Agricultural landscape pattern changes in response to urbanization at ecoregional scale

• Urbanization impacted agricultural landscape patterns at ecoregional scale.
• Impacts varied among urbanization indicators and landscape metrics.
• Expansion intensity index was the most powerful urbanization indicator.
• GDP acted as influential factor during 1980s.
• Impacts from demographic factors were weak.

Resource preservation efforts are increasingly made at ecoregional scale rather than at administrative level. However, the impact of urbanization on agricultural land at ecoregional scale remains poorly understood. This study integrated remote sensing, geographic information systems, landscape metric analysis, and spatial regression, to quantify agricultural landscape pattern changes in response to urbanization at ecoregional scale, with a case of Qiantang River watershed in China. Results showed that between 1979 and 2009 urbanization accelerated based on four indicators: gross domestic product (GDP), total population (TP), non-agricultural population proportion (NAPP), and expansion intensity index (EII). Characterized by five metrics, agricultural landscapes became less dominant and aggregated, but more instable, fragmented and irregular. Relationships between agricultural landscape pattern changes and urbanization presented great variability, as they differed through time and varied from variables (both urbanization indicators and landscape metrics). Generally, EII was the most powerful urbanization indicator explaining agricultural landscape pattern changes at ecoregional scale. GDP acted as influential factor during periods 1979–1985 and 1985–1994, corroborating the statement that economy was the main contributor to agricultural landscape pattern changes during the 1980s in China. Demographic factors, NAPP in particular, exerted no significant impact. Our study demonstrated an effective approach to identifying key urbanization indicators that governed agricultural landscape dynamics.