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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.

Volume 12

Our mission to transform conservation practice
Hopkins J., Ockendon N. & Sutherland W.J. (2015), 12, 1-1

It is ten years since the launch of Conservation Evidence, and this edition begins with a review that examines the papers published in the journal and the authors that have contributed them. We take this opportunity to assess our progress, and reiterate the aims of the journal.

Trends, biases and effectiveness in reported conservation interventions
Spooner F., Smith R.K. & Sutherland W.J. (2015), 12, 2-7

The journal Conservation Evidence was launched just over ten years ago and here we review the trends and biases in the studies published between 2004 and March 2014; 246 papers describing 439 conservation interventions in 35 countries. The aim of the journal is to provide a format for practitioners to publish the results of their work.  This seems to have been achieved as over 70% of the 609 authors were practitioners. As well as publishing the results of successful interventions, the journal encourages authors to report interventions that were unsuccessful and this was the case for almost a third (31%) of all those published. These results provide especially valuable information to practitioners. Studies published in the first few years tended to be carried out in the UK, but this bias has reduced over time, with at least 60% of papers from overseas in recent years. There continues to be a high rate of male authorship, which is likely to be a symptom of wider scale gender imbalances in conservation amongst both academics and practitioners. The majority of papers submitted to and published in Conservation Evidence have focussed on plants and birds (59%).  There is a clear need for more studies testing interventions for fish, reptiles, amphibians and fungi. Similarly, few studies so far have focused on the social aspects of conservation.

Translocation of individuals across a barrier which hampers natural colonisation is a potentially important, but debated, conservation tool for a variety of organisms in a world altered by anthropogenic influences. The apollo Parnassius apollo is an endangered butterfly whose distribution retracted dramatically during the 1900s across Europe. In Finland the apollo currently occupies only a fraction of the range of its suitable habitat and is apparently unable to re-colonise other areas. Using eggs collected from wild-caught females from the species’ current Finnish stronghold, a population was reared in order to translocate larvae into an unoccupied, but highly suitable, part of the Finnish archipelago where the species historically occurred until its national decline in the 1950s. In 2009 a restricted number of larvae (1 larva/10 host plants) were released on 25 islands in the inner, middle and outer archipelago zones. In 2010, nine islands situated in all three archipelago zones were (re)stocked with a high density of larvae (1/host plant). In 2011, apollo larval populations were found only on islands in the outer archipelago zone, which were then restocked. The species remained present here in the following two years (2012, 2013) and was hence able to sustain multi-annual population establishment without restocking. Our findings demonstrate that empty suitable habitat may in reality consist of only a few sites where population establishment is possible. Hence, starting the introduction in many sites, which are putatively suitable based on biotic and abiotic criteria derived from species’ existing populations, but then “zooming in” on a smaller set of promising sites showing evidence of successful establishment was key to the success of this translocation.

Sisal Agave sisalana is an invasive alien plant species of concern at the UNESCO World Heritage Site of Aldabra Atoll in the Seychelles. Physical control efforts since the 1970s to remove sisal from Aldabra have only been partially successful because the roots cannot be completely removed, resulting in continuous control efforts. We conducted a seven month herbicide trial, using different herbicide concentrations with two application methods, to determine the most effective and feasible control method for sisal. We also checked effects on surrounding native plants. The highest treatment mortality was from 50% herbicide concentration applied directly to the cut growth tip, which resulted in 80% sisal mortality after four months. Fewer treated plants died at lower herbicide concentrations and more small plants died than large plants. No sisal plant died that was foliar sprayed, only cut, or in the control group. There were no visible negative effects of any treatment on the surrounding native flora. The results indicate that chemical control of sisal is effective at high herbicide concentration applied directly to the cut growth tip. A full-scale eradication of sisal from Aldabra has been started based on the trial results.

Attempted re-establishment of a sooty tern Onychoprion fuscatus breeding colony on Denis Island, Seychelles
Feare C.J., French G.C.A., Nevill J.E.G., Pattison-Willits V.S., Wheeler V., Yates T.L., Hoareau C. & Prescott C.V. (2015), 12, 19-24

Seychelles supports around three million nesting pairs of sooty terns. However, there have been recent declines and the colonies continue to face ongoing threats from habitat change and excessive commercial harvesting of their eggs, as well as potential threats by commercial fishing and climate change. A possible method to counter these threats is to re-establish breeding colonies on islands from which they have disappeared. An attempt was made to attract birds to a previously occupied island through habitat management, decoy birds and playback of recorded sooty tern calls. Habitat preparation involved predator eradication and tree removal to provide open ground with bare sandy areas and low herb vegetation. Overflying birds were attracted by broadcast calls, with some circling over and landing among the decoys. Large three-dimensional plastic models were superior to other models presented. This study demonstrated that large numbers of birds can be attracted by these means and that the birds then undertook behaviour associated with breeding, including egg laying by a few birds. However, after five seasons a breeding colony has not yet been established; one possible cause is the emergence of unexpected egg predators, common moorhen Gallinula chloropus and common myna Acridotheres tristis.

The main goal of this study was to experimentally test whether maintaining a fraction of a meadow uncut would create a refuge that can efficiently conserve butterflies in extensively managed meadows registered as biodiversity promoting areas, the most common type of agri-environment scheme in Switzerland. Leaving part of the meadow uncut was expected to benefit butterflies by providing shelter and food resources once the rest of the meadow has been mown. The measure was experimentally applied since 2010 in 12 sites of the Swiss lowlands (Plateau). There were two experimental meadows per site, with one mowing regime applied at random within the pair. One meadow was managed according to the standard regulations for meadows in biodiversity promoting areas, meaning that the meadow was entirely mown at least once a year, but not before 15 June (control meadows). The second meadow was only partially mown, and a grass refuge of 10-20% of its area was left uncut during mowing operations (refuge meadows). In 2013 we conducted Pollard walk surveys to assess the efficiency of the refuge scheme. Results indicate that after mowing the uncut refuges were occupied by butterflies, with much higher abundances than in control meadows. Keeping an unmown grass refuge within hay meadows would be a simple and easy measure to promote butterfly populations within current agri-environment schemes.


This study aimed to assess the effectiveness of control measures undertaken by volunteer labour to impede the spread of wild Pacific oysters Crassostrea gigas within the inter-tidal zone of the North East Kent Marine Protected Areas. This was achieved by conducting a one-year field trial during which a small group of volunteers physically reduced the number of oysters towards a pre-determined target. The site contained a large number of oysters and had high levels of annual recruitment, thus posing a threat to native species and biotopes. Comparison of pre- and post-trial data indicated that oyster numbers were considerably reduced at the trial site although they had increased at each of three control sites. The method used had minimal impact on native species and habitats but was labour-intensive, warranting the use of volunteers. This method of control could be used effectively in other similar situations.


We report the results of a nine year study of the effects of restoring low-intensity cattle grazing on the post-fire recovery of vegetation on the lowland valley mire and wet heath of Folly Bog, Surrey, UK. Four distinct vegetation communities were studied, with repeated recording of quadrats (n = 652) inside and outside grazing exclosures. Species richness increased across the valley mire, largely as a result of grazing-induced decreases in purple moor-grass Molinia caerulea and litter and increases in bare ground. Uncompetitive liverworts and waterlogging tolerant graminoids were particularly favoured. Purple moor-grass and litter removal also encouraged the spread of bog-mosses Sphagnum spp., although trampling in the wettest vegetation resulted in locally severe damage to the moss layer. On the firmer substrates of the wet heath, there were no such deleterious trampling impacts. Here, both bog-moss cover and species richness increased significantly, largely due to suppression of shade-producing heather Calluna vulgaris and litter, and the maintenance of bare ground. Our results reveal that the resumption of low intensity cattle grazing had many positive conservation benefits. However, site managers need to consider grazing on a site-by-site basis and retain flexibility to change stocking times and levels as conditions dictate. Other forms of management to supplement grazing will most likely continue to be required.


The effect of meadow management on plant species diversity was examined in a meadow in the west of England. In 2002 the meadow was assessed as species-poor. From 2002 to 2013 the meadow, along with 11 surrounding fields, was managed as a hay meadow, with grass being mown for hay in late July or early August each year and the aftermath then grazed by cattle. Vegetation surveys from 2002 and 2013 showed that the diversity of the meadow was significantly enhanced over the period of management, with ten additional meadow herb species becoming established by unaided colonisation. In consequence, a colourful, nectar-rich meadow has been created within the space of 11 years.  However, a number of species present on the farm that are more closely associated with old meadows have not yet colonised the field.


A small area of ancient woodland in Essex, England was coppiced. Glow-worms Lampyris noctiluca were observed in the cut area in the first four seasons after winter coppicing, whereas significantly lower numbers were recorded in an uncut control. The highest abundance was observed in the second season after coppicing, only for numbers to decline as the area became overgrown with bramble Rubus fruticosus and shading from the maturing canopy occurred. Coppicing may promote the conservation of glow-worms in ancient woodland.

Possum control and bird recovery in an urban landscape, New Zealand
Johnstone Macleod L., Dickson R., Leckie C., Stephenson B.M. & Glen A. S. (2015), 12, 44-47

In New Zealand invasive brushtail possums Trichosurus vulpecula reduce nesting success of native birds and compete with them for food. As an urban biodiversity initiative, intensive possum control was carried out in a residential area on Napier Hill, North Island. Bird species were monitored using  five-minute point counts, conducted once before the possum control programme and then annually for a further five years afterwards. Significant increases in the relative abundance of bellbird Anthornis melanura and tui Prosthemadera novaeseelandiae were attributed to an increase in food supply due to reduced competiton from possums. Kereru Hemiphaga novaeseelandiae numbers remained relatively stable and a significant decline was recorded in the relative abundance of silvereyes Zosterops lateralis. Management of possum populations will be continued to try to further improve native bird abundance on Napier Hill.


Changes were made to the management of moorland and adjacent in-bye land at the Royal Society for the Protection of Birds' Lake Vyrnwy reserve in Wales with the aim of improving breeding habitat for Eurasian curlew Numenius arquata. Areas of tall, rank, moorland vegetation were cut to provide a mosaic of short areas for foraging and taller areas for nesting habitat. Some new moorland pools were also created, and enclosed improved grassland was managed with the aim of reducing compaction and improving invertebrate levels. The initial response of the breeding curlew population was encouraging but short-lived, although the population has remained at a slightly higher level than before the management was carried out.


Although guano from nesting seabirds is known to fertilize vegetation in nesting colonies, resulting in increased vegetation height and cover, little published research addresses the loss of nesting habitat that may result from this overgrowth. Terns, which nest in limited areas of predator-free, undeveloped coastal habitat, are especially vulnerable to nesting habitat loss due to vegetation overgrowth, but very little information in the scientific literature is applicable to management efforts in seabird nesting habitat. I gathered information on vegetation management effort and success at tern nesting colonies from a survey of colony managers throughout the temperate North Atlantic, as well as from published and unpublished literature. I identified twelve applicable techniques in three categories: vegetation control during the period of plant growth, vegetation control prior to the period of plant growth, and habitat construction. Although the effectiveness of all techniques varied widely across locations and application methods, habitat construction techniques were the most likely to provide nesting habitat for a full season without vegetation re-growth. I summarize general factors likely to influence the effectiveness of management efforts and offer guidelines for choosing different techniques for managing vegetation.