Abstract:

Background: With the accelerating pace of global urbanization, urban biodiversity is facing increasingly severe challenges, including habitat loss, ecological fragmentation, and the decline of native species. As the fundamental spatial and functional unit of urban spatial structure and ecological system, urban blocks not only support residential, commercial, and social functions, but also serve as critical interfaces where the built environment interacts with ecological systems. They play a vital role in maintaining ecosystem services, supporting habitat provision, and shaping local biodiversity patterns. In recent years, as urban regeneration progresses, how to effectively embed biodiversity enhancement goals into spatial planning at the scale of urban block has become a pressing and central issue in the field of urban ecological planning and sustainable design. 

Aims & Methods: While studies examining the impacts of urban block built environment on urban biodiversity have increased in recent years, systematic reviews and integrative theoretical frameworks remain insufficient, constraining theoretical development. To address this gap, this study conducts a bibliometric and content-based review of relevant domestic and international research, and categorizes built environment factors affecting urban biodiversity at the block scale into five categories: block greening, vegetation characteristics, land use, three-dimensional morphology, and mediating factors (human activity and climate factors). Based on this framework, the study comprehensively summarizes various impact factors and their relationships identified in existing research. 

Results: Findings reveal three key discoveries: (1) the urban block scale is critically important for biodiversity research, exhibiting distinct characteristics that differentiate it from other spatial scales; (2) the urban block built environment influences biodiversity through both direct and indirect pathways, creating complex impact mechanisms; (3) human activity in urban blocks demonstrate significant mediating effects, while climate factors play important moderating roles in shaping biodiversity patterns, suggesting these interactive effects warrant in-depth future investigation. 

Conclusion: Based on this, the study proposes four major directions for future research: (1) deepening research on the impacts of block three-dimensional morphology on urban biodiversity; (2) revealing mediating effects of human activities at block scale; (3) exploring regulatory mechanisms of climate factors on biodiversity patterns; (4) developing differentiated guidelines and standards for refined urban block regeneration. 

Perspectives: This review aims to provide a systematic theoretical foundation for urban block spatial planning oriented toward biodiversity enhancement, and to promote the construction of urban spatial systems characterized by ecological resilience and integration with nature.

Key words: Urban block, Built environment, Urban biodiversity, Impact factors, Research outlooks