Long-term ecological changes in the densely populated rural landscapes of China

Abstract

Asia's densely populated agricultural landscapes are undergoing unprecedented ecological changes caused by population growth and adoption of industrial technologies such as fossil fuel and chemical fertilizer. Covering nearly 6 × 10 6 km 2 , these landscapes now release more than half of global greenhouse gas emissions from agricultural land and biomass fuel. Measuring ecological processes and their changes in these highly heterogeneous village landscapes is made difficult by their very small scale of management, with households typically managing many small plots using a wide variety of inputs and methods. This chapter describes the global extent of village landscapes, characterizes their spatial heterogeneity, establishes appropriate scales for ecological change measurement, and demonstrates methods developed to measure long-term ecological changes across village landscapes in China. Reliable measurements of ecological change in village landscapes can be made by integrating high-resolution (≤1 m) landscape change measurements with household-level resource management data. These methods link local land use practices with regional and local ecological change, potentially aiding land use decision-making, but require far greater research effort than conventional land use measurements based on 30-1000 m resolution imagery and county or provincial data. Therefore, a multi-scale sampling and analysis system was developed to integrate local and regional data for estimating regional change across village landscapes in China. The strengths and weaknesses of this approach in measuring and mediating the impacts of ecological changes in densely populated landscapes are discussed in light of preliminary results indicating that population increase and modernization are increasing carbon sequestration across these landscapes.