Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Rewet peatland (raise water table) Thirty-six studies evaluated the effects of rewetting (without planting) on peatland vegetation. Fifteen studies were in bogs (two being restored as fens). Fifteen studies were in fens or fen meadows (two were naturally forested). Six studies were in general or unspecified peatlands. Some studies were based on the same experimental set-up or sites as each other: two studies in Germany, three studies in Sweden, two studies in west Finland and two studies in south Finland. Plant community composition (13 studies): Six before-and-after studies (four also replicated) in peatlands in Finland, Hungary, Sweden, Poland and Germany reported changes in the overall plant community composition following rewetting. Typically, drier grassland communities were replaced by more wetland- or peatland-characteristic communities. One replicated, paired, controlled study in a bog in the Czech Republic found that rewetted plots developed a different plant community to drained plots. Three site comparison studies in Finland and Canada reported that rewetted peatlands contained a different plant community to natural peatlands. Three replicated studies in peatlands in the UK and fens in Germany reported that rewetting typically had no effect, or insignificant effects, on the plant community. Characteristic plants (11 studies): Five studies (including one replicated site comparison) in peatlands in Canada, the UK, China and Poland reported that rewetting (sometimes along with other interventions) increased the abundance of wetland- or peatland-characteristic plants. Two replicated site comparison studies in fens or fen meadows in central Europe found that rewetting reduced the number of fen-characteristic plant species. Two studies (one replicated, paired, controlled, before-and-after) in fens in Sweden reported that rewetting had no effect on cover of fen-characteristic plants. Two before-and-after studies in fens in the USA and New Zealand reported that upland plant cover decreased following rewetting. Moss cover (19 studies): Twelve studies (five replicated, two also paired and controlled) in the UK, Ireland, Germany, Sweden, Latvia, Canada and Spain reported that rewetting bogs, fens or other peatlands (sometimes along with other interventions) increased Sphagnum moss cover or abundance. Three of these studies reported mixed responses by species. Two additional replicated studies, in bogs in Latvia and forested fens in Finland, reported that rewetting had no effect on Sphagnum cover. Five studies (one paired, controlled, before-and-after) in Finland, Sweden and Canada reported that rewetting bogs or fens had no effect on cover of non-Sphagnum mosses (or mosses/lichens). However, two controlled studies in bogs in Ireland and the UK reported that rewetting reduced cover of non-Sphagnum mosses or bryophytes. One site comparison study in Finland reported that a rewetted peatland had similar moss cover (Sphagnum and total) to a natural peatland, but another site comparison study in Canada reported that a rewetted bog had lower moss cover (Sphagnum and other) than nearby target peatlands. Herb cover (25 studies): Twenty-one studies (including four replicated, paired, controlled) reported that rewetting (sometimes along with other interventions) increased cover of at least one group of herbs. These studies were in bogs, fens or other peatlands in the UK, Finland, Ireland, the Czech Republic, the USA, the Netherlands, Sweden, Germany, China, Latvia, Poland, Canada and Spain. Specifically, rewetting increased other/total sedge cover in 13 of 15 studies, increased cottongrass cover in eight of nine studies, and increased reed/rush cover in five of seven studies. Three of four before-and-after studies in peatlands in the UK and Sweden reported that rewetting reduced purple moor grass cover; the other study reported no effect. One replicated site comparison study in forested fens in Finland reported that rewetting had no effect on total herb cover. Two site comparison studies in Europe reported greater herb cover in rewetted than natural peatlands (overall and sedges/rushes, but not forbs). Tree/shrub cover (13 studies): Ten studies (including two paired and controlled) in peatlands in Finland, the UK, Germany, Latvia and Canada reported that rewetting typically reduced (seven studies) or had no effect (six studies) on tree and/or shrub cover. Two before-and-after studies in fens in Sweden and Germany reported that rewetting increased tree/shrub cover. One before-and-after study in a bog in the UK reported mixed effects of rewetting on different tree/shrub species. Overall vegetation cover (4 studies): Of four before-and-after studies (three also controlled) that examined the effect of rewetting on overall vegetation cover, two in bogs in Ireland and Sweden reported that rewetting increased it. One study in a fen in New Zealand reported that rewetting reduced vegetation cover. One study in a peatland in Finland reported no effect. Overall plant richness/diversity (14 studies): Six studies (including one replicated, paired, controlled, before-and-after) in Sweden, Germany and the UK reported that rewetting increased total plant species richness or diversity in bogs, fens or other peatlands. However, five studies found no effect: in bogs in the Czech Republic and Latvia, fens in Sweden and Germany, and forested fens in Finland. One study in fen meadows in the Netherlands found scale-dependent effects. One paired, controlled, before-and-after study in a peatland in Finland reported that rewetting reduced plant diversity. Of four studies that compared rewetted and natural peatlands, two in Finland and Germany reported lower species richness in rewetted peatlands, one in Sweden found higher species richness in rewetted fens, and one in Europe found similar richness in rewetted and natural fens. Growth (1 study): One replicated site comparison study in forested fens in Finland found that rewetting increased Sphagnum moss growth to natural levels. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1756https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1756Mon, 27 Nov 2017 21:33:59 +0000Collected Evidence: Collected Evidence: Reduce water level of flooded peatlands We found no studies that evaluated the effects, on peatland vegetation, of reducing the water level in unnaturally flooded peatlands. ‘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%2F1757https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1757Mon, 27 Nov 2017 21:34:20 +0000Collected Evidence: Collected Evidence: Restore natural water level fluctuations We found no studies that evaluated the effects, on peatland vegetation, of restoring natural water level fluctuations per se. ‘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%2F1758https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1758Mon, 27 Nov 2017 21:34:36 +0000Collected Evidence: Collected Evidence: Cut/mow herbaceous plants to maintain or restore disturbance Fourteen studies evaluated the effects on peatland vegetation of cutting/mowing to maintain or restore disturbance. All 14 studies were in fens or fen meadows. Most studies examined the effect of annual mowing regimes, but three examined the effect of single cuts. N.B. Cutting/mowing in peatlands with no history of disturbance is considered as a separate action. Plant community composition (7 studies): Six replicated studies in fens and fen meadows in the UK, Belgium, Germany and the Czech Republic reported that mowing altered the overall plant community composition (compared to no mowing, before mowing or grazing). One site comparison study in Poland reported that mowing a degraded fen (along with other interventions) made the plant community more similar to a target fen meadow. Characteristic plants (5 studies): Four studies (including one replicated, paired, controlled, before-and-after) in fens and fen meadows in Switzerland, Germany, the Czech Republic and Poland found that cutting/mowing increased cover of fen- or wet meadow-characteristic plants. One replicated before-and-after study in fens in the UK found that a single mow typically had no effect on cover of fen-characteristic plants. In Poland and the UK, the effect of mowing was not separated from the effects of other interventions. Moss cover (6 studies): Of six studies (five replicated, paired, controlled) in fens or fen meadows, four in Belgium, Switzerland and the Czech Republic found that mowing increased total moss or bryophyte cover. Two studies in Poland and the UK found that a single mow typically had no effect on bryophyte cover (total or hollow-adapted mosses). Herb cover (8 studies): Six replicated studies (three also randomized and controlled) in fens and fen meadows in Belgium, Germany, Poland and the UK found that mowing reduced cover or abundance of at least one group of herbs (including bindweed, reeds, sedges, purple moor grass and grass-like plants overall). One before-and-after study in a fen in Poland found that mowing (along with other interventions) increased sedge cover. One replicated, randomized, paired, controlled study in fen meadows in Switzerland found that mowing had no effect on overall herb cover. Tree/shrub cover (3 studies): Of three replicated studies in fens, two in the UK found that a single mow (sometimes along with other interventions) reduced shrub cover. However, one study in Poland found that a single mow had no effect on shrub cover. Vegetation structure (7 studies): In the following studies, vegetation structure was measured 6–12 months after the most recent cut/mow. Three replicated studies in fens in Poland and the UK reported that a single mow (sometimes along with other interventions) had no, or no consistent, effect on vegetation height. One replicated, paired, site comparison study in fen meadows in Switzerland found that mowing reduced vegetation height. Three studies (including two replicated, paired, site comparisons) in fen meadows in Switzerland, Poland and Italy found mixed effects of mowing on vegetation biomass (total, sedge/rush, moss or common reed). One replicated, paired, site comparison study in Germany reported that mown fen meadows had similar vegetation structure to grazed meadows. Overall plant richness/diversity (11 studies): Eight studies in fens and fen meadows in the UK, Belgium, Switzerland, Germany, the Czech Republic and Poland found that mowing/cutting increased plant species richness (compared to no mowing, before mowing or grazing). Three studies (including two replicated, randomized, paired, controlled) in fens in Poland and the UK found that a single mow (sometimes along with other interventions) typically had no effect on plant species richness and/or diversity. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1759https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1759Mon, 27 Nov 2017 21:35:31 +0000Collected Evidence: Collected Evidence: Remove plant litter to maintain or restore disturbance Two studies evaluated the effects on peatland vegetation of removing plant litter to maintain or restore disturbance. One study was in fen meadow and one was in a fen. Plant community composition (2 studies): Two replicated, controlled studies (one randomized, one paired, before-and-after) in a fen meadow in Germany and a fen in Czech Republic found that removing plant litter did not affect plant community composition. Vegetation cover (1 study): One replicated, paired, controlled, before-and-after study in a fen in the Czech Republic found that removing plant litter did not affect bryophyte or tall moor grass cover. Overall plant richness/diversity (2 studies): One replicated, randomized, controlled study in a fen meadow in Germany reported that removing plant litter increased plant species richness and diversity. However, one replicated, paired, controlled, before-and-after study in a fen in the Czech Republic found that removing litter did not affect vascular plant diversity. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1760https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1760Mon, 27 Nov 2017 21:35:49 +0000Collected Evidence: Collected Evidence: Cut large trees/shrubs to maintain or restore disturbance Two studies evaluated the effects, on peatland vegetation, of cutting large trees/shrubs to maintain or restore disturbance. One study was in a forested fen and one was in an open fen. N.B. Cutting large trees/shrubs in peatlands with no history of disturbance is considered as a separate action. Plant community composition (1 study): One before-and-after, site comparison study in a fen in Poland found that in an area where shrubs were removed (along with other interventions), the plant community composition became more like a target fen meadow. Characteristic plants (1 study): One before-and-after, site comparison study in a fen in Poland found that in an area where shrubs were removed (along with other interventions), the abundance of fen meadow plant species increased. Vegetation cover (1 study): One replicated, paired, controlled study in forested fen in the USA found that cutting and removing trees increased herb cover, but had no effect on shrub cover. Vegetation structure (1 study): One replicated, paired, controlled study in a peat swamp in the USA found that cutting and removing trees increased herb biomass and height. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1761https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1761Mon, 27 Nov 2017 21:36:20 +0000Collected Evidence: Collected Evidence: Use grazing to maintain or restore disturbance Four studies evaluated the effects, on peatland vegetation, of using grazing to maintain or restore disturbance. All four studies were in fens or fen meadows. N.B. Grazing in peatlands with no history of disturbance is considered as a separate action. Plant community composition (1 study): One replicated, paired, site comparison study in Germany found that the overall plant community composition differed between grazed and mown fen meadows. Characteristic plants (3 studies): One replicated, paired, controlled study in Germany reported that the abundance of bog/fen-characteristic plants was similar in grazed and ungrazed fen meadows. One replicated before-and-after study in a fen in the UK reported that cover of fen-characteristic mosses did not change after grazers were introduced. One replicated, paired, site comparison study, also in Germany, found that grazed fen meadows contained fewer fen-characteristic plant species than mown meadows. Herb cover (2 studies): Two before-and-after studies in fens in the UK reported that grazing increased cover of some herb groups (cottongrasses, sedges or all grass-like plants). One of the studies found that grazing reduced purple moor grass cover, but the other found that grazing typically had no effect. Moss cover (2 studies): One replicated before-and-after study in a fen in the UK reported that cover of fen-characteristic mosses did not change after grazers were introduced. One controlled, before-and-after study in a fen in the UK found that grazing reduced Sphagnum moss cover. Tree/shrub cover (2 studies): Of two before-and-after studies in fens in the UK, one found that grazing reduced shrub cover but the other found that grazing typically had no effect on shrub cover. Overall plant richness/diversity (3 studies): Of two before-and-after studies in fens in the UK, one found that plant species richness increased after grazing was reinstated but the other reported that there was typically no effect. One replicated, paired, site comparison study in Germany found that grazed fen meadows contained fewer plant species than mown meadows. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1762https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1762Mon, 27 Nov 2017 21:36:40 +0000Collected Evidence: Collected Evidence: Use prescribed fire to maintain or restore disturbance Three studies evaluated the effects, on peatland vegetation, of using prescribed fire to maintain or restore disturbance. Two studies were in fens and one was in a bog. N.B. Prescribed burning in peatlands with no history of disturbance is considered as a separate action. Characteristic plants (1 study): One replicated before-and-after study in a fen in the UK reported that burning (along with other interventions) had no effect on cover of fen-characteristic mosses or herbs. Herb cover (2 studies): One replicated, controlled study in a fen in the USA reported that burning reduced forb cover and increased sedge/rush cover, but had no effect on grass cover. In contrast, one replicated before-and-after study in a fen in the UK reported that burning (along with other interventions) reduced grass/sedge/rush cover. Tree/shrub cover (2 studies): Two replicated studies in fens in the USA and the UK reported that burning (sometimes along with other interventions) reduced tree/shrub cover. Overall plant richness/diversity (3 studies): Two replicated, controlled studies in a fen in the USA and a bog in New Zealand found that burning increased plant species richness or diversity. However, one replicated before-and-after study in a fen in the UK reported that burning (along with other interventions) typically had no effect on plant species richness and diversity. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1763https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1763Mon, 27 Nov 2017 21:37:27 +0000Collected Evidence: Collected Evidence: Thin vegetation to prevent wild fires We found no studies that evaluated the effects, on peatland vegetation, of thinning vegetation to prevent wild fires. ‘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%2F1764https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1764Mon, 27 Nov 2017 21:39:26 +0000Collected Evidence: Collected Evidence: Rewet peat to prevent wild fires We found no studies that evaluated the effects, on peatland vegetation, of rewetting peat to prevent wild fires. ‘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%2F1765https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1765Mon, 27 Nov 2017 21:39:55 +0000Collected Evidence: Collected Evidence: Build fire breaks We found no studies that evaluated the effects, on peatland vegetation, of building fire breaks. ‘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%2F1766https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1766Mon, 27 Nov 2017 21:40:17 +0000Collected Evidence: Collected Evidence: Adopt zero burning policies near peatlands We found no studies that evaluated the effects, on peatland vegetation, of adopting zero burning policies near peatlands. ‘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%2F1856https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1856Wed, 29 Nov 2017 10:54:22 +0000Collected Evidence: Collected Evidence: Irrigate peatland (without planting) Two studies evaluated the effects of irrigation (without planting) on peatland vegetation. One study was in a bog and one was in a fen. Vegetation cover (2 studies): One replicated, paired, controlled, before-and-after study in a bog in Canada found that irrigation increased the number of Sphagnum moss shoots present after one growing season, but had no effect after two. One before-and-after study in Germany reported that an irrigated fen was colonized by wetland- and fen-characteristic herbs, whilst cover of dryland grasses decreased. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1859https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1859Mon, 11 Dec 2017 15:05:17 +0000