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: Provide artificial nest sites for solitary beesWe have captured 30 replicated trials of nest boxes for solitary bees in 10 countries, including Europe, North and South America and Asia. Twenty-nine of these trials showed occupancy by bees. Many species of solitary bee readily nest in the boxes, including some species considered endangered in a study on farmland in Germany, oil-collecting species of the genus Centris in South America and a recently discovered species in lowland tropical forest in Costa Rica. One trial in temperate forest in Canada recorded no bees using nest boxes. A set of replicated experiments in Germany estimated that four medium to large European species of solitary bee have a foraging range of 150 to 600 m, so nest boxes must be within this distance of foraging resources. Twenty-three replicated trials have shown nest boxes of cut hollow stems or tubes being occupied by solitary bees. Eleven trials demonstrated occupation of blocks of wood drilled with holes. Two trials in Neotropical secondary forest (one in Brazil, one in Mexico) showed that particular solitary bee species will nest in wooden boxes, without stems or confining walls inside. Two replicated trials have compared reproductive success in different nest box designs. One showed that reed stem and wooden grooved-board nest boxes produced more bees/nest than four other types. Nest boxes with plastic-lined holes, or plastic or paper tubes were much less productive, due to parasitism or mould. The other, a small trial, found nests of the oil-collecting bee Centris analis in Brazil were more productive in cardboard straws placed in drilled wooden holes than in grooved wooden boards stacked together. Three trials on agricultural land, one on a carpenter bee in India, one on a range of species in Germany and one on species of Osmia in the USA, have shown that the number of occupied solitary bee nests can double over three years with repeated nest box provision at a given site. One small replicated trial compared populations of solitary bees in blueberry fields in the USA with and without nest boxes over three years. The estimated number of foraging Osmia bees had increased in fields with nest boxes, compared to fields without nest boxes. Eleven replicated trials have recorded solitary bees in nest boxes being attacked by parasites or predators. Rates of mortality and parasitism have been measured in 10 studies. Mortality rates range from 13% mortality for cavity-nesting bees and wasps combined in Germany (2% were successfully parasitized), or 2% of bee brood cells attacked in shade coffee and cacao plantations in central Sulawesi, Indonesia, to 36% parasitism and 20% other mortality (56% mortality overall) for the subtropical carpenter bee Xylocopa fenestrata in India. Two replicated trials of the use of drilled wooden nest boxes by bees in California, USA, showed that introduced European earwigs Forficula auricularia and introduced European leafcutter bee species use the boxes. In one trial, these introduced species more commonly occupied the boxes than native bees. A small trial tested three soil-filled nest boxes for the mining bee Andrena flavipes in the UK, but they were not occupied.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F47https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F47Thu, 20 May 2010 07:16:20 +0100Collected Evidence: Collected Evidence: Protect nests from livestock to reduce trampling A before-and-after study from the Chatham Islands, New Zealand found that the population of Chatham Island oystercatcher increased following several interventions including the erection of fencing around individual nests. A replicated, controlled study in Sweden found that no southern dunlin nests were trampled when protected by cages; some unprotected nests were destroyed.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F237https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F237Tue, 17 Jul 2012 16:44:30 +0100Collected Evidence: Collected Evidence: Provide ‘sacrificial’ grasslands to reduce the impact of wild geese on cropsTwo studies in the UK found that managing grasslands for geese increased the number grazing there. However, both found that the birds were moving within a relatively small area (i.e. within the study sites) and therefore the grasslands may not reduce conflict with farmers.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F280https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F280Tue, 24 Jul 2012 12:48:14 +0100Collected Evidence: Collected Evidence: Protect nests from antsA randomised, replicated and controlled study from the USA found higher fledging success from white-eyed vireo Vireo griseus nests protected from ants with a physical barrier and a chemical repellent, compared to control nests.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F410https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F410Thu, 16 Aug 2012 15:15:18 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for divers/loons A replicated before-and-after study from the UK found that there was a very large increase in loon productivity on lakes provided with nesting rafts, with a corresponding increase in productivity across the whole country. Two studies from the USA found higher nesting success on lakes with floating  nesting rafts, compared to sites without rafts, but no new territories were established on lakes without loons but with rafts. A replicated study from the UK found that loons used nesting rafts and artificial islands in some areas of the UK, but not others.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F478https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F478Thu, 30 Aug 2012 14:13:43 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for grebesA single study from the UK found that grebes used nesting rafts in some areas of the UK but not others, and that the characteristics of used rafts differed geographically.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F479https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F479Thu, 30 Aug 2012 14:36:41 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for burrow-nesting seabirds Four studies from across the world found evidence for population increases or new populations being established in petrel species following the provision of nest boxes. In two cases nest boxes were combined with the translocation of chicks or other interventions. Six studies from across the world found high occupancy rates for artificial burrows by seabirds, with three finding that occupancy increased over time, taking years to build up. Three studies from across the world found very low occupancy rates for artificial burrows used by petrel species. Eight studies from across the world found that the productivity of birds using artificial burrows was high, in many cases as high or higher than in natural burrows. One replicated study from the USA and a small study from the Galapagos found low productivity of petrels using artificial burrows.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F481https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F481Thu, 30 Aug 2012 16:21:23 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for gamebirdsA replicated study in China found that an estimated 36–41% of the local population of Cabot’s tragopans Tragopan caboti used nesting platforms.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F484https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F484Sat, 01 Sep 2012 17:06:42 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for falcons Four studies from the USA and Europe found that local populations of falcons increased following the installation of artificial nesting sites, with one reporting that there was no decline in natural nest use following the installation and use of nest boxes. A replicated study from Canada found that the local population of American kestrels Falco sparverius did not increase following the erection of nest boxes. Eight studies from across the world found that the success and productivity of falcons in nest boxes was high and equal to, or higher than those in natural nests. Four studies from across the world found that productivities in nest boxes were lower than in natural nests or in previously published results, or that some falcons were evicted from their nests by barn owls Tyto alba. Four studies from across the world found no differences in productivity between nest box designs or positions, whilst two, from Spain and Israel found that productivity in boxes varied between designs and habitats. Twenty-one studies from across the world found nest boxes were used by falcons, with one in the UK finding that nest boxes were not used at all. One study from Canada found that falcons preferentially nested in nest boxes over natural nest sites; a study from Mauritius found that most breeding attempts were in nest boxes Four studies found that use increased over time. Seven studies found that position or design affected use, whilst three found no differences between design or positioning.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F489https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F489Mon, 03 Sep 2012 14:01:21 +0100Collected Evidence: Collected Evidence: Provide 'sacrificial' grasslands to reduce the impact of wild geese on crops All six studies from the UK (including four replicated, controlled trials) found that managing grasslands for geese increased the number grazing there. Two replicated, controlled studies found that fertilized and cut areas were grazed by more white-fronted geese or brent geese than control areas. A replicated, controlled trial found that re-seeded and fertilized wet pasture fields were used by more barnacle geese than control fields, and that fertilized areas were used less than re-seeded ones. A replicated, controlled study found that spring fertilizer application increased the use of grassland fields by pink-footed geese. A replicated study found that plots sown with white clover were preferred by dark-bellied brent geese compared to plots sown with grasses. However, four of the studies found that the birds were moving within a relatively small area (i.e. within the study site) and therefore the grasslands may not reduce conflict with farmers.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F641https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F641Mon, 15 Oct 2012 16:28:48 +0100Collected Evidence: Collected Evidence: Provide adequate signage of presence of primates on or near roads We found no evidence for the effects of providing adequate signage of presence of primates on or near roads 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%2F1466https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1466Tue, 17 Oct 2017 14:13:19 +0100Collected Evidence: Collected Evidence: Provide additional sleeping platforms/nesting sites for primates One before-and-after study in Brazil found that a translocated lion tamarin population declined after artificial nest boxes were provided, alongside other interventions. One before-and-after study in Brazil found that a majority of reintroduced golden lion tamarins died seven years after artificial nest boxes were provided, alongside other interventions. One before-and-after study in Gabon found that a majority of juvenile western lowland gorillas survived for at least seven years after nesting platforms were provided, alongside other interventions. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1530https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1530Thu, 19 Oct 2017 10:22:21 +0100Collected Evidence: Collected Evidence: Protect or prepare vegetation before planting (other interventions) We found no studies that evaluated the effects of protecting or preparing peatland vegetation before planting (other than by adding root-associated fungi). ‘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%2F1842https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1842Tue, 28 Nov 2017 08:56:10 +0000Collected Evidence: Collected Evidence: Protect roost trees during forest operations We found no studies that evaluated the effects of protecting roost trees during forest operations 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%2F1982https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F1982Tue, 04 Dec 2018 19:24:09 +0000Collected Evidence: Collected Evidence: Provide additional moorings to reduce anchoring We found no studies that evaluated the effects of providing additional moorings to reduce anchoring 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%2F2091https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2091Mon, 21 Oct 2019 15:21:08 +0100Collected Evidence: Collected Evidence: Provide artificial dens or nest boxes on trees Thirty studies evaluated the effects on mammals of providing artificial dens or nest boxes on trees. Fourteen studies were in Australia, nine were in the USA, three were in the UK, one was in each of Canada, Lithuania, South Africa and Japan. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (6 STUDIES) Abundance (5 studies): Three of five controlled studies (three also replicated) in the USA, the UK, Canada and Lithuania, found that provision of artificial dens or nest boxes increased abundances of gray squirrels and common dormice. The other two studies found that northern flying squirrel and Douglas squirrel abundances did not increase. Condition (1 study): A replicated, randomized, paired sites, controlled, before-and-after study in Canada found that nest boxes provision did not increase body masses of northern flying squirrel or Douglas squirrel. BEHAVIOUR (27 STUDIES) Use (27 studies): Twenty-seven studies, in Australia, the USA, the UK, Canada, South Africa and Japan found that artificial dens or nest boxes were used by a range of mammal species for roosting and breeding. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2584https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2584Wed, 10 Jun 2020 15:48:27 +0100Collected Evidence: Collected Evidence: Protect spawning fish from capture Four studies examined the effects of protecting spawning fish on marine fish populations. Two studies were in the North Atlantic Ocean (Canada, UK) and one study was in each of the Philippine Sea (Palau) and the Tasman Sea (Australia).  COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Abundance (1 study): One before-and-after, site comparison study in the Atlantic Ocean found no increase in the biomass of the spawning stock of Atlantic cod in the nine years following implementation of a seasonal fishery closure to protect spawning cod, compared to fished areas. Survival (1 study): One before-and-after, site comparison study in the Atlantic Ocean found no change in Atlantic cod survival in the nine years after a seasonal fishery closure to protect spawning cod was implemented, compared to fished areas. Condition (1 study): One before-and-after, site comparison study in the Atlantic Ocean found no change in the length composition of Atlantic cod in the nine years following a seasonal fishery closure to protect spawning cod, compared to fished areas. BEHAVIOUR (2 STUDIES) Use (2 studies): One site comparison study and one study in the Northeast Atlantic Ocean and Tasman Sea reported that spawning and/or nursery areas closed seasonally or permanently to fishing were used by tagged adult Atlantic cod for nearly a third of time during spawning, and by school sharks less than one year old for up to 80% of time, but by school sharks between one and two years old for 18% of time, compared to areas outside. OTHER (2 STUDIES) Commercial catch abundance (2 studies): One before-and-after, site comparison study in the Atlantic Ocean found no change over nine years in commercial catches of Atlantic cod following a seasonal fishery closure to protect spawning cod compared to fished areas. One replicated, controlled study in the Philippine Sea found that during seasonal closure of a grouper fishery to protect spawning individuals, the commercial catch numbers of other fish groups (herbivores) increased, indicating they were being targeted more by spear fishers compared to the open season. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2938https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2938Thu, 11 Feb 2021 16:13:52 +0000Collected Evidence: Collected Evidence: Provide alternative bat roosts during maintenance work at road/railway bridges and culverts One study evaluated the effects of providing alternative bat roosts during maintenance work at road bridges. The study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (0 STUDIES) BEHAVIOUR (1 STUDY)         Use (1 study): One review in the USA found that bat houses provided as alternative roosts during bridge replacement works were used by fewer Mexican free-tailed bats than the original roost at one site and were not used by bats at all at three sites. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2942https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F2942Fri, 12 Feb 2021 17:51:31 +0000Collected Evidence: Collected Evidence: Protect specific habitat structures We found no studies that evaluated the effects of protecting specific habitat structures on reptile 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%2F3665https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3665Fri, 10 Dec 2021 11:00:46 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using artificial nest covers: Tuatara We found no studies that evaluated the effects of protecting nests and nesting sites from predation using artificial nest covers on tuatara 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%2F3690https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3690Fri, 10 Dec 2021 17:29:54 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using visual deterrents One study evaluated the effects of protecting nests and nesting sites from predation using visual deterrents on reptile populations. This study was in Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Reproductive success (1 study): One replicated, controlled study in Australia found that a similar number of loggerhead turtle nests marked with red flags were predated compared to those marked only with wooden stakes. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3692https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3692Fri, 10 Dec 2021 17:37:45 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using chemical deterrents Four studies evaluated the effects of protecting nests and nesting sites from predation using chemical deterrents on reptile populations. Two studies were in the USA and one was in each of Spain and Australia. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (4 STUDIES) Reproductive success (4 studies): Three of four controlled studies (including three replicated studies) in Spain, the USA and Australia found that a similar number of artificial Hermann’s tortoise nests, diamondback terrapin nests and loggerhead turtle nests that had chemical deterrents, pepper powder or chilli powder applied were predated compared to nests with no deterrent. The other study found that fewer loggerhead turtle nets that had habanero pepper powder applied to the surface were predated than nests with no pepper powder, or nest with pepper powder below the surface. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3694https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3694Fri, 10 Dec 2021 18:08:18 +0000Collected Evidence: Collected Evidence: Protect nests and nesting sites from predation using conditioned taste aversion One study evaluated the effects of protecting nests and nesting sites from predation using conditioned taste aversion on reptile populations. This study was in the USA. COMMUNITY RESPONSE (0 STUDIES) POPULATION RESPONSE (1 STUDY) Reproductive success (1 study): One replicated, randomized, controlled, before-and-after study in the USA found that a similar number of loggerhead turtle nests were predated in areas of the beach where artificial nests containing unpalatable eggs were deployed (to condition taste aversion) compared to areas with no artificial nests with unpalatable eggs. BEHAVIOUR (0 STUDIES)Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3695https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3695Fri, 10 Dec 2021 18:18:32 +0000Collected Evidence: Collected Evidence: Protect or restore brownfield or ex-industrial sites We found no studies that evaluated the effects of protecting or restoring brownfield or ex-industrial sites on butterflies and moths. ‘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%2F3835https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F3835Mon, 04 Jul 2022 15:24:10 +0100
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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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