Macrophyte functional traits in channelized streams

PAZ, L. E.; ALTIERI P.; FERREIRA, A. C.; OCON C.; CAPÍTULO, ALBERTO RODRIGUES; CORTELEZZI A

AQUATIC BOTANY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2021

0304-3770

In lowland streams, channelization is a severe hydromorphological modification with negative impacts on ecosystem functioning and biological communities. We assessed the functional structure and spatial patterns of macrophyte assemblages in channelized streams, and we identified the most affected traits by this practice. We studied unchannelized (UCS) and channelized sites (CS) using a null model approach and functional diversity indices. The macrophyte coverage was higher in the UCS (mean: 86 ± 15 %) than in the CS (50 ± 35%). Unchannelized sites revealed a random pattern, with predominating submerged and free-floating species, as well as reproduction by turionsand tubers. Channelized sites showed a segregation pattern (C-score obs.: 23.08; C- coreexp.: 22.20; SES: 3.20) of functionally similar species indicating interspecific competition,and lower functional richness, evenness, and Rao quadratic entropy compared to theUCS. The predominant traits found for macrophyte assemblages of these sites wereemergent life form, and dispersion by stolons. Our results indicate that in CS, the abioticenvironment and biotic interactions act as filters and only macrophyte species with keytraits can colonize these streams. In this sense, the creation of backwater areas, thereestablishment of longitudinal and lateral connections of the streams, as well asmacrophyte transplants could favor the dispersal and establishment of macrophytespecies. These rehabilitation measures could positively improve the functionality of these ecosystems.