Two Decades of Land-Use Dynamics in an Urbanizing Tropical Watershed: Understanding the Patterns and Drivers

Java's Brantas River Basin (BRB) is an increasingly urbanized tropical watershed with significant economic and ecological importance; yet knowledge of its land-use changes dynamics and drivers as well as their importance have barely been explored. This is the case for many other tropical watersheds in Java, Indonesia and beyond. This study of the BRB (1) quantifies the land-use changes in the period 1995-2015, (2) determines the patterns of land-use changes during 1995-2015, and (3) identifies the potential drivers of land-use changes during 1995-2015. Findings show that from 1995 to 2015, major transitions from forest to shrubs (218 km(2)), forest to dryland agriculture (512 km(2)), and from agriculture to urban areas (1484 km(2)) were observed in the BRB. Responses from land-user questionnaires suggest that drivers include a wide range of economic, social, technological, and biophysical attributes. An agreement matrix provided insight about consistency and inconsistency in the drivers inferred from the Land Change Modeler and those inferred from questionnaires. Factors that contributed to inconsistencies include the limited representation of local land-use features in the spatial data sets and comprehensiveness of land-user questionnaires. Together the two approaches signify the heterogeneity and scale-dependence of the land-use change process.