Adapted to the dry: ostracod communities in agricultural landscapes of eastern Yunnan, China

Abstract

Research on non-marine ostracods in Yunnan Province, especially in desiccated and irrigation environments, is limited, restricting our understanding of their survival strategies, adaptation mechanisms, and biogeographical patterns within this region. The present study investigates ostracods across 43 sites in eastern Yunnan, including desiccated rice fields, ditches, rivers, ponds, vegetable fields, karstic cave, spring, and stream. A total of 483 living ostracod individuals were collected from 15 out of the 43 sampling sites, encompassing eleven species predominantly from the Cyprididae family, accompanied by species from the Candonidae, Cyclocyprididae and Ilyocyprididae families. Our results of culturing experiments with dried muds indicated survival of dormant ostracods, as an important strategy of recolonizing non-permanent water bodies after dry phases. Thus, recolonization is realized through an ‘ostracod bank’, not only an egg bank. Significant differences in species composition were observed across regions, reflecting the dynamic responses of ostracods to agricultural practices and environment. Furthermore, documented elevational distributions of some species could be extended based on our study areas in an elevation of 887‒2064 m asl. The study also documents three species new to Yunnan, increasing the number of known recent non-marine ostracod species in this province to 33. The newly recorded species are Stenocypris hirutai Smith and Kamiya (Hydrobiologia 559: 331–355, 2006), Stenocypris viridis Okubo, 1990 and Hemicypris ovata Sars, 1903. These findings provide insights into ostracod ecology, biogeography, and aquatic ecology, revealing adaptive and resilient mechanisms of ostracods in temporary, eutrophic habitats.