The urban environment has the potential to host a wide variety of microorganisms. However, gaining a better understanding of microbial community interaction with urban ecosystems requires a deeper understanding of the mechanisms driving the diversity and community assembly of testate amoebae and other microbial eukaryotes in diverse urban biotopes. To address this, we employed high-throughput sequencing of 18S rRNA genes to analyze microbial eukaryotes and microscopy to analyze testate amoebae in five distinct biotopes (tree hole, moss on the tree trunk, land soil, pond water, and pond sediment) within fourteen urban parks located in Moscow (Russia), Xiamen, and Shenzhen (China) during 2020 and 2021 summer seasons. The molecular diversity in 90 samples revealed that Opisthokonta was the most abundant supergroup across all biotopes. Dispersal limitation was identified as the key driving factor in the community assembly process within single or multiple biotopes, with soil recognized as the primary source of dispersal for protozoan amoebae among different biotopes. In comparison, microscopy analysis of tree hole, moss on the tree trunk, land soil, and pond sediment (132 samples) revealed a total of 116 testate amoeba morphospecies (28 genera), with 13‒26% of the total species richness shared among all biotopes, indicating high heterogeneity of testate amoeba community in urban parks. The distribution of testate amoebae is largely influenced by the biotope rather than elementary environmental conditions such as pH, moisture content, and the thickness of the leaf litter layer.

Ndayishimiye, J.C., Mazei, Y., Ren, K., Tsyganov, A. N., Smirnov, A., Mazei, N., Saldaev, D., Ivanovskii, A., Nyirabuhoro, P., Yang, J. (2023). Diversity and community assembly of testate amoebae and other microbial eukaryotes in diverse biotopes within urban parks: morphological and metabarcoding perspective. In: Lara (Ed.), E. 10^th International Symposium on Testate Amoebae (pp. 23). Abstract booklet, Royal Botanical Garden-CSIC, Madrid, Spain