The use of LPIS, aerial photographs and expert knowledge to quantify changes in farmland area

Farmland is under pressure. Several trends are at the basis of this pressure: processes of urbanisation and industrialisation, the decreasing number of farms and changing societal expectations towards the countryside (Busck et al., 2008; Kerselaers et al., 2011; Primdahl et al., 2013;). Part of the farmland that becomes available when farms quit is incorporated in other farms, which leads to a higher farmland area per farm and hence, a scale increase. However, another part of the farmland gets used for non-agricultural activities such as residential areas, all sorts of entrepreneurship, nature and forest development, gardens, pasture for (hobby-related) horses or other animals, … These changes in function stem from both planned and unplanned processes. In order to govern these land use changes we first need to understand and therefore quantify them. How much farmland is lost? Into which functions is this farmland transformed? Do we see a spatial pattern (e.g. more loss close to cities)? , …
The objective of this research is to quantify the amount of agricultural land use change in order to answer the above questions. The research starts from the Flemish LPIS data (land parcel identification system – EC, 2013), which is used for a temporal comparison between 1998 and 2013. LPIS data are considered the best available spatially linked data on agricultural land use. However, the dataset is developed in the framework of subsidies and is not a perfect source for temporal comparison (Grandgirard and Zielinski 2008). Therefore, the LPIS data are combined with aerial photographs and expert field knowledge for six case study areas.
Based on this research, we estimate the (agricultural) land use change. Given the spatially explicit data, the results complement the non-spatial statistics on farmland area that are generally available. This offers new insights and allows to broaden the discussion on landscape changes and the preservation of farmland and open space with policy makers and the general public. Moreover, we also explore the value of LPIS data for land use change monitoring. This adds to the question how to secure reliability and accountability when using data and data categories developed for different purposes and by different institutions at different time periods.