Stepping stones to the north
A new study involving BTO has shown how birds, insects and spiders have used nature reserves and areas protected for wildlife to expand northwards in response to climate change and other factors. Using data from volunteer recording and national monitoring (including BTO surveys) from the 1970s onwards, the researchers showed that species disproportionately colonised protected areas in their northward expansion. These sites were approximately four times more likely to be colonised than would be expected given their availability in the wider countryside. Three key vulnerable birds, the Bittern, Woodlark and Dartford Warbler were significantly more likely to be associated with protected areas in newly colonised areas than would be predicted by chance alone. As many species will need to shift their distribution to respond to climate change, this study underlines the vital long-term importance of protected areas in conserving biodiversity.
Quantity and quality: the importance of un-cropped land for farmland birds
European agri-environment schemes provide prescriptions to farmers to sustain wildlife and biodiversity on farmland. Such prescriptions include leaving areas of farmland un-cropped. New work by the BTO, the Game and Wildlife Conservation Trust, Rothamsted Research and NIAB-TAG has investigated the quantity of un-cropped land needed per farm to maintain bird populations. The average area of un-cropped land was found to be significantly associated with the abundance of key declining farmland bird species. Overall, farms in which at least 10% of land area was left un-cropped supported bird populations that were approximately 60% larger than farms with less than 5% un-cropped land. This research demonstrates the imperative need for sufficient habitat quantity and spatial management in European agricultural policy prescriptions, which together with habitat quality, are necessary for stabilising populations of declining farmland birds.
BBS data prove benefits of Environmental Stewardship for birds
Publicly funded agri-environment schemes are widely used in Europe to address biodiversity losses in farmland ecosystems, but evidence of their effectiveness has been limited. New research by the BTO has used BBS data to show that management to enhance winter seed availability for farmland birds in England as part of Environmental Stewardship (ES) has significantly reduced the rate of population decline for several species, including Yellowhammer, Linnet, Reed Bunting and Grey Partridge. The types of management involved (leaving stubble overwinter and planting wild bird seed crops in field margins) were mostly implemented under the “broad and shallow” Entry Level Stewardship (ELS) scheme. In keeping with previous research, measures to enhance breeding habitat had little effect across species. Although significant, the benefits of stubble and wild bird seed were small, and only slowed population declines rather than reversing them.
How can the farmland environment affect bird populations?
As farmland dominates the European landscape, its management has important consequences for the continent’s biodiversity. Farmland birds have declined in recent decades because of agricultural intensification, involving changes in cropping patterns, loss and deterioration of hedgerows and landscape simplification. A new study by the BTO and the University of Cambridge has used data from BBS to investigate the relative importance of these factors in driving farmland bird population trends. Landscape structure was the best predictor of farmland bird abundance for most species, followed by field boundary composition and finally cropping. The presence of hedges with trees was shown to positively influence populations of several species, as did high levels of landscape and cropping heterogeneity. This study has important conservation implications, because it shows the potential of different aspects of farmland management to contribute to bird conservation.
Diverse living: wader community trends on UK estuaries
Britain’s estuaries support internationally important communities of wading birds due to our mild climate and key position on the East Atlantic flyway. However, our estuarine ecosystems are under ever increasing pressure from human activities, such as development and agricultural intensification. Scientists from the BTO and the University of East Anglia have used data from WeBS to study our wader communities and found variation in space and time over almost three decades. This research improves our understanding of how our estuarine communities and ecosystems are sustained and assembled, with important implications for their conservation in the face of environmental change.