A new paper linking agriculture to declines of birds across Europe has just been published in PNAS. Professor Richard Gregory (Head of Monitoring, Centre for Conservation Science RSPB) and co-author, explains the background and importance of this new work.
With growing evidence of biodiversity loss in the UK, continental Europe, and globally, it is critical that we can capture and characterize that change in a solid fashion and that we can better understand how to respond. Nature is under attack from all angles it seems - so how we respond is vital.
Bird research has often led the way in this respect because birds have long fascinated both professional scientists and citizen scientists (formerly skilled voluntary birdwatchers!) creating a body of research and knowledge, and some of the best biodiversity datasets available to date, globally.
Taking advantage of such high-quality bird data, our new paper led by French researchers, looked at how 170 bird species have responded to major human-induced pressures in Europe, including land use and climate changes, with research carried out at over 20,000 monitoring sites across 28 countries over 37 years, including data from the UK.
Drivers of change
We know that biodiversity is under increasing pressure from land use and climate changes, but how species respond to those pressures, and which pressure is the most dominant, has been unclear.
Th authors examined four major anthropogenic pressures: agricultural intensification (measured by the high use of pesticides and fertilisers), climate change (focussing on temperature), change in forest cover and urbanisation, and it found that agricultural intensification was the main pressure for most bird population declines, especially for those that feed on invertebrates, including here Swift, Yellow Wagtail, Spotted Flycatcher, Wheatear and Stonechat. Bird responses to changes in forest cover, urbanisation and climate change were more variable and species specific.
Declines
Over the study period (1980 to 2016), common bird species in Europe declined in abundance of by a quarter. Numbers of farmland birds have more than halved over the same period. Declines were also noted in woodland birds, urban dwellers, among northern, cold-preferring birds and even southern, warm-preferring bird species; though the trend in the latter group of birds is now firmly upwards (see figure).
So, while many studies had previously tried to figure out what drives bird declines, this is the first to look at the big man-made drivers in one go, using some of the best available data and modern statistical methods. The results are compelling and clear cut. And they show the great power of citizen science and cooperation across borders to advance science, better understand the natural world and how to turn things around.
Importance of agriculture
One of the study’s key findings is that the intensification of farm practices, such as the use of pesticides and inorganic fertilisers, is the most significant driver of bird population declines across Europe, including the UK. Farming practices began to change significantly after the Second World War with agricultural policies focused on driving increased output.
Corn Bunting © Aurélien Audeverd
Yet efforts to increase output, including our increasing reliance on pesticides and fertilisers, has come at a significant cost to our birds and other wildlife, and critically the overall health of the environment. A recent UK Government report found that the loss of biodiversity, alongside climate change, presents the greatest medium- to long-term threat to domestic food production and security.
The question is how to respond. Nature is in trouble and farmers supported by the right policies are the solution. We need much greater support for nature-friendly farming practices and away from our reliance on pesticides and fertilisers. This would be good for nature, for farmers and food production, for the climate, for consumers - and many farmers are leading the way.
We need governments across Europe to support agri-environment schemes that reward nature-friendly farming, such as committing to managing at least 10% of their land for nature, which in turn will help sustain or even boost yields. But we also need wider food system reform, with retailers, suppliers and processors playing their part in supporting nature-friendly farming, and nature-friendly eating.
Access the paper here: Farmland practices are driving bird population decline across Europe
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