Could Agricultural Set-Asides Be Key to Maintaining Biodiversity on Farmland?

As we have been in the mist of Brexit chaos over the past few weeks, here at BEES we thought it was important to explore how this uncertainty could impact UK agriculture. In September 2020, a member of our team got the chance to attend The future for agricultural land use’ conference which examined the next steps for agricultural land use, policy and regulation in the UK. This informative conference left us wondering just how much our agricultural system will change because of Brexit and which methods we will utilise in the fight to make farming more sustainable.

Currently, we are experiencing an ecological crisis associated with our farming methods; agricultural intensification, which primarily consists of monocultures, has led to a startlingly loss of ecological heterogeneity and ecosystem diversity. It is well known among scientists that reduced biodiversity puts species at greater risk of extinction from pressures such as climate change. To make things worse, this form of agricultural system also reduces ecological connectivity, or in other words, the ability for animals (and even some plants) to move freely between habitats. Connectivity is vital in the survival and migration of many species as it allows access to varying resources and promotes diversity through interpopulation breeding (gene flow). In this post we will be assessing a particular type of farming practice that has been shown to have great benefits for improving biodiversity and connectivity - agricultural set-asides.

What are set-asides and how do they work?

Set-aside land can be defined as any section of farmland which has been taken out of production. They are usually characterised by grassland strips at the boundary of agricultural fields. Set-asides were originally implemented in 1992 to combat over production of crops and reduce soil erosion on farmland. Since 2008, most EU countries have abolished obligatory set aside management strategies to keep cereal production in pace with increasing demand. In some regions however (e.g., Hungary), this concept has been redesigned as a tool for reducing decades of biodiversity decline.

Research on agricultural set-asides has shown they support higher population densities and species number of animals such as birds, insects, spiders, and several plant species. Studies also show incredible co benefits for connectivity, in one study connectivity improved in 74% of landscapes, as shown by range expansion rates. This particularly impacts certain species such as birds and butterflies but also benefits mammals, flowering plants, arthropods and even soil microorganisms.

Consequently, many wildlife groups now stand behind retaining this scheme as a crucial method for preserving species numbers through increasing diversity and ecological connectivity. If these schemes come to an end, many conservation groups fear hugely detrimental impacts on wildlife. For example, the Royal Society for the Protection of Birds worries that Skylarks, Yellowhammers, Linnets and Stone Curlews are just some of the species that would suffer greatly from the loss of the set-aside areas.

Which species benefit most? When is it a viable strategy?

An important thing to consider with this dilemma is which species will benefit the most. The short answer is, it depends on a range of factors such as: location, size, agricultural policy in a given region, and duration of time land has been set-aside.

The British Trust for Ornithology (BTO) has explained that the use of set-asides may fill the "hungry gap" when farmland birds find it hard to find seed in the first two months of ploughing in mid-February. Paul Stancliffe, a BTO ornithologist explained: "It's that hungry gap we're most concerned about, something that would fill that gap would be great as far as the birds would be concerned."

Some species actually rely on the set-asides as a lifeline from extinction. The Little Bustard Tetrax tetrax has been driven to extinction by intensive agriculture in at least 11 European countries; the only remaining French population has merely 10% of its pre 1990 population levels and depends on set-asides for survival.

Set-asides also been found to be important for soil health as studies show higher diversity of woodlice species in set-aside fields compared with neighbouring wheat fields. This diversity is vital for ecosystem services as these organisms decompose dead plant material - a key step in the nutrient cycling process.

Problems and future considerations

Despite the urgent need for these set-asides to increase ecological connectivity and prevent extinction of certain species, or at least preserve a minimum level of populations of endangered species, like all conservation strategies, it is not perfect. The scheme fails to protect some species that urgently require conservation intervention as they have been found to have little impact on low density, low dispersal butterfly species which are at greater risk than high density, mobile butterflies for example.

Photo by Tim Gardiner

Studies also show that the older and larger the set-aside the more effective it is, but can many farmers afford to lose a large portion of their land for a considerable amount of time? We need more research into economic context and how these schemes effect the whole ecosystem in the context of entire landscapes. Is the trade off between economics and environment enough of a catalyst to drive changes in agricultural policy?

We must also consider the urgent need to reduce Carbon output from agriculture, the UK aims to reduce emissions by 57% by 2030, relative to 1990. Unfortunately, there is little evidence that this scheme will help reach that target so, do we need a more impactful approach? Some would argue we should be utilising methods that combat emissions whilst producing co-benefits for wildlife conservation on a much larger scale. For example, Agroforestry is a method that has been adopted by Brazil and has been hugely successful in exceeding agricultural emission targets. Utilising an area twice the size of the UK, trees and shrubs were grown alongside cropland, resulting in Brazil achieving 115% of their overall target by 2018. The key to their success it seems was to convince farmers that strong ecological improvements can bring great economic benefits. This logic may have some appeals too for UK farmers, if scientific research could generate arguments in favour.

This begs the question of what the future of agriculture will look like post-Brexit and how we will use this opportunity to implement our own policies to become more sustainable. Should we be focusing on strategies like set-asides which fail in generating wider scale impacts and only benefit a few species? Or are all initiatives that help preserve our wildlife necessary and valuable, and should be implemented as such? Even if the answer to that question is nothing but simple, we would be glad to read your opinion about it!



BirdLife International (2008). Abolition of set-aside in Europe threatens farmland birds. Downloaded from http://www.birdlife.org on 11/11/2020.

Buskirk, J. and Willi, Y. (2004). Enhancement of Farmland Biodiversity within Set-Aside Land. Conservation Biology, Volume 18, No. 4, Pages 987–994.

European Commission (2017). Science for Environment Policy. Thematic Issue: Agri-environment schemes: impacts on the agricultural environment. Issue 57.

Threadgill, K., McClean, C., Hodgson, J., Jones, N. and Hill, J. (2020). Agri-environment conservation set-asides have co-benefits for connectivity. Ecography, Volume 43, Pages 1-13.

Tóth, Z., Hornung, E., Báldi, A. & Kovács-Hostyánski, A. (2016). Effects of set-aside management on soil macrodecomposers in Hungary. Applied Soil Ecology, Volume 99, Pages 89–97.




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