SPECIES-ENVIRONMENT INTERACTIONS IN THE COLONIZATION OF A GULLY IN ITUMIRIM, MINAS GERAIS

Abstract

This work aimed to identify and evaluate the structure of regenerating species in a gully of Itumirim, MG (21º16’S and 44º50’W) and to verify the influence of edaphic factors on the distribution and occurrence of species. The gully in question covers an area of 0.9 ha and was divided into three sections, namely ‘A’, ‘B’ and ‘C’ arms. For the structural survey of vegetation the needle method was used, whereby 574 points systematically distributed across the three arms were sampled. Each point was stratified on the terrain as a function of a topographic gradient. In order to obtain environmental variables (physicochemical analysis, soil moisture and compaction), 119 soil collection points were defined, parallel with the transects of the structural survey. A prevalence of soils/sediments with high sand content and low fertility was observed in all three arms. Overall, species ordination in the gully through CCA showed that species in the ‘grass-like’ group tend to be more abundant in low, humid, relatively more fertile areas, whereas species in the ‘fern’ group tend to be more abundant in higher topographic positions where soil moisture is reduced and compaction increases. The vast majority of shrub and tree life forms failed to present significant correlations with the main environmental variables used in the CCA.