Collected Evidence: Collected Evidence: Cut/mow to control grass One controlled study in the UK found that mowing increased the number of heathland plants in one of two sites. The same study found that the presence of a small minority of heathland plants increased, but the presence of non-heathland plants did not change. Three replicated, controlled studies in the UK and the USA found that cutting to control grass did not alter cover of common heather or shrub seedling abundance. One replicated, controlled study in the UK found that cutting to control purple moor grass reduced vegetation height, had mixed effects on purple moor grass cover and the number of plant species, and did not alter cover of common heather. Two randomized, controlled studies in the USA found that mowing did not increase the cover of native forb species. Both studies found that mowing reduced grass cover but in one of these studies grass cover recovered over time. One replicated, controlled study in the UK found that mowing did not alter the abundance of wavy hair grass relative to rotovating or cutting turf. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1638https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1638Sun, 22 Oct 2017 12:12:02 +0100Collected Evidence: Collected Evidence: Strip topsoil Two randomized, replicated, controlled studies in the UK found that removal of topsoil did not increase heather cover or cover of heathland species. However, one controlled study in the UK found an increase in heather cover. One randomized, replicated, controlled study in the UK found that removing topsoil increased the cover of both specialist and generalist plant species, but did not increase species richness. One randomized, replicated, paired, controlled study in the UK found that removal of topsoil increased cover of annual grasses but led to a decrease in the cover of perennial grasses. One controlled study in the UK found that removal of turf reduced cover of wavy hair grass. One controlled, before-and-after trial in the UK found that stripping surface layers of soil increased the cover of gorse and sheep’s sorrel as well as the number of plant species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1685https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1685Mon, 23 Oct 2017 09:26:27 +0100Collected Evidence: Collected Evidence: Introduce seeds of peatland trees/shrubs Five studies evaluated the effects, on peatland vegetation, of introducing seeds of peatland trees/shrubs to restore or create forested/shrubby peatland. Three studies were in bogs and two were in fens. Germination (2 studies): Two replicated studies in a bog in Germany and a fen in the USA reported germination of heather and willow seeds, respectively, in at least some sown plots. Survival (2 studies): One replicated study in a bog in Germany reported survival of some heather seedlings over two years. One replicated study in a fen in the USA reported that all germinated willow seedlings died within one month. Shrub cover (3 studies): Two studies (one replicated, randomized, paired, controlled) in bogs in New Zealand and Estonia reported that plots sown with shrub seeds (sometimes along with other interventions) developed greater cover of some shrubs than plots that were not sown: sown manuka or naturally colonizing heather (but not sown cranberry). One replicated, randomized, paired, controlled study in a fen in the USA found that plots sown with shrub (and herb) seeds developed similar overall shrub cover to unsown plots within two years. Overall vegetation cover (3 studies): Two replicated, randomized, paired, controlled studies in a bog in New Zealand and a fen in the USA reported that plots sown with shrub (and herb) seeds developed greater total vegetation cover than unsown plots after two years. One site comparison study in bogs in Estonia reported that sowing shrub seeds (along with fertilization) had no effect on total vegetation cover after 25 years. Overall plant richness/diversity (3 studies): One site comparison study in bogs in Estonia reported that sowing shrub seeds (along with fertilization) increased plant species richness. However, one replicated, randomized, paired, controlled study in a bog in New Zealand reported that plots sown with shrub seeds typically contained fewer plant species than plots that were not sown. One replicated, randomized, paired, controlled study in a fen in the USA found that sowing shrub (and herb) seeds had no effect on plant species richness. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1824https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1824Tue, 28 Nov 2017 08:46:23 +0000Collected Evidence: Collected Evidence: Exclude or limit number of visitors to reserves or protected areas Five studies evaluated the effects on mammals of excluding or limiting the number of visitors to reserves or protected areas. Three studies were in the USA, one was in Ecuador and one was in Thailand. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (1 study): A site comparison study in Ecuador found that a road with restricted access had a higher population of medium-sized and large mammals compared to a road with unrestricted access. Survival (1 study): A before-and-after study in the USA found that temporarily restricting visitor access resulted in fewer bears being killed to protect humans. BEHAVIOUR (3 STUDIES) Use (3 studies): Three studies (one a before-and-after study), in the USA and Thailand, found that restricting human access to protected areas resulted in increased use of these areas by grizzly bears and leopards. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2330https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2330Thu, 21 May 2020 10:43:02 +0100Collected Evidence: Collected Evidence: Use collar-mounted devices to reduce predation by domestic animals Five studies evaluated the effects on mammals of using collar-mounted devices to reduce predation by domestic animals. Three studies were in the UK, one was in Australia and one was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (5 STUDIES) Survival (5 studies): Five replicated studies (including four randomized, controlled studies), in the UK, Australia and the USA, found that bells, a sonic device, and a neoprene flap (which inhibits pouncing) mounted on collars, and a brightly coloured and patterned collar all reduced the rate at which cats predated and returned home with mammals. In one of these studies, an effect was only found in autumn, and not in spring. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2332https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2332Thu, 21 May 2020 11:11:00 +0100Collected Evidence: Collected Evidence: Pay farmers to compensate for losses due to predators/wild herbivores to reduce human-wildlife conflict Five studies evaluated the effects on mammals of paying farmers compensation for losses due to predators or wild herbivores to reduce human-wildlife conflict. Three studies were in Kenya and one each was in Italy and Sweden. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (5 STUDIES) Abundance (2 studies): Two studies, in Italy and Sweden, found that compensating livestock owners for losses to predators led to increasing populations of wolves and wolverines. Survival (3 studies): Three before-and-after studies (including two replicated studies), in Kenya, found that when pastoralists were compensated for livestock killings by predators, fewer lions were killed. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2414https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2414Fri, 29 May 2020 15:48:47 +0100Collected Evidence: Collected Evidence: Use flags to reduce predation of livestock by mammals to reduce human-wildlife conflict Five studies evaluated the effects on mammals of using flags to reduce predation of livestock by mammals to reduce human-wildlife conflict. Three studies were in the USA, one was in Italy and one was in Canada. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (5 STUDIES) Human-wildlife conflict (5 studies): Three studies (including two before-and-after studies and a controlled study), in Italy, Canada and the USA, found that flags hanging from fence lines (fladry) deterred crossings by wolves but not by coyotes. A further replicated, controlled study in the USA found that electric fences with fladry were not crossed by wolves. A replicated, controlled, before-and-after study in the USA found that fladry did not reduce total deer carcass consumption by a range of carnivores. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2421https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2421Mon, 01 Jun 2020 13:54:30 +0100Collected Evidence: Collected Evidence: Deter predation of livestock by using shock/electronic dog-training collars to reduce human-wildlife conflict Five studies evaluated the effects of using shock/electronic dog-training collars to deter predation of livestock to reduce human-wildlife conflict. All five studies were in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (5 STUDIES) Human-wildlife conflict (5 studies): Three of four replicated studies (including two controlled studies), in the USA, found that electric shock collars reduced livestock predation or bait consumption by wolves, whilst one found that they did not reduce wolf bait consumption. One replicated, controlled study in the USA found that electric shock collars reduced the frequency of attacks by captive coyotes on lambs. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2446https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2446Tue, 02 Jun 2020 10:37:37 +0100Collected Evidence: Collected Evidence: Release translocated/captive-bred mammals in larger unrelated groups Five studies evaluated the effects of releasing translocated or captive-bred mammals in larger unrelated groups. Two studies were in South Africa, one was in Namibia and South Africa, one was in the USA and one was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (5 STUDIES) Reproductive success (3 studies): A replicated, paired sites study in the USA found that black-tailed prairie dogs translocated in larger groups had higher reproductive success than smaller groups. A study in South Africa found that Cape buffalo translocated to a fenced reserve as a larger group formed a single herd and reproduced, whilst a smaller group separated. A study in South Africa found that rehabilitated and captive-bred cheetahs released in groups (unrelated and family) and as individuals reproduced. Survival (4 studies): A replicated, paired sites study in the USA found that black-tailed prairie dogs translocated in larger groups had higher initial daily survival rate than smaller groups. Two studies (one controlled) in Namibia and South Africa and Australia found that releasing translocated black rhinoceroses and burrowing bettongs in larger groups did not increase survival. A study in South Africa found that most adult rehabilitated and captive-bred cheetahs released in groups (unrelated and family) and as individuals survived at least one year. BEHAVIOUR (2 STUDIES) Behaviour change (2 studies): A replicated, paired sites study in the USA found that black-tailed prairie dogs translocated in larger groups attracted more immigrants than smaller groups. A study in South Africa found that Cape buffalo translocated as a larger group formed a single herd and stayed in the fenced reserve, whilst a smaller group scattered and escaped the reserve. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2462https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2462Tue, 02 Jun 2020 12:01:41 +0100Collected Evidence: Collected Evidence: Use target species distress calls or signals to deter crop damage by mammals to reduce human-wildlife conflict Five studies evaluated the effects of using target species distress calls or signals to deter crop damage by these species to reduce human-wildlife conflict. Two studies were in the USA and one each was in Namibia, Australia and Sri Lanka. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (5 STUDIES) Human-wildlife conflict (5 studies): Two of five replicated studies (including four controlled studies), in the USA, Namibia, Australia and Sri Lanka, found that white-tailed deer and Asian elephants were deterred or repelled from areas by playing their respective distress calls. Two studies found that, in most cases, elephants and white-tailed deer were not deterred from entering or remaining at sites when distress calls were played. The fifth study found mixed results but, overall, eastern grey kangaroo foot-thumping noises did not increase numbers leaving a site. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2488https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2488Thu, 04 Jun 2020 13:14:16 +0100Collected Evidence: Collected Evidence: Restore or create forest Five studies evaluated the effects on mammals of restoring or creating forest. Two studies were in the USA and one each were in Colombia, Italy and Australia. COMMUNITY RESPONSE (2 STUDIES) Richness/diversity (2 studies): Two site comparison studies (one replicated) in the USA and Colombia found that mammal species richness in restored forest was similar to that in established forest. POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): One of two replicated studies (one a site comparison) in Australia and Italy found that replanted or regrowing forest supported a higher abundance of hazel dormice than did coppiced forest. The other study found only low numbers of common brushtail possums or common ringtail possums by 7–30 years after planting. BEHAVIOUR (1 STUDY) Usage (1 study): A replicated, site comparison study in the USA found that restored riparian forest areas were visited more by carnivores than were remnant forests when restored areas were newly established, but not subsequently, whilst restored areas were not visited more frequently by black-tailed deer. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2570https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2570Tue, 09 Jun 2020 17:06:23 +0100Collected Evidence: Collected Evidence: Prohibit or restrict hunting of a species Five studies evaluated the effects of prohibiting or restricting hunting of a mammal species. One study each was in Norway, the USA, South Africa, Poland and Zimbabwe. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (5 STUDIES) Abundance (2 studies): Two studies (including one before-and-after study), in the USA and Poland, found that prohibiting hunting led to population increases of tule elk and wolves. Survival (3 studies): A before-and-after study in Norway found that restricting or prohibiting hunting did not alter the number of brown bears killed. A study in Zimbabwe reported that banning the hunting, possession and trade of Temminck’s ground pangolins did not eliminate hunting of the species. A before-and-after study in South Africa found that increasing legal protection of leopards, along with reducing human-leopard conflict by promoting improved animal husbandry, was associated with increased survival. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2597https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2597Thu, 11 Jun 2020 15:05:02 +0100Collected Evidence: Collected Evidence: Use chemical repellents along roads or railways Five studies evaluated the effects on mammals of using chemical repellents along roads or railways. Two studies were in Canada and one each was in Germany, Norway and Denmark. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): Two studies (one before-and-after, one site comparison), in Germany and Norway, found that chemical-based repellents did not reduce collisions between ungulates and road vehicles or trains. BEHAVIOUR (4 STUDIES) Behaviour change (4 studies): Two of four studies (including three replicated, controlled studies), in Germany, Canada, and Denmark, found that chemical repellents, trialled for potential to deter animals from roads, did not deter ungulates. The other two studies found mixed results with repellents temporarily deterring some ungulate species in one study and one of three deterrents deterring caribou in the other. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2615https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2615Fri, 12 Jun 2020 08:24:14 +0100Collected Evidence: Collected Evidence: Provide mammals with escape routes from canals Five studies evaluated the effects on mammals of providing mammals with escape routes from canals. Two studies were in Germany and one each was in the USA, the Netherlands and Argentina. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Survival (2 studies): One of two studies (one before-and-after), in Germany and the USA, found that ramps and ladders reduced mule deer drownings whilst the other study found that ramps and shallow-water inlets did not reduce mammal drownings. BEHAVIOUR (3 STUDIES) Use (3 studies): Three studies (one replicated) in Germany, the Netherlands and Argentina, found that ramps and other access or escape routes out of water were used by a range of medium-sized and large mammals species. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2638https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2638Fri, 12 Jun 2020 13:06:54 +0100Collected Evidence: Collected Evidence: Establish long-term fishery closures Five studies examined the effects of establishing long-term fishery closures in an area on marine fish populations. One study was in each of the Norwegian Sea (Norway), the North Sea (UK), the Gulf of Maine (USA), the Bismark Sea (Papua New Guinea) and the Kattegat (Sweden/Denmark). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (4 STUDIES) Condition (2 studies): One replicated, before-and-after study in the Norwegian Sea found that in the five years after the long-term closure of a commercial coastal fishery, the weights of young salmon returning to rivers were higher than before, and weights of older salmon were similar or lower. One site comparison study in the Gulf of Maine found that there were smaller, but similar condition monkfish inside an area closed year-round to groundfish fishing for six to seven years than an area open to all fishing. Abundance (4 studies): Two site comparison studies in the Gulf of Maine and Bismark Sea found a higher abundance of only one of seven fish species and lower abundance of monkfish in areas closed to groundfish (bottom-dwelling) fisheries for six to eight years, compared to open areas. One of two replicated, before-and-after studies (one controlled) in the Norwegian Sea and North Sea found that there were more young salmon and similar numbers of older salmon returning to rivers than before, in the five years after the long-term closure of a commercial coastal fishery. The other study found that lesser sandeel biomass and density peaked but there was no overall increase in the three years after a long-term fishery closure compared to before. BEHAVIOUR (1 STUDY) Behaviour change (1 study): One site comparison study in the Bismark Sea found that in an area closed to customary fishing for eight years, six of seven fish species had a lower flight response distance compared to an area open to customary fishing, making them more vulnerable to capture with spear guns. OTHER (3 STUDIES) Reduction of unwanted catch (1 study): One replicated, before-and-after study in the Kattegat found that a combination of long-term fishery closures and areas limited to specific gears reduced unwanted catch of cod compared to before. Reduction of fishing effort (1 study): One replicated, controlled, before-and-after study in the North Sea found that long-term closure of a commercial fishery reduced overall fishing effort for lesser sandeel. Commercial catch abundance (1 study): One replicated, controlled, before-and-after study in the North Sea found that annual sandeel catch rates were varied after the indefinite closure of the commercial fishery in an area. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2655https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2655Thu, 12 Nov 2020 14:53:37 +0000Collected Evidence: Collected Evidence: Raise water level to restore degraded freshwater marshes Five studies evaluated the effects, on vegetation, of raising the water level to restore degraded freshwater marshes. There were three studies in the USA and one in each of the Netherlands and Japan. VEGETATION COMMUNITY Overall extent (1 study): One before-and-after study of a floodplain in Japan reported that the area covered by marsh vegetation was higher five years after dechannelizing a river than 10 years before. Community types (1 study): One before-and-after study of a floodplain in Japan reported changes in the area covered by different marsh plant communities over five years after dechannelizing a river compared to 10 years before. Community composition (1 study): One replicated study of dune slacks in the Netherlands reported changes in the overall plant community composition after stopping groundwater extraction (along with other interventions). Overall richness/diversity (2 studies): One replicated, site comparison study of dune slacks in the Netherlands reported that overall plant species richness was greater in restored slacks (groundwater extraction stopped five years previously, along with other interventions) than in mature unmanaged slacks. One replicated, before-and-after study of floodplain marshes in the USA reported that total plant species richness tended to be lower over nine years after raising the water table than before, but that there was no significant difference for diversity. Characteristic plant richness/diversity (1 study): One replicated study of dune slacks in the Netherlands simply quantified the richness of characteristic plant species – typical of dune slacks or nutrient-rich marshes – over five years after stopping groundwater extraction (along with other interventions). VEGETATION ABUNDANCE Overall abundance (3 studies): One replicated, before-and-after study of floodplain marshes in the USA reported that total vegetation cover tended to be lower over nine years after raising the water table than before. One replicated, randomized, paired, controlled, before-and-after study of freshwater marshes in the USA found that damming to raise the water table prevented increases in understory vegetation cover over the following year. One replicated study of dune slacks in the Netherlands simply quantified total vegetation over five years after stopping groundwater extraction (along with other interventions). Cover never exceeded 50%. Herb abundance (1 study): One replicated, randomized, paired, controlled, before-and-after study of freshwater marshes in the USA found that damming to raise the water table had no significant effect on cover of sedges Carex There were similar increases in dammed and undammed marshes over one year. Characteristic plant abundance (1 study): One replicated, before-and-after study of floodplain marshes in the USA reported changes in the cover of wetland- and habitat-characteristic plant species over nine years after raising the water table. Individual species abundance (3 studies): Three studies quantified the effect of this intervention on the abundance of individual plant species. For example, one replicated, before-and-after study in the USA reported that rewetted floodplain marshes became dominated by a non-native wetland shrub, approximately 4–9 years after raising the water table. One replicated study of a freshwater wetland in the USA reported that the effects of reflooding on the density of emergent plant species depended on the species and water level. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3026https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3026Wed, 31 Mar 2021 14:47:11 +0100Collected Evidence: Collected Evidence: Use grazing to maintain or restore disturbance: freshwater marshes Five studies evaluated the effects, on vegetation, of using grazing to maintain or restore disturbance in freshwater marshes. Two studies were in the UK. There was one study in each of the Netherlands, Germany and the USA. VEGETATION COMMUNITY Community types (2 studies): One study of a riparian wet meadow in Germany reported changes in the area of plant community types over four years of grazing (after cutting trees/shrubs). One replicated, before-and-after study of dune slacks in the UK reported that the plant community type within plots remained stable over 16 years of grazing. Community composition (3 studies): Two replicated, randomized, paired, controlled, studies in freshwater marshes/wet meadows in the UK and the USA reported that the overall plant community composition was similar in grazed and ungrazed plots after 2–9 years. One replicated study of dune slacks in the Netherlands simply reported changes in the overall plant community composition after resuming grazing (along with other interventions). Overall richness/diversity (4 studies): Two studies (one replicated, before-and-after) in wetlands in Germany and the UK reported that after resuming grazing (and cutting trees/shrubs in one study), there were increases in total plant species richness and/or diversity. One replicated, randomized, paired, controlled, before-and-after study in the UK reported that grazing had no significant effect on overall plant species richness in wet grassland and flush vegetation: there were similar declines over nine years in grazed and ungrazed plots. One replicated study of dune slacks in the Netherlands simply quantified total plant species richness over three years after resuming grazing (along with other interventions). Characteristic plant richness/diversity (2 studies): One replicated, before-and-after study in dune slacks in the UK reported that after resuming grazing, the number of dune-slack indicator species increased. One replicated study of dune slacks in the Netherlands simply quantified the richness of characteristic plant species – typical of dune slacks or nutrient-rich marshes – over three years after resuming grazing (along with other interventions). VEGETATION ABUNDANCE Overall abundance (2 studies): One replicated, randomized, paired, controlled, before-and-after study in freshwater marshes/wet meadows in the USA found that grazing typically had no significant effect on overall vegetation biomass after 1–2 years. One replicated study of dune slacks in the Netherlands simply quantified total vegetation cover over three years after resuming grazing (along with other interventions). Cover never exceeded 50%. Herb abundance (1 study): One replicated, randomized, paired, controlled, before-and-after study in the UK reported that grazing had no significant effect on the cover of forbs or grass-like plants in wet grassland and flush vegetation: there were similar declines over nine years in grazed and ungrazed plots. Tree/shrub abundance (1 study): One study of a riparian wet meadow in Germany reported that some trees/shrubs regrew over four years of grazing (after cutting trees/shrubs). Bryophyte abundance (1 study): One replicated, randomized, paired, controlled, before-and-after study in the UK reported that grazing had no significant effect on bryophyte cover in wet grassland and flush vegetation: there were similar changes over nine years in grazed and ungrazed plots. Individual species abundance (1 study): One replicated study of dune slacks in the Netherlands simply quantified the cover of individual species present over three years after resuming grazing (along with other interventions). Only two species had >1% cover in any slack. VEGETATION STRUCTURE Height (2 studies): One site comparison study of a riparian wet meadow in Germany reported that an area grazed by cattle (after cutting trees/shrubs) contained shorter vegetation than an adjacent unmanaged area. One replicated, randomized, paired, controlled study in wet grassland and flush vegetation in the UK found that the maximum vegetation height was typically similar, over four years, in plots grazed by cattle and plots from which cattle were excluded. OTHER Survival (1 study): One study of a riparian wet meadow in Germany reported that 20% of black alder Alder glutinosa trees were still alive after being cut back and grazed for four years. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3050https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3050Thu, 01 Apr 2021 19:34:04 +0100Collected Evidence: Collected Evidence: Physically remove problematic plants: freshwater marshes Five studies evaluated the effects, on vegetation, of physically removing problematic plants from freshwater marshes. Three studies were in the USA, one was in India and one was in France. Two of the studies in the USA were in the same site and shared some plots. VEGETATION COMMUNITY Community composition (1 study): One replicated, randomized, paired, controlled, before-and-after study in the USA found that physically removing all vegetation from a cattail-invaded marsh altered the overall plant community composition, over the following two years. Overall richness/diversity (3 studies): One replicated, randomized, paired, controlled, before-and-after study in the USA found that removing all vegetation from a cattail-invaded marsh increased overall plant species richness 1–2 years later. Two replicated, randomized, paired, controlled, before-and-after studies in wet meadows in the USA found that physically removing vegetation had no significant effect on overall plant species richness or diversity three years later. One of the studies removed all vegetation, whilst the other controlled regrowth of the invasive species (by physical removal along with herbicide application). Characteristic plant richness/diversity (1 study): One controlled, before-and-after study in a temporary marsh in France reported that stripping all vegetation increased the number of habitat-characteristic plant species present in the following two years. VEGETATION ABUNDANCE Overall abundance (3 studies): Three before-and-after studies (two also replicated, randomized, paired, controlled) in freshwater marshes/wet meadows in India and the USA found that physically removing vegetation had no clear or significant effect on overall vegetation cover, nine months or three years later. Two of the studies removed all vegetation, whilst one controlled regrowth of the invasive species (by physical removal along with herbicide application). Herb abundance (2 studies): Of two replicated, randomized, paired, controlled, before-and-after studies in loosestrife-invaded wet meadows in the USA, one reported that removing all vegetation increased the cover of grass-like plants, and reduced the cover of forbs, three years later. The other study found that controlling regrowth of the invasive species – by physical removal and applying herbicide – had no significant effect on cover of grass-like plants or forbs after three years. Algae/phytoplankton abundance (1 study): One before-and-after, site comparison study in India reported that removing all vegetation from a knotgrass-invaded marsh increased the cover of algae nine months later. Individual species abundance (3 studies): Three studies quantified the effect of this action on the abundance of individual plant species, other than the target problematic species. For example, one before-and-after, site comparison study in India reported that removing all vegetation from a knotgrass-invaded marsh increased the cover of some other common herb species nine months later. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3091https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3091Sat, 03 Apr 2021 14:59:31 +0100Collected Evidence: Collected Evidence: Physically damage problematic plants: freshwater marshes Five studies evaluated the effects, on vegetation, of physically damaging problematic plants in freshwater marshes. There were two studies in Australia and two in Costa Rica. In each country, the two studies were based in one study area but used different experimental set-ups. The final study was in Mexico. VEGETATION COMMUNITY Overall extent (1 study): One controlled, before-and-after study in a freshwater marsh in Costa Rica reported that crushing (and burning) cattail stands reduced the area of live vegetation present 5–22 months later. Community composition (1 study): One replicated, randomized, paired, controlled study in a marsh in Costa Rica found that plots in which cattail-dominated vegetation was crushed had a different overall plant community composition, over the following 15 months, to plots in which vegetation was not crushed. Overall richness/diversity (3 studies): Two controlled studies (one also replicated, randomized, paired) in one freshwater marsh in Costa Rica reported that in plots where cattail-dominated vegetation was crushed (sometimes along with burning), plant species richness and diversity were not lower than in plots where vegetation was not crushed (or burned). Vegetation was surveyed 2–22 months after intervention. One replicated, randomized, paired, controlled study in a freshwater marsh in Mexico found that disking after cutting grass-invaded vegetation increased overall plant diversity, after 4–8 months, compared to cutting alone. However, disking had no significant effect on plant richness. VEGETATION ABUNDANCE Overall abundance (2 studies): One controlled, before-and-after study in a freshwater marsh in Costa Rica reported that crushing (and burning) cattail stands reduced live vegetation cover 5–22 months later. One replicated, randomized, paired, controlled study in a freshwater marsh in Mexico found that disking after cutting grass-invaded vegetation typically had no significant effect on overall plant density, after 4–8 months, compared to cutting alone. Herb abundance (1 study): One study of a floodplain marsh in Australia simply reported grass/sedge cover for up to four years after crushing mimosa-invaded vegetation (along with other interventions). Native/non-target abundance (2 studies): One replicated, randomized, paired, controlled, before-and-after study in a mimosa-invaded wetland in Australia reported that crushing mimosa stands did not reduce – and often increased – cover of non-mimosa vegetation one year later. One study of a floodplain marsh in Australia simply reported non-target vegetation cover for up to four years after crushing mimosa-invaded vegetation (along with other interventions). Individual species abundance (2 studies): Two studies quantified the effect of this action on the abundance of individual plant species, other than the species being controlled. One replicated, randomized, paired, controlled study in a freshwater marsh in Costa Rica found that plots in which cattail-dominated vegetation was crushed supported a greater abundance of individual plant species other than cattail, over the following 15 months, than plots in which vegetation was not crushed. One replicated, randomized, paired, controlled study in a freshwater marsh in Mexico found that disking after cutting grass-invaded vegetation increased the cover of two of five common native plant species, after 4–8 months, compared to cutting alone. VEGETATION STRUCTURECollected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3095https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3095Sat, 03 Apr 2021 16:05:22 +0100Collected Evidence: Collected Evidence: Build barriers to protect littoral brackish/salt marshes from rising water levels and severe weather Five studies evaluated the effects, on vegetation, of building barriers to protect littoral brackish/salt marshes from rising water levels and severe weather. Three studies were in the USA, one was in Italy and one was in the Netherlands. VEGETATION COMMUNITY Overall extent (3 studies): Two controlled studies (one also replicated, randomized, paired) in Italy and the USA found that protecting salt marshes with offshore structures had no significant effect on the seaward limit of emergent vegetation, after 17–27 months. It was similar, or retreated at a similar rate, in protected and unprotected marshes. One replicated, randomized, paired, controlled study in the USA found that brackish marshes protected with oyster shell reefs receded less, over one year, than unprotected marshes. Community composition (1 study): One replicated, site comparison study in the Netherlands reported that marshes protected with low sea walls had a similar overall plant community composition to nearby natural salt marshes, 15–22 years after the walls were built. Overall richness/diversity (2 studies): One controlled study in Italy reported that a salt marsh protected with an offshore fence contained more plant species, after 17 months, than an unfenced marsh. One replicated, site comparison study in the Netherlands recorded 85 plant and algal species across two salt marshes that had developed behind low sea walls, over 15–22 years, compared to 155 species recorded across multiple natural marshes in the region. VEGETATION ABUNDANCE Overall abundance (2 studies): Two controlled studies (one also replicated, randomized, paired) in Italy and the USA found that brackish/salt marshes protected with offshore structures contained a similar total amount of vegetation to unprotected marshes. This was true for cover and biomass. Individual species abundance (2 studies): One replicated, paired, site comparison study in the USA found that salt marshes protected with offshore breakwaters (and planted with cordgrasses Spartina spp.) typically contained less smooth cordgrass S. alterniflora, after 2–3 growing seasons, than nearby natural marshes. One replicated, site comparison study in the Netherlands reported that in marshes protected with low sea walls for 15–22 years and nearby natural salt marshes, the same plant species were the most frequent. VEGETATION STRUCTURE Height (1 study): One replicated, paired, site comparison study in the USA found that salt marshes protected with offshore breakwaters (and planted with cordgrasses Spartina spp.) contained shorter smooth cordgrass S. alterniflora plants, after 2–3 growing seasons, than nearby natural marshes. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3182https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3182Tue, 06 Apr 2021 16:13:45 +0100Collected Evidence: Collected Evidence: Reprofile/relandscape: brackish/saline swamps Five studies evaluated the effects, on vegetation, of reprofiling/relandscaping to restore or create brackish/saline swamps. Three studies were in the USA. Two of these shared a study site. There was one study in Singapore and one in Thailand. VEGETATION COMMUNITY Overall extent (1 study): One study of a coastal site in the USA reported that the area of mangrove vegetation increased between 6 and 14 years after reprofiling (and planting propagules). Relative abundance (2 studies): Two site comparison studies in the USA and Singapore reported that areas of reprofiled coastal land (sometimes also planted with propagules) supported a different relative abundance of tree species to natural forests, after roughly 3–15 years. Overall richness/diversity (1 study): One site comparison study in Singapore reported that an area of reprofiled coastal land colonized by mangrove vegetation had higher plant species richness, after three and a half years, than an adjacent mature mangrove patch. Tree/shrub richness/diversity (3 studies): Two replicated, site comparison studies in the USA, reported that where mangrove forests developed on reprofiled (and planted) sites, they contained a similar number of tree species to nearby mature forests after 7–30 years. One study in a former shrimp pond in Thailand simply reported the number of mangrove tree species that spontaneously colonized in the six years after reprofiling (along with other interventions). VEGETATION ABUNDANCE Overall abundance (1 study): One site comparison study in Singapore reported that an area of reprofiled coastal land colonized by mangrove vegetation had a higher density of individual plants, after three and a half years, than an adjacent mature mangrove patch. Tree/shrub abundance (3 studies): Two replicated, site comparison studies in the USA, reported that where mangrove forests developed on reprofiled (and planted) sites, they contained a greater density of trees than nearby mature forests after 17–30 years. One study in a former shrimp pond in Thailand simply reported the number of mangrove trees that spontaneously colonized in the six years after reprofiling (along with other interventions). Individual species abundance (1 study): One study in a former shrimp pond in Thailand reported the number of mangrove trees, by species, that spontaneously colonized in the six years after reprofiling (along with other interventions). VEGETATION STRUCTURE Overall structure (1 study): One replicated, site comparison study in the USA reported that where mangrove forests developed on reprofiled (and planted) sites, they had a different overall structure to nearby mature forests after 17–30 years. Height (2 studies): One replicated, site comparison study in the USA, reported that where mangrove forests developed on reprofiled (and planted) sites, they had a shorter canopy than nearby mature forests after 17–30 years. One site comparison study in Singapore reported that in an area of reprofiled coastal land colonized by mangrove vegetation, most plants were in a similar height category to those in an adjacent mature mangrove patch, but that the maximum plant height was lower. Vegetation was surveyed three and a half years after reprofiling. Diameter/perimeter/area (2 studies): Two site comparison studies in the USA reported that mangrove forests that developed on reprofiled (and planted) coastal areas contained thinner trees, on average, than mature natural forests, after 7–18 years. Basal area (3 studies): Three site comparison studies in the USA compared mangrove forests that developed on reprofiled (and planted) coastal areas to mature natural forests. Two of the studies reported that restored forests had a smaller basal area than mature natural forests, after 7–18 years. The other study reported that restored forests had a similar basal area to mature natural forests, after 17–30 years. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3216https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3216Fri, 09 Apr 2021 09:10:45 +0100Collected Evidence: Collected Evidence: Add sediment: brackish/salt marshes Five studies evaluated the effects, on vegetation, of adding sediment to existing brackish/salt marshes. All five studies were in the USA. Two studies were based on one experimental set-up and two studies were based on another. VEGETATION COMMUNITY Relative abundance (1 study): One replicated, site comparison study in the USA found that salt marshes amended with sediment typically supported a greater relative abundance of smooth cordgrass Spartina alterniflora than degraded marshes after two years, but that this typically remained lower than in natural marshes. Overall richness/diversity (1 study): The same study found that salt marshes amended with sediment typically had greater plant species richness than degraded marshes, and statistically similar richness to natural marshes, after two years. VEGETATION ABUNDANCE Overall abundance (1 study): One replicated, site comparison study in the USA found that salt marshes amended with sediment typically had greater total vegetation cover than degraded marshes, and statistically similar cover to natural marshes, after two years. Individual species abundance (4 studies): Four studies quantified the effect of this action on the abundance of individual plant species. For example, all four studies (including two replicated, randomized, paired, controlled) of salt marshes in the USA found that adding sediment typically increased the abundance of smooth cordgrass Spartina alterniflora, over approximately 1–5 years. This is based on total biomass, density and/or cover. One of the studies reported that adding sediment increased the cover of three other species after one year. VEGETATION STRUCTURE Height (1 study): One replicated, randomized, paired, controlled study in a salt marsh in the USA found that the height of the dominant plant species, smooth cordgrass Spartina alterniflora, did not significantly differ between plots amended with sediment and unamended plots. Height was measured 16 months after sediment amendment began. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3231https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3231Fri, 09 Apr 2021 14:26:47 +0100Collected Evidence: Collected Evidence: Introduce fragments of non-woody plants: freshwater wetlands Five studies evaluated the effects, on vegetation, of introducing fragments of emergent, non-woody plants to freshwater wetlands. Three studies were in the USA. Two studies were in one marsh in Australia, but used different experimental set-ups. VEGETATION COMMUNITY   VEGETATION ABUNDANCE Overall abundance (2 studies): Two replicated, randomized, paired, controlled, before-and-after studies in a floodplain marsh in Australia found that plots planted with wick grass Hymenachne acutigluma had similar overall vegetation cover to unplanted plots after one year. One of the studies continued for longer, and found that planted plots had greater overall vegetation cover than unplanted plots after three years. Herb abundance (1 study): One replicated, randomized, paired, controlled, before-and-after study in a floodplain marsh in Australia found that plots planted with wick grass Hymenachne acutigluma had similar overall sedge/grass cover to unplanted plots after one year. Individual species abundance (4 studies): Four studies quantified the effect of this action on the abundance of individual plant species. For example, of two replicated, randomized, paired, controlled, before-and-after studies in a floodplain marsh in Australia, one found that wick grass Hymenachne acutigluma was more frequent and had greater cover, after 1–3 years, in plots where its runners had been planted than where they had not been planted. The other study reported that wick grass cover was present, with approximately 1% cover, in 5 of 10 plots where its runners had been planted. This study monitored vegetation one year after planting. VEGETATION STRUCTURE   OTHER Germination/emergence (1 study): One replicated, randomized, paired, controlled study in a floodplain marsh in Australia found that planting wick grass Hymenachne acutigluma had no significant effect on the germination rate of invasive mimosa Mimosa pigra over three years. Survival (5 studies): Two replicated studies planted sedge Carex fragments into freshwater wetlands in the USA. One study reported 38–79% survival of planted tubers over one growing season, whilst the other study reported 0–73% survival of planted rhizomes after 1–9 months. One replicated study in a tidal freshwater marsh in the USA reported that 6–31% of planted California bulrush Schoenoplectus californicus rhizomes had produced shoots after three months. For two other species, all planted rhizomes died within three months. Two replicated, randomized, paired, controlled, before-and-after studies in a floodplain marsh in Australia reported absence of planted wick grass Hymenachne acutigluma from 17–50% of plots after one year. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3260https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3260Sat, 10 Apr 2021 13:28:02 +0100Collected Evidence: Collected Evidence: Use fences or barriers to protect freshwater wetlands planted with trees/shrubs Five studies evaluated the effects, on vegetation, of using fences or barriers to protect freshwater wetlands planted with trees/shrubs. Four studies were in the USA and one was in Australia. VEGETATION COMMUNITY   VEGETATION ABUNDANCE Tree/shrub abundance (1 study): One replicated, paired, controlled study in a floodplain swamp clearing in the USA found that amongst plots sown with tree seeds, fencing to exclude deer had no significant effect on total tree seedling density after three years. VEGETATION STRUCTURE Height (2 studies): One replicated, paired, controlled study in a floodplain swamp clearing in the USA found that amongst plots sown with tree seeds, those also fenced to exclude deer contained taller tree seedlings, after three years, than those left unfenced. One replicated, paired, controlled study in created freshwater wetlands in the USA found that the average height of white cedar Thuja occidentalis saplings typically increased by a similar amount, between two and five years after planting, in plots fenced to exclude deer and plots left unfenced. OTHER Survival (3 studies): One replicated, paired, controlled study in floodplain swamps in Australia reported that planted swamp gum Eucalyptus camphora seedlings had a much higher survival rate, over one year, in plots fenced to exclude mammals than in open plots. Two replicated, paired, controlled studies in freshwater wetlands in the USA reported that exclusion fencing sometimes increased survival of planted tree seedlings but sometimes had no clear or significant effect. This depended on factors such as the season of planting, seedling elevation, and site. Growth (1 study): One replicated, randomized, controlled study in a nutria-invaded wetland in the USA found that planted baldcypress Taxodium distichum seedlings grew more, over one growing season, when protected than when left unprotected. Plastic guards increased height and diameter growth rates. Sticky, insect-repellent oil increased the growth rate for height, but not diameter. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3330https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3330Sun, 11 Apr 2021 13:15:05 +0100Collected Evidence: Collected Evidence: Remove vegetation that could compete with planted trees/shrubs: freshwater wetlands Five studies evaluated the effects, on trees/shrubs planted in freshwater wetlands, of removing competing plants. Four studies were in the USA. Two of these took place in the same swamp, but with different experimental set-ups. One study was in Australia. VEGETATION COMMUNITY   VEGETATION ABUNDANCE   VEGETATION STRUCTURE Height (3 studies): Three replicated, controlled studies (two also randomized, two also paired) in a wet meadow in Australia and a degraded swamp in the USA found that clearing vegetation before planting tree/shrub seedlings typically had no clear or significant effect on their height, after 1–4 growing seasons. However, one of the studies in the USA found that planted baldcypress Taxodium distichum seedlings were taller, after three growing seasons, when planted amongst cut woody vegetation than below an uncleared canopy. Diameter/perimeter/area (1 study): One replicated, randomized, paired, controlled study in a wet meadow in Australia found that clearing vegetation, before planting tree/shrub seedlings, typically had no significant effect on the diameter of these seedlings nine months later. OTHER Germination/emergence (1 study): One replicated, randomized, paired, controlled study in a wet meadow in Australia found that there were more seedlings in plots that had been cleared of vegetation before sowing tree/shrub seeds, than in plots that had not been cleared before sowing. Seedlings were counted two months after sowing. Survival (4 studies): Three replicated, controlled studies (two also randomized, two also paired) in a wet meadow in Australia and a degraded swamp in the USA found that clearing vegetation before planting tree/shrub seedlings typically had no clear or significant effect on their survival, after 1–4 growing seasons. However, one of the studies in the USA found that planted baldcypress Taxodium distichum seedlings had a lower survival rate, after three growing seasons, when planted amongst cut woody vegetation than below an uncleared canopy. One replicated, randomized, paired, controlled study in degraded swamps in the USA found that removing reed canarygrass Phalaris arundinacea before planting tree/shrub seedlings never significantly reduced their survival rate over 1–2 growing seasons, and often increased it. Growth (1 study): One replicated, randomized, controlled study in the USA found that baldcypress Taxodium distichum seedlings planted into a marsh grew more in diameter, but less in height, when planted into plots cleared of vines than when planted into uncleared plots. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3334https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3334Sun, 11 Apr 2021 14:09:05 +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.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust
For a full list of, and information about, our champions:
All Evidence Champions
About our champions, why and how to become one:
Become an Evidence Champion

This website uses Cookies

We use limited Cookies to run the site and to analyse our traffic (none for site vendors). By using this site, you will be providing your consent to our use of Cookies.

Accept & continue