Evidence of green space sparing to ecosystem service improvement in urban regions: A case study of China's Ecological Red Line policy

The debate on land-sparing versus land-sharing has continued for decades regarding which of the two approaches can optimize the yield-conservation tradeoff. Current opinions are mostly criticisms for the overly-narrow focus on specific biodiversity conservation and simplistic solution to the agri-environmental scheme. This study based on limitations in previous studies aims to advance the land-sparing versus land-sharing strategies from two perspectives. First,an extended framework highlighting the tradeoffs between built-up land and green space in urban regions was proposed. Second, the multi-functionality of natural land was characterized by various ecosystem services rather than merely biodiversity. To demonstrate the applicability of the framework, a practical case of green space sparing -the Ecological Red Line (ERL) policy currently implemented across China-was elaborated. Particularly, soil retention was selected as a proxy to compare the difference between green space and unprotected areas. It showed that (1) the soil retention difference between areas inside and outside the ERL continued steady before the implementing of the ERL and thereafter presented upward trend. (2) the aggregate pattern and scale of soil retention changed obvious after the implementing of the ERL. (3) environment factors underlying the spatial variation of soil retention varied in inner and outer areas of the ERL, and the ERL might ameliorate soil retention of different land use types by spill-over effect. These findings demonstrated the effectiveness of the ERL, and further supported that the green space sparing is a promising strategy for urban land management. The ERL case study provides empirical evidence to support applications of the extended land-sparing versus land-sharing framework in urban regions. (C) 2019 Elsevier Ltd. All rights reserved.