Driving Mechanism of Habitat Quality at Different Grid-Scales in a Metropolitan City

Effects of human activity intensity on habitat quality based on nighttime light remote sensing: A case study of Northern Shaanxi, China

Habitat quality is a crucial expression of the value of ecosystem services. Habitat quality issues caused by human activities are troubling dilemmas worldwide, and there is an urgent need to assess the impact of the large-scale human activity intensity on habitat quality. In this study, Northern Shaanxi, China, is used as an example to demonstrate how the impact on habitat quality can be explored by simulating the intensity of human activities using nighttime light remote sensing data from 2000 to 2020. Defense Meteorological Satellite Program-Operational Linescan System (DMSP-OLS) data, Visible Infrared Imaging Radiometer Suite-Day-Night Band (VIIRS-DNB) data, and Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model were used in this study. The results showed that from 2000 to 2020, human activity intensity in Northern Shaanxi increased by 361.4 %, and the habitat quality decreased by 2.3 %. Habitat quality was more spatially clustered and spatially dependent than habitat degradation. Human activity intensity and habitat quality were significantly correlated. Habitat quality in Yulin city decreased significantly compared with that in Yan'an city. The differences in human activity types and economic structures of Yulin and Yan'an were an important factor for this phenomenon. The assessment of the impact of human activity intensity on habitat quality using nighttime light data is feasible and can be applied in other larger regions worldwide.

How Urban Fringe Expansion Affects Green Habitat Diversity? Analysis from Urban and Local Scale in Hilly City

Hilly cities in China have gone through an extensive expansion, and urban fringe morphology has experienced a massive change. As a result, green habitats have been occupied or disturbed, and such landscape changes can impact biodiversity. Understanding how urbanization impacts green habitats is essential for urban sustainable development. However, such understanding is lacking for hilly city. This study has two objectives: (1) to quantify the spatiotemporal patterns of green habitats in hilly city fringe during 2000-2020; (2) to identify the differentiated impacts of different hilly city expansion shapes on green habitat. By using landscape indexes to characterize green habitat patterns, the green habitats impact analysis was processed in two scales, at urban scale and local scale. Information Entropy Model and Classification and Green Habitat Quality Evaluation were used to reveal the relationships of urban expansion shapes and green habitat quality in mountainous city. The results showed that, at urban scale, (1) the more complex the city fringe morphology is, the more negative impacts there are on green habitats, (2) and when Guiyang urban fringe green space declined, the green habitats type pattern was refactored. At the local scale, we classified urban fringe expansion into four shape styles; we then discussed the changes of green habitats from the perspective of shape style and stage of urbanization. The results showed that, (1) dispersed type and strip type of urban fringe expansion led to the largest green habitat lost, besides, spreading type and strip type resulted in the largest loss of green habitats core areas. (2) Moreover, at a different stage of urban fringe expansion, the challenge of green habitats persistence was varied, the legacy type has been eager for special species habitats. However, the new type has been facing the risks of guaranteeing habitats stock and quality.