Abstract:
Most ecological research on hypoliths, significant primary producers in hyperarid
deserts, has focused on the diversity of individual groups of microbes (i.e. bacteria).
However, microbial communities are inherently complex, and the interactions between
cyanobacteria, heterotrophic bacteria, protista and metazoa, are likely to be very
important for ecosystem functioning. Cyanobacterial and heterotrophic bacterial
communities were analysed by pyrosequencing, while metazoan and protistan
communities were assessed by T-RFLP analysis. Microbial functionality was estimated
using carbon substrate utilization. Cyanobacterial community composition was
significant in shaping community structure and function in hypoliths. Ecological
network analysis showed that most significant co-occurrences were positive,
representing potential synergistic interactions. There were several highly interconnected
associations (modules) and specific cyanobacteria were important in driving the
modular structure of hypolithic networks. Together, our results suggest that hypolithic
cyanobacteria have strong effects on higher trophic levels and ecosystem functioning.
