# A Novel Protistan Trait Database Reveals Functional Redundancy and Complementarity in Terrestrial Protists (Amoebozoa and Rhizaria)

## TL;DR

A new database of protist traits shows how Amoebozoa and Cercozoa differ in their functions and roles in ecosystems.

## Contribution

A novel trait database for Amoebozoa protists reveals functional redundancy and complementarity with Cercozoa.

## Key findings

- Amoebozoa show less feeding selectivity compared to Cercozoa.
- Differences in trait composition affect ecosystem functioning in soil, litter, and bark.
- Amoebozoa traits are linked to disease-relatedness and cell size.

## Abstract

The inclusion of functional traits of protists in environmental sequencing surveys, in addition to the traditional taxonomic framework, is essential for a better understanding of their roles and impacts on ecosystem processes. We provide a database of functional traits for a widespread and important clade of protists—the Amoebozoa—based on extensive literature research in eight trait categories: Habitat, locomotion, nutrition, morphology, morphotype, size, spore formation, and disease‐relatedness. The comparison of community traits of the Amoebozoa with sympatric but highly divergent Cercozoa (Rhizaria) revealed both convergent evolution of morphology or locomotion and distinct differences in habitat preference and feeding selectivity. Amoebozoa seem to be rather unselective in their prey choice compared to Cercozoa. Indeed, the feeding preferences of Amoebozoa appeared to be related to cell size, whereas Cercozoa selectively feed on prey. Applications to metatranscriptomic data from soil, litter, and bark surfaces revealed differences in the average community trait compositions and ecosystem functioning, such as an increased proportion of disease‐related Amoebozoa in soil or different proportions of nutrition types of Amoebozoa and Cercozoa on bark. This database will facilitate ecological analyses of sequencing data and improve our understanding of the diversity of adaptations of Amoebozoa to the environment and their functional roles in ecosystems.