New BTO research shows how data collected by an army of volunteer citizen scientists have been used to map bats in unprecedented detail. The Norfolk Bat Survey began in 2013, and represents a novel way of collecting high-quality and extensive data sets on the distribution and activity of bat species. The Norfolk Bat Survey was started in 2013 by BTO ecologist Stuart Newson. Stuart and his colleagues have taken advantage of advances in technology to map bat distributions, and activity on a scale never before seen. The Survey relies on a network of ‘Bat Monitoring Centres’ situated throughout the county, from which members of the public borrow passive bat detectors and set them up locally for three days at a time. Between 2013 and 2015, this cost-effective survey method generated over 1.2 million bat recordings, making it one of the most extensive high-quality data sets for bats from anywhere in the world and engaging volunteers with citizen science in the process. The project has improved our understanding of spatial patterns of bat distribution and activity of all species, from the near-ubiquitous Common Pipistrelle to the locally scarce Leisler’s Bat, increasing the number of records from Norfolk from 10 to almost 300. The study also reveals how bat activity varies through the night. For example, Common and Soprano Pipstrelles are most active shortly after sunset, when airborne small insect prey availability is at its peak, while Brown Long-eared Bats, which take prey from foliage are active throughout the night. On a seasonal timescale, several species have been found to disperse after breeding into areas that they are not reported from earlier in the season. Such information has important conservation implications. Surveys of many species of bat are required before land is developed. The techniques used by the Norfolk Bat Survey present a better way of carrying out such work, with more informative results. As more years’ data are collected, the technique will also allow changes in bat populations to be monitored in a way that has not previously been possible. The Norfolk Bat Survey has already been expanded into neighbouring parts of East Anglia by popular demand. In 2016, a new survey will also begin in southern Scotland using the Norfolk Bat Survey model, and we are discussing with BCT how this approach may inform bat monitoring more widely. This is an example of BTO research having a huge impact on our knowledge of the ecology of previously poorly understood species.

Cocoa and coffee are among the most valuable tropical crops, with much of their production in areas of high biodiversity. Although this could suggest a conflict between agricultural expansion and biodiversity conservation, these crops are normally grown in shade plantations—a more biodiversity-friendly agroforestry system. Using São Tomé Island as a case study, we examined if shade plantation can benefit biodiversity by protecting extinction-prone island endemic species. We found that shade plantations held rich assemblages, even in comparison with forest: we estimated 30 bird and 74 tree species occurring in plantations compared to 24 bird and 108 tree species in forests. However, the structure of the assemblages was significantly different between ecosystems, with an average dissimilarity of 33.8 percent and 87.9 percent for birds and trees, respectively. Shade plantations had consistently less endemic species than the forest; we estimated a drop from 17 to 13 in birds and from 17 to 3 in trees. We also found that despite marked differences in the response of bird species to the vegetation characteristics of shade plantations, there was a strong positive link between aboveground tree biomass and endemic species richness and abundance. These results show that shade plantations hold assemblages impoverished in endemic species, but that management can improve their value for the conservation of these species. Finally, we suggest that biodiversity-friendly certification and carbon markets are used to implement and guarantee the long-term economical sustainability of practices that favor the endemic species in São Tomé's shade plantations.

The impacts of projected climate change on the populations and distributions of species pose a challenge for conservationists. In response scientists and policy makers have proposed a number of management strategies to try and enable species to persist in a changing climate. However there is limited evidence to support these management interventions, making it difficult for conservationists to decide on the most appropriate action to take for different circumstances. New research just published by the BTO, in collaboration with CEH and Natural England, has used long-term monitoring data for woodland birds to support the prediction that habitat attributes (woodland patch isolation and area of woodland at the site and at the wider landscape scale) may influence the ability of some species to withstand weather-mediated population declines. Results suggest that these effects were most apparent among generalist woodland species, such as Bullfinch and Robin. However several specialist woodland species, like Nuthatch and Willow Tit, were also more likely to increase following population decline where there was more woodland at the site and in the wider landscape. While management is unlikely to provide a universal benefit to all woodland species, landscape-scale conservation initiatives that maximize woodland patch size and minimize patch isolation may allow the populations of some woodland bird species to be more resilient to climate change.

Mammals are an important part of the UK’s biodiversity but can be difficult to monitor, requiring special surveys to determine their distribution or how their populations are changing over time. However, some widespread and easily detected species, such as deer, rabbits and squirrels, can be monitored as part of bird surveys. Volunteer birdwatchers taking part in the Breeding Bird Survey have been recording mammals alongside birds since 1995. Now BTO scientists have used these data to investigate national and regional population changes of nine common species. Populations of four deer species (Roe Deer, Reeves’ Muntjac, Fallow Deer and Red Deer) all increased between 1995 and 2012. This is of concern given that increased deer browsing in woodland can reduce the vegetation understorey and impact negatively on other wildlife. In contrast, Rabbit numbers declined by 48% over the same period, following a large increase prior to 1995 (as revealed by other studies). There are fascinating regional differences in the trends for some species; Brown Hare populations declined by 50% in Northwest England but increased by 70% in the East Midlands. A significant increase in non-native Grey Squirrel numbers in Northwest England may be of concern because of their potential impacts on native Red Squirrels that are now largely confined to Scotland. The study highlights the value of the BTO’s network of volunteers for monitoring groups other than birds. The species covered include some rapidly spreading invasive non-native species, and others that are of conservation concern. Many important conservation questions could be investigated in future using this valuable long-term dataset.

New research led by the BTO shows that the UK’s internationally important seabird populations are being affected by fishing activities in the North Sea. Levels of seabird breeding failure were higher in years when a greater proportion of the North Sea’s sandeels, important prey for seabirds, was commercially fished. The UK’s seabirds are under pressure from human activities, such as resource extraction and fishing, as well as climate change. Under the European Marine Strategy Framework Directive, the UK is legally bound to make sure human activities are kept at levels consistent with “clean, healthy and productive” seas, and as top predators, monitoring seabirds can give insights into the state of the wider marine environment. In many species, counts of breeding individuals reflect population-level impacts of environmental pressures, but this is not necessarily the case with seabirds. This is because seabirds are long-lived and can delay breeding for several years after they reach maturity, or skip breeding seasons when conditions are poor. Scientists at the BTO and JNCC have now shown monitoring seabird breeding performance to be the way forward. The study, using long-term datasets from the JNCC’s Seabird Monitoring Programme for nine seabird species, showed the knock-on effects of fishing activities in the North Sea on seabird breeding at colonies on the east coast of England and Scotland. Sandeels are typically fished for use in animal feed and fertilizer. There is a large fishery on Dogger Bank, which is within the foraging range of many seabirds. In years when a greater proportion of the North Sea’s sandeels was fished, rates of seabird breeding failure rose. The study also found that seabirds breeding on the UK’s western colonies are faring better than those on the North Sea coast. Population declines and elevated breeding failures were found for eight out of nine species at North Sea colonies (with Kittiwakes particularly badly affected), compared to three out of nine on the west coast. The results demonstrate that seabird breeding can show how these key species are responding to environmental pressures before such changes become evident at the population level. Detecting such impacts as early as possible is a priority, as the management of the marine environment is changing, with expansion of offshore developments, the introduction of marine protected areas, and modification of fishing discards policy.

New research by the BTO reveals that most seabirds fly near the sea surface, avoiding collision with wind turbines by flying under the blades. Those birds that fly higher above the sea are at greater risk of collision. Building offshore turbines higher above the sea surface, or installing fewer large turbines instead of several smaller turbines, could reduce the number of collisions. In a project funded by The Crown Estate via the Strategic Ornithological Support Services (SOSS) work programme, BTO scientists examined the importance of flight heights in determining the risk posed to seabirds from collision with offshore wind turbines. Innovative statistical techniques were used to combine data from over 30 sites and a detailed description of the proportion of birds that fly at different altitudes were produced for each species. Results show that many species, including Puffins and Arctic Terns, spend most of their time within 5 m of the sea surface, while gulls flew more regularly at 20 m above the sea surface. These findings are particularly critical, in the light of the high number of offshore wind farms which are currently proposed in UK waters. Although wind farms are a key part of the government’s strategy to meet its renewable energy targets, they may potentially affect local birds, including protected and declining species. In severe cases, birds can collide with turbine blades and die. Estimates of the proportion of birds flying at different heights are fed into an assessment of the potential impact on wildlife for each wind farm, and can influence the likelihood that proposed renewable developments will go ahead. The results presented in this study show that if turbines are located higher above the sea surface, more birds will naturally fly underneath the turbine blades. The authors also suggest that seabird collision risk could be reduced by installing fewer but larger turbines, which produce the same energy output as a greater number of smaller turbines.