherlands showed that bee numbers and species richness are not higher in farmland 50-1,500 m away from planted flower patches. Two trials in Germany found no or relatively few species of solitary bee nesting on set-aside fields sown with phacelia or clover respectively. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F17https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F17Thu, 20 May 2010 20:02:31 +0100Collected Evidence: Collected Evidence: Sow uncropped arable field margins with an agricultural nectar and pollen mixFive replicated trials in Europe (three controlled) have documented bumblebees foraging on field margins sown with an agricultural nectar and pollen seed mix. Four replicated trials showed that field margins sown with perennial leguminous flowering plants attract significantly more foraging bumblebees than naturally regenerated (two trials), grassy (four trials) or cropped (three trials) field margins. Three replicated trials showed that a mix of agricultural forage plants including legumes (all annual plants in one trial) attracts greater numbers of bumblebees than a perennial wildflower mix, at least in the first year. Three trials in the UK found evidence that margins sown with agricultural legume plants degrade in their value to bumblebees and would need to be re-sown every few years. We have captured no evidence on the effects of field margin management on solitary bees. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F18https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F18Thu, 20 May 2010 20:59:45 +0100Collected Evidence: Collected Evidence: Manage hedges to benefit beesOne replicated controlled trial showed that hedges managed under the Scottish Rural Stewardship scheme do not attract more nest-searching or foraging queen bumblebees in spring than conventionally managed hedgerows. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F15https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F15Thu, 20 May 2010 21:16:02 +0100Collected Evidence: Collected Evidence: Provide set-aside areas in farmland Two replicated trials showed that species richness of bees nesting (one study) or foraging (one study), is higher on set-aside that is annually mown and left to naturally regenerate for two years or more, relative to other set-aside management regimes or, in the nesting study, to arable crop fields. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F7https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F7Thu, 20 May 2010 21:22:12 +0100