To some degree, these patterns can be linked to the geographical resources themselves, with abundant shoreline, generally calm seas, and steady winds favouring the use of sailing vessels, and fertile valleys and plains-at least in the Greater Sunda Islands-permitting irrigated rice farming.
Each of these patterns of ecological and economic adaptation experienced tremendous pressures during the 1970s and 1980s, with rising population density, soil erosion, river-bed siltation, and water pollution from agricultural pesticides and off-shore oil drilling.