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Conservation Evidence Journal

Publishing evidence to improve practice


The Conservation Evidence Journal shares the global experience of those on the front line of conservation practice about the effectiveness of conservation actions. All papers include monitoring of the effects of the intervention and are written by, or in partnership with, those who did the conservation work. We encourage articles from anywhere around the world on all aspects of species and habitat management such as habitat creation, habitat restoration, translocations, reintroductions, invasive species control, changing attitudes and education. 

The Conservation Evidence Journal publishes peer-reviewed papers throughout the year collected in an annual Volume. We publish Special Issues and collate Collections on specific topics, such as management of particular groups of species or habitats. To search for papers on a specific topic within the journal select Advanced search, enter your keyword(s) and within the Source box type: "conservation evidence". This will take you to a list of actions that contain Conservation Evidence Journal papers. In order to see the list of individual Conservation Evidence Journal papers on the topic, please click on 'You can also search Individual Studies' at the top of this page.

Creative Commons License Copyright is retained by the author(s). All papers published in the Conservation Evidence Journal are open access and licensed under a Creative Commons Attribution 4.0 International License

The Conservation Evidence Journal is a separate publication within the Conservation Evidence project. Conservation Evidence is a free, authoritative information resource designed to support decisions about how to maintain and restore global biodiversity. You can search for summarised evidence from the scientific literature about the effects of actions for species groups and habitats using our online database

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Mammal management

This virtual collection contains 30 papers describing interventions for mammal conservation.

Exclusion of barn owls Tyto alba from a greater horseshoe bat Rhinolophus ferrumequinum roost in Devon, UK

Bollo Palacios M., Kitching T., Wright P.G.R., Schofield H. & Glover A. (2023), 20, 8-12


The greater horseshoe bat Rhinolophus ferrumequinum is a rare species in the UK that relies heavily on undisturbed stone buildings in which to breed. Barn owls Tyto alba are also a protected species that roost and raise their broods in similar places. This overlap in roosting requirements can lead to barn owls moving into buildings containing well-established greater horseshoe bat maternity colonies. This in turn could result in disturbance and abandonment of the building by the bats. Such an event occurred at one of the largest greater horseshoe bat roosts in the UK in 2018 when the colony deserted the roost after barn owls moved in. We describe measures used to exclude the owls while retaining access for the bats, to encourage the colony to return. The suite of modifications consisted primarily of wooden baffles and smooth surfaces on the entrances and doorways. Monitoring showed that the interventions were effective in excluding barn owls whilst allowing bats to access the building. Exclusion of the owls resulted in the return of the greater horseshoe bat colony in similar numbers to 2017 when owls were absent (2022: 92% of the adults) and breeding resumed (2022: 93% of the juveniles in 2017). This paper is the first to evaluate the before and after effects of protecting a bat roost from disturbance or predation by other species.


The implementation and effectiveness of bat roost mitigation and compensation measures for Pipistrellus and Myotis spp. and brown long-eared bat (Plecotus auritus) included in building development projects completed between 2006 and 2014 in England and Wales.

Collins J. H., Ross A. J., Ferguson J. A., Williams C. A. & Langton S.D. (2020), 17, 19-26


We investigated the implementation and effectiveness of bat roost mitigation in building developments completed between 2006 and 2014 in England and Wales. Common and soprano pipistrelle Pipistrellus pipistrellus and P. pygmaeus, brown long-eared bat Plecotus auritus and any of the Myotis spp. were selected for the study.

Building inspection and emergence/re-entry surveys were carried out at 71 sites during 2017 and 2018.

Implementation: 61% of new roosts/access points were implemented precisely as specified, 19% deviated, 11% were absent and 1% were damaged. The remaining 8% were enhancements rather than mitigation or compensation.

Effectiveness: 14% of sites did not retain roosting bats at all, 86% of sites had some bats post-development but only 13% maintained or increased numbers of all target species. Only 18% of new roosting provisions were occupied by bats post-development compared to 52% for adapted buildings and 25% for retained roosts. No bat lofts in new buildings were occupied in comparison to 55% of those in adapted buildings and 65% where bat loft roosts were retained after works. Breeding brown long-eared bats were least likely to return in similar numbers, particularly in roost destruction cases. Bat boxes mounted externally on buildings showed the highest occupation rate regardless of species. Common pipistrelle showed a preference for these over tree mounted boxes; the opposite was true for soprano pipistrelle. Only 8% of new, 8% of adapted and 21% of retained access points were used. These low percentages may be because most roosts were accessed from only one entrance point although multiple entrance points were provided at most sites. Significant relationships were observed between bat use and aperture width and height above ground level.

The findings give important insights into degrees of implementation and effectiveness and how these might be improved, through changes in the licensing process, associated policy and guidance, to serve bat conservation. Further investigation is necessary to drive greater improvements (for example, for other bat species).


Trial of a bridge for reconnecting fragmented arboreal habitat for hazel dormouse Muscardinus avellanarius at Briddlesford Nature Reserve, Isle of Wight, UK

White I.C. & Hughes S.A. (2019), 16, 6-11


The hazel dormouse Muscardinus avellanarius has experienced a marked decline in the UK in recent years, attributable in part to habitat fragmentation associated with an expanding road and rail network. A number of arboreal crossing structures have been installed in the UK to reconnect fragmented habitat, but the only proven usage of such structures by wild hazel dormice has been associated with a large-scale land bridge. This has highlighted the need for affordable, evidence-based alternative designs. We tested the effectiveness of a new dormouse bridge, previously shown to be used by Japanese dormice Glirulus japonicas in Japan, in reconnecting two woodland patches bisected by a railway in southern England. Hazel dormice were recorded on the bridge within nine hours of its erection and exhibited a clear preference for using the bridge, with more than ten times more observations of dormice on the bridge compared to crossing the railway at ground level. Red squirrels Sciurus vulgaris, another rare UK mammal, were also recorded on the bridge. The trial provided evidence of the effectiveness of this design of crossing structure in reconnecting arboreal habitat for hazel dormice and other wildlife, with implications for hazel dormouse mitigation in infrastructure projects.


Effectiveness of mitigation of the impacts of a new road on horseshoe bats Rhinolophus ferrumequinum in Wales, UK

Davies J.G. (2019), 16, 17-23


The intervention described in this paper was designed to allow greater horseshoe bats Rhinolophus ferrumequinum to cross safely underneath a newly constructed road scheme in Pembrokeshire, Wales. The mitigation measures, consisting of bridges, culverts and underpasses, were designed and positioned to increase the likelihood that they would be used by bats. These features were then monitored to determine their effectiveness from the proportion of bats flying safely through the mitigation compared to over the carriageway. This was done using a combination of bat surveyors with hand-held detectors and night-vision equipment, and automated bat detectors. Effectiveness of the different mitigation features increased with increasing cross-sectional area, with a culvert of 1500 mm diameter used less frequently than a larger culvert of 1800 mm x 3000 mm. The larger mitigation measures were generally more than 85% effective. Position in the landscape and the presence of features to guide bats into the mitigation are also likely to be important. In order to assess the likely impacts of a new road scheme on a designated bat population this study also considers local bat population trends, the time of night when most bats cross the road and approximate traffic volumes at these times.


The response of water voles Arvicola amphibius to 'displacement' when using water draw-down and habitat removal in grazing marsh habitat, lowland England

Baker R. J., Scott D. M., Keeling C. & Dwight C. (2019), 16, 37-42


Displacement is a form of mitigation that involves the removal of habitat to relocate water voles Arvicola amphibius from <50m sections of watercourse where their presence conflicts with small-scale development works. The technique is permitted under license in England to minimise negative impacts of development on water voles that are protected under UK law. Despite its widespread use, displacement as a mitigation tool is controversial due to the paucity of evidence relating to its effectiveness and disparity in the methods used to remove habitat. This study aimed to investigate the response of water voles to displacement when using a combination of water draw-down and vegetation removal. We radio-collared 20 water voles and used recapture data to monitor the movement and fate of individuals at three displacement sites and two control sites located in grazing marsh habitat in England during spring 2017. We found that all voles moved to alternative habitat following the removal of vegetation and water and no individuals were discovered in the works area following a destructive search of burrows seven days later. There was no significant difference between the fate and movement of displaced and control individuals. We conclude that displacement of water voles was effective when using both water draw-down and vegetation removal, but recommend further research is carried out to investigate other potentially confounding factors including population density and habitat type.


The effect of using ‘displacement’ to encourage the movement of water voles Arvicola amphibius in lowland England

Gelling M., Harrington A.L., Dean M., Haddy E.C., Marshall C.E. & Macdonald D.W. (2018), 15, 20-25


Water voles are nationally protected as one of Britain’s most endangered wild mammals.  However conflict can arise where works are required along short sections of riverbank. Vegetation removal is commonly used with the aim of displacing water voles towards safety prior to development, despite a lack of evidence demonstrating its efficacy. This study aimed to investigate the movement and fate of water voles in response to vegetation removal, by radio-tracking individuals during spring and autumn at 12 experimental and four control sites. Vegetation was removed to ground level from 50 m of riverbank at experimental sites, and observed home ranges were compared before and after vegetation removal. There was no significant net movement of water voles out of areas where vegetation had been removed in either spring or autumn, although movement of individuals both in and out of the works area did occur. There was no impact of treatment on water vole survival in either season.


Cutting trees in a secondary forest to increase gaur Bos gaurus numbers in Khao Phaeng Ma Reforestation area, Nakhon Ratchasima Province, Thailand

Prayong N. & Srikosamatara S. (2017), 14, 5-9


The value of tourism for gaur Bos gaurus in the Khao Phang Ma reforestation area at the edge of Khao Yai – Dong Phaya Yen World Heritage Site decreased when a large number of gaurs moved away from the watching area of the former grassland in the middle of the secondary forest. A major cause appeared to be an increase in the number and size of pioneer trees Macaranga siamensis that overshadowed their food patches. We constructed a 5.7 ha pilot plot where 407 pioneer trees were cut down in an attempt to attract gaurs back to the area. Since tree cutting was a controversial practice, especially with the local people, we engaged with, and were supported by, a local non-governmental organization throughout the process. We monitored the density of gaurs using the total counts of dung piles. The estimated density of gaurs was significantly higher in the pilot plot compared with an adjacent control plot (8.62 individuals/km2/day versus 3.95 individuals/km2/day), demonstrating a positive impact of tree felling in attracting this species back to an area.



Boma fortification is cost-effective at reducing predation of livestock in a high-predation zone in the Western Mara region, Kenya

Sutton A.E., Downey M.G., Kamande E., Munyao F., Rinaldi M., Taylor A.K. & Pimm S. (2017), 14, 32-38


Lions Panthera leo kill livestock in the pastoral steppe of East Africa. The subsequent lethal retaliation by livestock owners has helped reduce lion numbers by more than 80% and driven the species from most of its historic range. This conflict is especially intense along the western edge of the Maasai Mara National Reserve in Kenya, where some of the densest lion and livestock populations in Africa overlap. We evaluated the effectiveness of implementation for one proposed solution – the Anne K. Taylor Fund’s subsidized construction of fortified, chain-link livestock fences (‘bomas’) – in reducing livestock loss to depredation. Between 2013 and 2015 we collected 343 predation reports, based on semi-structured interviews and predation records. We used these data to study the impact of subsidised boma fortification on the depredation of cattle, sheep and goats. Of 179 fortified bomas, 67% suffered no losses over one year whereas only 15% of 60 unfortified bomas had no losses over one year. Furthermore, losses of greater than five animals per year occurred at only 17% of fortified bomas, compared to 57% of unfortified bomas. The overall reduction in losses to predation at fortified bomas equated to savings of more than $1,200 USD per household per year.




Effects of culverts and roadside fencing on the rate of roadkill of small terrestrial vertebrates in northern Limpopo, South Africa

Collinson W. J., Davies-Mostert H. T. & Davies-Mostert W. (2017), 14, 39-43


We tested the effectiveness of low-level roadside fencing to direct wildlife towards existing culverts beneath the road (underpasses) in order to reduce road deaths of small terrestrial vertebrates. While our results showed a reduction in roadkill count (from eight to one) along the stretches of road where we installed barriers (from an average of 0.33 roadkill/day/km to 0.04 roadkill/day/km), this decrease was not significant, possibly due to the small number of dead animals detected across all sites. Our trial highlights the challenges in acquiring robust evidence for roadkill reduction interventions and, given the small sample size, we were unable to elicit firm conclusions for this study. We therefore propose further testing of the efficacy of roadside fencing to reduce roadkill.


Designing a new access point for lesser horseshoe bats, Gloucestershire, UK

Reason P.F. (2017), 14, 52-57


The aim of this intervention was to create a new flight-path and roost access point for lesser horseshoe bats (Rhinolophus hipposideros) in Gloucestershire, UK. Their existing access point was to be enclosed within an extension to the building they occupied, as part of a redevelopment project. Two designs were tried, and detailed observations were made of bats exiting and attempting to return to their roost. The initial design required the bats to execute a 90° turn at the base of a short vertical shaft, and very few bats returned to the roost through this access point design. The final design provided a clear ‘line-of-sight’ through the structure enclosing the flight-path; bats did return to the roost via this access point. Before the intervention colony numbers did not exceed 35 bats (adults and young); during the construction period, numbers dropped to just seven individuals. Post-intervention (after 15 years), numbers of lesser horseshoe bats (adults and young) have exceeded 400 individuals.


Performance of artificial maternity bat roost structures near Bath, UK

Garland L., Wells M. & Markham S. (2017), 14, 44-51


Surveys were undertaken in 2010 to assess the potential impacts on maternity roosts of brown long-eared bat Plecotus auritus and common pipistrelle bat Pipistrellus pipistrellus before the demolition and redevelopment of a converted farm house and associated outbuildings in the Cotswolds Hills near Bath, UK. As all bat species and their roosts are afforded statutory protection in the UK, a licence was required before the buildings could be demolished. This licence required the construction of two new purpose-designed bat structures in compensation, with the specific goal being the re-establishment of the displaced maternity colonies. Separate bat house and bat wall structures were completed by early spring 2011 with the primary purpose of attracting void-dwelling brown long-eared and crevice-dwelling common pipistrelle bats respectively. Roosting brown long-eared bats established in the Bat House from late 2012, with observed numbers peaking at 20-25 in summer 2013, indicating that a maternity colony had probably re-established. Although a common pipistrelle maternity roost had not established by 2017, small numbers of common pipistrelles were using features within both the bat house and bat wall.


Den boxes as a tool for pine marten Martes martes conservation and population monitoring in a commercial forest in Scotland

Croose E., Birks J.D.S. & Martin J. (2016), 13, 57-61


The pine marten Martes martes is a woodland specialist that favours above-ground arboreal den sites to rest and breed in. Sheltered, elevated den sites are particularly crucial for meeting the needs of breeding females and a scarcity of suitable sites may be a critical constraint upon pine marten populations. An artificial den box for pine martens was designed and 50 boxes were installed in part of Galloway Forest, south-west Scotland, in order to (a) increase the availability and diversity of suitable den sites for breeding female martens and (b) aid monitoring of the marten population. The boxes were monitored for signs of use once per year. A proportion of the boxes was occupied by martens every year and the boxes were used by breeding females to raise their young. The den boxes can be implemented as a habitat enhancement and conservation tool, particularly in commercial forests, and used to monitor marten populations and breeding success. We recommend that conservation programmes for pine martens should consider the installation of den boxes as a habitat enhancement and monitoring tool.


Bear-proof fences reduce livestock losses in the Tibetan Autonomous Region, China

Papworth S.K., Kang A., Rao M., Chin S.T., Zhao H., Zhao X. & Corrasco L.R. (2014), 11, 8-11


Tibetan brown bears Ursus arctos pruinosus in the Tibetan Plateau attack and kill livestock and ransack homes for food, causing significant economic costs for local herders. Although a government fund compensates herders for livestock lost to bear attacks in the Tibetan Autonomous Region (China), compensation may not reflect the real cost of losing livestock and payments can be delayed. We investigate whether bear-proof fences are a cost-effective method for reducing bear attacks and livestock losses. In January 2009, 14 bear-proof fences were constructed from wire mesh and steel posts around households which had previously experienced substantial losses to bear attacks in the Nagqu Prefecture of the Tibetan Autonomous Region. These households lost 162 animals to bears in the year before fence construction, whereas just three animals were lost in the year after fence construction. Fences were still standing 4.8 years after completion and any small damage has been repaired by households. For households that suffer substantial losses to bear attacks, bear-proof fences appear to be an effective and cost-saving intervention to reduce human-bear conflict.


Applying “Diffusion of innovation” theory and social marketing for the recovery of pileated gibbon Hylobates pileatus in North Ta-riu watershed, Khao Soi Dao wildlife sanctuary, Thailand

Kolasartsanee I. & Srikosamatara S. (2014), 11, 61-65


Population density of endangered pileated gibbon Hylobates pileatus in 9 km2 of North Ta-riu watershed, located in the centre of Khao Soi Dao wildlife sanctuary, dramatically declined from 6.4 groups/km2 in 1979 to 2 groups/km2 in 2006. Opportunistic poaching during non-timber forest product (NTFP) collection and insufficient patrolling were considered the main cause of decline. An alternative strategy is needed to enhance pileated gibbon conservation. We applied diffusion of innovation theory to change and expand conservation behaviour among NTFP collectors, although this study does not endorse illegal NTFP collection. After a meeting with NTFP collectors in May 2009, a network of NTFP collectors for pileated gibbon conservation was successfully established with 16 members. The aim of the network was to abstain from poaching on pileated gibbon during NTFP collection. Interpersonal persuasion along with social marketing were used to expand the network. In December 2009, the network had expanded to 101 members. In 2012, six new groups of pileated gibbons (24% increase) were found in the North Ta-riu watershed. The density had increased to 2.8 groups/km2.


A comparison of different bat box types by bat occupancy in deciduous woodland, Buckinghamshire, UK

Dodds M. & Bilston H. (2013), 10, 24-28


An experiment was conducted to determine if Natterer’s bat Myotis nattereri and brown long-eared bat Plecotus auritus exhibited an occupation preference between five different bat box types in an ancient, lowland mixed deciduous woodland in Buckinghamshire. Groups of Schwegler 2F, 2FN, 1FS, 1FF woodcrete boxes and 1 wooden Apex box were erected in 13 locations (5 around each tree). The box clusters were located on trees with a proven history of good box occupancy levels - part of a 10 year woodland bat box scheme. The group positions were evenly spaced along a transect line of 300m in homogenous habitat of predominantly semi mature Pendunculate Oak Quercus robur and Ash Fraxinus excelsior closed canopy with lapsed Hazel Corylus avellana coppice understorey. The temperature regimes of the boxes were compared and found to be similar, and consistent with the ambient temperature due to the shaded nature of the sites. Aspect was experimentally controlled by progressively rotating the box positions around the tree. The occupancy rates of the five boxes were compared and showed a selection bias towards two box types, influenced by seasonal bird competition.


Using social marketing tools to increase fuel-efficient stove adoption for conservation of the golden snub-nosed monkey, Gansu Province, China

DeWan A., Green K., Xiaohong L. & Hayden D. (2013), 10, 32-36


Fuel wood is a key source of energy for many families in developing areas of China.  Fuel efficient stoves are often identified as a win-win solution for forest protections and public health/development in China and across the globe. However, the communication and connection between stoves and biodiversity conservation has been less clear, by both those who are promoting their use as well as those adopting the technology. Social marketing is the application of marketing principles used to sell products applied to “sell” ideas, attitudes, and behaviours to benefit the public good. The Campaign to Protect the Sichuan Golden Snub-nosed Monkey in the Yuhe Nature Reserve, Gansu Province, China, was initiated in 2008 in an effort to inspire communities to protect forest habitat in the reserve, and quickly adopt fuel-efficient stoves.  Results of this study show significant increases in knowledge, attitudes, and interpersonal communication pre and post campaign (16 – 49 percentage points).  Post-campaign (within 1 year) results concluded 28.0% and 43.1% of those surveyed within 1 year of and 2.5 years adopted the technology.  For those households that adopted fuel-efficient stoves, consumption and gathering time were reduced by 40.1% and 38.2% respectively.  Finally, preliminary research suggests that adoption of fuel-efficient stoves also lead to a reduction in forest destruction, with a 23.7 % reduction in the number of newly felled trees in areas where the stoves had been adopted by greater than half of the surrounding community.  The results of this study suggest that social marketing can be an effective tool for improving community knowledge and attitudes, decreasing destructive behaviour, and reducing threats to biological important forests in China.


Effectiveness of a social marketing strategy, coupled with law enforcement, to conserve tigers and their prey in Nam Et Phou Louey National Protected Area, Lao People’s Democratic Republic

Saypanya S., Hansel T., Johnson A., Bianchessi A. & Sadowsky B. (2013), 10, 57-66


The Nam Et Phou Louey National Protected Areain the Lao People’s Democratic Republic contains the last confirmed breeding population of tigers (Panthera tigris) in Indochina.  There are two main threats to tigers, direct killing of tigers and the illegal hunting of wild ungulates, the tigers’ principle prey.  Villagers living around the National Protected Area rely on these same ungulates as an important source of protein in their daily diet.  The illegal hunting of tigers and prey for commercial trade is unsustainable and is driven by a lack of ownership by local villagers who engage in illegal activities and by government agencies that do not enforce the laws.  To reduce these threats the Nam Et Phou Louey National Protected Area is using a social marketing campaign in parallel with traditional enforcement to change the behavior of illegal hunters, village members, and government officials.  To determine campaign effectiveness, a survey instrument was developed to measure knowledge, attitudes and behavior change, which included both a control and pre and post surveys of target audiences.  The pre and post surveys indicate a significant shift along the theory of change from knowledge to behavior change.  The assumption is that over time this shift will also lead to threat reduction to, and thus increase of, tiger and prey populations.


Rapid response mitigation to noctule Nyctalus noctula roost damage, Buckinghamshire, UK

Damant C.J. & Dickins E.L. (2013), 10, 93-94


Historical records over the last century suggest an overall decline in UK bat populations, with the cause speculated to include a decline in roost availability. In 2009, a noctule maternity roost was recorded in an ash tree within ancient semi-natural woodland in Milton Keynes, UK, where up to 75 bats including lactating females were recorded. In December 2011, the ash tree was accidentally felled by contract staff operating on behalf of the landowner whilst carrying out ride habitat and tree safety management as the tree was considered to be a public safety concern. A mitigation and compensation strategy was implemented, with a noctule maternity colony returning in 2012 and 2013. The landowner has subsequently altered internal working practices in relation to bats and trees. This case study exemplifies the need for sharing ecological data records within organisations, and to and from third parties. Good record keeping including photographic and video evidence together with a ‘rapid response’ procedure is demonstrated.



Reducing the impacts of leg hold trapping on critically endangered foxes by modified traps and conditioned trap aversion on San Nicolas Island, California, USA

Jolley W.J., Campbell K.J., Holmes N.D., Garcelon D.K., Hanson C.C., Will D., Keitt B.S., Smith G. & Little A.E. (2012), 9, 43-49


Padded leg-hold live traps were used as the primary removal technique in the successful eradication of feral cats Felis silvestris catus from San Nicolas Island, California, USA. Risk of injury to endemic San Nicolas Island foxes Urocyon littoralis dickeyi, a similarly sized and more abundant non-target species, was mitigated by using a smaller trap size, modifying the trap and trap set to reduce injuries, and utilising a trap monitoring system to reduce time animals spent in traps. Impacts to foxes during the eradication campaign were further reduced by having a mobile veterinary hospital on island to treat injured foxes. Compared to other reported fox trapping efforts, serious injuries were reduced 2-7 times. Trapping efforts exceeded animal welfare standards, with 95% of fox captures resulting in minor or no injuries. Older foxes were more likely to receive serious injury. Fox captures were also reduced through aversive conditioning, with initial capture events providing a negative stimulus to prevent recaptures. Fox capture rates decreased up to six times during seven months of trapping, increasing trap availability for cats, and improving the efficacy of the cat eradication program. No aspect of the first capture event was significantly linked to the chance of recapture.


Use of badger tunnels on Highway Agency schemes in England

Eldridge B. & Wynn J. (2011), 8, 53-57


Monitoring of badger tunnels using clay mats on nine Highways Agency road schemes was undertaken to establish their effectiveness in terms of use by large mammals (primarily European badger Meles meles), as well as the efficacy of tunnel design advice provided by the agency.  The results indicate that tunnels are an effective means of mitigating the effects of all types of new road schemes on badgers; 89% of the tunnels monitored were used.  The results suggest that no one factor is of over-riding importance in tunnel design; however, design features that appeared to be associated with the use of tunnels were good vegetation cover, habitat connectivity, good drainage and a tunnel width of at least 600 mm.


Managing competition between birds and bats for roost boxes in small woodlands, north-east England

Meddings A., Taylor S., Batty L., Knowles M. & Latham D. (2011), 8, 74-80


A total of 196 bat boxes were installed between 2005 and 2009 across 21 sites throughout the Highways Agency's (HA) 'soft estate' woodland in north-east England in support of the HA's Biodiversity Action Plan. The woodlands are typically small linear blocks (<3 ha) with trees mostly less than 40 years of age. Suitable natural cavity sites are thus very limited, hence the attractiveness of bat boxes as a conservation measure to enhance these woodland habitats. Monitoring in 2006-2007 had shown that in some areas (seven woodland sites) over 40% of bat boxes were being used by nesting passerine birds. Bird boxes were installed in an attempt to reduce bird occupancy of bat boxes. Provision of bird boxes significantly reduced bird use of bat boxes (a 50% overall reduction in occupancy) thus potentially making more bat boxes available for bat use. We also assessed if there was any relationship between the number/density of available bat boxes and level of bat occupancy to assess if there was a limit to the occupancy levels that could be achieved, thus determining an approach that could maximise benefits and cost effectiveness of box installation. Occupancy of bat boxes by bats appears not to increase above 30% utilisation with an increasing number of boxes on site after eight boxes. This suggests that, as bat boxes are installed three boxes per tree (as per best practice guidelines), the optimal number to install would generally be between nine to 12 boxes in these small woodland areas.


Hand-augering to locate European badger Meles meles tunnels and chambers as part of emergency mitigation along water pipe installation works near Stanway, Essex, England

Adderton I.V.P. (2011), 8, 6-10


European badgers Meles meles and their setts are legally protected in the UK. If setts are to be damaged or destroyed as part of development, humane exclusion of badgers is usually required in advance of works. Exclusion can be achieved by erecting one-way gates over sett entrances which allow badgers to exit but not regain entry. Natural England (the governmental conservation advisory body in England) recommends that exclusion is maintained for 21 days before construction work begins to ensure that the sett has been vacated. In this study, a large diameter (400 mm) water main was installed through a badger sett without exclusion of animals due to discovery of the sett only after construction work had commenced. The sett location and the presence of numerous European rabbit Oryctolagus cuniculus burrows interspersed with sett entrances would have made exclusion difficult. As an emergency mitigation measure, a 1.4 m deep, 40 cm wide trench was excavated 6 m from the sett entrances (located mostly in a lapsed field boundary using a combination of hand augering (to detect badger tunnels and chambers; these were then excavated by hand), followed by mechanical excavation. Subsequent to this, work to excavate the trench, lay the pipe through the sett and back-fill the trench took one week. Despite the disturbance caused by this approach, badgers were not excluded from the entire sett and the risk of killing badgers which may have been present below ground was significantly reduced; no badger or other large mammal activity was evident during the mitigation works.

All works were carried out under Natural England licence and under the supervision of an ecologist and a Natural England Wildlife Management Adviser.


Provision of artificial badger setts and use of remote camera monitoring to determine Eurasian badger Meles meles sett occupancy, Suffolk, England

McDonald P.J. & Allen T.P. (2011), 8, 107-110


During electricity substation upgrading works at a site in Suffolk (England), five Eurasian badger Meles meles setts were closed (under licence) in 2009 as they were directly under the footprint of the works. As part of the licence agreement, mitigation included provision of three artificial setts. After completion of construction, monitoring indicated that all three setts displayed signs of occupancy and increased badger commuting and foraging evidence around their vicinity. In 2011, a remote motion-activated  infra-red camera was used to determine badger occupancy at a three-entrance outlier sett that also required closure during the badger breeding season. Previous extensive monitoring showed that badgers were unlikely to be present. However, a monitoring program using the remote camera was implemented to ensure that this was the case. When evident that badgers were not using the sett, it was destroyed under supervision of an ecologist. Being a novel, non-invasive monitoring technique this was done in liaison with the governmental statutory body, Natural England, but without the need for a licence. Remote monitoring techniques like this could be applied in similar situations where work is required during the badger breeding season (December to June) when licences are not normally issued.


Lemur bridges provide crossing structures over roads within a forested mining concession near Moramanga, Toamasina Province, Madagascar

Mass V., Rakotomanga B., Rakotondratsimba G., Razafindramisa S., Andrianaivomahefa P., Dickinson S., Berner P.O. & Cooke A. (2011), 8, 11-18


The Ambatovy Project includes a large, open-pit nickel mine located in Madagascar's eastern humid forest, and an associated pipeline to remove laterite slurry off site. The area is recognized for its high biodiversity exemplified by the presence of at least 13 lemur species in forests surrounding the mine site. In order to reduce potential habitat fragmentation impacts on the lemur populations as a consequence of recent access road construction, seven crossing structures (referred to as 'lemur bridges') were erected within the mine footprint area and along the slurry pipeline that will remain in place until rehabilitated forest allows for movement over roads via the forest canopy. Two bridge designs were used due to differences in road width and vehicle traffic type. Lemur bridges have been monitored since their construction in January-February 2009. To date (10 August 2010), bridges have been used by six lemur species. Mine footprint type bridges (suspension bridge design) have been used more frequently than slurry pipeline bridges (plank bridge design) and, overall, there has been an increase in bridge use in 2010 when compared to 2009 (from 8 % to 24 % of total observations where lemurs are present in proximity to bridges). These results suggest that although a certain time period may be required for lemurs to locate and habituate to bridges, these crossing structures offer an effective mitigation measure to assist in reducing the impacts of habitat fragmentation.


Post-release GPS tracking of hand-reared Irish hare Lepus timidus hibernicus leverets, Slemish, Co. Antrim, Northern Ireland

Reid N. & Harrison A.T. (2010), 7, 32-38


Animal rescue centres release large numbers of captive-bred, rehabilitated or translocated animals into the wild annually but little is known about their post-release survival and behaviour. We developed a novel and innovative coupling of traditional radio-tags with new GPS loggers to track hand-reared Irish hare Lepus timidus hibernicus leverets after release into the wild. Cyanoacrylate SuperGlue® proved a poor fixative with two out of three leverets managing to detach their tags within 24 hours. Nevertheless, a total of 2,505 GPS locations were recorded every 60 seconds for one leveret over three nights (approx. 835 per night). The leveret dispersed <410 m from the original release site. It demonstrated exploratory behaviour including an ability to navigate accurately in a complex and unfamiliar environment returning to a habitual lie-up site each day. Its survival was confirmed up to 9 days post-release at which time its radio-tag detached, however, similarly aged leverets were sighted in the area for up to 2 months post-release (suggesting possible longer term survival). This is the first study to publish data from any GPS tagged lagomorph and provides 'proof-of-concept' that large quantities of behavioural data can be recovered from small mammals 1-2 kg. Further development of these techniques will be highly valuable to future studies.



Use of a remote camera to rapidly assess Eurasian badger Meles meles occupancy within a sett to be lost due to pipeline laying near Uppingham, Rutland, England

Griffiths L. (2008), 5, 92-94


A remote controlled camera proved a practical solution to survey a single, one-entrance outlying badger Meles meles sett in late January (outside the normal licensing period for disturbing badger setts), which was found to be present on the route of a proposed water pipeline. Upon ascertaining that the sett was almost certainly unoccupied, the sett was immediately taken apart and filled in following strict guidelines specified under the terms of the Natural England licence (supervised by the relevant authority), to allow pipe-laying activities to continue. Once the pipeline is installed and construction completed, badgers will be able to re-colonise the same area of ground.



Creation of a 'water pathway' for otters Lutra lutra, under an electric fence at Kingfishers Bridge, Cambridgeshire, England

Gulickx M.M.C., Beecroft R.C. & Green A.C. (2007), 4, 28-29


A 'water pathway' was devised for allowing otters Lutra lutra to pass into an area enclosed by an electric fence to prevent fox access. After its construction, several otter spraints (some close to the water pathway) were subsequently found within the fenced area. There was no evidence that foxes Vulpes vulpes, entered by this route.


Creating a bat hibernaculum at Kingfishers Bridge, Cambridgeshire, England

Gulickx M.M.C., Beecroft R.C. & Green A.C. (2007), 4, 41-42


To provide a winter hibernation site for bats, an artificial cave was constructed at a nature reserve in eastern England. Subsequent to its completion, in the winter of 2005/06, two brown long-eared bats Plecotus auritus hibernated in the cave and in the subsequent winter one hibernated within it. It is considered likely that bat numbers will build up in future years.


Using clay drain seals to assess the use of dry culverts installed to allow mammals to pass under the A1 trunk road, Northumberland, England

Baker A., Knowles M. & Latham D. (2007), 4, 77-80


Monitoring the use of dry culverts installed as underpasses enables their effectiveness to be evaluated. We used clay-based drain seals to record mammal tracks in three different culverts under a section of a major road in Northumberland, UK. Prints including badger Meles meles, American mink Mustela vison and hedgehog Erinaceus europaeus were recorded on the clay drain seals demonstrating animal movement in both directions through the culverts. The prints were well preserved and easily recognisable.



The Tree Kangaroo Conservation Program - community-based conservation on the Huon Peninsula, Papua New Guinea

Ross T. & Dabek L. (2006), 3, 47-48


Following a community-based conservation programme started in 1996, with the endangered Matschie's tree kangaroo Dendrolagus matschiei as the project's flagship species, a joint proposal for the regions first protected area, comprising over 60,000 ha, was submitted to the regional government and approved in 2006.


The use of floating rafts to detect and trap American mink Mustela vison for the conservation of water voles Arvicola terrestris along the River Wensum in Norfolk, England

Thompson H. (2006), 3, 114-116


Mink rafts positioned along stretches of the River Wensum proved very successful in terms of American mink Mustela vison detection and trapping effectiveness. Survey results indicated that there has been an expansion in the range of water voles Arvicola terrestris along the river from 2003 to 2005, perhaps in response to the removal of American mink.


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