ABSTRACT The present study aims to analyze the potential of areas for the implementation of ecological corridors. The study area represents a transition between the Atlantic Forest and Cerrado domains and is extensively fragmented. Geographic Information System was used to determine suitable areas for the implementation of ecological corridors based on their ecological and structural potential, while multi-criteria classification was used to generate a final ecological map of the area. Weights and notes were assigned to vegetation class, river width, elevation and declivity in their respective maps, which were overlaid using ArcGis 10.3 software. Structural analysis of the area used the landscape metrics mean area, mean shape and total edge of fragments and mean connectivity among fragments in Fragstats software. The results indicated an ecologically and structurally suitable area for the implementation of ecological corridors in the study area.

RESUMO O presente estudo tem como propósito analisar áreas potenciais para a implantação de Corredores Ecológicos. Atualmente a área encontra-se fragmentada e está sob os domínios de Cerrado e Mata Atlântica. Baseado no Sistema de Informações Geográficas, foram determinadas possíveis áreas, do ponto de vista ecológico e estrutural, para a implantação dos Corredores Ecológicos. Para a geração do mapa final de potencial ecológico da área, utilizou-se a metodologia de classificação por múltiplos critérios. Foram atribuídos pesos e notas às classes de vegetação, largura dos rios, altitude e declividade em seus respectivos mapas. Após a determinação dos pesos e notas, realizou-se a sobreposição dos mapas no software ArcGis 10.3. Para analise estrutural da área utilizou-se às métricas de paisagem área média, formato médio e borda total dos fragmentos e conectividade média entre os fragmentos no software Fragstats. Os resultados apontaram para uma área ecologicamente e estruturalmente viável para a implantação dos Corredores Ecológicos na área de estudo.

Abstract Fragmentation of natural areas alters the natural landscape, removing native vegetation and creating an anthropic matrix. In order to better understand the consequences of grazing in areas of campo rupestre and forest, the present study aimed to analyze changes in the vegetation of Cerrado and Atlantic Forest, in the Southern Espinhaço, between 1979 and 2015. The vegetation of the study area was identified as arboreal (forest), or herbaceous or shrubby (campo rupestre) by visual classification of a mosaic of aerial photographs from 1979 and the supervised classification of land use from a Landsat 8 image from 2015. Differences in vegetation were analyzed using a transition matrix based on the “Markov model”, which indicated conversions of vegetation classes due to the misuse of land, mainly as pasture. The results indicate the conversion of arboreal vegetation area into areas of exotic herbaceous vegetation, and stability in the area of shrubby vegetation.

Resumo Este estudo teve como objetivo analisar a dinâmica da estrutura de espécies arbóreas e relacionar as mudanças com as condições edáficas em fitofisionomias de cerrado stricto sensu (de 2010 a 2015), cerradão (de 2010 a 2015) e floresta estacional semidecidual (de 2011 a 2015) em Curvelo, Minas Gerais. O inventário florestal considerou amostragens do tipo sistemática em 15 unidades amostrais de 20 × 50 metros no cerrado stricto sensu (CSS), 10 unidades amostrais 20 × 50m no cerradão (CD), CAS ≥ 15,7cm) e 25 unidades amostrais de 10 × 40m na floresta estacional semidecidual (FES - CAP ≥ 15,7 cm). Amostras de solo foram coletadas em todas as unidades amostrais para caracterização química e granulométrica. Nas três fitofisionomias, o número de indivíduos ingressantes foi inferior ao de egressos. No CSS, a área basal no inventário final foi superior à área basal inicial (23,675 - 25,845m2/ha), devido ao incremento expressivo dos sobreviventes. Ocorreram reduções na área basal no CD (19,322 - 17,008 m2/ha) e na FES (28,183 - 28,148 m2/ha), decorrente da alta taxa de mortalidade. Nas três fitofisionomias, a mortalidade foi maior nas primeiras classes diamétricas. De forma lenta, o CSS e CD estão se recuperando pós-distúrbio (fogo), estão surgindo novos indivíduos (recrutas) e crescimento diamétrico dos sobreviventes. Durante o intervalo de 5 anos, não foi possível identificar a recuperação do número de indivíduos, enquanto a FES sem distúrbio do fogo, a perda de indivíduos pela mortalidade e a inclusão de novos indivíduos pelo recrutamento foram mais equilibradas.

Abstract This study aimed to analyze the structural dynamics of tree species and to relate changes with edaphic conditions in the phytophysiognomies of cerrado stricto sensu (from 2010 to 2015), cerradão (from 2010 to 2015) and seasonal semideciduous forest (from 2011 to 2015) in Curvelo, state of Minas Gerais, Brazil. Forest inventories involved systematic sampling in 15 sample units (20 × 50m) in cerrado strict sensu (CSS), 10 sample units (20 × 50m) in cerradão (CD; CAS ≥ 15.7 cm) and 25 sample units (10 × 40m) in semideciduous seasonal forest (SSF; CAP ≥ 15.7 cm). Soil samples were collected in all sample units for the chemical and granulometric characterization. The number of individuals entering was lower than the total recruitment in all phytophysiognomies. Basal area in the final inventory of CSS was higher than initial basal area (23.675 - 25.845m2/ha), due to a significant increase in the surviving individuals. There were reductions in the basal area for DC (19.322 - 17.008 m2/ha) and SSF (28.183 - 28.148 m2/ha), due to high mortality rates. The mortality was higher for the first diametric classes in all three phytophysiognomies. Individual recruitment and diametric growth of survivors during post fire disturbance recovery was slow for CSS and CD. The number of individuals recovering during a 5-year interval could not be determined, however, without fire disturbance, the loss of individuals due to mortality and the recruitment of new individuals in FES were more balanced.

Abstract This study aimed to evaluate the changes in the floristic composition at the Cerrado (Brazilian Savannah) stricto sensu and Cerradão (xeromorphic forest) phytophysiognomies. In the first inventory in 2010, 15 soil plots of 20 × 50 m in the Cerrado stricto sensu (CSS) and 10 soil sample plots of 20 × 50 m in the Cerradão (CD) were separated, and individual samples with diameter at soil height ≥ 5 cm were measured. The second inventory, conducted in 2015, used the same criteria. A fire hit both phytophysiognomies after the first inventory. Species loss and a mortality rate higher than recruitment rate were observed in both phytophysiognomies. Species richness and individual density have been diversified over time. Floristic changes were more intense in CD, with significant alterations between mortality and recruitment rates - the species that disappeared were represented by a few individuals; in the CSS, the changes were not significant.

ABSTRACT Water is considered the most important environmental resource for the germination process. This study aimed to evaluate the germination performance of Parkia platycephala seeds under different conditions of water and saline stress. Seed germination was tested with solutions of poly (ethylene glycol) 6000 and sodium chloride (NaCl) at seven osmotic potentials [0.0, -0.2, -0.4, -0.6, -0.8, -1.0, and -1.2MPa (megapascal)] and four replicates with 25 seeds in a completely randomized design, simulating the water and saline stress levels, respectively. The following seedling variables were evaluated: germination percentage, germination speed index, length, and dry mass. Results showed significant interaction between the agent and the osmotic potential for all evaluated variables. P. platycephala seeds presented higher tolerance to saline stress simulated by NaCl than to water stress, showing germination performance appropriate for glycophyte plants.

RESUMO: Objetivou-se com a realização deste estudo determinar as condições mais adequadas de temperatura e substrato para germinação e desempenho de plântulas de Albizia niopoides. O delineamento utilizado foi o inteiramente casualizado em arranjo fatorial 10x7 (oito temperaturas constantes de 5, 10, 15, 20, 25, 30, 35 e 40°C e duas alternadas 20-30 e 25-35°C e sete substratos: papel tolha, vermiculita, areia, papel mata borrão, pó de coco, bagaço de cana e tropstrato®), com quatro repetições de 25 sementes. Foram analisadas as seguintes variáveis: percentagem de germinação, índice de velocidade de germinação, comprimento de parte aérea e raiz primária e massa seca da parte aérea e do sistema radicular. Houve interação significativa dos fatores testados para as todas as variáveis analisadas. As sementes de A. niopoides germinam em uma ampla faixa de temperatura, com limite mínimo e máximo nas temperaturas de 10 e 40°C, respectivamente. As temperaturas alternadas de 20-30°C e 25-35 °C com o substrato areia são condições ideais para germinação e desempenho de plântulas de A. niopoides.

ABSTRACT: This study aimed to determine the most appropriate conditions of temperature and substrate for germination and performance of A. niopoides seedlings. The design was completely randomized in 10x7 factorial arrangement (eight constant temperatures of 5, 10, 15, 20, 25, 30, 35, and 40°C and two alternating temperatures of 20-30 and 25-35°C, and seven substrates, that are paper towel, vermiculite, sand, blotting paper, coir dust, sugarcane bagasse, and tropstrato®) with four replicates of 25 seeds. The following variables were analyzed: (1) germination percentage; (2) germination speed index; (3) shoot length and primary root; and (4) dry weight of shoot and of root system. There was a significant interaction among the tested factors for all variables. The A. niopoides seeds germinate under a wide temperature range, with minimum and maximum limit at 10 and 40°C temperatures, respectively. Alternating temperatures of 20-30 and 25-35°C with sand substrate are ideal conditions for germination and performance of A. niopoides seedlings.