Collected Evidence: Collected Evidence: Provide artificial nest sites for bumblebees We have captured 11 replicated trials of bumblebee nest boxes. Several different types of nest box have been shown to be acceptable to bumblebees, including wooden or brick and tile boxes at the ground surface, underground tin, wooden or terracotta boxes and boxes attached to trees.   Three replicated trials since 1989 in the UK have shown very low uptake rates (0-2.5%) of various nest box designs (not including underground nest boxes), while seven trials in previous decades in the UK, USA or Canada, and one recent trial in the USA, showed overall uptake rates between 10% and 48%.   Wooden surface or above ground nest boxes of the kind currently marketed for wildlife gardening are not the most effective design. Eight studies test this type of nest box. Five (pre-1978, USA or Canada) find 10-40% occupancy. Three (post-1989, UK) find very low occupancy of 0-1.5%. The four replicated trials that have directly compared wooden surface nest boxes with other types all report that underground, false underground or aerial boxes are more readily occupied.   Nest boxes entirely buried 5-10 cm underground, with a 30-80 cm long entrance pipe, are generally the most effective. Seven replicated trials in the USA, Canada or the UK have tested underground nest boxes and found between 6% and 58% occupancy.   We have captured no evidence for the effects of providing nest boxes on bumblebee populations.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F48https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F48Thu, 20 May 2010 02:19:20 +0100Collected Evidence: Collected Evidence: Manage ditches to benefit wildlife Five out of a total eight studies from the Netherlands and the UK (including one replicated, controlled paired study and three replicated site comparisons) looking at the effects of managing ditches on biodiversity, found that this intervention resulted in increased invertebrate biomass or abundance, plant species richness, emergent plant cover, amphibian diversity and abundance, bird visit rates and higher numbers of some bird species or positive impacts on some birds in plots with ditches managed under agri-environment schemes. One replicated controlled and paired study from the Netherlands found higher plant diversity on ditch banks along unsprayed edges of winter wheat compared to those sprayed with pesticides. Three studies from the Netherlands and the UK (including two replicated site comparisons) found that ditch management had negative or no clear effects on some farmland bird species or plants.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F135https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F135Thu, 17 Nov 2011 21:35:00 +0000Collected Evidence: Collected Evidence: Exclude grazers from semi-natural habitats Two replicated (one controlled) studies from the USA found higher species richnesses on sites with grazers excluded; a replicated and controlled study from Argentina found lower species richness in ungrazed sites and a study from the USA found no difference. Seven studies from the USA (three controlled, two replicated) found that overall bird abundance, or the abundances of some species were higher in sites with grazers excluded; seven studies from the USA and Argentina found that overall abundance or the abundances of some species were lower on sites without grazers, or did not differ between treatments. Three studies from the USA investigated productivity and found it higher in sites with grazers excluded. In one study this difference was only found on improved, not unimproved pastures.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F236https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F236Tue, 17 Jul 2012 15:59:50 +0100Collected Evidence: Collected Evidence: Restore or create inland wetlands Of eleven studies captured, 11, from the mainland USA, Guam, Canada and Hawaii, found that birds used artificially restored or created wetlands. Two found that rates of use and species richness were similar or higher than on natural wetlands. One found that use rates were higher than on unrestored wetlands. Three studies from the USA and Puerto Rico found that restored wetlands held lower densities and fewer species of birds than natural wetlands. A replicated study from the USA found that least bittern productivity was similar in restored and natural wetlands. Two replicated studies examined wetland characteristics: one from the USA found that semi-permanent restored wetlands were used more than temporary or seasonal ones. A study from Hawaii found that larger restored wetlands were used more than smaller sites.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F366https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F366Mon, 06 Aug 2012 13:34:38 +0100Collected Evidence: Collected Evidence: Remove ectoparasites from nests to increase survival or reproductive success Six of the seven studies that investigated infestation rates found lower rates in nests treated for ectoparasites, one (that used microwaves to treat nests) did not find fewer parasites. Two studies from the USA found higher survival or lower abandonment in nests treated for ectoparasites, whilst seven studies from across the world found no differences in survival, fledging rates or productivity between nests treated for ectoparasites and controls. Two studies from the USA and the UK found that chicks from nests treated for ectoparasites were in better condition than those from control nests. Four studies found no such effect.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F438https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F438Wed, 22 Aug 2012 18:20:13 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for ground and tree-nesting seabirds Three studies from the UK and the Azores found increases in gull and tern populations following the provision of rafts/islands or providing nest boxes alongside other interventions. A controlled, replicated study from the USA found that terns had higher nesting success on nesting rafts in one of two years monitored and a before-and-after study from Japan found that nesting success increased after the provision of nesting substrate. Five studies from Canada and Europe found that terns used re-profiled or artificial islands or nesting rafts, but pelicans did not. A small study from Hawaii found that red-footed boobies Sula sula preferentially nested in an artificial ‘tree-style’ nesting structure, compared to other designs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F480https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F480Thu, 30 Aug 2012 14:40:27 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for woodpeckers Four studies from the USA found local increases in red-cockaded woodpecker Picoides borealis populations or the successful colonisation of new areas following the installation of ‘cavity inserts’ (described above). One study also found that the productivity of birds using the inserts was significantly higher than the regional average. Two studies from the USA found that red-cockaded woodpeckers Picoides borealis used cavity inserts, in one case more frequently than making their own holes or using natural cavities. One study from the USA found that woodpeckers roosted, but did not nest, frequently in nest boxes. Five studies from the USA found that some woodpeckers excavated holes in artificial snags but only ever roosted in excavated holes or in nest boxes provided. A small study in the USA found that modifying artificial nests to allow easy access did not alter the behaviour of birds using them.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F496https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F496Tue, 04 Sep 2012 12:45:28 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for parrots A before-and-after study from Costa Rica found that the local population of scarlet macaws Ara macao increased following the installation of nest boxes along with several other interventions. Five studies from South and Central America and Mauritius that nest boxes were used by several species of parrots, with one finding an increase in use over time until the majority of the population used them. One replicated study from Peru found that blue-and-yellow macaws Ara ararauna only used modified palms, not ‘boxes’, whilst another replicated study found that scarlet macaws Ara macao used both PVC and wooden boxes, but that PVC lasted much longer. Four studies from Venezuela and Columbia found that several species very rarely, if ever, used nest boxes. Six studies from Central and South America found that parrots nested successfully in nest boxes, with two species showing higher levels of recruitment into the population following nest box erection and another finding that success rates for artificial nests were similar to natural nests. Three studies from South America found that artificial nests had low success rates, in two cases due to poaching.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F497https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F497Tue, 04 Sep 2012 13:10:55 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of raptors with wild conspecifics Ten out of 11 studies from across the world found that fostering raptor chicks to wild conspecifics had high success rates. A single study from the USA found that only one of six eggs fostered to wild bald eagle Haliaeetus leucocephalus nests were hatched and raised. The authors suggest that the other eggs may have been infertile. A replicated study from Spain found that Spanish imperial eagle Aquila adalberti chicks were no more likely to survive to fledging if they were transferred to foster nests from three chick broods (at high risk from siblicide), compared to chicks left in three-chick broods. A replicated study from Spain found that young (15–20 years old) Montagu's harrier Circus pygargus chicks were successfully adopted, but three older (27–29 day old) chicks were rejected.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F510https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F510Thu, 06 Sep 2012 14:42:31 +0100Collected Evidence: Collected Evidence: Create skylark plots All four studies from the UK and Switzerland (two replicated and controlled, and one review) investigating the effect of skylark plots on Eurasian skylarks, found a positive effect, reporting increases in skylark population size, breeding density, duration or success or a lower likelihood of skylarks abandoning their territory relative to fields without plots. A replicated study from Denmark found that skylarks used undrilled patches within cereal fields more than expected by an even distribution across the landscape. Four studies reported the effect of undrilled patches on wildlife other than skylarks. Three studies from the UK (including two replicated studies, of which one also controlled and a review) found benefits to plants and invertebrates. Whilst two studies (both replicated, one also controlled) from the UK found no significant differences in the number of some invertebrates or seed-eating songbirds between skylark plots and conventional crop fields. One replicated study from the UK investigated different skylark plot establishment techniques. Plots that were undrilled had greater vegetation cover and height than plots established by spraying out with herbicide. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F540https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F540Tue, 11 Sep 2012 16:08:32 +0100Collected Evidence: Collected Evidence: Control predatory mammals and birds (foxes, crows, stoats and weasels) A total of nine individual studies from France and the UK (including five replicated controlled studies and a systematic review) looked at the effects of removing predators on birds. Three studies found controlling predatory mammals or birds (sometimes alongside other interventions) increased the abundance or population size of some birds. One of these studies from the UK found numbers of nationally declining songbirds increased on a site where predators were controlled, but there was no overall difference in bird abundance, species richness or diversity between predator control and no-control sites. Five studies (two replicated and controlled, two before-and-after trials) from the UK found some evidence for increased productivity, nest or reproductive success or survival of birds following bird or mammal predator control (sometimes alongside other interventions). A randomized, replicated, controlled study found hen harrier breeding success was no different between areas with and without hooded crow removal. A global systematic review including evidence from European farmland found that reproductive success of birds increased with predator removal.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F699https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F699Thu, 20 Dec 2012 13:08:22 +0000Collected Evidence: Collected Evidence: Delay mowing or first grazing date on pasture or grasslandNatural enemy abundance: One replicated, randomised, controlled study found fewer predatory spiders with delayed cutting. Three studies from the UK (two of them replicated, randomised and controlled) found no change in insect predator numbers and one replicated study from Sweden found mixed effects between different predator groups. Natural enemy diversity: One replicated study from Sweden found a decrease in ant diversity with delayed cutting and one replicated, randomised, controlled study from the UK found no effect on spider and beetle diversity. Pests: One of two replicated, randomised, controlled studies from the UK and USA found more pest insects in late-cut plots and one found no effect. Insects in general: Four replicated, randomised, controlled studies measured the abundance of insect groups without classifying them as pests or natural enemies. One UK study found lower numbers in late-cut plots, while two found effects varied between groups. Two studies from the UK and USA found no effect on insect numbers. Crops studied were barley, bird’s-foot trefoil, clovers, fescues, rapeseed, ryegrass, other grasses and wheat.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F727https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F727Thu, 30 May 2013 13:34:12 +0100Collected Evidence: Collected Evidence: Release captive-bred frogs Four of five studies (including one replicated study and one review) in Europe, Hong Kong and the USA found that captive-bred frogs released as tadpoles, juveniles or adults established populations or stable breeding populations at 88-100% of sites, and in some cases colonized new sites. One study found that stable breeding populations were not established. One before-and-after study in Spain found that released captive-bred, captive-reared and translocated frogs established breeding populations at 79% of sites. Three replicated studies in Australia and the USA found that a high proportion of captive-bred frogs released as eggs survived to metamorphosis, some released as tadpoles survived at least the first few months or few released as froglets survived. Three studies (including two replicated studies) in Australia, Italy and the UK and a review in the USA found that captive-bred frogs reproduced at all or 31–33% of release sites, or that there was very limited breeding by released frogs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F870https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F870Wed, 11 Sep 2013 14:52:42 +0100Collected Evidence: Collected Evidence: Add mulch to cropsBiodiversity: Three replicated trials from Canada, Poland and Spain (including one also controlled, one also randomized and one also controlled and randomized) showed that adding mulch to crops (whether shredded paper, municipal compost or straw) increased soil animal and fungal numbers, diversity and activity. Of these, one trial also showed that mulch improved soil structure and increased soil organic matter. Nutrient loss: One replicated study from Nigeria found higher nutrient levels in continually cropped soil. Erosion: Five studies from India, France, Nigeria and the UK (including one controlled, randomized, replicated trial, one randomized, replicated trial, two replicated (one also controlled), and one controlled trial) found that mulches increased soil stability, and reduced soil erosion and runoff. One trial found that some mulches are more effective than others. Drought: Two replicated trials from India found that adding mulch to crops increased soil moisture. Yield: Two replicated trials from India found that yields increased when either a live mulch or vegetation barrier combined with mulch was used. SOIL TYPES COVERED: clay, fine loam, gravelly sandy loam, sandy, sandy-clay, sandy loam, sandy silt-loam, silty, silty loam.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F887https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F887Fri, 27 Sep 2013 08:43:03 +0100Collected Evidence: Collected Evidence: Amend the soil using a mix of organic and inorganic amendmentsBiodiversity: Five controlled trials from China and India (four also randomized and replicated), and one study from Japan found higher microbial biomass and activity in soils with a mix of manure and inorganic fertilizers. Manure alone also increased microbial biomass. One trial found increased microbial diversity. Erosion: One controlled, replicated trial from India found that mixed amendments were more effective at reducing the size of cracks in dry soil than inorganic fertilizers alone or no fertilizer. SOC loss: Four controlled, randomized, replicated trials and one controlled trial from China and India found more organic carbon in soils with mixed fertilizers. Manure alone also increased organic carbon. One trial also found more carbon in soil amended with inorganic fertilizers and lime. SOM loss: Two controlled, randomized, replicated trials from China and India found more nutrients in soils with manure and inorganic fertilizers. One controlled, randomized, replicated trial from China found inconsistent effects of using mixed manure and inorganic fertilizers. Yield: Two controlled, randomized, replicated trials from China found increased maize Zea mays yield in soils with mixed manure and inorganic fertilizer amendments. SOIL TYPES COVERED: clay, clay loam, sandy-loam, silt clay loam, silty-loam.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F902https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F902Tue, 01 Oct 2013 14:46:11 +0100Collected Evidence: Collected Evidence: Use an alternative protein source: plant-based Six studies (four replicated, controlled) in Norway, Scotland and the USA found that inclusion of plant-based proteins within feed led to decreased growth rates in salmon. Three replicated and/or controlled studies from Norway, Canada and Scotland found similar growth rates in salmon fed either plant-based or fish meal diets. Four replicated, controlled studies (three randomised) from Norway and Scotland found reduced final body weights in salmon fed plant-based protein diets compared to fish meal-based diets. Two controlled studies (one replicated) from Norway found similar final body weights in salmon fed either plant-based or fish meal diets. Two replicated, controlled studies (one randomised) from Norway found lowered levels of feeding efficiency, whereas a replicated study in Norway found increased levels of feeding efficiency in salmon fed plant-based protein diets compared to fish meal diets. Two replicated studies (one controlled) in Canada and Scotland study found similar levels of feeding efficiency across both diet types. Digestibility of feed components by salmon was found to be lower in two replicated, controlled studies when the diets contained plant proteins compared to fish meal. Similar levels of digestibility across both diet types were identified by two randomised, replicated, controlled studies in Scotland and Norway. Two of the studies found that survival rates and appetite were not affected by plant- or fish meal-based protein diets. However morphology of the distal intestine was altered in two randomised, replicated, controlled studies where salmon were fed diets containing plant-based proteins. Condition of the salmon was increased in plant-based protein diets in one randomised, replicated, controlled study but reduced in two other replicated studies.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F924https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F924Fri, 25 Oct 2013 13:26:05 +0100Collected Evidence: Collected Evidence: Create artificial reefs Twelve studies examined the effects of creating artificial reefs on subtidal benthic invertebrate populations. Three studies were in the Mediterranean Sea (Italy); three were in the North Atlantic Ocean (USA, Portugal, France); one in the Firth of Lorn (UK); two in the North Pacific Ocean (USA); one in the English Channel (UK), one in the Gulf of Mexico (USA); and one in the Yellow Sea (China).   COMMUNITY RESPONSE (8 STUDIES) Overall community composition (3 studies): Two site comparison studies (one replicated) in the English Channel and North Atlantic Ocean found that invertebrate communities growing on artificial reefs were different to that of natural reefs. One replicated study the North Pacific Ocean found that invertebrate community composition changed over time on an artificial reef. Overall richness/diversity (6 studies): Two site comparison studies (one replicated) in the Mediterranean Sea and North Atlantic Ocean found that invertebrate species richness and/or diversity on the artificial reef or in the sediments inside and adjacent to the reef area were lower compared to on natural reefs or in nearby natural sediments. One replicated, site comparison study in the Gulf of Mexico found that artificial breakwaters had more species of nekton compared to adjacent mudflats. One site comparison study in English Channel recorded 263 taxa on the artificial reef, including at least nine not recorded on nearby natural reefs but excluding at least 39 recorded on natural reefs. One replicated study in the North Pacific Ocean found a 49% increase in species richness over five years on an artificial reef. One study in the North Atlantic Ocean found that artificial reefs hosted at least five species of large mobile invertebrates. Mollusc richness/diversity (1 study): One replicated, site comparison study in the Mediterranean Sea found that mollusc species richness and diversity were lower on artificial reefs compared to natural reefs. Worm community composition (1 study): One replicated, site comparison study in the North Pacific Ocean found that polychaete worm community composition was similar at one of two artificial reefs compared to a natural reef. Worm richness/diversity (1 study): One replicated, site comparison study in the North Pacific Ocean found that polychaete worm species richness and diversity were similar at one of two artificial reefs compared to a natural reef, but lower at the second artificial reef. POPULATION RESPONSE (12 STUDIES) Overall abundance (10 studies): One of two site comparison studies (one replicated) in the Mediterranean Sea found that abundance of invertebrates in the sediment was lower at the reef sites than in nearby natural sediments, but increased in the sediments directly adjacent to the reefs, while the other study found that abundance was similar in the sediments inside and directly adjacent to the artificial reef area, but lower than in nearby natural sediments. Of five site comparison studies (four replicated) in the North Pacific Ocean, the North Atlantic Ocean, the Gulf of Mexico and the Yellow Sea, one found that invertebrate biomass was higher on the artificial reef than in adjacent natural sediments, two that invertebrate abundance and biomass and nekton abundance were similar on artificial reefs and natural habitats (reef; mudflat), and two found mixed effects on abundances of invertebrates. One site comparison study in the English Channel reported that the abundances of some species were lower on the artificial reef compared to natural reefs. One replicated study in the North Pacific Ocean reported an 86% increase in invertebrate abundance growing on an artificial reef over five years. One study in the North Atlantic Ocean found that two of five species at one artificial reef, and three of seven at another, were recorded during >50% of dives. Overall condition (1 study): One replicated, site comparison study in the Yellow Sea found mixed effects of creating an artificial reef on the sizes of mobile invertebrates. Mollusc abundance (1 study): One replicated, site comparison study in the Mediterranean Sea found that mollusc abundance was lower on artificial reefs compared to natural reefs. Crustacean abundance (1 study): One replicated, site comparison in the Firth of Lorn found that abundances of edible crabs and velvet swimming crabs were typically higher on artificial than natural reefs. OTHER (1 STUDY) Biological production (1 study): One site comparison study in North Atlantic Ocean found that secondary production was higher from invertebrates growing on an artificial reef than from invertebrates in adjacent natural sediments. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2258https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2258Wed, 23 Oct 2019 10:26:30 +0100Collected Evidence: Collected Evidence: Use guardian animals (e.g. dogs, llamas, donkeys) bonded to livestock to deter predators to reduce human-wildlife conflict Twelve studies evaluated the effects of using guardian animals (e.g. dogs, llamas, donkeys) bonded to livestock to deter mammals from predating these livestock to reduce human-wildlife conflict. Four studies were in the USA, two were in Kenya and one each was in Solvakia, Argentina, Australia, Cameroon, South Africa, and Namibia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (12 STUDIES) Human-wildlife conflict (12 studies): Four of seven studies, (including four site comparison studies), in the USA, Kenya, Solvakia, Australia and Cameroon, found that guardian animals reduced attacks on livestock by predators. The other three studies reported mixed results with reductions in attacks on some but not all age groups or livestock species and reductions for nomadic but not resident pastoralists. Two studies, (including one site comparison study and one before-and-after study), in Argentina and Namibia, found that using dogs to guard livestock reduced the killing of predators by farmers but the number of black-backed jackals killed by farmers and dogs combined increased. A replicated, controlled study in the USA found that fewer sheep guarded by llamas were predated by carnivores in one of two summers whilst a replicated, before-and-after study in South Africa found that using dogs or alpacas to guard livestock reduced attacks by predators. A randomized, replicated, controlled study in USA found that dogs bonded with livestock reduced contact between white-tailed deer and domestic cattle. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2433https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2433Tue, 02 Jun 2020 08:41:54 +0100Collected Evidence: Collected Evidence: Restore former mining sites Twelve studies evaluated the effects of restoring former mining sites on mammals. Eleven studies were in Australia and one was in the USA. COMMUNITY RESPONSE (8 STUDIES) Species richness (8 studies): A review in Australia found that seven of 11 studies indicated that rehabilitated areas had lower mammal species richness compared to unmined areas. Four of five replicated, site comparison studies, in Australia, found that mammal species richness was similar in restored mine areas compared to unmined areas or higher in restored areas (but similar when considering only native species). One study found that species richness was lower in restored compared to in unmined areas. A replicated, controlled study in Australia found that thinning trees and burning vegetation as part of mine restoration did not increase small mammal species richness. A replicated, site comparison study in Australia found that restored mine areas were recolonized by a range of mammal species within 10 years. POPULATION RESPONSE (5 STUDIES) Abundance (5 studies): A review of rehabilitated mine sites in Australia found that only two of eight studies indicated that rehabilitated areas had equal or higher mammal densities compared to those in unmined areas. One of three replicated, site comparison studies, in the USA and Australia, found that small mammal density was similar on restored mines compared to on unmined land. One study found that for three of four species (including all three native species studied) abundance was lower in restored compared to unmined sites and one study found mixed results, including that abundances of two out of three focal native species were lower in restored compared to unmined sites. A replicated, controlled study in Australia found that thinning trees and burning vegetation as part of mine restoration did not increase small mammal abundance. BEHAVIOUR (2 STUDIES) Use (2 studies): A replicated, site comparison study in Australia found that most restored former mine areas were not used by koalas while another replicated site comparison study in Australia found quokka activity to be similar in revegetated mined sites compared to in unmined forest. OTHER (1 STUDY) Genetic diversity (1 study): A site comparison study in Australia found that in forest on restored mine areas, genetic diversity of yellow-footed antechinus was similar to that in unmined forest. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2490https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2490Thu, 04 Jun 2020 14:08:11 +0100Collected Evidence: Collected Evidence: Use repellents that taste bad (‘contact repellents’) to deter crop or property damage by mammals to reduce human-wildlife conflict Twelve studies evaluated the effects of using repellents that taste bad (‘contact repellents’) to deter crop or property damage by mammals to reduce human-wildlife conflict. Nine studies were in the USA, two were in the UK and one was in Italy. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (0 STUDIES) OTHER (12 STUDIES) Human-wildlife conflict (12 studies): Five of 11 controlled studies (including 10 replicated studies), in the USA, Italy and the UK, of a range of contact repellents, found that they reduced herbivory or consumption of baits. The other six studies reported mixed results with at least some repellents at some concentrations deterring herbivory, sometimes for limited periods. A replicated, controlled study in the USA found that a repellent did not prevent chewing damage by coyotes. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2509https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2509Thu, 04 Jun 2020 16:44:38 +0100Collected Evidence: Collected Evidence: Install barrier fencing along roads Twelve studies evaluated the effects on mammals of installing barrier fencing along roads. Eight studies were in the USA, one each was in Canada, Germany and Brazil and one spanned the USA, Canada and Sweden. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (9 STUDIES) Survival (9 studies): Three controlled studies, in the USA, Germany and Brazil, found that roadside fencing or equivalent barrier systems reduced the numbers of mammals, including wildcats and coypu, killed by vehicles on roads. Two before-and-after studies, in the USA, found that roadside fencing with one-way gates to allow escape from the road, reduced the number of collisions between vehicles and deer. A study in the USA found that a 2.7-m-high fence did not reduce road-kills of white-tailed deer compared to a 2.2-m-high fence. A controlled, before-and-after study in the USA found that barrier fencing with designated crossing points did not significantly reduce road deaths of mule deer. A replicated, controlled, before-and-after study in Canada found that electric fences, (along with an underpass beneath one highway), reduced moose-vehicle collisions. A review of fencing studies from USA, Canada and Sweden, found that longer fencing along roadsides led to a greater reduction of collisions between large mammals and cars than did shorter fence sections. BEHAVIOUR (5 STUDIES) Behaviour change (5 studies): A controlled, before-and-after study in the USA found that 2.3-m-high fencing in good condition prevented most white-tailed deer accessing a highway. A replicated, controlled, before-and-after study in Canada found that electric fences reduced moose access to highways. Three studies (two replicated), in the USA, found that higher fences (2.4–2.7 m) prevented more white-tailed deer from entering highways than did fences that were 2.2 m high, 1.2 m high with outriggers or 1.2–1.8 m high. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2567https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2567Tue, 09 Jun 2020 14:55:48 +0100Collected Evidence: Collected Evidence: Thin trees within forest Twelve studies evaluated the effects on mammals of thinning trees within forests. Six studies were in Canada and six were in the USA. COMMUNITY RESPONSE (2 STUDIES) Species richness (2 studies): A replicated, site comparison study the USA found that in thinned tree forest stands, there was similar mammal species richness compared to in unthinned stands. A replicated, controlled study in Canada found that thinning of regenerating lodgepole pine did not increase small mammal species richness 12–14 years later. POPULATION RESPONSE (8 STUDIES) Abundance (8 studies): Three of eight replicated, controlled and replicated, site comparison studies, in the USA and Canada, found that thinning trees within forests lead to higher numbers of small mammals. Two studies showed increases for some, but not all, small mammal species with a further study showing an increase for one of two squirrel species in response to at least some forest thinning treatments. The other two studies showed no increases in abundances of small mammals or northern flying squirrels between 12 and 14 years after thinning. BEHAVIOUR (4 STUDIES) Use (4 studies): Three of four controlled and comparison studies (three also replicated, one randomized) in Canada found that thinning trees within forests did not lead to greater use of areas by mule deer, moose or snowshoe hares. The other study found that a thinned area was used more by white-tailed deer than was unthinned forest. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2650https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2650Sat, 13 Jun 2020 18:09:47 +0100Collected Evidence: Collected Evidence: Hand-rear orphaned or abandoned marine and freshwater mammal young Twelve studies evaluated the effects of hand-rearing orphaned or abandoned marine and freshwater mammal young. Four studies were in the North Pacific Ocean (USA), two studies were in captive facilities (USA), and one study was in each of the North Atlantic Ocean (USA), the Indian River Lagoon (USA), the Salish Sea (USA), the Guerrero Lagoon (USA), the South Atlantic Ocean (Brazil) and water bodies in Florida (USA). COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (11 STUDIES) Reproductive success (1 study): One replicated study in the South Atlantic Ocean found that most captive-reared Antillean manatees released back into the wild reproduced. Survival (11 studies): Three studies (including one replicated and controlled study) in the North Pacific Ocean, and the Indian River Lagoon found that a gray whale calf, three Steller sea lion pups, and a common bottlenose dolphin calf that were released after being reared in captivity survived during post-release monitoring periods of between three days to three months. Two replicated studies in the South Atlantic Ocean and water bodies in Florida found that approximately three-quarters of Antillean manatees and two-thirds of Florida manatees that were captive-reared and released were known to survive for at least one year, and some survived for more than seven years. Three studies in the North Atlantic Ocean, the North Pacific Ocean and the Guerrero Lagoon found that three West Indian manatee calves, seven Hawaiian monk seal pups and one Antillean manatee calf that were captive-reared either died before or after release, had to be returned to captivity after release, or survived in the wild only with supplemental feeding. Two studies at captive facilities found that a captive-reared grey whale calf and five pygmy and dwarf sperm whale calves increased in body weight but were either not released or died in captivity. One controlled study in the North Pacific Ocean found that captive-reared, released Pacific harbour seal pups had similar survival estimates to wild pups. BEHAVIOUR (3 STUDIES) Behaviour change (3 studies): Two controlled studies (including one replicated study) in the North Pacific Ocean found that captive-reared and released Pacific harbour seal pups and Steller sea lion pups had similar diving behaviour to wild pups. One controlled study in the Salish Sea found that captive-reared and released harbour seal pups travelled greater distances and further from the release site than wild pups born at the same site and in the same season. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2926https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2926Tue, 09 Feb 2021 10:51:31 +0000Collected Evidence: Collected Evidence: Increase or maintain the proportion of natural or semi‐natural habitat in the farmed landscape Twelve studies evaluated the effects of increasing or maintaining the proportion of natural or semi-natural habitat in the farmed landscape on butterflies and moths. Three studies were in Switzerland, two were in each of Germany, Sweden and the UK, and one was in each of the USA, Malaysia, and New Zealand. COMMUNITY RESPONSE (11 STUDIES) Richness/diversity (11 studies): Nine of eleven studies (including one replicated, randomized, controlled study, one before-and-after study and eight replicated, site comparison studies) in Germany, Sweden, Malaysia, Switzerland, the UK, and New Zealand found that the species richness of butterflies, burnet moths and all moths was higher on farms with a greater proportion of semi-natural habitat or with a greater proportion of woodland in the surrounding landscape, or after semi-natural habitat had been created, compared to conventional farmland or farmland with a greater proportion of arable land in the surrounding landscape. One study found that species richness of butterflies in oil palm plantations was higher where ground coverage of weeds had been maintained but similar whether or not epiphyte or fern coverage was maintained. The eleventh study found that the species richness of butterflies was similar on farms with different proportions of semi-natural habitat. POPULATION RESPONSE (8 STUDIES) Abundance (8 studies): Six replicated studies (including one randomized, controlled study and five site comparison studies) in Sweden, the UK, New Zealand, and Switzerland found that the abundance of butterflies and moths was higher on farms with a greater proportion of semi-natural habitat, or in semi-natural habitat compared to conventional farmland. One of two replicated, site comparison studies in the USA and Sweden found that the abundance of four out of eight species of butterflies was higher on farms surrounded by woodland, but the abundance of least skipper was lower on farms with more semi-natural habitat. The other study found that overall butterfly abundance was similar on farms surrounded by different proportions of woodland and arable land. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3910https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3910Wed, 10 Aug 2022 14:34:14 +0100Collected Evidence: Collected Evidence: Reduce management intensity on permanent grasslands (several interventions at once) Twelve studies evaluated the effects on butterflies and moths of reducing management intensity on permanent grasslands. Seven studies were in Switzerland, three were in the UK, and one was in each of Greece and Germany. COMMUNITY RESPONSE (12 STUDIES) Community composition (2 studies): Two replicated studies (including one controlled study and one site comparison study) in Switzerland found that the composition of butterfly communities differed between low-input and intensively managed grasslands. One of these studies found that low-input grasslands tended to have more butterfly species whose caterpillars feed on a single host plant, have one generation/year and poor dispersal ability. Richness/diversity (11 studies): Six of 10 studies (including five controlled studies and five site comparison studies) in Switzerland, the UK, Greece and Germany found that less intensively managed grasslands had a higher species richness of butterflies and moths than conventionally managed grasslands, although two of these studies only found a difference in one of two years or regions. The other four studies found that less intensively managed grasslands had a similar species richness of butterflies and moths to conventionally managed grasslands. However, one of these studies also found that less intensively managed grassland had more specialist species of moths, and species of conservation concern, than conventionally managed grassland. One before-and-after study in the UK found that after grazing was reduced and chemical application stopped, the species richness of large moths increased. POPULATION RESPONSE (5 STUDIES) Abundance (5 studies): Three of four replicated studies (including two controlled studies and two site comparison studies) in Switzerland, the UK and Germany found that low-input or unfertilized, ungrazed grassland managed with a single cut had a higher abundance of butterflies, micro-moths and declining macro-moths than intensively managed grassland. Two of these studies also found that the abundance of caterpillars and of all macro-moths was similar between less intensively and more intensively managed grasslands. The other study found that less intensively managed grassland had a similar abundance of moths to more intensively managed grassland. One before-and-after study in the UK found that after grazing was reduced and chemical application stopped, the total abundance of large moths and the abundance of five out of 23 butterfly species increased, but the abundance of two butterfly species decreased. BEHAVIOUR (1 STUDY) Use (1 study): One replicated, site comparison study in Germany reported that 24 out of 58 moth species preferred less intensively managed grasslands, but 12 species preferred more intensively managed grasslands. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3958https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3958Sun, 14 Aug 2022 10:37:05 +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