Campos de altitude do Maciço Marins-Itaguaré, Serra da Mantiqueira SP/MG: composição florística, fitogeografia e estrutura da vegetação

Abstract

The Marins-Itaguaré Massif (MI) is located in the southern portion of the Serra da Mantiqueira, on the border of the states of Minas Gerais and São Paulo, and consists of altimontanous vegetation formations with altitudes that reach 2,420.7m. The objectives of this study were: i) to identify the floristic composition of the altitude fields of the MI Massif, ii) to evaluate their phytogeographical relationships with other rural areas of the South and Southeast regions of Brazil, and iii) to analyze the vegetation structure along an altitudinal gradient. Monthly field trips were carried out in the months of February, March, April, July, September, October, and December 2013, April, May, June, July, October 2017 and January 2018 for the collection of botanical material and the performance of phytosociological inventories. Horizontal lines of 150 meters in length were implanted in each altitudinal range (2000m, 2100m, 2200m, 2300m and 2400m), in which were parcels of 1m2 allocated with an interval of the 5m distance between them, totaling 30 plots in each line. To analyze the phytogeographic relationships, 17 locations in Southern and Southeastern Brazil were selected. Quantitative and qualitative similarity analyses were carried out in addition to the calculation of the diversity for each altitudinal range to evaluate the formation of groups related to altitude. Chapter 1 shows the floristic composition of the MI Massif, where 240 species, 141 genera, and 54 families were found. The richest families were Asteraceae (46 spp.), Melastomataceae (19 spp.), Poaceae (16 spp.), Rubiaceae (12 spp.) and Cyperaceae and Orchidaceae (11 spp.), with 58.9 percent of the massif flora. Seven species present some degree of threat. Sixteen new occurrences were also confirmed for MG and 22 for SP. The analysis of floristic similarity showed that the flora of the massif MI is related mainly to the Serra Fina and Itatiaia National Park. The results also showed an association between the floristic composition and the lithology of the analyzed areas. Chapter 2 presents the distribution of species along different altitudinal ranges. A total of 84 species were found at the sampled altitudes, with Poaceae (21%), Cyperaceae (18.7%) and Asteraceae (15.6%) being the families with the highest coverage values. The Shannon Diversity Index (H') for each altitude showed significant differences between altitudes 1 and 2 and did not show differences between altitudes 3, 4, and 5. The analysis of similarity variance showed a significant difference between the altitudinal bands, both qualitatively and quantitatively, demonstrating that factors other than altitude can influence vegetation structure and species composition in tropical mountain ecosystems. The high degree of conservation of the flora of the MI massif and the new records of species show the importance of the preservation of these areas of the Serra da Mantiqueira.