Collected Evidence: Collected Evidence: Scare birds from fish farms One before-and-after study from Israel found that the population of pygmy cormorants in the area increased after birds were scared away from fish farms, possibly due to lower persecution. One of two studies that examined fish stocks found that fewer fish were taken from a farm when heron distress calls were played. The other study, a literature review, found no evidence for the effects of scaring birds on fish stocks. Two replicated studies from Belgium and Australia found that using foot patrols to disturb birds from fish farms did not reduce the number of birds present or fish consumption. Ten of eleven studies from across the world, three controlled, found evidence that playing distress calls or using other acoustic deterrents (some with flashes of light) reduced the number of birds at fish farms, or changed bird behaviours. One of these involved underwater broadcasting. One study found effects were only temporary and five found that birds became habituated to noises. Four studies, one replicated and controlled, two before-and-after, found that acoustic deterrents were not effective in scaring birds. Five of seven studies, one controlled, found evidence that visual deterrents (including inflatable ‘Scarey Man’ scarecrows) reduced the number of birds at fish farms. Three found evidence for habituation to deterrents and three studies found no evidence that visual deterrents were effective. Two studies examined other deterrents, finding that trained raptors were effective but that the effects of helicopters and ultra-light aircraft were either inconclusive or very temporary.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F244https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F244Wed, 18 Jul 2012 11:00:04 +0100Collected Evidence: Collected Evidence: Reduce incidental mortality from birds being attracted to artificial lights We found no evidence for reduced incidental mortality from birds being attracted to artificial lights. '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%2F466https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F466Wed, 29 Aug 2012 16:14:05 +0100Collected Evidence: Collected Evidence: Install culverts or tunnels as road crossings Thirty-two studies investigated the effectiveness of installing culverts or tunnels as road crossings for amphibians. Six of seven studies (including three replicated studies) in Canada, Germany, Italy, Hungary and the USA found that installing culverts or tunnels significantly decreased amphibian road deaths; in one study this was the case only when barrier fencing was also installed. One found no effect on road deaths. Fifteen of 24 studies (including one review and 17 replicated studies) in Australia, Canada, Europe and the USA found that culverts/tunnels were used by amphibians, by 15–85% of amphibians or 3–15 species, or that 23–100% of culverts or tunnels were used by amphibians or used in 12 of 14 studies reviewed. The majority of culverts/tunnels had barrier fencing to guide amphibians to entrances. Four found mixed effects depending on species, or for toads depending on the site or culvert type. Five found that culverts were used by less than 10% of amphibians or were not used. The use of culverts/tunnels was affected by diameter in three of six studies, with wider culverts used more, length in one of two studies, with long culverts avoided, lighting in all three studies, with mixed effects, substrate in three of six studies, with natural substrates used more, presence of water in two of three studies, with mixed effects, entrance location in one and tunnel climate in one study. Six studies (including one replicated, controlled study) in Canada, Spain, the Netherlands and USA investigated the use of culverts with flowing water and found that they were used by amphibians, or rarely used by salamanders or not used, and were used more or the same amount as dry culverts. Certain culvert designs were not suitable for amphibians; one-way tunnels with vertical entry chutes resulted in high mortality of common toads and condensation deposits from steel culverts had very high metal concentrations. One study found that thousands of amphibians were still killed on the road.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F884https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F884Mon, 16 Sep 2013 12:20:30 +0100Collected Evidence: Collected Evidence: Remove turbine lighting to reduce bat and insect attraction We found no studies that evaluated the effects of removing turbine lighting to reduce bat and insect attraction on bat populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F969https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F969Fri, 20 Dec 2013 12:15:27 +0000Collected Evidence: Collected Evidence: Deter bats from roads/railways using lighting We found no studies that evaluated the effects of deterring bats from roads/railways using lighting on bat populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F982https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F982Fri, 20 Dec 2013 14:27:40 +0000Collected Evidence: Collected Evidence: Leave bat roosts and roost entrances unlit Five studies evaluated the effects of leaving bat roosts and roost entrances unlit on bat populations. Two studies were in the UK, and one study was in each of Canada, Hungary and Sweden. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (1 study): One replicated, controlled study in Canada found that numbers of big brown bats and little brown bats roosting in buildings increased when roosts were left unlit and decreased when roosts were illuminated with artificial lights. Condition (1 study): One replicated, controlled study in Hungary found that juvenile bats had a higher body mass and greater forearm length at unlit roosts than at roosts with artificial lighting. BEHAVIOUR (4 STUDIES)      Use (1 study): One replicated, before-and-after study in Sweden found that all of 13 unlit churches continued to be used by brown long-eared bat colonies over 25 years, but bat colonies abandoned their roosts at 14 of 23 churches that were either partly or fully lit with floodlights. Behaviour change (3 studies): Three controlled studies (including two replicated studies) in the UK and Hungary found that more bats emerged, and bats emerged earlier and foraged for shorter periods, when roosts were left unlit than when they had artificial lighting. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1017https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1017Fri, 20 Dec 2013 17:54:28 +0000Collected Evidence: Collected Evidence: Use tree guards or shelters to protect planted trees One replicated, randomized, controlled study in the USA found that using light but not dark coloured plastic tree shelters increased the survival rate of planted tree seedlings. One replicated, controlled study in Hong Kong found that tree guards increased tree height after 37 but not 44 months.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1268https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1268Fri, 10 Jun 2016 09:07:23 +0100Collected Evidence: Collected Evidence: Humans chase primates using bright light We found no evidence for the effects of humans chasing primates using bright light to deter crop-raiding on primate 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%2F1450https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1450Tue, 17 Oct 2017 12:17:40 +0100Collected Evidence: Collected Evidence: Amphibians: Vary duration of enclosure lighting to simulate seasonal changes in the wild No evidence was captured for the effects of varying duration of enclosure lighting to simulate seasonal changes in the wild. '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%2F1866https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1866Fri, 19 Jan 2018 08:53:32 +0000Collected Evidence: Collected Evidence: Amphibians: Manipulate quality and quantity of enclosure lighting to improve development or survival to adulthood No evidence was captured for the effects of manipulating quality and quantity of lighting to improve development or survival to adulthood. '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%2F1892https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1892Fri, 19 Jan 2018 14:54:25 +0000Collected Evidence: Collected Evidence: Deter bats from turbines using low-level ultraviolet light We found no studies that evaluated the effects of deterring bats from turbines using low-level ultraviolet light on bat populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1958https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1958Tue, 04 Dec 2018 15:13:08 +0000Collected Evidence: Collected Evidence: Minimize road lighting to reduce insect attraction We found no studies that evaluated the effects of minimizing road lighting to reduce insect attraction on bat populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1969https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1969Tue, 04 Dec 2018 18:13:16 +0000Collected Evidence: Collected Evidence: Avoid illumination of bat commuting routes Three studies evaluated the effects of avoiding the illumination of bat commuting routes on bat populations. Two studies were in the UK and one was in the Netherlands. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (3 STUDIES) Abundance (3 studies): One replicated, before-and-after study in the Netherlands found similar numbers of pond bats flying along unlit canals and canals illuminated with lamps. Two replicated, controlled studies in the UK found greater activity (relative abundance) of lesser horseshoe bats and myotis bats along unlit hedges than along hedges illuminated with street lights, but activity was similar for common and soprano pipistrelles and Nyctalus/Eptesicus species along unlit and illuminated hedges. BEHAVIOUR (2 STUDIES)      Behaviour change (2 studies): One replicated, before-and-after study in the Netherlands found that 28–96% of pond bats changed their flight paths along canals to avoid light spill from lamps. One replicated, controlled study in the UK found that lesser horseshoe bats were active earlier along unlit hedges than along those illuminated with street lights. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2017https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2017Wed, 05 Dec 2018 17:50:59 +0000Collected Evidence: Collected Evidence: Avoid illumination of bat foraging, drinking and swarming sites Two studies evaluated the effects of avoiding the illumination of bat drinking sites on bat populations. Both studies were in Italy and one was also in Israel. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (2 STUDIES) Abundance (2 studies): Two replicated before-and-after studies (one randomized) in Italy found that unlit water troughs had greater activity (relative abundance) of five of six bat species/species groups and six of eight bat species/species groups than troughs illuminated with artificial light. One of the studies also found that unlit desert ponds in Israel had greater activity (relative abundance) of three bat species than illuminated ponds. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2018https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2018Wed, 05 Dec 2018 17:52:42 +0000Collected Evidence: Collected Evidence: Direct lighting away from bat access points or habitats We found no studies that evaluated the effects of directing lighting away from bat access points or habitats on bat populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2019https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2019Wed, 05 Dec 2018 17:53:34 +0000Collected Evidence: Collected Evidence: Use 'warm white' rather than 'cool' LED lights We found no studies that evaluated the effects of using ‘warm white’ LED lights rather than ‘cool’ LED lights on bat populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2020https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2020Wed, 05 Dec 2018 18:01:53 +0000Collected Evidence: Collected Evidence: Use glazing treatments to reduce light spill from inside lit buildings We found no studies that evaluated the effects of using glazing treatments to prevent light spill from inside lit buildings on bat populations. ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2022https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2022Wed, 05 Dec 2018 18:07:22 +0000Collected Evidence: Collected Evidence: Limit, cease or prohibit industrial and urban lighting at night We found no studies that evaluated the effects of limiting, ceasing or prohibiting industrial and urban lighting at night on subtidal benthic invertebrate populations.   ‘We found no studies’ means that we have not yet found any studies that have directly evaluated this intervention during our systematic journal and report searches. Therefore, we have no evidence to indicate whether or not the intervention has any desirable or harmful effects.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2208https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2208Tue, 22 Oct 2019 13:20:07 +0100Collected Evidence: Collected Evidence: Designate a Marine Protected Area and prohibit bottom trawling Three studies examined the effects of prohibiting bottom trawling in marine protected areas on subtidal benthic invertebrates. Two studies were in the South Pacific Ocean (Australia) and one in the Coral Sea (Australia).   COMMUNITY RESPONSE (3 STUDIES) Overall community composition (2 studies): One of two replicated, site comparison studies in the South Pacific Ocean found that seamounts within a protected area closed to trawling had different invertebrate community composition compared to trawled seamounts and to never-trawled seamounts after four to nine years. The second study found that seamounts within a protected area closed to trawling had different invertebrate community composition compared to shallow unprotected seamounts (heavily trawled) after two years, but not compared to deep unprotected seamounts (lightly trawled). Overall diversity/species richness (3 studies): One of two replicated, site comparison studies in the South Pacific Ocean found that seamounts within a protected area closed to trawling had similar invertebrate species richness and diversity to trawled seamounts and never-trawled seamounts after four to nine years. The second study found that seamounts within a protected area closed to trawling had more invertebrate species compared to shallow unprotected seamounts (heavily trawled) after two years, but not compared to deep unprotected seamounts (lightly trawled). One randomized, replicated, site comparison study in the Coral Sea found similar combined invertebrate and fish species richness in areas closed to trawling and adjacent fished areas, after seven to eight years. POPULATION RESPONSE (3 STUDIES) Overall abundance (3 studies): One of two replicated, site comparison studies in the South Pacific Ocean found that seamounts within a protected area closed to trawling had lower invertebrate biomass compared to trawled seamounts and never-trawled seamounts after four to nine years. The second study found that seamounts within a protected area closed to trawling had higher invertebrate biomass compared to shallow unprotected seamounts (heavily trawled) after two years, but not compared to deep unprotected seamounts (lightly trawled). One randomized, replicated, site comparison study in the Coral Sea found similar invertebrate and fish biomass in areas closed to trawling and adjacent fished areas, after seven to eight years. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2226https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2226Tue, 22 Oct 2019 15:03:50 +0100Collected Evidence: Collected Evidence: Use light/lasers to deter crop damage by mammals to reduce human-wildlife conflict Two studies evaluated the effects of using light or lasers to deter crop damage by mammals to reduce human-wildlife conflict. Both studies were in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (2 STUDIES) Human-wildlife conflict (2 studies): A replicated, randomized, controlled study in the USA found that red lasers did not disperse white-tailed deer from fields at night whilst a study in India found that spotlights directed at the eyes of Asian elephants did reduce the probability of crop damage. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2496https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2496Thu, 04 Jun 2020 15:25:19 +0100Collected Evidence: Collected Evidence: Install wildlife warning reflectors along roads Fifteen studies evaluated the effects on mammals of installing wildlife warning reflectors along roads. Nine studies were in the USA, three were in Austalia, two were in Germany and one was in Denmark. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (10 STUDIES) Abundance (1 study): A before-and-after study in Australia found that when warning reflectors were installed (along with speed restrictions, reflective wildlife signs, rumble strips, wildlife escape ramps and an educational pamphlet) a small population of eastern quoll re-established in the area. Survival (10 studies): Five of eight controlled or before-and-after studies in the USA and Germany found that wildlife warning reflectors did not reduce collisions between vehicles and deer. Two studies found that vehicle-deer collisions were reduced by reflectors and one found that collisions were reduced in rural areas but increased in suburban areas. A before-and-after study in Australia found that when warning reflectors were installed (along with speed restrictions, reflective wildlife signs, rumble strips, wildlife escape ramps and an educational pamphlet) vehicle collisions with Tasmanian devils, but not eastern quolls, decreased. A review of two studies in Australia found mixed responses of mammal road deaths to wildlife warning reflectors. BEHAVIOUR (5 STUDIES) Behaviour change (5 studies): Three of four studies (including three controlled studies), in the USA, Denmark and Germany, found that wildlife warning reflectors did not cause deer to behave in ways that made collisions with vehicles less likely (such as by avoiding crossing roads). The other study found that deer initially responded to wildlife reflectors with alarm and flight but then became habituated. A replicated, controlled study in Australia found that one of four reflector model/colour combinations increased fleeing behaviour of bush wallabies when lights approached. The other combinations had no effect and none of the combinations affected red kangaroos. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2591https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2591Thu, 11 Jun 2020 09:30:25 +0100Collected Evidence: Collected Evidence: Fit a size-sorting escape grid (rigid or flexible) to a fish trawl net Eighteen studies examined the effects of fitting size-sorting escape grids to a fish trawl net on marine fish populations. Six studies were in the North Sea (France, Norway, Scotland), three were in the North Atlantic Ocean (Portugal, USA), and two were in the Norwegian Sea (Norway). One study was in each of the Barents Sea (Norway), the South Atlantic Ocean (Namibia), the Mediterranean Sea (Spain), the Adriatic Sea (Italy), the Gulf of Maine (USA), and the Baltic Sea (northern Europe). One study was in a laboratory (Japan).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (1 STUDY) Use (1 study): One replicated study in a laboratory in Japan found that masu salmon were able to actively escape through a rigid escape grid, irrespective of grid orientation and towing speed, but escape was reduced in dark conditions compared to light. OTHER (17 STUDIES) Reduction of unwanted catch (14 studies): Eleven of 14 replicated studies (three paired and controlled) in the North Sea, North Atlantic Ocean, Barents Sea, South Atlantic Ocean, Mediterranean Sea, Adriatic Sea, Gulf of Maine and Baltic Sea found that fitting size-sorting escape grids of various types and configurations to fish trawl nets reduced the catches of unwanted small mackerel, small monkfish, non-target whiting and haddock, small hake, unwanted spiny dogfish, non-target herring, prohibited halibut, unwanted sizes of cod and other non-target fish, relative to the retained codend catch or compared to trawls without grids. One study found that fitting size-sorting escape grids of three designs to fish trawl nets reduced the discarded catch of nine of 12 fish species and the overall amount of discarded catch (fish and invertebrates combined), relative to the retained codend catch. One study found that fitting size-sorting escape grids had a mixed effect on the reduction of unwanted and/or undersized fish catch relative to the retained codend catch depending on fish ecological group. The other study found that, compared to standard trawl nets without escape grids, trawls with size-sorting escape grids reduced the overall catch of whiting, but not of undersized whiting. Improved size-selection of fishing gear (3 studies): Two of three replicated studies (two paired and controlled and one controlled) in the North Sea and Norwegian Sea, found that a size-sorting escape grid fitted to trawl nets improved the size-selection of haddock, but not saithe or cod, compared to standard nets without grids. One study found that trawl nets fitted with an escape grid did not improve the size-selection of cod and haddock compared to trawl nets fitted with square mesh escape windows. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2720https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2720Fri, 08 Jan 2021 16:54:19 +0000Collected Evidence: Collected Evidence: Use a different design or configuration of size-sorting escape grid/system in trawl fishing gear (bottom and mid-water) Twenty-three studies examined the effects of using a different design or configuration of size-sorting escape grid/system in trawl fishing gear on marine fish populations. Ten studies were in the Atlantic Ocean (Canada, USA, Brazil, Spain, Norway). Five studies were in the Barents and/or Norwegian Sea (Norway). Two studies were in the Kattegat and Skagerrak (Denmark/Sweden). One study was in each of the Arafura Sea (Australia), the Greenland Sea (Norway), the North Sea (Norway), the North Pacific Ocean (USA) and the Indian Ocean (Australia). One study was in a laboratory (Japan).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) OTHER (23 STUDIES) Reduction of unwanted catch (17 studies): Six of 16 replicated studies (eight paired and controlled, three controlled, one randomized and controlled, and one paired) in the Atlantic Ocean, a laboratory, Arafura Sea, Barents Sea, Kattegat and Skagerrak, Greenland Sea, North Sea, Pacific Ocean and the Indian Ocean, and one controlled study in the Barents Sea found that using a different design or configuration of size-sorting escape grid/system in trawl nets reduced the unwanted (undersized, non-target, discarded) catches of all or most of the fish species assessed, compared to standard or other grid designs/configurations. Four studies found that the effect of using different escape grids on the reduction of unwanted catch varied with fish species, light conditions, and the type of trawl net used. The other six found that, overall, using a different escape grid did not reduce unwanted fish catch. Improve size-selectivity of fishing gear (7 studies): Three of seven replicated studies (three controlled, one paired and controlled) in the Barents/Norwegian Sea, the Atlantic Ocean and the Greenland Sea found that different types or configurations of size-sorting escape grid systems in trawl nets resulted in better size-selectivity for unwanted redfish and Greenland halibut and of commercial target hake compared to other designs or configurations. Three studies found that the effect of using a different design or configuration of size-sorting escape grid/system on improving the size-selectivity of trawls varied between fish species compared to standard or other escape grid designs. The other study found that a new design of grid system did not improve the size-selectivity of unwanted redfish compared to an existing system. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2728https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2728Mon, 25 Jan 2021 16:30:19 +0000Collected Evidence: Collected Evidence: Exclude or remove livestock from historically grazed brackish/salt marshes Fifteen studies evaluated the effects, on vegetation, of excluding or removing livestock from historically grazed brackish/salt marshes. There were five studies in Germany. There were two studies in the UK, Denmark and the Netherlands. There was one study in each of the USA, Sweden, France and Argentina. Livestock were sheep, cattle, sheep and cattle, cattle and horses, or unspecified. There was overlap in the sites used in two studies. Two other studies took place in one marsh, but with different experimental set-ups. VEGETATION COMMUNITY Overall extent (1 study): One controlled study of a salt marsh in Germany reported that in a plot fenced to exclude cattle for eight years, the total vegetated area was greater than in a plot that remained grazed. Community types (1 study): One site comparison study of brackish and salt marshes in Germany reported that reducing (or stopping) grazing affected the nature of transitions between vegetation types over time, but that the precise effect varied with environmental conditions. Community composition (5 studies): Three paired studies (two also replicated and controlled) in brackish/salt marshes in France, Argentina and the Netherlands reported that the effect of excluding livestock for 5–30 years on the overall plant community composition depended on plot elevation/flooding regime. In one of these studies, the effect of livestock exclusion was not separated from the effect of general legal protection. Two studies in one salt marsh in Denmark reported that excluding livestock had little effect on the identity of plant species in the community after six years. Overall richness/diversity (6 studies): Two studies (one controlled, one before-and-after) in one salt marsh in Denmark reported that excluding sheep and cattle for 6–7 years had no effect on overall plant species richness. One replicated, paired, controlled study in a salt marsh in the Netherlands reported that plots fenced to exclude cattle for seven years had lower plant species richness than areas that remained grazed. Two controlled studies (one also replicated and paired) in salt marshes in Germany found that the effect of removing sheep on overall plant species richness depended on the scale of measurement and the grazing intensity used for comparison – with inconsistent results across these studies even for similar scales and intensities. One paired, site comparison study of salt marshes in Argentina found that the effect of excluding cattle (along with legal protection) increased plant species richness at lower elevations, but did not significantly affect plant diversity at any elevation. VEGETATION ABUNDANCE Overall abundance (4 studies): Three studies (two controlled, one before-and-after) in salt marshes in the UK and Denmark reported that excluding livestock for 2–6 years maintained or increased overall vegetation abundance (although in one study, only by a small amount). One controlled study in a salt marsh in Germany found that a paddock left ungrazed for 16–18 years had greater overall vegetation cover than lightly or heavily grazed paddocks, but lower cover than a moderately grazed paddock. Individual species abundance (11 studies): Eleven studies quantified the effect of this action on the abundance of individual plant species. For example, five studies (four controlled, one before-and-after) on salt marshes in the UK, Denmark, Germany and the Netherlands reported that excluding livestock for 2–8 years reduced (or prevented increases in) cover of saltmarsh grass Puccinellia maritima. However, two controlled studies (one also replicated and paired) on salt marshes in Denmark and Sweden reported greater saltmarsh grass cover in areas fenced to exclude livestock for 1–6 years than in areas that remained grazed. Four studies (three controlled, one before-and-after) on salt marshes in Denmark and Germany reported that excluding or removing livestock for 4–16 years increased cover of sea purslane Halimione portulacoides. VEGETATION STRUCTURE Height (5 studies): Five controlled studies (two also replicated and paired) in salt marshes in Sweden and Germany, and brackish wet grassland in the UK, found that ungrazed plots (livestock excluded or removed) contained taller vegetation than plots that remained grazed. Vegetation was surveyed after one month, 1–8 years or 16–22 years. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2967https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2967Thu, 25 Mar 2021 14:15:09 +0000Collected Evidence: Collected Evidence: Reduce intensity of livestock grazing: freshwater marshes Three studies evaluated the effects, on vegetation, of reducing livestock grazing intensity in freshwater marshes (without stopping grazing entirely). Two studies were in the USA and the other was in Ireland. In all three studies, livestock were cattle. VEGETATION COMMUNITY Community composition (1 study): One site comparison study in Ireland found that lightly and heavily grazed wet meadows contained a similar overall mix of plant species. Relative abundance (1 study): One replicated, randomized, paired, controlled study in the USA found that seasonally and continuously grazed ephemeral pools had similar cover of grasses relative to forbs. Overall richness/diversity (1 study): One site comparison study in Ireland found that lightly and heavily grazed wet meadows had similar overall plant species richness. Native plant richness/diversity (1 study): One replicated, randomized, paired, controlled study in the USA found that seasonally and continuously grazed ephemeral pools experienced similar changes in native plant species richness over three years. VEGETATION ABUNDANCE Overall abundance (1 study): One site comparison study in Ireland reported that lightly and heavily grazed wet meadows had similar overall vegetation cover. Herb abundance (1 study): One replicated, randomized, paired, controlled, before-and-after study in the USA found that lightly and moderately grazed springs/creeks had similar herb cover. Individual species abundance (1 study): One study quantified the effect of this action on the abundance of individual plant species. The site comparison study in Ireland reported, for example, that lightly grazed wet meadows had greater cover of black sedge Carex nigra, and lower cover of creeping bent Agrostis stolonifera, than more heavily grazed wet meadows. VEGETATION STRUCTURE Height (1 study): One site comparison study in Ireland found that lightly grazed wet meadows contained taller vegetation than heavily grazed wet meadows. Vegetation was measured in the summer, during the grazing season. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2970https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2970Thu, 25 Mar 2021 14:15:51 +0000
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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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