Response of agroecosystem services to urbanization based on social-ecological networks: A case study of the Guanzhong...

Deeply understanding the impact of urbanization on agroecosystems and their services is a key scientific issue in the field of human-land coupling system. In current studies, less attention has been paid to the complicated interrelation between the natural and socio-economic factors, and the properties of agroecosystem, being insufficient to systematically describe their influence of urbanization on AES, with a gap in deeply understanding the complicated intrinsic influence mechanisms between them. Taking Guanzhong Plain Urban Agglomeration (GPUA) as an example, the correlation networks of AES and vegetation, climate, landscape, geomorphology, and agricultural practices under different urbanization gradients were constructed by network analysis, and revealed how urbanization changes the impact of agroecosystems on AES. The results indicate that during the study period, habitat quality decreased by 1 % in GPUA, the water yield first increased and then decreased, with a change range of 27.86 %, and carbon sequestration and oxygen release, soil conservation, economic production, and tourism and leisure increased by 23 %, 67.34 %, 80.47 % and 5 % respectively. The supply of AES is strongly related to the structural features of urban and agricultural networks. With urbanization increased, the network structure became looser, and the network complexity and stability decreased by 16.27 % and 40.83 % respectively, while, and the links between network components weakened. The network transitivity and density have significant positive effects on AES. Totally, network structural properties accounted for 81.62 % of the variation of AES across the urbanization gradient in GPUA. Furtherly, these suggested that urbanization weakens AES by reducing the complexity and stability of agroecological networks. This study has significant implications for sustainable AES management and planning, and could provide a new perspective for investigating the maintenance mechanism of AES in complex agroecosystems.