Macroalgas em nascentes e arredores de riachos na região noroeste do estado de São Paulo

Abstract

-(Macroalgae in springs and surrounding streams of northwestern region of São Paulo State). Macroalgae are typically benthic organisms that a mature, discreet and recognizable naked eye thallus, and microscopic identification is necessary. Several studies have been carried out aiming to the taxonomic knowledge in Brazilian streams, however works dealing with algae from springs are rare. Monthly sampling were carried out from February to September/2007 in springs and the surrounding (humid soil near the springs) of four streams in the northwestern region of São Paulo State. The floristic survey resulted in the identification of 13 species, being 54% of taxa belong Cyanophyta and 46% to Chlorophyta. Cylindrospermum gorakhpurense, Mougeotia gotlandica, Spirogyra gallica and S. taftiana were recorded for the first time to Brazil. The aquatic flora differed from the regional records due to presence of organisms of Zygnemataceae family (Chlorophyta) in reproductive stage. This type of habitat revealed to be very favorable to the Zygnemataceae reproduction. Key words: flora, Spirogyra, subaerial, Zygnemataceae RESUMO -(Macroalgas em nascentes e arredores de riachos na região noroeste do Estado de São Paulo). Macroalgas são organismos tipicamente bentônicos, constituídos por um talo maduro, discreto e reconhecível a olho nu, cuja identificação microscópica é necessária. Diversos estudos foram realizados visando o conhecimento taxonômico em riachos brasileiros, no entanto, são raros os trabalhos que abordam as algas que se desenvolvem nas nascentes destes riachos. De fevereiro a setembro/2007 coletas mensais foram realizadas em nascentes e em suas imediações (solos úmidos dos afloramentos d'água) de quatro riachos na região noroeste do estado de São Paulo. O levantamento taxonômico resultou na identificação de 13 espécies, sendo 54% dos táxons pertencentes a Cyanophyta e 46% a Chlorophyta. Cylindrospermum gorakhpurense, Mougeotia gotlandica, Spirogyra gallica e S. taftiana são registradas pela primeira vez para o Brasil. A flora aquática encontrada diferiu da regional devido à presença de organismos da família Zygnemataceae (Chlorophyta) em estágio reprodutivo. Este tipo de hábitat mostrou-se especialmente favorável à reprodução das Zygnemataceae.

Stream macroalgal flora from Parnaíba River Basin, Brazil: reducing Wallacean shortfall

“…The total number of taxa found in the present study (38) can be considered high when compared to studies carried out in other Brazilian regions that used similar methodology, namely: i) 13 taxa (Pereira & Branco 2010) and 21 taxa (Almeida et al 2011) in the northwest of the São Paulo State; ii) 23 taxa (Branco et al 2008) and 34 taxa , in the central-southern region of the Paraná State; iii) 24 taxa (Branco et al 2009) in the mid-western region of the Paraná State, and; iv) 19 taxa (Peres et al 2008) reported to the eastern region of Paraná State. Likewise, when considering the relative richness, found 1.81 taxa per sampling point, which is also higher when compared to what was reported in those other regions (taxa per sampling point and respective studies: 1.09 in Branco et al 2009, 1.23 in Almeida et al 2011, 1.35 in Peres et al 2008, 1.78 in Krupek et al 2008, 2.09 in Branco et al 2008.…”

“…Particularly for stream macroalgae (sensu Sheath & Cole 1992), the floristic surveys have focused basically only the Southeastern (Branco & Necchi Júnior 1996, Pereira & Branco 2010, Almeida et al 2011 and Southern regions of Brazil (Krupek et al 2008, 2009. Although these efforts have contributed profoundly to the knowledge of Brazilian flora, there is a huge gap in the knowledge of the distribution of organisms throughout the territory, thus clearly contributing to the Wallacean shortfall in the group.…”