The loss of fallow land and farmland birds in Spain

A science blog post by Prof. Gregory discusses the links between the loss of fallow land in Spain and the loss of farmland birds. The story comes from the new research The decline of farmland birds in Spain is strongly associated to the loss of fallow land.

The authors use the area of fallow land in Spain as a measure of landscape-scale agriculture intensification which is believed to be an important driving factor leading to the decline in farmland birds across Europe in recent decades. This is shown e. g. by  The European Farmland Bird Index, the FBI, which has fallen by nearly 60% since 1980, considerably more than for bird populations living in other habitats.

Adequately managed, fallows are one of the most important habitats for wildlife, and particularly for farmland birds, due to the high diversity and abundance of food resources that they provide such as weeds, seeds, and invertebrates, as well as vegetation cover for foraging or nesting. Traba and Morales argue that fallows have been crucial for the maintenance of farmland biodiversity in Mediterranean countries, and that is likely to be true right across Europe.

The authors show, using bird data from the Spanish national bird monitoring program (the ‘SACRE’ Program which has operated since 1998 and was established with the assistance of the RSPB), that the annual rate of change in fallow land was correlated significantly with the rate of change in the numbers of Little Bustard – a typical bird species of cereal-Steppe, as well as with a Spanish Farmland Bird Index.

In the blog post, Prof. Gregory points out also some caveats with this study and discusses it in more detail. However, he agrees with the recommendation of the authors to bring back an EU obligation under a revised  Common Agricultural Policy (CAP) to devote 10% of farmland to wildlife-friendly measures. Prof. Gregory believes that this solution makes a great deal of sense and would be well supported by science-led practitioners and conservationists.

Traba, J. & Morales M.B. (2019) The decline of farmland birds in Spain is strongly associated to the loss of fallow land. Scientific Reports 9, 9473, https://doi.org/10.1038/s41598-019-45854-0.