The Big Picture: Landscape Dynamics in the Pearl River Delta

This paper focuses on landscape dynamics in the Pearl River Delta region and highlights some of the key issues and drivers influencing future change. Delta landscapes are characterised by natural dynamics and processes. Sedimentation is the key factor in delta landscapes. The Pearl River Delta landscape today is highly influenced by human activities. Primary forests were harvested centuries ago. Large-scale deforestation caused massive erosion leading to sedimentation and growth of the delta. Only since the late 20th century rehabilitation and afforestation programmes helped preventing erosion. Agriculture and aquaculture in the low-lying alluvial plain largely depends on dike systems and management of water tables. Traditional and unique dike-pond systems found in parts of the delta providing a variety of fish as well as agricultural products including fruit, vegetables, sugar cane and mulberry trees for silk production are on a steady decline. Instead, highly intensive aquaculture is spreading on a big scale in the Pearl River Delta. Massive population increase in recent decades has turned the Pearl River Delta into a megacity of an estimated 120 million inhabitants. This corresponds directly to a rocketing demand in construction material for infrastructure and housing projects. The demand is largely satisfied through sand mining and dredging in the delta region. In addition, the construction of dams and reservoirs reduces sediment supply resulting in an overall dramatic negative balance in sedimentation in the delta region. While wetlands in the Pearl River delta are under pressure e.g. through urbanisation, the reduced sediment load in the rivers combined with the sand extraction in turn amplifies the negative impact in particular on coastal and estuary wetlands. This high level of complexity of interconnected issues requires multi-scale, crossdisciplinary and collaborative approaches leading to a more sustainable environmental management.