Evaluation of roe deer effects upon forest structure in Nogueira Mountain (NE of Portugal)

Abstract

Analytical methodologies that describe ecological functionalities in the landscape are decisive to quantify the effects of their apparent modifications. When dealing with game resource management it is necessary to understand how landscape variables respond to changes in the abundance of particular species. The main goal of the present work is to evaluate how a forest ecosystem reacts to an increment of roe deer ( Capreolus capreolus L.) abundance in a reproduction enclosure. This experience has been developed in the Nogueira Mountains (Tras-os-Montes, NE of Portugal), where a relict nucleus of roe deer persists. In order to promote a roe deer increment, a 15 ha enclosure was installed eight years ago in a natural forest of Quercus pyrenaica. The methodology presently proposed is based on a phytostructural approach, where structural basic matrices of vegetation diversity, abundance and cover, obtained from 10 x 10 m sampling areas along two transepts (inside and outside the enclosure) are resumed in a contingency structural matrix. This contingency matrix is characterised according to a set of multivariate statistical analysis (Principal Component Analysis, Discriminant Canonical Analysis, ANOVAs) and results are correlated with roe deer food preferences (previously typified in four classes according to selectivity). The present results emphasised the roe deer’s capacity to transform the structural organization of the vegetation and therefore, the methodology used is a functional tool to describe landscape changes processes promoted by ungulates.