Spatial and temporal factors determining the structure of ciliate protist communities in neotropical streams

Fatores espaciais e temporais que determinam a estrutura das comunidades de protistas ciliados em riachos neotropicais

Abstract:

Aim  In this study, we focused on patterns of ciliate protist community composition in urban and rural streams.

Methods  We analyzed 12 urban and rural streams during two different periods of the year (rainy and dry seasons) across three different stream mesohabitats (riffles, runs, and pools). We predicted that the species composition of ciliates would differ between types of environments (rural and urban), between basins (Pirapó and Ivaí), between mesohabitats (riffles, runs, and pools), and between seasonal periods. We also expected that ciliate species composition would be similar between streams within the same basin.

Results  Contrary to our expectations, our results showed that the richness and abundance of ciliates were higher in urban streams than in rural streams. In the analysis of beta diversity, we observed that this measure was higher in rural environments, but only during one period (dry season). Among the mesohabitats, no significant alterations in ciliate species composition were noted, contrary to our predictions.

Conclusions  The results obtained in this study demonstrated the effect of multiple spatial (basin, type of environment) and temporal (rainy and dry seasons) factors on the structure of ciliate protists in the water column of neotropical streams. No differences in ciliate attributes were found among the mesohabitats analyzed in this study.

Keywords:
streams; urbanization; agriculture; ciliates; mesohabitat