Understanding the dynamics of farmland loss in a rapidly urbanizing region: a problem-driven, diagnostic approach to landscape sustainability

Abstract

Existing landscape sustainability studies mostly follow design-based, practical approaches, emphasizing “linking knowledge to action;” while the problem-driven, diagnostic approach that emphasizes “understanding human–environment interactions” remains underused. To apply the problem-driven, diagnostic approach to a widespread and controversial landscape-relevant problem: farmland loss associated with the long-term, global trend of urbanization. We comparatively analyzed the farmland loss and landscape dynamics in the core and peripheral areas of rapidly urbanizing Tongling City in China, by using 30 m-grid land use/cover data in 2000, 2005, 2010, and 2015. To understand the temporal trends and abnormalities of farmland loss, we identified probable regime shifts of socioeconomic and agrifood dynamics by changepoint detection using relevant data from 2000 to 2015. Changes of the whole landscape were dominated by persistent aggressive land gains of developed lands and increasing land losses of farmland and densely/moderately vegetated land. The ratio of farmland loss to total land conversion (8–77%) decreased in general during 2000–2015, with urban encroachment of farmland accounting for 14.72–74.36% of total farmland loss. Farmland had become smaller in patch size, less regular in patch shape, and more isolated between patches since 2005, indicating farmland deintensification. Three temporal abnormalities of farmland change were identified, which were associated with abrupt socioeconomic and agrifood dynamics affecting farmland demand–supply. Farmland loss is more of an economic issue than a resource issue, and focusing on urban expansion is often inadequate. Policy efforts are needed to address the real problem of social injustice in mandatory farmland preservation practices.