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Providing evidence to improve practice

The journal, Conservation Evidence

Our online journal publishes research, monitoring results and case studies on the effects of conservation interventions. All papers include some monitoring of the effects of the intervention and are written by, or in partnership with, those who did the conservation work. It includes interventions such as habitat creation, habitat restoration, translocations, reintroductions, invasive species control, and education or integrated conservation development programmes, from anywhere around the world.

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A volume is created each year with peer-reviewed papers published throughout the year. We now accept Short Communications as well as standard papers.

Special issues contain new papers on a specific topic.

Virtual collections collate papers published in the journal on specific topics such as management of particular groups of species.

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 papers. In order to see the list of individual Conservation Evidence papers on the topic, please click on 'You can also search Individual Studies' at the top of this page.

Latest papers

The red-footed falcon is a near threatened species, which breeds mainly in agricultural landscapes, typically nesting in empty corvid nests on trees. In Europe, this species is declining due to habitat degradation and agriculture intensification. The aim of our study was to determine the reproductive success and the increase in the number of nesting pairs after the installation of nest boxes. This study took place in the Italian province of Parma, the southernmost part of the red-footed falcon’s breeding range. Nest boxes were provided in four locations, where falcons were already breeding in corvid nests, to assess if this action could increase the falcon population and breeding success in the study area. After the deployment of 117 nest boxes from 2010 to 2018 the Parma population increased from 25 to 82 pairs, occupying up to 50% of available boxes in 2018. The breeding success remained unvaried over the study period with an average of 2.06 and 2.37 chicks fledged per pair in corvid nests and nest boxes respectively. It also did not differ between the two nest categories. These results could indicate that a lack of suitable nesting sites is a major limiting factor for the falcon population in the Parma province rather than lack of food.

A replicated, controlled study in 2011-2012 found that using home-made fish traps reduced the capture of unwanted, small shannies Lipophrys pholis compared to using conventional hand-nets in intertidal habitats.

Sea wall flood defences provide important grassland habitats for bumblebees in the UK but the abandonment of cutting could be deleterious for declining species, such as the shrill carder bee Bombus sylvarum, due to the development of floristically-poor swards and scrub encroachment. This paper reports the results from a study of bumblebees (Bombus spp.) and forage plants in rotational summer cut plots with winter soil disturbance (cut and rut) implemented in grassland unmanaged for over 10 years on a sea wall. For the cut and rut plots, bumblebee forage-plant species richness significantly increased, but not on the control, suggesting that the cut and rut management was leading to the improvement of the tussocky sward for pollinators with the increased frequency of leguminous species (e.g. Lotus tenuis and Trifolium pratense) favoured by long-tongued bumblebees (e.g. B. humilis, B. muscorum). Queens of B. sylvarum were seen foraging on the cut and rut plots four years after restoration management was initiated. An increase in the floristic diversity of the cut and rut treatment was evident after four years, suggesting that there is the potential for a significant corridor of favourable bumblebee habitat to be created in the long-term on the Essex coast.

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).

Solitary bees have experienced a decline in both diversity and abundance over the past decade. Although their foraging requirements have been the subject of some recent studies, their nesting requirements have received little attention. Some species of ground-nesting solitary bees have shown an affinity for hard, bare ground as preferred locations for nests. Here we assessed two different methods for creating bare ground plots on farmland and observed the different rates at which these plots recruited ground-nesting bees. Three approximately 6 m2 plots were created at each of 19 locations. One was scraped bare using machinery, a second was sprayed-off with herbicide, and the third was left undisturbed as a control plot. The results showed a significantly greater number of nests in the scraped plots compared to the sprayed or control plots, with the majority of these nests being created in April. This trial shows that an agri-environment scheme could be effective to support the creation of nesting areas for solitary bees on farmland.

A successful Pacific rat Rattus exulans eradication on tropical Reiono Island (Tetiaroa Atoll, French Polynesia) despite low baiting rates
Samaniego A., Griffiths R., Gronwald M., Murphy F., Le Rohellec M., Oppel S., Meyer J-Y. & Russell J. C. (2020), 17, 12-13

We successfully eradicated rats from Reiono Island despite reducing the interval between bait applications from the recommended 10-21 days to 7 days, and reducing bait availability from the recommended >4 nights, to 2 nights. We focused on meeting the eradication principle of exposing all rats to poison bait by ensuring complete bait coverage across the island. Relative to current practice our approach saved 3,032 kg of bait and 168 person-days of labour on a 22-ha island, or US$42,626 in bait and accommodation costs. In line with other recent cases, the Reiono eradication suggests that using moderate baiting rates and short baiting intervals can lead to significant financial and logistical savings. Yet, baiting strategies should be tailored to the risk environment of each project.

The translocation of reptiles from development sites is a frequent but controversial intervention to resolve reptile-development conflicts. A general lack of post-translocation monitoring means that the fate of translocated reptiles is largely unknown. Here we report on the outcome of six reptile translocations carried out to mitigate the impacts of development. Through detailed post-translocation monitoring, we sought to determine whether translocated reptiles established populations within the receptor sites.

To determine the effect of translocation, we investigated six sites within the UK that had received populations of translocated slow-worm Anguis fragilis, viviparous lizard Zootoca vivipara, adder Vipera berus and / or grass snake Natrix helvetica. Identification photographs were taken of all reptiles during the translocation. Following release, between one and three years of post-translocation monitoring was undertaken; during the monitoring, identification photographs were again collected to establish whether captured individuals were part of the translocated populations.  

Very few translocated individuals were encountered during the post-translocation monitoring. The mean number of translocated reptiles was 98 (SE 19.61). Of these, an average of 1.5 (SE 0.72) individuals or 1.6% of the population were captured during the monitoring. No recaptures of translocated reptiles were made at three (50%) of the study sites. The low recapture rates of translocated reptiles could be due to mortality, imperfect detection (including inaccurate identification of individuals) or post-translocation dispersal. There is some limited evidence to support each of the possible options, but post-translocation dispersal is considered to be the most likely explanation.

The study found no confirmatory evidence that mitigation-driven translocations are compensating for the losses of populations to development.

The use of storm fragments and biodegradable replanting methods allows for a low-impact habitat restoration method of seagrass meadows, in the eastern Aegean Sea
Ward E. A., Meek S. K. , Gordon D. M., Cameron T. C. , Steer M. D., Smith D. J. , Miliou A. & Tsimpidis T. (2020), 17, 1-6

Seagrasses are important marine ecosystems but are vulnerable to physical damage from anthropogenic activities such as anchoring and trawling. Replanting damaged areas can represent a viable restoration strategy, yet current methods rely on the removal of plants from existing meadows and in some cases the use of non-sustainable planting materials. In this paper, we present evidence of a sustainable replanting strategy. Storm fragments of the endemic Mediterranean seagrass, neptune grass Posidonia oceanica were collected from the shore and shallow water, both the plagiotropic and orthotropic (horizontal and vertical) growth forms were then replanted using one of two biodegradable materials, coconut fibre pots or bamboo stakes, to secure them to the seafloor. Establishment of plagiotropic fragments were increased by bamboo anchorage (x̅ = 89% SE ± 0%) compared to orthotropic storm fragments (x̅ = 66.5% SE ± 6.5%). By contrast a coconut fibre method resulted in greater establishment of orthotropic fragments (x̅ = 79% SE ± 7%) compared to plagiotropic (x̅ = 51% SE ± 11%). Fragments showed some blade growth, but little shoot growth after 15 months. The fragment shoot and blade growth did not differ between the plagiotropic or orthotropic fragments replanted by bamboo stakes or coconut fibre pot. Our results suggest that the use of storm fragments and biodegradable anchoring materials constitutes a viable, non-destructive replanting technique in seagrass restoration. Furthermore success can be increased by selecting a growth-form appropriate planting method.