Variation in ecosystem services with rapid urbanization: A study of carbon sequestration in the Beijing-Tianjin-Hebei region, China

摘要

Land use and land cover change (LUCC) has had a profound effect on terrestrial carbon stocks, though its impact on the terrestrial carbon cycle remains uncertain. LUCC and rapid urbanization have occurred in the Beijing-Tianjin-Hebei (BTH) region over the past decades, which have greatly influenced regional carbon stocks. Based on the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, this paper estimated the temporal and spatial variation of carbon stocks in the BTH region from 1990 to 2015 and explored the relationship between carbon sequestration and urbanization level at the county scale. Our results showed: (1) There was a built-up land expansion (5795 km(2)) at the expense of other land use types (-5548 km(2), including cultivated land, woodland and grassland). (2) The total carbon stock of the BTH region decreased from 40.55 x 10(8) t in 1990 to 40.04 x 10(8) t in 2015. The soil organic matter stock accounted for more than 60% of the total carbon stock. (3) Carbon density decreased from northwest to southeast in the BTH region. Meanwhile, carbon stocks for 134 county districts decreased (carbon sources), while the other 26 county districts increased (carbon sinks) from 1990 to 2015. (4) The urbanization level had significant negative correlations with carbon sequestration in the BTH region at a county scale. Our results provide a unique perspective on LUCC and ecosystem services, which can influence the implementation of regional planning and policy.