Vulnerability assessment of urban remnant mountain ecosystems based on ecological sensitivity and ecosystem services

Urban remnant mountains (URMs) are precious natural green habitat patches that can provide a series of ecosystem services for multi-mountainous cities. The increase in ecological sensitivity and degradation of ecosystem services affected by urban expansion and climate change have led to an increasing vulnerability of urban remnant mountain ecosystems (URMEs). To explore the vulnerability of URMEs, taking the central urban built-up area of the Guiyang city as the study area and URMs as the research object, the vulnerability of URMEs under natural factors and human disturbance was analyzed based on the Pressure-State-Response (PSR) model. The results showed that: (1) Karst rocky desertification, human disturbance, and road density within the buffer zones around URMs were the most important factors affecting the vulnerability of URMEs. Karst rocky desertification was the most likely eco-environmental problem of URMs, and carbon storage was the most important ecosystem service of URMEs. (2) Characteristics of fragile karst habitats in URMs and unreasonable human activities led to high ecological vulnerability, mainly with moderate and severe vulnerability predominating, and the low vulnerability of URMEs when they had moderate park utilization. (3) The ecological vulnerability of small URMs and those distributed in the urban center is higher, and the invulnerable URMEs and the slightly vulnerable URMEs are mainly distributed in the urban edge. The results of this study could provide references for ecological restoration and protection of URMs, and offer a basis for improving the resilience of multi-mountainous cities.