Dynamics of vegetation structure in a fragmented landscape in Minas Gerais, Brazil / Dinâmica da estrutura da vegetação em uma paisagem fragmentada em Minas Gerais, Brasil

Abstract Considering that area and edge effects are the most important factors that lead to landscape changes from the fragmentation of terrestrial communities, the present study aimed to analyze changes in the structure of vegetation classes of a fragmented landscape. The methodology employed was based on a model of patch dynamics for the years between 1979 and 2015. The analysis was performed with quantitative (area, shape and edge effect) and qualitative (low declivity of the terrain, fire resistance and tolerance to variation in light) variables of the classes of vegetation. Processes of retraction and expansion of the vegetation classes were identified, as well as the alteration of the structure of the fragments, which resulted in the intensification of the edge effect.

Resumo Considerando que os efeitos de área e os efeitos de borda são os mais importantes fatores que levam às alterações na paisagem através da fragmentação de comunidades terrestre, o presente estudo teve por objetivo analisar as mudanças em área e estrutura das classes de vegetação de uma paisagem fragmentada. Para tanto, a metodologia foi baseada no modelo de dinâmica de manchas entre os anos de 1979 e 2015 e a análise por meio de variáveis quantitativas (área, formato e efeito de borda) e qualitativas (baixa declividade do terreno, resistência ao fogo e tolerância à variação de luz) das classes de vegetação. O presente estudo identificou processos de retração e expansão das classes de vegetação e a alteração na estrutura dos fragmentos resultando na intensificação do efeito de borda.

Dynamics of vegetation structure in a fragmented landscape in Minas Gerais, Brazil.

Considering that area and edge effects are the most important factors that lead to landscape changes from the fragmentation of terrestrial communities, the present study aimed to analyze changes in the structure of vegetation classes of a fragmented landscape. The methodology employed was based on a model of patch dynamics for the years between 1979 and 2015. The analysis was performed with quantitative (area, shape and edge effect) and qualitative (low declivity of the terrain, fire resistance and tolerance to variation in light) variables of the classes of vegetation. Processes of retraction and expansion of the vegetation classes were identified, as well as the alteration of the structure of the fragments, which resulted in the intensification of the edge effect.

Dynamics of vegetation structure in a fragmented landscape in Minas Gerais, Brazil

Abstract Considering that area and edge effects are the most important factors that lead to landscape changes from the fragmentation of terrestrial communities, the present study aimed to analyze changes in the structure of vegetation classes of a fragmented landscape. The methodology employed was based on a model of patch dynamics for the years between 1979 and 2015. The analysis was performed with quantitative (area, shape and edge effect) and qualitative (low declivity of the terrain, fire resistance and tolerance to variation in light) variables of the classes of vegetation. Processes of retraction and expansion of the vegetation classes were identified, as well as the alteration of the structure of the fragments, which resulted in the intensification of the edge effect.

Resumo Considerando que os efeitos de área e os efeitos de borda são os mais importantes fatores que levam às alterações na paisagem através da fragmentação de comunidades terrestre, o presente estudo teve por objetivo analisar as mudanças em área e estrutura das classes de vegetação de uma paisagem fragmentada. Para tanto, a metodologia foi baseada no modelo de dinâmica de manchas entre os anos de 1979 e 2015 e a análise por meio de variáveis quantitativas (área, formato e efeito de borda) e qualitativas (baixa declividade do terreno, resistência ao fogo e tolerância à variação de luz) das classes de vegetação. O presente estudo identificou processos de retração e expansão das classes de vegetação e a alteração na estrutura dos fragmentos resultando na intensificação do efeito de borda.

Spatial patterns of a tropical tree species growing under an eucalyptus plantation in South-East Brazil.

The objectives of this study were to evaluate the influence of propagules source and the implication of tree size class on the spatial pattern of Xylopia brasiliensis Spreng. individuals growing under the canopy of an experimental plantation of eucalyptus. To this end, all individuals of Xylopia brasiliensis with diameter at soil height (dsh) > 1 cm were mapped in the understory of a 3.16 ha Eucalyptus spp. and Corymbia spp. plantation, located in the municipality of Lavras, SE Brazil. The largest nearby mature tree of X. brasiliensis was considered as the propagules source. Linear regressions were used to assess the influence of the distance of propagules source on the population parameters (density, basal area and height). The spatial pattern of trees was assessed through the Ripley K function. The overall pattern showed that the propagules source distance had strong influence over spatial distribution of trees, mainly the small ones, indicating that the closer the distance from the propagules source, the higher the tree density and the lower the mean tree height. The population showed different spatial distribution patterns according to the spatial scale and diameter class considered. While small trees tended to be aggregated up to around 80 m, the largest individuals were randomly distributed in the area. A plausible explanation for observed patterns might be limited seed rain and intra-population competition.