Effects of crevice size on the establishment of macroalgae in subtropical streams

Author(s)

Tonetto, A. F. ^[1] ; Peres, C. K. ^[2] ; Khnayfes, M. A. ^[1] ; Branco, C. C. Z. ^[1]

Affiliation

^[1] Sao Paulo State Univ UNESP, Dept Biol Sci, Lab Aquat Biol, BR-19806900 Assis, SP - Brazil

^[2] Univ Fed Integracao Latino Americana UNILA, BR-85867970 Foz Do Iguacu, PR - Brazil

• Document type: Journal article
• Source: Brazilian Journal of Biology; v. 74, n. 4, p. 803-809, NOV 2014.
• Web of Science Citations: 0

Abstract

Considering that in previous studies, the surface roughness (micrometric dimension) showed a weak effect on the colonization of stream macroalgae, we investigated the effects of different crevice sizes (milimetric dimension, a scale slightly higher than previous investigations) on the macroalgal abundance in three streams exposed to full sunlight in southern Brazil. We used smooth sterile glass plates with different shapes: P – plane surface without crevices; S – sinuous surface (depth of crevices with 0.159 mm ± 0.03); N – non-unifom surface (0.498 mm ± 0.09); C – surfaces with convex structures (1.190 mm ± 0.12); and three additional surface types with different patterns of heterogeneity with combinations of glass pieces: P + S (H1); P + S + N (H2) and P + S + N + C (H3). The plates were placed into the streams and after 105 days the percent cover of macroalgal community was measured. No significant differences among treatments were recorded. However, we observed a trend of macroalgae occurs within the crevices in all treatments and this suggests that, for stream macroalgae, the crevice sizes used in this study was still not enough to provide an expressive algal growth, even in the treatment with bigger crevices. (AU)

• FAPESP's process: 10/17563-0 - Ecological interactions between periphytic and macroalgal communities in lotic ecossystems
• Grantee: Aurélio Fajar Tonetto
• Support Opportunities: Scholarships in Brazil - Doctorate