The assembly and maintenance of biodiversity has historically been an important direction for ecological studies, and the spatiotemporal patterns are the focus of research. However, most of these studies focused on the species-area relationship of animals/plants, and bacteria were largely ignored. As vertebrates born free of microorganisms, the microbiota that colonize the intestine immigrate from the outside, and the intestinal microbiota typically occupies a habitat with definable limits/borders that are comparable to oceanic islands. Therefore, the intestine can be considered as an ‘island’ for colonizing bacteria within a ‘sea’ of surrounding (body part) environments according to biogeographic theory. However, spatiotemporal patterns within these systems were never studied. 

The Research Group of Taxanomy and Ecology of Protozoa (Principal Investigator: Prof. YU Yuhe) at Institute of Hydrobiology, Chinese Academy of Sciences (IHB) firstly applied zebrafish (Danio rerio) as an ‘island’ model and studied the bacterial community assembly and turnover within the intestines of developing zebrafish (from larvae to adult animals).  

Results suggested that the spatial and temporal species-richness relationships in the intestinal ‘island’ model can be expressed as power models of S = cA^z or S = cT^z. Mantel and partial Mantel tests revealed that turnover was low and that richness and composition was best predicted by time and not intestinal volume (habitat size) or changes in food diet. Moreover, the bacterial communities within the zebrafish intestines were deterministically assembled switching to stochastic assembly in the later stages of zebrafish development.  

This study is of importance as it provides a novel insight into how intestinal bacterial communities assemble in tandem with the host’s development. It is also valuable as that studying intestinal microbiota of this vertebrate model could well provide ecological insights and benefit mammals and human studies. 

The related article, which fulfilled by Dr. Yan et al., was published in PLoS ONE under the Subject of Ecology (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030603). This work was funded by the Major State Basic Research Development Program of China and the National Natural Science Foundation of China.