Response relationship between insect diversity and vegetation types of urban green space ——case study of China-Singapore Tianjin Eco-City

As a vital ecological infrastructure in cities, green spaces play a crucial role in maintaining biodiversity. Insects, highly dependent on their environment, can effectively reflect the health status of green space ecosystems, providing quantifiable scientific evidence for biodiversity conservation. To explore the relationship between vegetation types in urban green spaces and insect diversity, we conducted surveys on insect and plant diversity in 24 sample plots of Sino-Singapore Tianjin Eco-City using point-sample and line-transect methods from August to September 2024. We analyzed the distribution characteristics of insects in urban green spaces, the diversity differences of plants and insects in different types of green spaces, and explored the relationship between insect diversity, vegetation types and environmental factors. The results showed that: a total of 7416 insect individuals were collected, belonging to 10 orders, 67 families and 121 species. Among them, Hymenoptera and Diptera accounted for a high proportion, with 6061 individuals in total, accounting for 81.73% of the total samples; there were 398 plant species, belonging to 246 genera and 79 families, among which Asteraceae, Rosaceae and Poaceae had the largest number of species. Among the three types of green spaces (woodland, shrub and grassland), there were significant differences in Shannon-Wiener diversity index, Simpson diversity index and Pielou evenness index in plant communities, but no significant differences in these three indexes were found in insect communities. Different plant species had positive and negative correlations of varying degrees with the number of insect individuals and species; among them, the number of insect individuals in shrub plots had the highest negative correlation with plant diversity index, and Hymenoptera had the highest negative correlation with the number of Amaranthaceae plants. Redundancy analysis (RDA) showed that environmental factors affected insect diversity and individual number to varying degrees, among which humidity was the main environmental factor affecting insect quantitative characteristics. In general, insects in urban green spaces were characterized by Hymenoptera and Diptera as dominant species, with fewer insects of other orders. Plant species and environmental factors jointly affected insect diversity. In the future construction, maintenance and management of urban green spaces, the support capacity of habitats for insect survival can be improved by adjusting plant types, so as to enhance the level of urban insect diversity.