The Temporal Variation and Spatial Scale Dependence of the Trade-Offs and Synergies among Multiple Ecosystem Services in the World Heritage Site of South China Karst

The World Natural Heritage Sites (WNHSs), which have unique ecosystems, ecological landscapes, and biodiversity, are the common heritage of all of humanity. The evolutionary pathway of ecosystem services (ESs) in the Karst WNHS between the years 2000 and 2020 has been examined, and the trade-offs and synergies among the ESs have been quantified. This research serves as a point of reference for the rational utilization of natural resources and for the protection of the ecological environment within the Karst WNHS. This research aims to assess the following ESs in the Karst WNHS, for the period 2000–2020: water conservation (WC), soil conservation (SC), carbon sequestration (CS), and habitat quality (HQ). Additionally, the objective of this study is to examine the space–time evolution of these ESs. Spearman’s correlation coefficient and spatial auto-correlation analyses were utilized to ascertain the temporal and spatial trade-offs and synergies for each ES. The results of this study indicate the following: (1) Between the years 2000 and 2020, the inter-annual changes in HQ and CS at the Shibing and Libo-Huanjiang WNHS exhibited a relatively stable pattern, with a gradual increasing trend, and in contrast, the inter-annual changes in WC and SC exhibited greater fluctuations; (2) the distribution of ESs is closely linked to land use patterns, and woodland is the most critical land type of the ESs, contributing the most to each ES; (3) population density is negatively correlated with various ecosystem services, while GDP is positively correlated with each ecosystem service; and (4) the Karst WNHS in Southern China demonstrates a clear and significant synergistic relationship between WC and CS. This relationship is primarily characterised by a strong synergistic effect. The synergistic relationship between HQ and WC exhibited a weakening trend within both study areas. Furthermore, the SC demonstrated a spatial trade-off relation with HQ, CS, and WC.