Parasites dominate hyperdiverse soil protist communities in Neotropical rainforests

Area of Science:

• Ecology
• Microbiology
• Biodiversity Science

Background:

• Tropical rainforests exhibit high animal and plant diversity, a phenomenon not fully understood at the microbial level.
• The diversity patterns of unicellular eukaryotes (protists) in these ecosystems remain largely unexplored.

Purpose of the Study:

• To investigate whether hyperdiversity patterns observed in macroorganisms extend to protist communities in Neotropical rainforests.
• To identify dominant protist groups and their potential ecological roles in these hyperdiverse environments.

Main Methods:

• Environmental metabarcoding of soil samples was employed to analyze protist communities.
• A novel phylogeny-aware cleaning step was utilized to refine the operational taxonomic unit (OTU) data.

Main Results:

• Protist communities in Neotropical rainforest soils are hyperdiverse, exceeding that of other eukaryotes.
• The parasitic Apicomplexa were found to dominate these communities, potentially influencing animal diversity through density-dependent regulation.
• Few Oomycota OTUs were detected, suggesting they do not broadly drive tropical tree diversity via host-specific interactions.

Conclusions:

• Protists represent the most diverse eukaryotes in tropical rainforests, surpassing even arthropods in diversity.
• These findings highlight the significant, yet often overlooked, role of protists in tropical terrestrial ecosystems.
• Parasitic protists may be key drivers of macroorganism diversity in these environments.