Distribution patterns and drivers of urban green space and plant diversity in Haikou, China.

Investigating historical and ongoing changes in urban green space (UGS) and urban plant diversity (UPD) provides critical insights into urban ecology and urban planning development. The present study illuminates some of the transformations which can occur in rapidly developing urban landscapes. In this work, we used 30 m resolution images from the Landsat 5 satellite from 2015 to investigate UGS patterns in Haikou City, China. Metrics of UPD were obtained using field surveys, allowing the proportion of UGS and UPD to be determined in each urban functional unit (UFU) of Haikou. The results revealed that leisure and entertainment areas (such as parks) had the highest diversity, whereas roads and transportation hubs had the lowest. More frequent anthropogenic maintenance had a positive effect on the total number of species, including cultivated, tree, and herb species. Similarly, increased watering frequency had a positive impact on the diversity of cultivated and shrub species. By providing demonstrating a crucial link between UGS and UPD, the results provide valuable information for planning sustainable urban development in Haikou City and other tropical regions. They highlight the important role of UGS in maintaining biodiversity and providing a range of ecosystem services. This research will inform policymakers and urban planners about the need to consider UGS and UPD in urban planning and management process, in order to promote sustainability and conservation of biodiversity.

Spatiotemporal Variation of Urban Plant Diversity and above Ground Biomass in Haikou, China.

Understanding the drivers of urban plant diversity (UPD) and above ground biomass (AGB) in urbanized areas is critical for urban ecosystem services and biodiversity protection. The relationships between UPD and AGB have been investigated simultaneously. However, the drivers of UPD and AGB have been explored independently in tropical coastal areas at different time points. To fill this gap, we conducted a remote sensing interpretation, field plant plot surveys, and compiled socioeconomic and urban greening management survey data. We conducted spatial analyses to investigate the relationships among UPD and socioeconomic variables across different primary and secondary urban functional units (UFUs) in the tropical urban ecosystems of the coastal city of Haikou, China. The primary UFUs with the highest AGB were the recreation and leisure districts in 2015 and 2021. In 2015, AGB was mainly correlated with the number of herb species in undeveloped land and the districts of industry, business, recreation, and leisure. In 2021, AGB was affected primarily by the frequency of fertilizing, maintenance, and watering. Our study found that the relationship between UPD and AGB varied across time and space in Haikou. The plant diversity and AGB's response to human activities and socioeconomics appear to have a time-lag effect. These results provide new insights in understanding how management decisions affect urban vegetation and could be used to guide future urban green space planning in Haikou.

Complete plastome sequence of Balakata baccata (Roxb.) Esser (Euphorbiaceae).

Balakata baccata belongs to the family Euphorbiaceae and is distributed in Yunnan province, China, and other southeast Asian countries, e.g., Bangladesh, Cambodia, India, Indonesia, etc. Here, we report and characterize the complete plastome of B. baccata. The complete plastome is 163,988 bp in length and contains a typical quadripartite structure and gene content found in angiosperms, including two inverted repeat (IR) regions of 27,274 bp, a large single-copy (LSC) region of 90,946 bp and a small single-copy (SSC) region of 18,494 bp. The plastome contains 129 genes, consisting of 84 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The overall G/C content in the plastome of B. baccata is 35.6%. Phylogenetic results show that B. baccata is the earliest diverging lineage of Euphorbioideae. Euphorbia helioscopia + E. esula, E. tirucalli + E. milii and B. baccata have a closer phylogenetic relationship than other taxa within Euphorbiaceae. The complete plastome sequence of B. baccata will provide a useful resource for the conservation genetics of this species as well as for phylogenetic studies in Euphorbiaceae.