Suchergebnisse

Context Determining the biodiversity of an area is essential for making targeted conservation decisions. Undertaking surveys to confirm species presence or to estimate population sizes can be difficult, particularly for elusive species. Bats are able to detect and avoid traps, making it difficult to quantify abundance. Although acoustic surveys using bat detectors are often used as a surrogate for relative abundance, the implicit assumption that there is a positive correlation between activity levels and abundance is rarely tested. Aims We assessed the effectiveness of surveying techniques (i.e. trapping and acoustic monitoring) for detecting species presence and tested the strength of collinearity among methods. In addition, we tested whether the use of an acoustic lure (a bat-call synthesiser) increased bat-capture rate and therefore species detectability. Methods Surveying was carried out over 3 years in central Scotland (UK), in 68 woodlands within predominantly agricultural or urban landscapes. Key results There was a significant positive relationship between bat activity recorded on ultrasonic detectors and the relative abundance of Pipistrellus pygmaeus and P. pipistrellus, but not those in the genus Myotis. In general, acoustic monitoring was more effective than trapping at determining species presence; however, to ensure rarer or quiet species are recorded, a complementary approach is required. Broadcasting four different types of echolocation call resulted in a 2–12-fold increase in trapping success across four species of insectivorous bat found in the study region. Whereas lure effectiveness remained unchanged for female P. pygmaeus over time, there was a marked increase in the number of males captured using the lure throughout the summer (May to September). Conclusions In the present study, we have demonstrated a variety of ways to increase surveying efficiency, which can maximise the knowledge of diversity in an area, minimise wildlife disturbance, and enhance surveying effectiveness. Implications Increasing surveying efficiency can improve the accuracy of targeted conservation decisions.

1. The United Kingdom's forests currently store 1.09 billion tonnes of carbon and sequester about 4.6% of the country's total emissions. The UK government's commitment to plant over 30,000 extra hectares of woodland per year by 2025 offers significant opportunities to mitigate climate change through carbon sequestration, although the full benefits will not be felt before 2050. Depending on the choice of site, species and establishment method, these new woodlands could also benefit biodiversity and deliver multiple ecosystem services. 2. Large-scale afforestation should avoid peatlands, productive agricultural lands and habitats of high conservation value, focussing instead on poor-quality grazing land of which there is more than enough to fulfil government planting commitments. However, this loss of grasslands would reduce the UK's capacity to produce meat and dairy products (unless other regions were further intensified), which could do more harm than good unless we switch to more vegetable-based diets, if tropical forests were destroyed to create pastures which supply the UK with imported meat. 3. Small-scale establishment of native woodlands within agricultural landscapes would provide opportunities to reconnect fragments of ancient woodland, protect wildlife, and better connect people with nature if made accessible. Natural establishment of woodlands should be encouraged, where appropriate. 4. Non-native conifer plantations provide timber and other wood products, reducing the UK's international environmental footprint; conifer plantations can be damaging for nature, but careful planning can reduce that impact and even benefit some species. In order for plantations to meet their potential, adaptation of woodlands and forestry to future hazards is essential. This includes ensuring diversity is increased in plantations, pests and diseases are controlled, and creating complex canopy structure. 5. Selective harvesting of trees in native woodlands provides a source of fuelwood (i.e. a renewable energy that ...