High diversity and strong habitat preference of bdelloid rotifers in the moss and leaf litter from a small area of urban plain and adjacent hill in China

Biodiversity patterns of microscopic organisms, such as bdelloid rotifers are generally lacking. In this study, bdelloid rotifers from moss and leaf litter habitats were collected from a small area of 14 square kilometres in Changde City, Southern China. Species diversity and habitat preferences were examined using morphological methods. A total of 64 morphological species (including subspecies) were identified, accounting for 65.3% of the bdelloid rotifers recorded in China. The DNA taxonomy of rotifers ( Rotaria sordida with no preference and leaf litter-preferring Adineta beysunae ) with high Indicator Values (IndVal) identified eight and two cryptic species, respectively, in Changde. The species richness of bdelloid rotifers was significantly (Student’s t test, p < 0.01) lower in moss than in leaf litter, and the bdelloid rotifer communities differed significantly (analysis of group similarities, p < 0.01) between moss and leaf litter habitats. Indicator species analysis revealed that A. beysunae had a strong habitat preference (IndVal, p < 0.01). Additionally, Pearson’s phi correlation analysis indicated that the cryptic species within the species complex of R. sordida had a weak habitat preference (phi, p < 0.05). Bayesian phylogenetic trees and genetic diversity analyses of R. sordida and A. beysunae indicated that genetic diversity differed between different habitats. These findings indicate high bdelloid rotifer biodiversity with strong habitat preferences between moss and leaf litter habitats at the morphological taxonomy level but weak habitat preferences at the genetic taxonomy level, implying that bdelloid species can be used as indicators of heterogeneous habitats and provide an ecological basis for the discovery and conservation of bdelloid rotifer species diversity.