Collected Evidence: Collected Evidence: Plant parks and gardens with appropriate flowersTwo replicated trials in the USA and Canada have found more wild bees (either more species or more individuals) in gardens planted with bee forage or native plants, relative to conventionally managed gardens. Another USA trial found more bee species after the addition of bee forage plants to a community garden. Three trials in the UK or USA have shown that native flowering plants or bee forage plants are well used by wild bees when planted in gardens. A UK trial demonstrated that some popular non-native or horticulturally modified garden flowers are not frequently visited by insects, despite providing nectar in some cases.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1Tue, 18 May 2010 15:19:40 +0100Collected Evidence: Collected Evidence: Plant nettle strips A small study from Belgium found that planting nettle strips in the margins of three arable fields resulted in a higher number of aphid predator species. The number of aphid predators on a natural patch of nettles was higher than on crops, however there were fewer predators on nettle strips than on crops. Three insect families, including green lacewings, were only found on nettles.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F118https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F118Tue, 01 Nov 2011 20:40:45 +0000Collected Evidence: Collected Evidence: Plant new hedgesA small study from the USA found that the population of northern bobwhites increased following several interventions including the planting of new hedges.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F178https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F178Wed, 30 May 2012 14:09:27 +0100Collected Evidence: Collected Evidence: Plant nettle strips We found no evidence for the effects of planting nettle strips on bird populations. '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%2F205https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F205Sun, 15 Jul 2012 17:08:57 +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: Plant new hedgesFive studies in Slovakia, Kenya and Thailand measured the effects of planting grass or shrub hedgerows on soil animals and soil fertility. All five found hedgerows to maintain or improve soil fertility and soil animal activity. Of these, three replicated studies found reduced soil erosion and higher soil organic matter levels. Another replicated trial found a higher diversity of soil animals near to the hedgerows. One of the replicated studies and one review found that adding woody species to the hedgerows improved many factors contributing to soil fertility. SOIL TYPES COVERED: Alluvial, clay, sandy-loam.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F744https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F744Tue, 04 Jun 2013 16:25:36 +0100Collected Evidence: Collected Evidence: Plant new hedgesNatural enemies: One randomised, replicated, controlled study from China compared plots with and without hedges and found no effect on spiders in crops. One of two studies from France and China found more natural enemies in a hedge than in adjacent crops while one study found this effect varied between crop types, hedge species and years. Two randomised, replicated, controlled studies from France and Kenya found natural enemy abundance in hedges was affected by the type of hedge shrub/tree planted and one also found this effect varied between natural enemy groups. Pests: One randomised, replicated, controlled study from Kenya compared fallow plots with and without hedges and found effects varied between nematode (roundworm) groups. Crops studied were barley, beans, maize and wheat.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F752https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F752Thu, 01 Aug 2013 09:28:37 +0100Collected Evidence: Collected Evidence: Plant new hedges We found no evidence for the effects of planting hedges on amphibian populations. '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%2F791https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F791Thu, 22 Aug 2013 14:34:21 +0100Collected Evidence: Collected Evidence: Plant riparian buffer strips One replicated, controlled study in the USA found that planting buffer strips along streams did not increase amphibian abundance, numbers of species, or the ratio of adults to tadpoles.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F819https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F819Fri, 23 Aug 2013 09:57:29 +0100Collected Evidence: Collected Evidence: Plant trees after wildfire We found no evidence for the effects of planting trees after wildfire 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%2F1235https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1235Fri, 03 Jun 2016 08:29:53 +0100Collected Evidence: Collected Evidence: Plant spiny shrubs to act as barriers to people We found no studies that evaluated the effects of planting spiny shrubs to act as barriers to people 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%2F1621https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1621Sun, 22 Oct 2017 10:37:20 +0100Collected Evidence: Collected Evidence: Plant seed balls A randomized, replicated, controlled study in the USA found that planting seed balls resulted in lower seedling numbers than sowing seed. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1712https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1712Mon, 23 Oct 2017 13:30:52 +0100Collected Evidence: Collected Evidence: Plant shrubs in clusters A randomized, controlled study in South Africa found that when shrubs were planted in clumps more of them died than when they were planted alone. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1715https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1715Mon, 23 Oct 2017 13:57:53 +0100Collected Evidence: Collected Evidence: Plant shelter belts to protect peatlands from wind We found no studies that evaluated the effects, on peatland vegetation, of planting shelter belts to protect peatlands from wind. ‘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%2F1793https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1793Tue, 28 Nov 2017 08:19:25 +0000Collected Evidence: Collected Evidence: Plant new hedges We found no studies that evaluated the effects of planting new hedges on bat populations. ‘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%2F1942https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1942Tue, 04 Dec 2018 09:51:33 +0000Collected Evidence: Collected Evidence: Plant riparian buffer strips We found no studies that evaluated the effects of planting riparian buffer strips on bat populations. ‘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%2F2016https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2016Wed, 05 Dec 2018 17:43:25 +0000Collected Evidence: Collected Evidence: Plant new or maintain existing hedgerows on farmland Three studies evaluated the effects on mammals of planting new or maintaining existing hedgerows on farmland. Two studies were in the UK and one was in Switzerland. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Abundance (3 studies): One of two replicated, site comparison studies, in the UK and Switzerland, found that retaining and enhancing hedgerows along with other field boundary features was associated with higher brown hare density in arable sites but not in grassland sites while the other study found that Irish hare numbers did not increase. A replicated, site comparison study in the UK found that establishing hedgerows alongside arable land increased small mammal abundance. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2383https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2383Wed, 27 May 2020 14:36:44 +0100Collected Evidence: Collected Evidence: Plant trees on farmland Four studies evaluated the effects on mammals of planting trees on farmland. Two studies were in the UK, one was in Italy and one was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): Two replicated studies (including one controlled, and one site comparison study), in the UK, found that farm woodland supported a higher small mammal abundance than on arable land or similar abundance compared to uncultivated field margins and set-aside. BEHAVIOUR (2 STUDIES) Use (2 studies): A study in Italy found that tree stands were used more by European hares compared to the wider farmed landscape. A replicated study in Australia found that trees planted on farmland were used by koalas. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2386https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2386Wed, 27 May 2020 15:47:33 +0100Collected Evidence: Collected Evidence: Plant trees following clearfelling One study evaluated the effects on mammals of planting trees following clearfelling. This study was in Canada. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (1 STUDY) Use (1 study): A replicated, site comparison study in Canada found that forest stands subject to tree planting and herbicide treatment after logging were used more by American martens compared to naturally regenerating stands. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2631https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2631Fri, 12 Jun 2020 12:45:40 +0100Collected Evidence: Collected Evidence: Plant non-woody plants into moisture-retaining peat pots: freshwater wetlands One study evaluated the effects of using moisture-retaining peat pots when planting emergent, non-woody vegetation in freshwater wetlands. The study was in the USA. VEGETATION COMMUNITY   VEGETATION ABUNDANCE Individual species abundance (1 study): One replicated, randomized, paired, controlled study in a wetland in the USA found that tussock sedge Carex stricta cover was similar across plots, after two growing seasons, whether sedges were planted into peat pots or into existing wetland soil. VEGETATION STRUCTURE Individual plant size (1 study): One replicated, randomized, paired, controlled study in a wetland in the USA found that the biomass of tussock sedge Carex stricta plants was similar, after two growing seasons, whether they were planted into peat pots or into existing wetland soil. OTHER Survival (1 study): One replicated, randomized, paired, controlled study in a wetland in the USA found that the survival rate of tussock sedge Carex stricta plants was similar, after two growing seasons, whether they were planted into peat pots or into existing wetland soil. Growth (1 study): The same study found that the growth rate of tussock sedge Carex stricta was typically similar, over two growing seasons, when planted into peat pots or into existing wetland soil. However, in a dry area and in a dry year, planting in peat pots did increase the growth rate. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3341https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3341Sun, 11 Apr 2021 16:45:47 +0100Collected Evidence: Collected Evidence: Plant non-woody plants into moisture-retaining peat pots: brackish/saline wetlandsWe found no studies that evaluated the effects of using moisture-retaining peat pots when planting emergent, non-woody vegetation 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%2F3342https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3342Sun, 11 Apr 2021 16:46:08 +0100Collected Evidence: Collected Evidence: Plant trees on farmland Two studies evaluated the effects of planting trees on farmland to benefit reptiles. Both studies were in Australia. COMMUNITY RESPONSE (2 STUDIES) Richness/diversity (2 studies): One replicated, paired sites study in Australia found that pastures with tree plantings had similar rare reptile species richness compared to pastures with no trees, but that more rare species were present with 50% canopy cover compared to 5% cover. One replicated, site comparison study in Australia found that farms with restoration planting (of native ground cover and trees) had lower reptile species richness than farms with remnant vegetation (of old growth woodland or natural regrowth). POPULATION RESPONSE (1 STUDY) Abundance (1 study): One replicated, paired sites study in Australia found that pastures with tree plantings had higher abundance of rare reptiles than pastures with no trees, and that rare reptiles were more abundant with 50% canopy cover compared to 5% cover. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3527https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3527Tue, 07 Dec 2021 15:32:49 +0000Collected Evidence: Collected Evidence: Plant riparian buffer strips One study evaluated the effects of planting riparian buffer strips on reptile populations. The study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (1 STUDY) Use (1 study): One replicated study in the USA found that grassed riparian buffer strips were used by up to five snake species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3586https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3586Wed, 08 Dec 2021 15:46:10 +0000Collected Evidence: Collected Evidence: Plant parks, gardens and road verges with appropriate native species Eight studies evaluated the effects on butterflies and moths of planting parks and gardens with appropriate native species. Seven were in the USA and one was in Germany. COMMUNITY RESPONSE (5 STUDIES) Richness/diversity (5 studies): Three of five replicated studies (including three paired, three controlled and two site comparison studies) in Germany and the USA found that gardens and road verges planted with native species had a greater species richness of butterfly and moth adults and caterpillars than gardens or verges with mixed or exclusively non-native plant species. The other two studies found that the species richness of adult butterflies was similar in areas planted with native or non-native flowers. POPULATION RESPONSE (6 STUDIES) Abundance (4 studies): Two of three replicated studies (including two paired and two controlled studies) in the USA found that gardens planted with native species had a higher abundance of butterfly and moth caterpillars than gardens with mixed or exclusively non-native plant species. The third study found that the abundance of adult butterflies was similar in areas planted with native or non-native flowers. One replicated, randomized, controlled study in the USA found that when taller native milkweed species were planted, they had a higher abundance of monarch butterfly eggs and caterpillars than shorter milkweed species. Survival (2 studies): One of two replicated, site comparison studies in the USA found that the survival of pipevine swallowtail eggs and caterpillars was lower on California pipevine planted in gardens than in natural sites. The other study found that the survival of monarch butterfly caterpillars was similar on common milkweed planted in gardens and meadows. Condition (1 study): One replicated, randomized, controlled study in the USA found that the growth of monarch butterfly caterpillars was similar on eight different native milkweed species. BEHAVIOUR (2 STUDIES) Use (2 studies): One of two replicated, site comparison studies in the USA found that monarch butterfly adults used common milkweed planted in gardens more than milkweed planted in meadows. The other study found that pipevine swallowtail adults used California pipevine planted in gardens less than in natural sites. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3842https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3842Tue, 05 Jul 2022 09:53:23 +0100Collected Evidence: Collected Evidence: Plant new hedges Seven studies evaluated the effects of planting new hedges on butterflies and moths. Five studies were in the UK and one was in each of Ireland and Canada. COMMUNITY RESPONSE (5 STUDIES) Richness/diversity (5 studies): Three of four site comparison studies (including three replicated and three paired studies) in the UK, Ireland and Canada found that established hedgerows had a higher species richness of butterflies and macro-moths than in-field beetle banks, crops or pasture. The other study found that hedgerows had a similar species richness of butterflies to grass banks between fields. One replicated study in the UK found that gorse, oak and blackthorn planted within hedgerows had more species of arthropods, including caterpillars, than more commonly planted hawthorn. POPULATION RESPONSE (6 STUDIES) Abundance (6 studies): Five of six studies (including one replicated, controlled study, three paired, site comparison studies and two site comparison studies) in the UK, Ireland and Canada found that the abundance of butterflies, moths, macro-moths and gatekeepers was higher along hedgerows than on beetle banks, grass margins without hedgerows, in field interiors, or 5–10 metres away from hedgerows.The other study found that the abundance of butterflies along hedgerows was similar to grass banks between fields without hedgerows. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One site comparison study in the UK found that moths recorded close to hedgerows were more likely to be flying parallel to it than moths recorded further away. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3976https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3976Thu, 18 Aug 2022 10:00:38 +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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