Land-use type was determined for each site using land cover datasets published in 1931, 1990 and 2007. Comparing between a 1990 and 2007 and b 1931 and 2007, each site was classified according to whether it had the same land-use type in both years or had changed in the interim (possibly due to methodological artefacts, rather than true land-use change). Here, data are shown only from sites which were consistently classified to the same land-use type in both years. Biomass at individual traps sites is shown in grey, and geometric mean as a black zig-zag. Black line depicts the trend fitted by a segmented regression.