Competição por água em ambientes sazonalmente secos: conservadorismo filogenético ou convergência de estratégias fisiológicas?

Abstract

Over time, ecologists have attributed the maintenance of biological diversity to the stabilizing mechanisms of niche differences. Functional similarity promotes competition by reducing niche differences and is often associated with phylogenetic conservatism. Although it is a common hypothesis, there is evidence that the sharing of functional characteristics due to phylogenetic proximity is not consensus. In this context, we investigate whether evolutionary kinship influences water competition or whether there is a divergence of physiological strategies related to water use. For this, we measured morphological, physiological and hydraulic characteristics to determine if there is phylogenetic conservatism and what strategies of resistance to drought. Among the 11 functional characteristics analysed, similar species of the same taxon exhibited 7 equal, while the congenital pair of distinct taxa had 5 and the Co-familiar pair 3 had the same characteristics. Our results indicate that evolutionary kinship was not responsible for the conservatism of functional characteristics. Although functional similarity is greater in pairs of more related species, negative interactions (competition) were not necessarily influenced only by functional similarity. In addition, the strategies associated with drought were observed, using two main characteristics, the iso / anisohydric paradigm and πTLP. These traits provided evidence that the competition process occurs mainly due to divergence of water use strategies.