  Ecosystem services are the direct and indirect contributions of an ecosystem
to human well-being and survival. Ecosystem valuation is a method of assigning
a monetary value to an ecosystem with its goods and services,often referred to
as ecosystem service value (ESV). With the rapid expansion of cities, a
mismatch occurs between urban development and ecological development, and it is
increasingly urgent to establish a valid ecological assessment method. In this
study, we propose an ecological evaluation standard framework by designing an
ESV monitoring workflow based on the establishment of multi-level grids. The
proposed method is able to capture multi-scale features, facilitates
multi-level spatial expression, and can effectively reveal the spatial
heterogeneity of ESV. Taking Haian city in the Jiangsu province as the study
case, we implemented the proposed dynamic multi-level grids-based (DMLG) to
calculate its urban ESV in 2016 and 2019. We found that the ESV of Haian city
showed considerable growth (increased by 24.54 million RMB). Negative ESVs are
concentrated in the central city, which presented a rapid trend of outward
expansion. The results illustrated that the ongoing urban expanse does not
reduce the ecological value in the study area. The proposed unified grid
framework can be applied to other geographical regions and is expected to
benefit future studies in ecosystem service evaluation in terms of capture
multi-level spatial heterogeneity.
