Collected Evidence: Collected Evidence: Reduce frequency of cutting/mowing: freshwater marshes Four studies evaluated the effects, on vegetation, of reducing the frequency of cutting/mowing in freshwater marshes (or cutting/mowing them at different frequencies). There was one study in each of USA, the Netherlands, Belgium and Italy. VEGETATION COMMUNITY Community composition (1 study): One replicated, randomized, paired, controlled study of farmland ditches in the Netherlands found that marshy areas cut once, twice or three times/year had a similar overall plant community composition, when surveyed in July. Overall richness/diversity (2 studies): Two replicated, paired, controlled studies in farmland ditches in the Netherlands and wet grasslands in Belgium reported that overall plant species richness was similar in plots cut once or twice/year (and three times/year in the Netherlands). VEGETATION ABUNDANCE Overall abundance (1 study): One replicated, paired, controlled, before-and-after study in wet grasslands in Belgium reported that the effect of cutting twice/year (in July and October) on total above-ground biomass was intermediate between the effects of cutting once/year in July or October. Individual species abundance (4 studies): All four studies quantified the effect of this action on the abundance of individual plant species. For example, one replicated, paired, controlled study in freshwater marshes in the USA reported that cattail Typha spp. biomass was greater, nine months after the last cut, in plots cut every six weeks than in plots cut every three weeks. One paired, controlled, before-and-after study in reedbeds in Italy found that common reed Phragmites australis biomass was similar in plots mown once or twice/year, when measured at least five months after the last cut. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3066https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3066Fri, 02 Apr 2021 13:14:38 +0100Collected Evidence: Collected Evidence: Reduce frequency of cutting/mowing: brackish/salt marshesWe found no studies that evaluated the effects, on vegetation, of reducing the frequency of cutting/mowing in brackish/salt marshes (or cutting/mowing them at different frequencies).   ‘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%2Fconservationevidencejournal.com%2Factions%2F3067https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3067Fri, 02 Apr 2021 13:17:06 +0100Collected Evidence: Collected Evidence: Reduce intensity of cutting/mowingWe found no studies that evaluated the effects, on vegetation, of reducing the intensity of cutting/mowing in marshes or swamps (or cutting/mowing them at different intensities).   ‘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%2Fconservationevidencejournal.com%2Factions%2F3068https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3068Fri, 02 Apr 2021 13:29:11 +0100Collected Evidence: Collected Evidence: Change season/timing of cutting/mowing: freshwater marshes Four studies evaluated the effects, on vegetation, of cutting/mowing freshwater marshes in different seasons or at different times. There was one study in each of Switzerland, the Netherlands, Belgium and Japan. VEGETATION COMMUNITY Community composition (2 studies): Two replicated, randomized, paired, controlled studies in wet meadows in Switzerland and farmland ditches in the Netherlands reported that cutting vegetation in different seasons typically had similar effects on the overall plant community composition, over 1–4 years. Overall richness/diversity (2 studies): One replicated, randomized, paired, controlled study in farmland ditches in the Netherlands found that marshy areas cut in May and areas cut in November typically contained a similar number of plant species, when surveyed in July. One replicated, paired, controlled study of wet grasslands in Belgium reported that the effect of a single mow between June and November on overall plant species richness depended on the month of mowing. VEGETATION ABUNDANCE Overall abundance (1 study): One replicated, paired, controlled study of wet grasslands in Belgium reported that the effect of a single mow between June and November on overall vegetation abundance (including litter) depended on the month of mowing. Individual species abundance (4 studies): All four studies quantified the effect of this action on the abundance of individual plant species. The studies all reported that the abundance of some plant species responded differently to cutting in different seasons. The controlled, before-and-after study in Japan, for example, reported that cutting in June reduced the abundance of common reed Phragmites australis in the following summer more than cutting in July. VEGETATION STRUCTURE Overall structure (1 study): One replicated, randomized, paired, controlled study in wet meadows in Switzerland reported that summer-mown and winter-mown plots both experienced a shift in vegetation cover towards lower vegetation layers, over 3–4 years. Diameter/perimeter/area (1 study): The same study reported that summer-mowing and winter-mowing had opposite effects on the diameter of common reed Phragmites australis shoots: they became thinner over four years of summer mowing but thicker over three years of winter mowing. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3070https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3070Fri, 02 Apr 2021 13:38:46 +0100Collected Evidence: Collected Evidence: Change season/timing of cutting/mowing: brackish/salt marshesWe found no studies that evaluated the effects, on vegetation, of cutting/mowing brackish/salt marshes in different seasons or at different times.   ‘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%2Fconservationevidencejournal.com%2Factions%2F3071https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3071Fri, 02 Apr 2021 13:41:04 +0100Collected Evidence: Collected Evidence: Reduce frequency of prescribed burningWe found no studies that evaluated the effects, on vegetation, of reducing the frequency of prescribed burning in marshes or swamps (or burning them at different frequencies).   ‘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%2Fconservationevidencejournal.com%2Factions%2F3072https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3072Fri, 02 Apr 2021 14:40:50 +0100Collected Evidence: Collected Evidence: Reduce intensity of prescribed burningWe found no studies that evaluated the effects, on vegetation, of reducing the intensity of prescribed burning in marshes or swamps (or burning them at different intensities).   ‘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%2Fconservationevidencejournal.com%2Factions%2F3073https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3073Fri, 02 Apr 2021 14:44:31 +0100Collected Evidence: Collected Evidence: Change season/timing of prescribed burning: freshwater marshes One study evaluated the effects, on vegetation, of burning freshwater marshes in different seasons or at different times. The study was in the USA. VEGETATION COMMUNITY Overall richness/diversity (1 study): One replicated, randomized, controlled study in a marsh in the USA found that spring-burned plots had greater plant species richness than summer-burned plots, at the end of the growing season. VEGETATION ABUNDANCE Overall abundance (1 study): One replicated, randomized, controlled study in a marsh in the USA found that spring-burned plots had greater overall vegetation cover than summer-burned plots, at the end of the growing season. Individual species abundance (1 study): The same study reported that the cover and frequency of some individual plant species responded differently to spring vs summer burning. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3074https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3074Fri, 02 Apr 2021 14:45:30 +0100Collected Evidence: Collected Evidence: Change season/timing of prescribed burning: brackish/salt marshesWe found no studies that evaluated the effects, on vegetation, of burning brackish/salt marshes in different seasons or at different times.   ‘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%2Fconservationevidencejournal.com%2Factions%2F3075https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3075Fri, 02 Apr 2021 14:45:47 +0100Collected Evidence: Collected Evidence: Change season/timing of prescribed burning: freshwater swampsWe found no studies that evaluated the effects, on vegetation, of burning freshwater swamps in different seasons or at different times.   ‘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%2Fconservationevidencejournal.com%2Factions%2F3076https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3076Fri, 02 Apr 2021 14:46:01 +0100Collected Evidence: Collected Evidence: Change season/timing of prescribed burning: brackish/saline swampsWe found no studies that evaluated the effects, on vegetation, of burning brackish/saline swamps in different seasons or at different times.   ‘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%2Fconservationevidencejournal.com%2Factions%2F3077https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3077Fri, 02 Apr 2021 14:46:19 +0100Collected Evidence: Collected Evidence: Raise water level to prevent wild firesWe found no studies that evaluated the effects, on marsh/swamp vegetation, of raising the water level to prevent wild fires in or near these habitats.   ‘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%2Fconservationevidencejournal.com%2Factions%2F3079https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F3079Fri, 02 Apr 2021 16:56:58 +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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