Abstract: Aims The Shenzhen Bay Mangrove Nature Reserve is the only national nature reserve in China located within an urban area. Studying the potential biodiversity of urban mangrove wetlands, which are significantly impacted by human disturbance, can provide a pathway for the sustainable management of mangrove ecosystems. Methods This study conducted an ecological survey of different areas (core/non-core) in the Shenzhen Bay Mangrove National Nature Reserve. Species co-occurrence and distribution probability was assessed using the hy-pergeometric method, and the vegetation characteristics of the area were analyzed based on the survey data. Important findings (1) A total of nine mangrove species were distributed in the Shenzhen Bay Mangrove Nature Reserve, with Kandelia obovata being the dominant species. In the core area, K. obovata had the highest importance value (IV) (mean = 96.4%), while its importance value in the non-core area was significantly lower (p < 0.05), where Sonneratia apetala and S. caseolaris appeared. (2) In the Shenzhen Bay mangrove ecosystem, S. caseolaris and S. apetala exhibited a strong coexistence tendency, with a z-score value of 2.82. Meanwhile, S. apetala and K. obovata displayed competitive exclusion, with a z-score value of -2.41. Z-score values reflect non-random species co-occurrence patterns. (3) A significant positive correlation was found between the existing species diversity and the community integrity index in the Shenzhen Bay mangroves. The higher the community integrity, the higher the existing species diversity. Some non-core area plots are at risk of S. apetala spreading, and ecosystem management and protection should be strengthened. The distribution probability of K. obovata in the core area (0.51 ± 0.09) is significantly higher than that in the non-core area (0.41 ± 0.15). However, in certain plots of the core area, such as the plots in the mid-tide zones of transects 8, community completeness is relatively low. It is recommended to appro-priately replant native mangroves to enhance species diversity.

Key words: mangrove, species co-occurrence, distribution probability, potential biodiversity