Contribution to the study of the Taenianthero-Aegilopion geniculatae alliance in Portugal

Abstract

This paper deals with the study of Taeniathero-Aegilopion geniculatae subnitrophilous communities found in the centre and south of Portugal, particularly in abandoned olive groves with vegetal cover. The edaphic and phytosociological study reveals that these pasturelands thrive on neutro-basic soils. In the corresponding dendrogram and in the co-location network, their peculiar floristic composition and, in particular, the co-existence of acidophilous and basophilous species give rise to a cluster of relevés distinctly separated from the rest. Consequently we propose the new Plantagini bellardii-Aegilopetum geniculatae association. It is different from the rest not only because of a number of differential species, but also for ecological reasons. In this respect, the edaphic analysis clearly reveals that all these samples correspond to soils with a pH value equal to or higher than 7, whereas the closest association, Trifolio cherleri-Taenitheretum capitis-medusae, presents a pH record below 7. There are also differences as far as the biogeographical unit and the vegetation series are concerned.