Floristic variation within seasonally dry tropical forests of the Caatinga Biogeographic Domain, Brazil, and its conservation implications

Seasonally Dry Tropical Forests (SDTF) are gaining recognition as a significant biome and poorly conserved tropical biodiversity refuge. Understanding floristic relationships within SDTF is essential for their effective conservation. This study examines the floristic variation within SDTF of the Caatinga Biogeographic Domain, in north-eastern Brazil. SDTF trees, shrubs and arborescent cacti were sampled in six localities in the Brazilian states of Minas Gerais and Bahia. A number of soil chemical attributes were also measured to analyse vegetation-soil relationships across the study sites. Five floristically distinct SDTF communities were delineated. Differences in these communities are attributable to influences from adjacent savanna and rain forest surrounding the study sites, and also to soil properties such as Al3+, base saturation and gravel content. The high species richness of, and species dissimilarity between communities reflect the need for judicious conservation planning for SDTF that account for biodiversity values and forest structural integrity

Phanerogamic flora and phytogeography of the Cloud Dwarf Forests of Ibitipoca State Park, Minas Gerais, Brazil

Abstract: This study was developed in Ibitipoca State Park (ISP), a mountainous massif that stands out in the Serra da Mantiqueira, in the Southeastern Region of Brazil. The vegetation is represented by a phytophysiognomic mosaic where areas of campos rupestres interspersed with cloud dwarf forests predominate, at altitudes of 1100 to 1700 m.s.m. The cloud dwarf forests exist in narrow altitude belts on the mountain peaks, immersed in a layer of clouds. They form a peculiar landscape high in the mountains by the short stature of the arboreal elements and richness of lichens and bryophytes, which develop under constant condensation of humidity, low temperatures, and frequent winds. The objective of the present work was to determine the floristic composition and phytogeography of the cloud dwarf forests of ISP. Twelve monthly campaigns were conducted to collect botanical material during the years 2014 and 2015. The collected material was deposited in the collection of the CESJ Herbarium. A total of 372 species, 209 genera, and 73 families of phanerogams were found. The richest families were Orchidaceae (84 spp.), Asteraceae (39 spp.), and Melastomataceae (21 spp). The genera with the greatest wealth were Leandra (09 spp.), Epidendrum (09 spp.), Pleurothallis (09 spp.), Mikania (07 spp.), and Miconia (07 spp). The arboreal habit was predominant with 103 species (27.7%), followed by 83 shrubs (22.3%), 82 epiphytic herbs (22%), 80 terrestrial herbs (21.5%), and 23 lianas (6.5%). The floristic composition presents elements typical of altitude vegetation, including species of campos rupestres and high epiphytes richness, especially of the families Orchidaceae and Bromeliaceae. The genera with tropical distribution represent 86.5%, whereas the temperate elements represent 13.5% of the total. The cloud dwarf forests presented similarity, at the family and gender levels, with the upper montane forests of the Andes, besides phytogeographic characteristics that allow to associate them to a transition environment between the campos rupestres and the upper montane forests of the Southeast Region of Brazil