Are functional freshwater Nematode traits a good tool for view an early succession on hard artificial substrate in a reservoir of Brazilian semiarid?

Traços funcionais dos Nematoda são uma boa ferramenta para visualizar uma sucessão ecológica em substratos artificiais em um reservatório do semiárido brasileiro?

Abstract

Aim

The Brazilian tropical semiarid is a biome with small freshwater ecosystems, often intermittent, acting as a mosaic in constant transformation between dry and rainy seasons. Meiobenthic communities play crucial roles in these environments, and understanding their colonization and succession processes is essential to comprehend how these organisms’ structure in a defaunated habitat. In addition to the traditional taxonomic approach, functional traits provide valuable insights into the dynamics of these processes. In this study, we tested the following hypotheses: i) although meiofauna consists of microscopic organisms with limited active dispersion, they quickly colonize new substrates, increasing in abundance, richness, and diversity; ii) functional traits of freshwater Nematoda are a good tool for view an early succession on hard artificial substrate in a lentic reservoir.

Methods

We placed 27 ceramic plates in a reservoir in the Brazilian semiarid and randomly sampled three replicates each week over nine weeks. Weekly differences in community abundance, richness, and diversity were tested with one-way ANOVA and pairwise PERMANOVA.

Results

Nematoda predominated in the first week, with Rotifera taking over from the second week of the experiment. No differences were observed in the Nematode taxonomic structure over the weeks. There was an increase in the functional complexity of the Nematoda community over time, as indicated by the maturity index and trophic structure. Colonizers/persistents emerged quickly in the first week. Deposit feeders dominated, but an increase in trophic diversity was observed with the growing presence of chewers over the weeks.

Conclusions

This study highlights that the functional traits of Nematoda represent a robust tool for assessing ecological succession in freshwater lentic environments in the tropical semiarid.

Keywords:
maturity index; trophic structure; Caatinga; meiobenthos