The basic characteristics and spatial patterns of global cultivated land change since the 1980s

In this paper, we analyzed the spatial patterns of cultivated land change between 1982 and 2011 using global vector-based land use/land cover data. (1) Our analysis showed that the total global cultivated land area increased by 528.768x10(4) km(2) with a rate of 7.920x10(4) km(2)/a, although this increasing trend was not significant. The global cultivated land increased fastest in the 1980s. Since the 1980s, the cultivated land area in North America, South America and Oceania increased by 170.854x10(4) km(2), 107.890x10(4) km(2), and 186.492x10(4) km(2), respectively. In contrast, that in Asia, Europe and Africa decreased by 23.769x10(4) km(2), 4.035x10(4) km(2) and 86.76x10(4) km(2), respectively. Furthermore, the cultivated land area in North America, South America and Oceania exhibited significant increasing trends of 7.236x 10(4) km(2)/a, 2.780x10(4) km(2)/a and 3.758x10(4) km(2)/a, respectively. On the other hand, that of Asia, Europe and Africa exhibited decreasing trend rates of-5.641x10(4) km(2)/a,-0.831x10(4) km(2)/a and-0.595x10(4) km(2)/a, respectively. Moreover, the decreasing trend in Asia was significant. (2) Since the 1980s, the increase in global cultivated lands was mainly due to converted grasslands and woodlands, which accounted for 53.536% and 26.148% of the total increase, respectively. The increase was found in southern and central Africa, eastern and northern Australia, southeastern South America, central US and Alaska, central Canada, western Russia, northern Finland and northern Mongolia. Among them, Botswana in southern Africa experienced an 80%-90% increase, making it the country with the highest increase worldwide. (3) Since the 1980s, the total area of cultivated lands converted to other types of land was 1071.946x10(4) km(2). The reduction was mainly converted to grasslands and woodlands, which accounted for 57.482% and 36.000%, respectively. The reduction occurred mainly in southern Sudan in central Africa, southern and central US, southern Russia, and southern European countries including Bulgaria, Romania, Serbia and Hungary. The greatest reduction occurred in southern Africa with a 60% reduction. (4) The cultivated lands in all the continents analyzed exhibited a trend of expansion to high latitudes. Additionally, most countries displayed an expansion of newly increased cultivated lands and the reduction of the original cultivated lands.