Hepáticas (Marchantiophyta) do Parque Estadual do Ibitipoca (MG-Brasil): florística e ecologia

Abstract

The Atlantic Forest is considered a global biodiversity hotspot by presenting high rates of endemism, great richness and plant abundance, including bryophytes (hornworts, liverworts, mosses). Liverworts are important organisms in the composition and richness of Atlantic Forest and they belong to Marchantiophyta. The Atlantic Forest is composed by heterogeneous landscapes including different phytophysiognomies. In Parque Estadual de Ibitipoca such heterogeneity forms a complex mosaic of forest vegetation types, shrub, countryside and savannas, which are continuous to each other forming regions of edge. The edges can be natural created by the natural dynamics of environmental formation, and caused by mankind in order to establish their activities. The edges support community with different characteristics from continuing communities, showing changes in species richness, abundance, density and diversity, a process known as edge effect. The liverworts are bioindicators organisms and then they are important in studies on edge influence. Studies on edge effect on species composition in Minas Gerais Atlantic Forest are essential for their conservation. Therefore, this study was developed in Broadleaved Cloud Evergreen Upper Highlands Tropical Forest (Broadleaved Forest) from Parque Estadual de Ibitipoca (Minas Gerais, Brazil), also known as “Mata Grande”, and with a goal of studying the liverworts species (Marchantiophyta) through systematic collections, identification of species and ecological assessments (cluster analysis, One-way ANOSIM, richness, abundance, frequency and tolerance to light). Samples were collected in 2013 and 2014 distributing 20 plots of 5x5m2 each from the edge through the interior of Broadleaved Forest. The results indicate abundance 1220 specimens and richness of 90 species distributed in 29 genera and nine families. From the total species identified nine are endemic to Brazil and eight represent new records for Minas Gerais State. The Lejeuneaceae family is the most rich and abundant in the forest studied. The cluster analysis showed the formation of two distinct groups (edge and forest interior), and One-way ANOSIM analysis confirms that this difference is significant. The edge richness was 64 species (22 exclusive) and in the forest interior the richness was 68 species (26 exclusive). The frequency classes distribution in the edge area presented predominance of species considered rare, followed by infrequent, assiduous, very common and common. However, the forest interior plots reversed infrequent class by assiduous. The species were classified as generalist, sun specialist and/or shade specialist and when they were compared the difference were not statistically significative between the edge and forest interior. It is important to highligh this forest for bryophytes conservation because of its size (64 ha) and its high species richness associated with the occurrence of endemic taxa to Brazil.