Wire-mesh nest exclosures installed around Hudson's canastero Asthenes hudsoni nests were associated with 57% cumulative survival compared with 4.5% for nests without exclosures. Adults rapidly resumed nest attendance, no abandonment was attributed to installation, and camera traps recorded at least 16 predation attempts blocked by the exclosures.
Foxes prey upon clutches of ground-nesting birds, and in Australia this constitutes a conservation problem for which no effective solution currently exists. We trialled the application of dog urine spray around camera-monitored, mock plover nests in a wetland (eight with urine, eight with a water control) in an attempt to reduce loss to predators and increase clutch survival. No survival benefit was detectable. We also studied predator visits to treated and control nests; no difference occurred in the number of putative predators at urine-treated nests, including foxes. This small trial suggests there would be little benefit to further study, or application of, dog urine to protect nests in our study system.
The hard-ground swamp deer Rucervus duvaucelii branderi, once widespread in Central India, is now restricted to a single population in Kanha Tiger Reserve. To reduce extinction risk and expand the subspecies’ range, the Madhya Pradesh Forest Department translocated 98 individuals from Kanha to Satpura Tiger Reserve between 2015 and 2023. Deer were moved in seven phases and released across three sites: a predator-proof enclosure in the Bori range, and open grasslands in Bori and Churna (Malini). We evaluated the effectiveness of this conservation translocation through nine years of monitoring data on population size, age–sex structure, and body condition. By 2023, the population had grown to 172 individuals. Body condition scores showed that deer in Satpura were comparable to the source population in Kanha. Mortality remained low, with most deaths attributed to predation or natural causes. These results show that the reintroduction, supported by habitat restoration, veterinary care, and regular monitoring, has established a stable and growing population. This case study illustrates the value of long-term planning, adaptive management, voluntary village relocation, and targeted habitat investment in recovering threatened herbivores. It offers a practical and replicable model for future reintroduction efforts in managed landscapes across India and beyond.
A dramatic decline in American eel Anguilla rostrata abundance led to the species being assessed as Endangered in Ontario (Canada) and the closure of fisheries. As part of efforts to recover populations, four million eels (glass eels and elvers) were batch marked and released over a five-year period (2006-2010) into the upper St. Lawrence River and Lake Ontario. Over 2019-2022, we repeated an earlier large-scale electrofishing survey of eastern Lake Ontario tributaries done to assess the distribution and survival of the released eels. A decade later, we collected two hundred and fifteen eels from 19 sites along four rivers near the release site. Eels were absent from three tributaries occupied in 2010-2011. Along the Trent River, navigational locks have likely permitted migration past seven large dams previously assessed as probably impassable. Growth of translocated eels was variable among rivers. As well, many eels were still smaller than yellow eels naturally migrating into Lake Ontario. Our study indicates high, long-term post-release survival in these rivers. However, timing of out-migration and potential for successful spawning migrations remain unknown.
Corn bunting Emberiza calandra is a UK red-listed species that requires significant conservation effort within agricultural landscapes to maintain populations. Its preference for nesting in cereal fields and other crops puts it at considerable risk from farming operations. In North East Scotland, where most cereals are spring-sown and nesting attempts in May and June are often in the taller denser swards of grass silage fields, nest destruction during mowing is a major problem. Delayed mowing increases nest survival rates, but also lowers the quality of forage so has limited uptake in agri-environment schemes. Potentially a more attractive solution to farmers are ‘green manure’ crops, which involve growing plants with nitrogen-fixing and other properties to improve soil condition in arable fields. These crops are becoming increasingly popular amongst farmers, but in North East Scotland are usually sown during spring. To test whether autumn-sown green manure would provide an attractive, safe nesting habitat for corn buntings in May and June the following year, we conducted a trial across six farms in 2021–2023. Results confirmed that sowing in September enabled the crop swards to become sufficiently tall and dense to attract nesting corn buntings the following spring. Furthermore, average nest survival rates in the trial plots (60%) were similar to those in cereal fields later in the season (70%), and much higher than grass fields (25%). We conclude that autumn-sown green manure crops can provide a safe alternative to grass silage fields during late spring to early summer, when corn buntings have few other nesting habitats available.
Weirs are a globally abundant type of low-head dam that negatively alter river ecosystems. Their removal is an increasingly popular river restoration measure in many countries. However, it is unclear what benefits weir removal might provide for the typically depauperate macroinvertebrate communities of urban rivers, which are usually subject to a range of anthropogenic pressures. This Before-After Control-Impact Paired study tested whether the removal of a weir on an urban river in the UK resulted in a shift in the aquatic macroinvertebrate community towards a more natural state. Macroinvertebrates were sampled before and after removal, above and below the structure and at control sites over four years. Following weir removal, the proportion of macroinvertebrate families that were made up of mayfly, stonefly or caddisfly families (an indicator of stream health) underwent a statistically significant increase at the upstream impact sites. There was a concurrent statistically significant increase in two indices, the Lotic-invertebrate Index for Flow Evaluation and the Empirically-weighted Proportion of Sediment-sensitive Invertebrates index, suggesting weir removal had an ameliorating effect on flow and sediment stressors acting on the macroinvertebrate community upstream of the weir. ‘Reference samples’ for the study location were generated using the River Prediction and Classification System, which are predictions of what the macroinvertebrate community would likely be if the study site was in a near natural state. Non-metric multidimensional scaling ordination showed that the macroinvertebrate community upstream of the weir became more similar to the ‘reference samples’, suggesting that it had shifted towards a more natural composition.
In 2023, record-breaking global temperatures intensified marine heatwaves, causing extensive coral bleaching in subtropical and tropical oceans, severely impacting the Caribbean. This study assesses artificial shading as a strategy to mitigate thermal and light stress on cultivated staghorn corals at two water depths. We distributed 485 coral fragments across two shading treatments: clear vinyl sheets and green cloth, and an unshaded control at 6.3 m and 12.2 m deep. Growth, mortality, phenoloxidase activity, total protein content, and green fluorescent proteins in the corals were monitored from September 2023 to February 2024. Additionally, water temperature and solar radiation were monitored within each treatment. Both shading and depth affected the environmental conditions surrounding the corals as well as their growth, mortality, and physiology. All shading materials, particularly the green cloth, reduced the surrounding water temperature and light intensity compared to the control. Bleaching was lower for corals shaded with green cloth at lower depth compared to clear-shaded and unshaded corals. However, growth was higher in shallower waters compared to deeper waters and shaded corals at both depths displayed more growth than the unshaded corals. Shaded corals showed less variation in immune-related protein levels compared to unshaded corals. These findings suggest that shading cultivated corals can support coral health.
A replicated, controlled trial in 2023 to test whether Trico® deer repellent spray is effective for protecting coppice re-growth from deer browsing found significantly fewer visible signs of browsing and significantly higher average re-growth for sprayed coppice than for an unsprayed control.
Since 2020, the SHOT-SWITCH research project has monitored the proportion of wild-shot common pheasants Phasianus colchicus in Great Britain that were killed using lead and non-lead shot. This was set up in response to UK shooting and rural organisations’ announcement that game shooters should make a full voluntary transition from lead to non-lead shotgun ammunition by 2025 and initiatives by retailers and wholesalers of game meat products. In the study’s fifth and final season (2024/2025), 99% of pheasants obtained from businesses other than Waitrose & Partners had been killed using lead ammunition. There has only been a slight, non-significant downward trend in the proportion of pheasants killed using lead shot over the five-year transition period. Although some food retailers have stated their intention to cease selling game meat products from animals killed using lead ammunition, our study indicates that these initiatives have made limited progress so far. It appears that voluntary efforts to encourage shooters to switch from lead to non-lead shotgun ammunition for game shooting have been unsuccessful and have been diminishing as the deadline for complete transition approached.
The 2024/2025 shooting season for red grouse Lagopus scotica in Britain was the last during a five-year voluntary transition period proposed by shooting and rural organisations in 2020, during which it was suggested that shooters of all live quarry switch from the use of lead to non-lead shotgun ammunition. We purchased carcasses of red grouse and dissected them to recover shotgun pellets for chemical analysis. All of the 78 carcasses from which shot were recovered contained lead shotgun pellets. One carcass had both lead and bismuth pellets. Samples of grouse meat had, on average, concentrations of lead that were substantially higher than is permitted in meat from farmed animals and poultry, even though shotgun pellets were removed from the meat before analysis. Lead levels were similar to those from grouse sampled five and 12 years before the beginning of the transition. X-rays of 12 carcasses revealed small (mostly 0.2 – 0.5 mm diameter) fragments in most of them, in addition to whole shot. Lead concentration in the meat was strongly correlated with the number of these fragments, which are too small to be detected and potentially rejected by scavenging animals and predators. We conclude that most of the lead found in meat from red grouse carcasses results from fragmentation of shotgun pellets impacting the birds’ bodies. The intended voluntary five-year transition has been unsuccessful in relation to red grouse.
Insect pollinators are currently declining, in part due to the loss of habitats and foraging resources. However, one potential source of refuge is lawns in urban areas and the floral resources within them. Lawns represent a substantial proportion of urban green space and, if managed with pollinators in mind, could become a major component of a matrix of foraging resources. This study used Ministry of Justice prison and court sites as a case study for the management of urban lawn space. Sites contained four patches, one control patch mown as normal every two weeks and then three patches mown either every four, six or 12 weeks. Weekly pollinator and flowering plant surveys were completed at each site over 12 weeks from June – August 2023. We found that patches with less frequent mowing (every six and 12 weeks) had a significantly higher abundance of pollinators, >170% higher than the typically used mowing frequency of every two weeks. Lawns left unmown for 12 weeks also had higher floral species richness and flower cover than lawns mown every two weeks. Consequently, we recommend that lawns within urban and suburban building complexes are mown at an interval of at least six, but ideally 12, weeks to improve floral resources and pollinator abundance.
The European pine marten Martes martes typically occupies woodland and preferentially rests and breeds in arboreal, insulated den sites, which are particularly critical for breeding females. An absence of elevated cavities may force pine martens to use suboptimal den sites, and consequently limit population distribution, abundance, and breeding success. Artificial den boxes have been designed and installed in recent years and occupied by both non-breeding and breeding pine martens. However, the large size and weight of these boxes makes them too heavy to use in young forestry plantations. We tested two smaller, lighter box designs (the Galloway Lite Mk1 (‘GLMk1’) and Galloway Lite Mk2 (‘GLMk2’)) that could be more easily deployed in commercial conifer plantations. Fifty boxes of each design were installed in Galloway Forest, south-west Scotland, and monitored for evidence of pine marten occupation and breeding. Overall, GLMk2 boxes were occupied more frequently than the GLMk1 boxes, including for breeding. The Galloway Lite boxes provide a lightweight, economical and practical option for increasing the availability of elevated den sites for pine martens and can be deployed as a conservation tool to enhance habitat conditions.
Coconut palms (Cocos nucifera) cultivated for copra are agricultural resources on many of the world’s low-lying tropical oceanic islands where they provide sustenance and economic value to human communities. However, coconut palms, when dominant in island plant communities, can outcompete native plants for above- and below-ground resources. Furthermore, when coconut palms displace native plant species preferred by seabirds as roosting and nesting habitats, they may disrupt beneficial nutrient pathways in both marine and terrestrial ecosystems. At Palmyra Atoll, located in the Northern Line Islands, Pacific Ocean, evaluation of three methods for controlling coconut palm seedlings (foliar herbicide application, cut-stem, and cut-stem combined with herbicide) showed that mortality was highest with the cut-stem combined with herbicide application. A comparison of herbicide volumes injected directly into stems of mature palms showed that mortality increased with herbicide volume; an injection of 10 ml of undiluted Roundup CustomTM herbicide (53.8% glyphosate) achieved 100% mortality within 8 months.
The 2023/2024 shooting season was the fourth since UK shooting and rural organisations announced their intention that hunters should make a full voluntary transition from the use of lead to non-lead shotgun ammunition by 2025. The SHOT-SWITCH research project has monitored 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 each of the shooting seasons since the beginning of the transition. In the study’s fourth season, 2023/2024, 93% of pheasants obtained during the usual sampling period had been killed using lead ammunition. Whilst this indicates a marginal decline in the proportion of pheasants shot using lead since the beginning of the transition, when it was over 99%, much remains to be done if the intended full voluntary transition to non-lead shotgun ammunition is to be achieved in its final season (2024/2025). Some food retailers intend to cease selling game meat products from animals killed using lead ammunition. Our study indicates that whilst all of a small sample of pheasant carcasses obtained from one of these retailers (Marks & Spencer) were from birds killed using non-lead shot, a larger sample obtained from another of the retailers (Waitrose) had mostly been killed using lead shot.
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 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.
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.
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.
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.
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.
