Effects of agricultural intensification on landscape structure and diversity on the Uruguayan soybean region

Abstract

Ecología Austral 24:212-219 (2014)

In recent decades, driven by the worldwide growing demand for food and biofuels, agriculture has grown exponentially at the expense of natural ecosystems. The same phenomenon is happening in Uruguay, with greater intensity on the west region of the country during the last decade, driven by the soybean crop. The objective of our study was to assess the territorial changes occurred at the landscape level, associated with agricultural intensification, on a department (political division) on the western region of Uruguay, between 1990 and 2009. Crop areas increased 27% during this period, advancing over native forest (BN) and grasslands/rangelands (CN) areas. The BN decreased 30% mainly through the loss of small fragments (<10 ha). The CN was reduced by a 23%, mostly through the disappearance of fragments up to 50 ha. In relation to connectivity, average distances between patches of CN have changed from 168 m to 192 m, whereas in BN they have gone from 365 m to 255 m in 2009. This last observation is consistent with a more disperse distribution in 1990, that will become more compact by 2009 through the disappearance of small peripheral patches. The fragmentation of CN showed a slightly increment in the period, while a decrease was observed in BN, possibly caused by the disappearance of small fragments (less than 10 ha). Between 1990 and 2009, 2000 fragments of BN <10 ha and 2500 fragments from 1-100 CN have disappeared, becoming in most cases on soybean crops. The effects of this process on agricultural production has been quantified but the impact on landscape's capacity to sustain biodiversity and provide a wide range of ecosystem goods and services, is still poorly understood.