Collected Evidence: Collected Evidence: Plant wild bird seed or cover mixture All seven studies (based on five replicated experiments and a review) that investigated species richness or diversity were from the UK and found that fields or farms with wild bird cover had higher bird diversity than those without, or that more species were found in wild bird cover than in surrounding habitats. Thirty-two studies out of 33 from the UK and North America that examined abundance and population data, found that bird densities, abundances, nesting densities or use of wild bird cover was higher than in other habitats or management regimes, or that sites with wild bird cover had higher populations than those without. These studies included a systematic review and seven randomised, replicated and controlled studies. Some studies found that this was the case across all species or all species studied, while others found that only a subset showed a preference. Four studies investigated other interventions at the same time. Thirteen of the 33 studies (all replicated and from Europe and the USA), found that bird populations or densities were similar on wild bird cover and other habitats, that some species were not associated with wild bird cover or that birds rarely used wild bird cover. Three studies from the UK and Canada, two replicated, found higher productivities for some or all species monitored on wild bird cover, compared to other habitats. Two replicated and controlled studies from Canada and France found no differences in reproductive success between wild bird cover and other habitats for some or all species studied. Three studies from Europe and the USA investigated survival, with two finding higher survival of grey partridge Perdix perdix released on wild bird cover or of artificial nests in some cover crops. The third found that survival of grey partridge was lower on farms with wild bird cover, possibly due to high predation. Five studies from the UK, three replicated, found that some wild bird cover crops were preferred to others. A randomised, replicated and controlled study and a review from the UK found that the landscape surrounding wild bird cover and their configuration within it affected use by birds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F187https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F187Sun, 10 Jun 2012 13:10:33 +0100Collected Evidence: Collected Evidence: Plant trees to act as windbreaks One of two before-and-after studies, from the UK, found that the local population of European nightjars increased following several interventions including the planting of windbreaks. A before-and-after study, from the USA, found that erecting a windbreak appeared to disrupt lekking behaviour in greater prairie chicken territories nearby.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F351https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F351Sun, 29 Jul 2012 15:42:39 +0100Collected Evidence: Collected Evidence: Plough habitats One of four studies (of two experiments), from the USA, found that bird densities were higher on ploughed wetland areas, compared to unploughed areas. Three studies of a site comparison study from the UK found that few whimbrels nested on ploughed and re-seeded areas of heathland, but these areas were used for foraging in early spring. There were no differences in chick survival between birds that used ploughed and re-seeded heathland and those that did not.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F358https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F358Sun, 29 Jul 2012 17:05:56 +0100Collected Evidence: Collected Evidence: Play spoken-word radio programmes to deter predators We found no published evidence for the effects of playing the radio on predation rates. '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%2Fwww.conservationevidence.com%2Factions%2F414https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F414Thu, 16 Aug 2012 15:20:00 +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: Pollard trees (top cutting or top pruning) We captured no evidence for the effects of tree pollarding on forests. '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%2Fwww.conservationevidence.com%2Factions%2F1189https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1189Thu, 19 May 2016 11:49:12 +0100Collected Evidence: Collected Evidence: Pollination: Plant or maintain ground cover in orchards or vineyardsPollination (0 studies) Crop visitation (0 studies) Pollinator numbers (0 studies) Implementation options (1 study): One replicated site comparison from Greece found more bee species and more deposited pollen grains in managed olive orchards, compared to abandoned olive orchards, which differed in ground cover.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1404https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1404Fri, 19 May 2017 09:24:59 +0100Collected Evidence: Collected Evidence: Pollination: Plant flowersPollination (0 studies) Crop visitation (1 study): One replicated, controlled study from Spain found more pollinators on coriander flowers next to planted flower strips, compared to coriander flowers next to unplanted field margins. Pollinator numbers (1 study): One replicated, controlled study from the USA found more wild bee species and individuals in planted flower strips, compared to unplanted strips, in some comparisons, but found no differences for syrphid flies. Implementation options (8 studies): Five replicated studies from Spain and the USA found that some planted flower species were more attractive to pollinators than others. Four replicated studies from Italy and Spain found more pollinators where more flower species had been planted, in some comparisons, but in other comparisons found fewer pollinators where more flower species had been planted. One replicated, controlled study from Italy found that bee numbers increased over time in areas planted with three or six flower species, but decreased over time in areas planted with nine flower species.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1406https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1406Fri, 19 May 2017 09:31:02 +0100Collected Evidence: Collected Evidence: Pollination: Plant hedgerowsPollination (1 study): One replicated, paired site comparison from the USA found higher seed-set in canola plants due to flower visitation by native bees in fields next to planted hedgerows, compared to fields next to unplanted edges. However, this study found no difference in seed-set due to flower visitation by honey bees or syrphid flies. Crop visitation (2 studies): One replicated, paired, site comparison from the USA found higher crop visitation rates by native bees, but not by honey bees or syrphid flies, in fields next to planted hedgerows, compared to fields next to unplanted edges. Another replicated, paired, site comparison from the USA found no difference in flower visitation rates by bees in fields next to planted edges. Pollinator numbers (6 studies): Five replicated studies from the USA found more bee species in fields with hedgerows, or in hedgerows themselves, compared to fields or field edges without hedgerows. Three of these studies found more syrphid fly species in hedgerows, compared to field edges without hedgerows. One of these studies found similar numbers of syrphid fly species in fields with or without hedgerows. Two of these studies found more native bee and hoverfly individuals or more specialist bees in hedgerows, compared to field edges without hedgerows. One replicated site comparison from the USA found fewer ground-nesting bees, but similar numbers of bee species and flower-visiting bees, in planted hedgerows, compared to unplanted edges. Implementation options (3 studies): Two replicated site comparisons from the USA found more bee species in old hedgerows, compared to young hedgerows, and one of these studies also found more syrphid fly species. One replicated site comparison from the USA found more bee species on native plants, compared to non-native plants, in old hedgerows, but not in young hedgerows.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1407https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1407Fri, 19 May 2017 09:34:29 +0100Collected Evidence: Collected Evidence: Pollination: Restore habitat along watercoursesPollination (0 studies) Flower visitation (1 study): One replicated, paired site comparison from the USA found that bee visitation rates to native flowers did not differ between restored and remnant sites, but there were different plant-insect interactions. Pollinator numbers (1 study): One replicated, paired site comparison from the USA found similar numbers of bees and bee species, but different bee communities, in restored and remnant sites. Implementation options (0 studies)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1408https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1408Fri, 19 May 2017 09:36:25 +0100Collected Evidence: Collected Evidence: Plant vegetation to act as a buffer to exclude pollution We found no studies that evaluated the effects of planting vegetation to act as a buffer to exclude pollution on shrublands. 'We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2Fwww.conservationevidence.com%2Factions%2F1665https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1665Sun, 22 Oct 2017 15:11:46 +0100Collected Evidence: Collected Evidence: Plant turf Two randomized, controlled studies in the UK found that planting turf from intact heathland sites increased the abundance or cover of heathland species. One of these studies also found that planting turf increased the seedling abundance for a majority of heathland plant species. One randomized, controlled study in the UK found that planting turf increased forb cover, and reduced grass cover. One randomized, replicated, controlled study in Iceland found that planting large turves from intact heathland sites increased the number of plant species, but smaller turves did not. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1703https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1703Mon, 23 Oct 2017 11:28:15 +0100Collected Evidence: Collected Evidence: Plant/sow seeds of nurse plants alongside focal plants A randomized, replicated, controlled study in the UK found that sowing seeds of nurse plants and heathland plants did not increase the cover of common heather. One replicated, randomized, controlled study in the USA found that sowing seeds of nurse plants and California sagebrush seeds together reduced survival of shrubs in more than half of cases. The same study found that California sagebrush biomass was also reduced when its seeds were sown with those of nurse plants. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1713https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1713Mon, 23 Oct 2017 13:44:40 +0100Collected Evidence: Collected Evidence: Plant/seed under established vegetation A replicated, randomized, controlled study in the USA found that sowing seed under established shrubs had mixed effects on blackbrush seedling emergence. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1714https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1714Mon, 23 Oct 2017 13:53:01 +0100Collected Evidence: Collected Evidence: Play predator calls to deter crop damage by mammals to reduce human-wildlife conflict We found no studies that evaluated the effects on mammals of playing predator calls to deter crop damage to reduce human-wildlife conflict. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this intervention during our systematic journal and report searches. Therefore, we have no evidence to indicate whether or not the intervention has any desirable or harmful effects.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2487https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2487Thu, 04 Jun 2020 13:12:20 +0100Collected Evidence: Collected Evidence: Play predator calls to deter mammals from fishing gear One study evaluated the effects of playing predator calls to deter mammals from fishing gear. The study was in the South Atlantic Ocean (Africa). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (1 STUDY) Human-wildlife conflict (1 study): One study in the South Atlantic Ocean found that playing killer whale vocalisations did not deter Cape fur seals from feeding on fish catches in a purse-seine net or trawl net. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2817https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2817Fri, 05 Feb 2021 15:08:39 +0000Collected Evidence: Collected Evidence: Plug/dam canals or trenches: freshwater marshes One study evaluated the effects, on vegetation, of plugging/damming canals or trenches in freshwater marshes. The study was in the USA. VEGETATION COMMUNITY Overall extent (1 study): One replicated, site comparison study of backfilled canals in freshwater marshes in the USA reported that emergent marsh vegetation coverage was greater within the channels of plugged than unplugged canals, after 6–60 months. However, coverage on former spoil areas did not significantly differ between plugged and unplugged canals. VEGETATION ABUNDANCE   VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2991https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2991Mon, 29 Mar 2021 12:08:23 +0100Collected Evidence: Collected Evidence: Plug/dam canals or trenches: brackish/salt marshes Two studies evaluated the effects, on vegetation, of plugging/damming canals or trenches in brackish/salt marshes. Both studies were in the USA. There was overlap in the canals used in the studies. Both studies included some freshwater areas in some analyses, but all results are based predominantly on canals in brackish or saline marshes. VEGETATION COMMUNITY   VEGETATION ABUNDANCE Overall abundance (2 studies): Two replicated, site comparison studies studied emergent vegetation of backfilled canals in the USA. One study reported that plugged canals had greater coverage of emergent marsh vegetation than unplugged canals after 6–60 months. One study found that emergent vegetation coverage on former spoil heaps did not significantly differ alongside plugged and unplugged canals after 6–11 years. The first study also reported that plugged canals were more likely to contain floating/submerged vegetation than unplugged canals. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2992https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2992Mon, 29 Mar 2021 12:08:35 +0100Collected Evidence: Collected Evidence: Plug/dam canals or trenches: freshwater swampsWe found no studies that evaluated the effects, on vegetation, of plugging/damming canals or trenches in freshwater swamps.   ‘We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2Fwww.conservationevidence.com%2Factions%2F2993https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2993Mon, 29 Mar 2021 12:08:51 +0100Collected Evidence: Collected Evidence: Plug/dam canals or trenches: brackish/saline swampsWe found no studies that evaluated the effects, on vegetation, of plugging/damming canals or trenches in brackish/saline swamps.   ‘We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2Fwww.conservationevidence.com%2Factions%2F2994https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2994Mon, 29 Mar 2021 12:09:11 +0100Collected Evidence: Collected Evidence: Plant trees/shrubs into moisture-retaining peat pots: freshwater wetlandsWe found no studies that evaluated the effects of using moisture-retaining peat pots when planting trees/shrubs in freshwater wetlands.   ‘We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2Fwww.conservationevidence.com%2Factions%2F3343https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3343Sun, 11 Apr 2021 16:46:17 +0100Collected Evidence: Collected Evidence: Plant trees/shrubs into moisture-retaining peat pots: brackish/saline wetlandsWe found no studies that evaluated the effects of using moisture-retaining peat pots when planting trees/shrubs in brackish/saline wetlands.   ‘We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2Fwww.conservationevidence.com%2Factions%2F3344https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3344Sun, 11 Apr 2021 16:46:35 +0100Collected Evidence: Collected Evidence: Plant vegetation into heavy containersWe found no studies that evaluated the effects of planting emergent wetland vegetation into heavy containers.   ‘We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2Fwww.conservationevidence.com%2Factions%2F3345https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3345Sun, 11 Apr 2021 16:55:25 +0100Collected Evidence: Collected Evidence: Plant trees to reduce temperatures in cities We found no studies that evaluated the effects of planting trees to reduce temperatures in cities on butterflies and moths. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated 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%2Fwww.conservationevidence.com%2Factions%2F3838https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3838Mon, 04 Jul 2022 15:35:33 +0100Collected Evidence: Collected Evidence: Plant wild bird seed or cover mixture Seven studies evaluated the effects of planting wild bird seed or cover mixture on butterflies and moths. All seven were in the UK. COMMUNITY RESPONSE (4 STUDIES) Richness/diversity (4 studies): Two of three replicated, controlled studies (including two randomized and one paired study) in the UK found that plots sown with wild bird seed mixture had a greater species richness of butterflies than wheat crop or extensively or conventionally managed grassland. The other study found that land managed under an agri-environment scheme, including wild bird seed plots, had a similar species richness of butterflies to conventional farmland. One replicated, randomized, controlled study in the UK found that plots sown with lucerne had a greater species richness of butterflies than plots sown with borage, chicory, sainfoin and fodder radish. POPULATION RESPONSE (7 STUDIES) Abundance (7 studies): Two replicated, controlled studies (including one randomized study) in the UK­ found that plots sown with wild bird seed had a higher abundance of butterflies than wheat crop or extensively or conventionally managed grassland, but that caterpillar abundance was lower in wild bird seed plots than either grassland. Two replicated, site comparison studies in the UK found that the abundance of butterfly and moth caterpillars in wild bird seed plots was similar to a range of other cropped and non-cropped farm habitats. Two replicated, randomized, controlled studies (including one paired study) in the UK found that farms with wild bird seed plots (along with other agri-environment scheme options) had a higher abundance of some butterflies and micro-moths, a similar abundance of macro-moths, but a lower abundance of other butterflies, than farms without agri-environment scheme management. One replicated, randomized, controlled study in the UK found that plots sown with lucerne and red clover had a higher abundance of butterflies than plots sown with borage, chicory and sainfoin. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3930https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3930Thu, 11 Aug 2022 19:22:03 +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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