Aspectos brioflorísticos e fitogeográficos de duas formações costeiras de Floresta Atlântica da Serra do Mar, Ubatuba/SP, Brasil

Abstract

Bryophytes are indicators of climatic, environmental and ecology conditions and are useful in the characterization of the vegetation types. In this study, we analyzed the brioflora of 2-ha plots, one of Restinga Forest (RF) and the other of Lowland Ombrophilous Dense Forest (LF), located in the Núcleo Picinguaba, State Park of Serra do Mar (São Paulo state, Brazil) aiming to: a) compare the structure of these communities; b) compare the floristic composition between these areas and with other coastal vegetations of southeastern Brazil; c) verify if the bryophytes of the Atlantic Forest lowlands have phytogeographic patterns wider than those of the montane species. In each plot, the bryophytes samples were collected at ten randomized subplots (10 × 10 m). We found 152 species (87 liverworts, 64 mosses and one hornwort), of which 109 occur in RF (40 exclusives) and 112 in LF (43 exclusives). In terms of species richness and taxonomic diversity, LF was more diverse; however, the Simpson and Shannon index of diversity is higher in RF. The floristic composition, life form and ecological groups of light tolerance were significantly different between these two forests. Canopy opening (RF) and number of rocks (LF) were important environmental variables that influenced bryophyte distribution in the study areas. When evaluated in terms of landscape, the subplots of RF and LR form distinct floristic groups; however, at the regional level, the bryophytes of these two forest types have more similarities among themselves than with other Atlantic Forest areas. Bryophyte community observed in the Restinga Forest of Picinguaba shows more similarity with that of the neighbor Lowland Ombrophilous Dense Forest than with other Restinga or coastal formation, such as mangroves and caxetal. In both forests types studied, the majority of taxa (> 90%) is widely distributed in the world, presenting phytogeographic pattern equal to or wider than the Neotropical. Our results corroborate the idea that the RF of Picinguaba is a unique vegetation formation, presenting elements of ombrophilous and dryer forests. In addition, they reinforce the idea that, for the tropical bryophyte species, the phytogeographic patterns are wider in areas of lower altitudes. Resumo: Briófitas são bioindicadoras de condições climáticas, ambientais e ecológicas, sendo úteis na caracterização de tipos vegetacionais. Neste trabalho, foi analisada a brioflora de duas áreas de 1 ha, uma de Floresta de Restinga (FR) e outra de Floresta Ombrófila Densa de Terras Baixas (TB) do Núcleo Picinguaba, PE Serra do Mar (São Paulo, Brasil), com o objetivo de: a) comparar a estrutura dessas comunidades; b) entender as relações florísticas dessas áreas entre si e com outras formações litorâneas brasileiras; c) verificar se as briófitas de áreas de baixada apresentam padrões fitogeográficos mais amplos do que aquelas de áreas montanas. As briófitas foram coletadas em 10 subparcelas (10 × 10 m) distribuídas aleatoriamente em cada fitofisionomia. Variáveis ambientais foram q...

Bryophytes in fragments of Terra Firme forest on the great curve of the Xingu River, Pará state, Brazil 1 Part of Master's Dissertation of the first author.

“…Regarding to the light tolerance guilds, the result was similar to that found by Silva and Pôrto (2009 and Santos et al (2011), conducted in lowland forests in Atlantic Forest. In a study conducted in submontane forest, in Bolivia, Acebey et al (2003) realized that generalist species are apparently indifferent to forest destruction, while those with smaller niches (experts) seem to be less likely to survive the deforestation, as observed in this study where there was predominance of generalists.…”

“…This method was applied with the intention to engage a larger species composition within the fragments, since it is known that the edge have effect in floristic composition. Plot size was based on the subplots of Santos et al (2011) and for the collection of material, each plot was subdivided into five corridors 2 × 10 m, where traversing each one, the material were collected on all types of substrates only reaching the understory.…”

“…The Amazon and Atlantic Forest are the two most significant phytogeographic regions in terms of richness for bryophytes in Brazil (Santos et al, 2011). Even the Amazon being the largest extension of humid tropical forest characterized by a remarkable richness of species and high levels of endemism (Mittermeier et al, 1992), it is the second most important region for the bryoflora in the country.…”

Can regional and local filters explain epiphytic bryophyte distributions in the Atlantic Forest of southeastern Brazil?

“…The RF demonstrated greater canopy openness than LF in the study area (Santos et al 2011), so that the bryophyte species in RF must have greater tolerances to solar radiation as compared to those present on mountain slopes (LF and SF), which have more amenable temperature and luminosity conditions. Some morphofunctional groups were restricted to mountain slope sites (LF and SF).…”

“…The RF had the largest percentage of species with mat life forms, and the marked occurrence of turf species, together with the absence of pendant and dendroid forms, reflected the greater degree of luminosity encountered in that phytophysiognomy (Glime 2007;Santos et al 2011) -as life forms respond to environmental conditions (Giminghan & Birse 1957). As a consequence of these traits, bryophytes can be used as bioindicators of environmental and microclimatic conditions, and have shown themselves to be efficient indicators of phytophysiognomies and/or elevational belts in humid tropical forests (e.g., Frahm & Gradstein 1991;Gradstein et al 2001;Costa & Lima 2005;Santos & Costa 2010;Santos et al 2014).…”