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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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Volume 20

Voluntary transition by hunters and game meat suppliers from lead to non-lead shotgun ammunition: changes in practice after three years

Green R.E., Taggart M.A., Pain D.J., Clark N.A., Clewley L., Cromie R., Green R.M.W., Giui M., Huntley B., Huntley J., Leslie R., Porter R., Roberts J., Robinson J.A., Robinson R.A., Sheldon R., Smith K.W., Smith L., Spencer J. & Stroud D. (2023), 20, 1-7


In 2020, UK shooting and rural organisations pledged to achieve a voluntary transition from the use of lead shotgun ammunition to non-lead alternatives for hunting by 2025. The SHOT-SWITCH research project was set up in 2020 to monitor progress towards this aim by examining the proportions of wild-shot common pheasants Phasianus colchicus available to consumers in Great Britain that were killed using lead and non-lead shot. In the study’s third season, 2022/2023, 94% of pheasants sampled had been killed using lead ammunition. Statistically, this is a significantly smaller proportion than in the preceding two seasons (both > 99% lead), but it remains large. We found no direct evidence of any effect of recent voluntary initiatives to promote the replacement of lead with non-lead ammunition by suppliers and retailers of wild-shot game.


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 effect of prescribed burning on Pulsatilla vernalis at Marma military training area in Sweden

Hagström C., Löfgren T., Lindquist I., Forslund M. & Jandér K.C. (2023), 20, 13-20


Changes in habitat have led to a decline in many species which are now threatened. One of them is the spring pasque flower Pulsatilla vernalis, which grows on well-drained soils and is sensitive to competition. The species has in the past benefited from disturbances such as grazing, mowing and forest fires. Now that these do not occur as frequently, it has been suggested that prescribed burning could be used as a conservation intervention to benefit P. vernalis. In this study, we tested whether prescribed burning in 2018 benefited a population of P. vernalis at Marma military training area, outside Älvkarleby in eastern Sweden. Due to unexpected windy conditions on the day of the prescribed burning, not all the planned area was burned. This created a natural experiment that enabled us to compare burned areas with unburned areas (control) in both heathland and forested heathland habitats. The study includes data gathered before and after the experimental treatment. We found that compared to the control areas, the burned areas had a significantly higher number of P. vernalis tufts (clusters of leaf rosettes), as well as a greater number of flower stalks per tuft. Although limited due to lack of replication, this study supports the suggestion that prescribed burning benefits P. vernalis, both in open areas as well as in forests. 


Artificial lighting technologies to support aquatic plants in rivers which are shaded by bridges and culverts

Fleming S.D., House T.M., Boyd J.D., Lister J.D., Lavelle A.M. & German S.E. (2023), 20, 21-29


Aquatic plant communities are important components of river ecosystems, providing food sources and functional habitats through the provision of refuge and spawning substrate for animals including fish and macroinvertebrates. Types of urban infrastructure including bridges and culverts present a major challenge to rivers; for example, the shading effects of these structures can exclude aquatic and wetland plants, degrade and fragment habitats and inhibit the movement of aquatic and riparian species in rivers.

Few studies have investigated the potential to reconnect riverine habitats through artificial lighting technologies. In this study, a 12-month controlled laboratory trial was undertaken to investigate the potential for using artificial lighting to support aquatic plants shaded by urban infrastructure. Two artificial lighting scenarios were compared to a natural light (control) scenario to determine the potential for supporting eight aquatic plant species common in UK rivers.

Overall, growth rates, flower numbers and biomass values were higher for all species under the natural light scenario. However, the artificial lighting scenarios also enabled selected plants to grow and survive over the trial period with variable success in line with shade tolerance, suggesting that it is feasible to grow aquatic plants under urban infrastructure using artificial lighting. This study provides a basis of understanding on how to design an artificial lighting strategy that can support a community of aquatic plants; however, further study and in river trials are required to optimise such as system.


Effectiveness of different nursery designs for the restoration of the threatened coral Acropora cervicornis in Culebra, Puerto Rico

Aponte-Marcano P.I., Suleimán-Ramos S.E. & Mercado-Molina A.E. (2023), 20, 30-39


The threatened staghorn coral Acropora cervicornis is an important reef-builder species in the Caribbean. Its ecological importance and critical status have prompted efforts to restore degraded populations. In this respect, nursery-based programmes have effectively propagated A. cervicornis and helped to increase population sizes. Despite many advances in low-cost coral nursery designs, there is still a need to increase productivity while reducing costs. This study evaluates A. cervicornis demographic performance in two propagation structures: floating trees (FT) and floating horizontal frames (HF). Two equal-sized fragments were collected from 50 healthy staghorn coral colonies. Each fragment was placed into an FT or HF design. Survival, growth, branching, and productivity were recorded for seven months. To address the cost-effectiveness of the coral propagation techniques, we compared the total cost of producing corals between the two designs. Survival was similar, with 91% and 92% of the coral fragments surviving in the FT and HF, respectively. Although colonies in HF nurseries grew faster and produced more branches than those in FT nurseries, these differences were not statistically significant. Likewise, productivity did not differ statistically between nursery designs despite fragments in HF nurseries being 1.5 times more productive than those in FT nurseries. Because of the similarity in demographic performance, the selection of nursery designs could be based solely on their cost-effectiveness. In this respect, the cost-effectiveness analysis shows that producing corals using HF costs about 70% less than FT. Thus, we conclude that floating horizontal frame (HF) nurseries are better for propagating A. cervicornis and accelerating coral restoration activities.


Effectiveness of regulations intended to reduce the use of lead shotgun ammunition in and over coastal intertidal and riparian habitats in Scotland

Green R.E., Goater R., Hodgson D., Lang I., Orr-Ewing D.C., Pickett D. & Swann B. (2023), 20, 40-46


The use of lead shot for hunting in wetlands is banned in many countries because ingestion of spent shot causes lead poisoning of wildfowl. In Scotland (UK), the Environmental Protection (Restriction on Use of Lead Shot) (Scotland) (No. 2) Regulations 2004 were introduced to reduce the exposure of wildfowl to lead shot by making its use in wetlands unlawful. We assessed the degree to which the regulations are being complied with by wildfowlers by conducting analyses of the shot metal type contained within shotgun cartridges discarded in coastal intertidal and riparian habitats across Scotland. Despite efforts to encourage compliance with the regulations, which had been in force for 17-18 years at the time of the surveys, about half of the cartridges used appeared to have contained lead gunshot, indicating unlawful use. Hence, efforts to restrict the use of lead ammunition in coastal and riparian wetlands by regulation, with the intention of reducing the risk of lead poisoning of waterfowl, have had limited effectiveness so far.


Perennial plant recovery after the removal of invasive Pinus halepensis in coastal habitats in Cádiz, southern Spain

García-de-Lomas J., Rendón J.L., Pacheco M.J., Riches Z.O.V. & López J.M. (2023), 20, 47-54


Aleppo pine Pinus halepensis is a tree native to the Mediterranean basin. Even within its native range, P. halepensis may behave as an invasive species when planted beyond the original forest areas. Despite its potentially negative effects on the receiving ecosystems, little is known about the response of native plant communities following removal of P. halepensis. In southern Spain, P. halepensis plantings are outcompeting native shrubland communities (Juniperus spp.), which are home to several endangered and protected species. We present the results of an intervention to control the spread of P. halepensis in an area of coastal dunes at the La Breña y Marismas del Barbate Natural Park, Cádiz, southern Spain in 2016. An area of 22.4 ha of P. haplensis cover was removed using portable chainsaws and a forwarder. We analysed the species richness and composition of native perennial plant species recorded three and six years after the removal of P. halepensis in treated, invaded and uninvaded areas. Removal of P. halepensis increased the cover of perennial grasses and woody shrubs typical of sun-exposed areas, such as esparto grass Stipa tenacissima, rosemary Rosmarinus officinalis, turbith Globularia alypum, white-leaved rock-rose Cistus albidus and the shrub Anthyllis citisoides. We conclude that P. halepensis removal promotes coastal shrub recovery. We recommend periodic rounds of manual, selective control every three to five years to avoid reinvasion.



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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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