Transformation of agricultural landscapes under rapid urbanization: A threat to sustainability in Hang-Jia-Hu region, China

This paper analyzed the spatiotemporal dynamics of agricultural landscapes within Hang-Jia-Hu region (China) from 1994 to 2003 using a set of metrics that relate closely with sustainability. Considerable urban expansion was identified with the total built-ups increasing by 224.7% from 6.99 × 104 ha to 22.7 × 104 ha. The outcomes indicated that, at the whole region scale, agricultural landscapes became lost, fragmented, transformed and isolated as urbanization intensified. Global Moran’s I statistics and Local Indicators of Spatial Association (LISA) analysis were employed to characterize the spatial dependence and hotspots for intra-level agricultural landscape changes at two grid scales. Generally, isolation of agricultural patches was a localized problem, while shape transformation of agricultural landscapes was a more regionalized problem; hotspots for lost, fragmentation and irregularity of agricultural landscapes concentrated around urban centers, while those for isolation of agricultural patches appeared in rural mountain areas. Spatial regression models further revealed that changes of agricultural landscapes showed diverging relationships with urbanization indicators for each landscape metric. The character and strength of relationships for each landscape metric were different and changed with scale. While our results of agricultural landscape changes consisted with some theoretical predictions in the literature, they also showed different spatiotemporal signatures of urbanization. Resolving these differences will certainly contribute to the ongoing landscape transformation and sustainability debate. This study demonstrated complexities of relationships between urbanization and agricultural landscape changes, and highlighted the importance of selected variables, spatial and temporal scales and incorporation of spatial dimensions when quantifying these relationships.

Research highlights
► Agricultural landscapes became lost, fragmented, transformed and isolated as urbanization intensified.
► Isolation of agricultural patches was a localized problem, while irregularity in shape was a more regionalized problem.
► Hotspots for lost, fragmentation and irregularity of agricultural landscapes concentrated around urban centers, while those for patch isolation appeared in rural mountain areas.
► The character and strength of relationships between agricultural landscape changes and urbanization were different and changed with scale for each landscape metric.
► Agricultural landscape changes reflected different spatiotemporal signatures of urbanization with theoretical predictions in the literature.