Ecological guilds of epiphytic diatoms (Bacillariophyta) on Acrostichum danaeifolium Längst. & Fisch in a subtropical wetland in southern Brazil

Guildas ecológicas de diatomáceas (Bacillariophyta) epífitas em Acrostichum danaeifolium Langst. & Fisch em uma área úmida subtropical do sul do Brasil

Abstract

Aim: Seasonal patterns diatom community on Acrostichum danaeifolium were examined in a wetland in southern Brazil.

Methods

The adhered diatoms were removed from the plant, species identification and growth forms were performed, and determined physical-chemical parameters of water.

Results

In total, 96 taxa belonging to 46 genera were identified. Nitzschia frustulum, Pseudostaurosira brevistriata and Plagiogramma tenuissimum were abundant species. Distinct growth forms that formed low-and high-profile ecological guilds and a mobile guild were observed. Navicula and Nitzschia were the genera with the greatest number of species, and these diatoms formed mucilage tubes. The water temperature varied from 10-26 °C, the depth from 0.35-0.80 m, the transparency from 0.20-0.23 m, the flow from 9.4-42.12 m³ s^–1, the pH from 7.08-8.89, the electrical conductivity from 0.65-15.83 mS cm^–1, the total organic phosphorus from 0.03-0.11 mg L^–1, and the total organic nitrogen from 0.29-0.49 mg L^–1. In summer, marine species such as Thalassiosira eccentrica and Rhaphoneis castracanii were also present.

Conclusions

The high-profile guild prevailed in all seasons of the year, with higher number of growth forms in the guild in winter. The richness found on A. danaeifolium shows that this plant provide a favorable habitat for epiphytic diatoms in wetlands such as Lagoa Pequena.

Keywords:
Acrostichum danaeifolium; epiphytic diatoms; growth forms; ecological guilds