Collected Evidence: Collected Evidence: Add lime to water bodies to reduce acidification One before-and-after study in the UK found that adding limestone to ponds resulted in establishment of one of three translocated populations of natterjack toads. One replicated, site comparison study in the UK found that species-specific habitat management that included adding limestone to ponds increased natterjack toad populations. One before-and-after study in the UK found that adding limestone to ponds temporarily increased breeding by natterjack toads. Three before-and-after studies (including one controlled, replicated study) in the Netherlands and UK found that adding limestone increased larval and/or egg survival of moor frogs and common frogs and resulted in metamorphosis of natterjack toads at two of three sites. Two before-and-after studies (including one controlled study) in the UK found that adding limestone to ponds resulted in high tadpole mortality and pond abandonment by natterjack toads and higher numbers of abnormal common frog eggs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F748https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F748Thu, 18 Jul 2013 15:41:50 +0100Collected Evidence: Collected Evidence: Add nutrients to new ponds as larvae food source We found no evidence for the effects of adding nutrients, such as zooplankton, to new ponds 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%2F812https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F812Thu, 22 Aug 2013 15:07:50 +0100Collected Evidence: Collected Evidence: Add mulch to cropsBiodiversity: Three replicated trials from Canada, Poland and Spain (including one also controlled, one also randomized and one also controlled and randomized) showed that adding mulch to crops (whether shredded paper, municipal compost or straw) increased soil animal and fungal numbers, diversity and activity. Of these, one trial also showed that mulch improved soil structure and increased soil organic matter. Nutrient loss: One replicated study from Nigeria found higher nutrient levels in continually cropped soil. Erosion: Five studies from India, France, Nigeria and the UK (including one controlled, randomized, replicated trial, one randomized, replicated trial, two replicated (one also controlled), and one controlled trial) found that mulches increased soil stability, and reduced soil erosion and runoff. One trial found that some mulches are more effective than others. Drought: Two replicated trials from India found that adding mulch to crops increased soil moisture. Yield: Two replicated trials from India found that yields increased when either a live mulch or vegetation barrier combined with mulch was used. SOIL TYPES COVERED: clay, fine loam, gravelly sandy loam, sandy, sandy-clay, sandy loam, sandy silt-loam, silty, silty loam.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F887https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F887Fri, 27 Sep 2013 08:43:03 +0100Collected Evidence: Collected Evidence: Add lime to the soil to increase fertility One replicated, randomized controlled study in the USA found that adding lime increased vegetation cover.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1249https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1249Fri, 03 Jun 2016 12:48:10 +0100Collected Evidence: Collected Evidence: Add lime to the soil after tree planting One of two replicated, randomized, controlled studies in the USA found that adding lime before restoration planting decreased the survival of pine seedlings. The other study found no effect of adding lime on planted oak seedling growth.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1259https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1259Mon, 06 Jun 2016 10:42:49 +0100Collected Evidence: Collected Evidence: Add mulch to control grass One randomized, controlled study in the USA found that areas where mulch was used to control grass cover had a similar number of shrub seedlings to areas where mulch was not applied. The same study found that mulch application did not reduce grass cover. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1649https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1649Sun, 22 Oct 2017 13:43:52 +0100Collected Evidence: Collected Evidence: Add mulch to control grass and sow seed One randomized, controlled study in the USA found that adding mulch, followed by seeding with shrub seeds, increased the seedling abundance of one of seven shrub species but did not reduce grass cover. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1650https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1650Sun, 22 Oct 2017 13:46:49 +0100Collected Evidence: Collected Evidence: Add lime to shrubland to reduce the impacts of sulphur dioxide pollution We found no studies that evaluated the effects of adding lime to reduce the impacts of sulphur dioxide 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%2F1671https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1671Sun, 22 Oct 2017 15:18:10 +0100Collected Evidence: Collected Evidence: Add mulch and fertilizer to soil One randomized, controlled study in the USA found that adding mulch and fertilizer did not increase the seedling abundance of seven shrub species. The same study also reported no change in grass cover. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1694https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1694Mon, 23 Oct 2017 10:48:55 +0100Collected Evidence: Collected Evidence: Add manure to soil One replicated, randomized, controlled study in South Africa found that adding manure to the soil increased plant cover and the number of plant species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1695https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1695Mon, 23 Oct 2017 10:50:48 +0100Collected Evidence: Collected Evidence: Add mulch to soil (alongside planting/seeding) A replicated, randomized, controlled study in the USA found that using mulch did not increase the number of shrubs, or the height of California sagebrush. A randomized, controlled study in South Africa found that applying mulch and sowing seeds increased the number of seedlings, but not their survival. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1706https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1706Mon, 23 Oct 2017 11:59:05 +0100Collected Evidence: Collected Evidence: Add mulch and fertilizer to soil (alongside planting/seeding) A randomized, controlled study in the USA found that adding mulch and fertilizer, followed by sowing of seeds increased the abundance of seedlings for a minority of shrub species. The same study found that adding mulch and fertilizer, followed by sowing seeds had no significant effect on grass cover. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1707https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1707Mon, 23 Oct 2017 12:01:19 +0100Collected Evidence: Collected Evidence: Add lime to reduce acidity and/or increase fertility One study evaluated the effects of liming (without planting) on peatland vegetation. The study was in a fen meadow. N.B. Liming is considered in different contexts here and here. Vegetation structure (1 study): One replicated, controlled study in a fen meadow in the Netherlands found that liming increased overall vegetation biomass (mostly grass). Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1790https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1790Tue, 28 Nov 2017 08:18:28 +0000Collected Evidence: Collected Evidence: Add mosses to peatland surface Thirteen studies evaluated the effects of adding mosses or moss fragments onto peatland surfaces. Eleven were in bogs and two in were in fens. One study was a continuation of an earlier study. Three of the studies involved sowing moss in gel beads. Sphagnum moss cover (12 studies): Eleven studies in bogs in the UK, Canada, Finland and Germany and fens the USA reported that Sphagnum moss was present, after 1–4 growing seasons, in at least some plots sown with Sphagnum. Cover ranged from negligible to >90%. Six of these studies were controlled and found that Sphagnum cover or abundance was higher in sown than unsown plots. One of the studies reported that Sphagnum only survived in one of three sites, and only when plots were mulched. One additional study in Canada found that adding Sphagnum to bog pools did not affect Sphagnum Other moss cover (4 studies): Four studies (including one replicated, randomized, paired, controlled, before-and-after) in bogs in Canada and fens in Sweden and the USA reported that mosses or bryophytes other than Sphagnum were present, after 2–3 growing seasons, in at least some plots sown with moss fragments. Cover ranged from negligible to 76%. In the fens in Sweden and the USA, moss cover was low (<1%) unless the plots were mulched, shaded or limed. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1821https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1821Tue, 28 Nov 2017 08:45:38 +0000Collected Evidence: Collected Evidence: Add mixed vegetation to peatland surface Eighteen studies evaluated the effects on peatland vegetation of spreading mixed vegetation onto the peatland surface. All 18 studies were in bogs (two being restored as fens). One study was a continuation of an earlier study. Characteristic plants (1 study): One replicated, randomized, paired, controlled, before-and-after study in a degraded bog in Canada found that adding fen vegetation increased the number and cover of fen-characteristic plant species. Sphagnum moss cover (17 studies): Seventeen replicated studies (five also randomized, paired, controlled, before-and-after) in bogs in Canada, the USA and Estonia reported that Sphagnum moss was present, after 1–6 growing seasons, in at least some plots sown with vegetation containing Sphagnum. Cover ranged from <1 to 73%. Six of the studies were controlled and found that Sphagnum cover was higher in sown than unsown plots. Five of the studies reported that Sphagnum cover was very low (<1%) unless plots were mulched after spreading fragments. Other moss cover (8 studies): Eight replicated studies (seven before-and-after, one controlled) in bogs in Canada, the USA and Estonia reported that mosses or bryophytes other than Sphagnum were present, after 1–6 growing seasons, in at least some plots sown with mixed peatland vegetation. Cover was <1–65%. Vascular plant cover (10 studies): Ten replicated studies in Canada, the USA and Estonia reported that vascular plants appeared following addition of mixed vegetation fragments to bogs. Two of the studies were controlled: one found that vascular plant cover was significantly higher in sown than unsown plots, but one found that sowing peatland vegetation did not affect herb cover. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1822https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1822Tue, 28 Nov 2017 08:45:54 +0000Collected Evidence: Collected Evidence: Add lime (before/after planting) Six studies evaluated the effects on peatland vegetation of liming areas planted with peatland plants. Four studies involved fen plants, one involved bog plants and one involved peat swamp plants. Two of the studies were in greenhouses/nurseries. Survival (2 studies): One replicated, controlled study in the Netherlands reported that liming typically reduced survival of planted fen herbs after two growing seasons. One replicated, randomized, paired, controlled study in Sweden found that liming increased survival of planted fen mosses over one growing season. Growth (3 studies): Two controlled, before-and-after studies found that liming did not increase growth of planted peatland vegetation. Liming reduced or had no effect on Sphagnum moss growth in bog pools in the UK, and reduced growth rates for the majority of peat swamp tree seedlings in a nursery in Indonesia. One replicated, controlled, before-and-after study in Sweden found that liming increased growth of planted fen mosses. Cover (2 studies): One replicated, randomized, paired, controlled, before-and-after study in a fen in Sweden found that liming increased cover of sown mosses. However, one replicated, randomized, paired, controlled study in a bog in Canada found that liming plots sown with fen vegetation fragments had no effect on total vegetation, vascular plant or bryophyte cover. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1825https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1825Tue, 28 Nov 2017 08:50:30 +0000Collected Evidence: Collected Evidence: Add lime or similar chemicals: freshwater marshes One study evaluated the effects, on vegetation, of adding neutralizing chemicals to freshwater marshes or their catchments. The study was in the USA. VEGETATION COMMUNITY Relative abundance (1 study): One replicated, controlled, before-and-after study of marsh vegetation in the USA found that liming had little effect on the relative abundance of plant taxa. For 48 of 49 taxa, differences or similarities in relative abundance between limed and unlimed areas before intervention persisted over two years after intervention. VEGETATION ABUNDANCE Individual species abundance (1 study): One replicated, controlled, before-and-after study of marsh vegetation in the USA found that for most plant taxa, differences or similarities in abundance between limed and unlimed areas before intervention persisted over two years following intervention. This was true for 33 of 38 herbaceous plant taxa, eight of eight woody plant taxa, and two of three moss taxa. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3157https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3157Tue, 06 Apr 2021 12:16:26 +0100Collected Evidence: Collected Evidence: Add lime or similar chemicals: brackish/salt marshesWe found no studies that evaluated the effects, on vegetation, of adding neutralizing chemicals to brackish/salt marshes or their catchments.   ‘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%2F3158https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3158Tue, 06 Apr 2021 12:16:51 +0100Collected Evidence: Collected Evidence: Add lime or similar chemicals: freshwater swamps One study evaluated the effects, on vegetation, of adding neutralizing chemicals to freshwater swamps or their catchments. The study was in the USA. VEGETATION COMMUNITY Relative abundance (1 study): One replicated, controlled, before-and-after study of shrubby wetland vegetation in the USA found that liming had no significant effect on the relative abundance of plant taxa. For 49 of 49 taxa, differences or similarities in relative abundance between limed and unlimed areas before intervention persisted over two years after intervention. VEGETATION ABUNDANCE Individual species abundance (1 study): One replicated, controlled, before-and-after study of shrubby wetland vegetation in the USA found that for most plant taxa, differences or similarities in abundance between limed and unlimed areas before intervention persisted over two years following intervention. This was true for 31 of 31 herbaceous plant taxa, 16 of 16 woody plant taxa, and one of two moss taxa. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3159https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3159Tue, 06 Apr 2021 12:17:03 +0100Collected Evidence: Collected Evidence: Add lime or similar chemicals: brackish/saline swampsWe found no studies that evaluated the effects, on vegetation, of adding neutralizing chemicals to brackish/saline swamps or their catchments.   ‘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%2F3160https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3160Tue, 06 Apr 2021 12:17:14 +0100Collected Evidence: Collected Evidence: Add lime or similar chemicals before/after planting non-woody plants: freshwater wetlandsWe found no studies that evaluated the effects, on vegetation, of adding neutralizing chemicals to freshwater wetlands planted with emergent, non-woody plants.   ‘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%2F3300https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3300Sun, 11 Apr 2021 08:46:21 +0100Collected Evidence: Collected Evidence: Add lime or similar chemicals before/after planting non-woody plants: brackish/saline wetlands Three studies evaluated the effects, on vegetation, of adding neutralizing chemicals to brackish/saline wetlands planted with emergent, non-woody plants. Two studies were in Canada. One study was in the USA. One study was in a greenhouse. VEGETATION COMMUNITY   VEGETATION ABUNDANCE Characteristic plant abundance (1 study): One replicated, paired, controlled, before-and-after study in salt-contaminated bogs in Canada reported that liming reduced the above-ground biomass of planted salt marsh vegetation after one year. Individual species abundance (2 studies): One controlled study in former borrow pits in the USA found that limed and unlimed plots supported similar biomass of a planted herb species after 1–2 growing seasons. In contrast, one replicated, randomized, paired, controlled study in salt-contaminated peat in Canada found that limed pots supported lower biomass of two sown herb species than unlimed pots, after four months. VEGETATION STRUCTURE   OTHER Germination/emergence (1 study): One replicated, randomized, paired, controlled study in salt-contaminated peat in Canada found that for each of two sown herb species, germination rates were similar in limed and unlimed pots. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3301https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3301Sun, 11 Apr 2021 08:46:32 +0100Collected Evidence: Collected Evidence: Add lime or similar chemicals before/after planting trees/shrubs: freshwater wetlandsWe found no studies that evaluated the effects, on vegetation, of adding neutralizing chemicals to freshwater wetlands planted with trees/shrubs.   ‘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%2F3302https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3302Sun, 11 Apr 2021 08:46:44 +0100Collected Evidence: Collected Evidence: Add lime or similar chemicals before/after planting trees/shrubs: brackish/saline wetlandsWe found no studies that evaluated the effects, on vegetation, of adding neutralizing chemicals to brackish/saline wetlands planted with trees/shrubs.   ‘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%2F3303https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3303Sun, 11 Apr 2021 08:46:55 +0100Collected Evidence: Collected Evidence: Add mulch before or after seeding/planting Six studies examined the effects of adding mulch before or after seeding/planting on grassland vegetation. Two studies were in Canada, two were in the USA, and one study was in each of the UK and Germany. VEGETATION COMMUNITY (1 STUDY) Characteristic plant richness/diversity (1 study): One replicated, controlled study in Germany found that adding mulch before sowing seeds did not alter the species richness of target plants. VEGETATION ABUNDANCE (4 STUDIES) Overall abundance (1 study): One replicated, controlled study in Canada found that adding mulch before sowing seeds did not increase plant cover. Characteristic plant abundance (1 study): One replicated, controlled study in Germany found that adding mulch before sowing seeds increased the cover of target plant species. Sown/planted species abundance (2 studies): One of two replicated, randomized, controlled studies in the USA and UK found that adding mulch before sowing seeds did not alter the density of six sown plant species in most cases. The other study found that adding mulch before planting seedlings reduced the cover of planted species. Individual species abundance (1 study): One replicated, randomized, controlled study in the UK found that adding mulch before planting seedlings did not alter the cover of common knapweed. VEGETATION STRUCTURE (0 STUDIES) OTHER (2 STUDIES) Germination/Emergence (1 study): One replicated, controlled study in Canada found that adding mulch before sowing seeds increased the number of seedlings in most cases. Growth (1 study): One replicated, randomized, controlled study in the USA found that adding mulch after planting native prairie plants did not alter the growth of any of seven plant species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3425https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3425Mon, 28 Jun 2021 10:05:54 +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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