Vegetação de áreas úmidas (banhados) em campos naturais no Planalto Sul Catarinense: espacialização e métricas da paisagem, diversidade e distribuição florística

Abstract

Wetlands are ecosystems which embrace a great number of botanical species and they may include endangered and endemic species and others with economic potentialities. However, the studies of these environments are still in their beginnings, mostly those about Santa Catarina‟s South Plateau. The main aims of this study were: 1. to test digital classification techniques on wetlands mapping and to analyze their size pattern, the forms and density of their landscape occurrence; 2. to list botanical species, their ecological aspects and their economic potentialities; 3. to establish the spatial distribution of species. In order to mapping, a Landsat-5 image and some digital ortoimages were used, they were processed with ArcGIS 9.3, ENVI 4.7 and ENVI EX softwares; metrics in landscape were analyzed with FRAGSTATS 4.0 software. The floristic survey was made in Aug./2011-Jan./2013 in three areas: Bom Jardim da Serra, Lages (Coxilha Rica) and Painel cities. Habits, life forms, frequency of species, stature classes, species economical potential uses and conservation status indicators were analyzed. Data about species distribution were collected in Jan.- Feb./2012, by means of six transects (4x27 m), placed in the three research wet areas, from border to center (n=168). The ordering analysis applied was non-metric multidimensional scaling (NMDS), used in two stages: among areas and in the transections, using R 2.15 software. Digital classification showed up as a satisfactory one and wetlands represented 12% of the landscape; frequency of one wetland/10 hectare; the area occupied by wetlands presented a great largeness (0,01-37 ha.), most with less than 2 ha. Total richness was of 156 species, distributed in 96 genera and 47 families. Families with greater richness, were Poaceae (26 spp.), Asteraceae (23) and Cyperaceae (23), while 24 families were represented by one specie each. The most common habit was herbaceous (124), life forms were amphibians (107) and emergent (30); the majority of species had a regular frequency classification (77); the stature class with a bigger number of species was class III (≥ 50 e < 100 cm). Among species with economical uses (61), pointed out the bioactive ones (30) and also were observed endangered (four) and endemic species (three); as well as some high land grasslands conservation status indicator species (38) and turf indicator species (four). Floristic diversity was considered high (Shannon: 3.32; 3.53 e 3.62), and the three areas showed 17 species in common. Regarding to the ordination analyses, two zones were observed: border (≤ 7 m) and center (> 7 m), border species represented 70%, of total species collected. Dates achieved in this study shall be important helping to recognize the preservation significance of these ecosystems, as well as helping to understand the ecological processes that occur in these environments.