Response of habitat quality to urban spatial morphological structure in multi-mountainous city

Revealing the relationship between urban spatial morphological structure (USMS) and habitat quality (HQ) is of great significance for high-quality urban development. In this study, the central urban area of a typical multi -mountainous city (Guiyang, China) was taken as research area. Two-dimensional (2D) and three-dimensional (3D) characteristic indicators system of USMS was constructed. The InVEST model was used to evaluate the HQ in the study area, and the spatial pattern characteristics of USMS and HQ in the multi-mountainous city were analyzed. Finally, the response relationship of HQ to USMS was revealed through Pearson correlation analysis and curve fitting. The results showed that: (1) The average level of HQ in the study area is low and the spatial aggregation effect is obvious; the spatial distribution difference between the high value area and the low value area is significant; the high value area is mainly distributed in the area where the large area of urban green space (UGS) and the urban remnant mountains (URMs) are located, while the low value area is mainly distributed in the high-intensity urban construction area. (2)The URMs have a significant impact on the USMS within the city, the intelligibility(I), spatial permeability, spatial aggregation degree, and spatial traffic attraction potential were poor; the buffer zone within 4 km of the urban center is the core area of urban development, and the buffer zone within 15 km is the rapid urban development area. (3)Among the USMS indicators, Choice(C) was significantly positively correlated with the HQ, while the Connectivity(Con), I, Average height(AVH), and Otherness(O) were significantly negatively correlated with the HQ. (4)Stepwise regression results showed that USMS could explain the difference of HQ in the study area well, and the values of fitting coefficient R2 were 0.975, 0.837 and 0.945 in 2008, 2013 and 2018, respectively. (5)There was a quadratic function relationship between HQ and USMS principal component factor f, and there was a threshold effect, and the thresholds were 0.798 in 2008, 0.905 in 2013 and 0.474 in 2018, respectively. This study confirmed the response relationship of HQ to USMS and demonstrates the existence of a threshold, which has important reference significance for urban biodiversity conservation and high-quality urban development.