Dynamic changes of the complex coupling relationships between ecosystem services and socio-ecological factors and the impact of human activities: Insights from network analysis

Understanding the coupling relationships linking ecosystem services (ESs) and socio-ecological factors (SEF) is important to the sustainability of ecosystems. However, the majority of earlier research concentrated on the separate effects of SEF on ESs, without thoroughly investigating their coupling dynamics, trends, and the role of human activities. To address this gap, we analyzed the spatiotemporal variation of the ESs on Hainan Island from 2000 to 2020, including food production (FP), soil conservation (SC), water yield (WY), carbon sequestration (CS), water purification (WP), and habitat quality (HQ). Network analysis and the generalized additive model were used to investigate the coupling relationships and trends linking ESs and SEF. We also evaluated the variations of this coupling relationship under different human activity intensities. The results showed that HQ, WP, and CS exhibited relatively small changes during the study period, whereas SC, WY, and FP showed greater fluctuations. The coupling relationships linking ESs and SEF gradually weakened over time, with network complexity and connectivity declining. The positive contributions of HQ, CS, normalized difference vegetation index, and landscape pattern factors to network connectivity and complexity gradually diminished. In contrast, the negative contributions of SEF, including the percentage of construction land, gross domestic product, and percentage of cultivated land gradually increased. As human activity intensity increased, network connectivity and complexity showed a declining trend. This study not only offers new insights into comprehending the complex relationships linking ESs and SEF, but also provides theoretical support for future ecological protection policies on Hainan Island.