RICHNESS, A RESPONSE VARIABLE OF THE VEGETATION TO THE BUFFEL GRASS INTRODUCTION

Abstract

This study intends to know the effect of the Buffel (Cenchrus ciliaris L.) grass introduction on the behaviour of richness, as a response variable of vegetation specially in relation to two ecological process: a) Buffel grass? invasion and b) its establishment. Other factors, as kind and intensity of grazing, and kind and age of land clearing, were also under consideration. A direct gradient approach using ordination through Canonical Correspondence Analysis (CCA) was used. The results show the presence of two trends: 1) Buffel invasion reduces richness through the increment of plant cover; and 2) Moderate rather than light or heavy grazing increases richness. Since richness relates to vegetation dynamics it can be considered as a structural atribute of vegetation that can be used effectively as a response variable of it to the invasion and establishment of Buffel, land clearing and grazing besides showing the dynamic of vegetation.