Abstract

DUARTE, Maria Cristina; AGUIAR, Francisca Constança; FERREIRA, Maria Teresa  and  ALBUQUERQUE, António. It is Possible for the Vegetation of the Marginal Galleries to Reflect the Resultant Disturbances of Human Activities? . Silva Lus. [online]. 2007, vol.15, n.2, pp.257-276. ISSN 0870-6352.

We explored the relations between species traits (e.g. life span, body architecture, dispersal mode) and community traits (e.g. floristic richness, number of vegetation strata), and human-disturbance in Mediterranean-type rivers. Two hundred and five floristic surveys were undertaken in 100-metres river stretches of Central and South Portugal (Western Iberia). Disturbance related variables were estimated for each site, using a five degree-scale, from no obvious alterations to highly impacted. We used taxonomical, functional and biological traits of the surveyed species, and community traits that might indicate the ecosystem's structure and naturalness. Potential relationships between community and species traits and the disturbance variables were analysed using Spearman's Correlation. In general, the life span, the type of vegetative reproduction, the taxonomic class, and the woodiness were the most responsive species traits to disturbance. This study also showed that native and exotic components of the flora displayed opposing responses to disturbance, exception made to the river connectivity. The hydrological regime, the acidification/toxicity, the nutrient inputs, the river morphology, the global habitat quality and the land-use impact positively affected the exotic flora, and negatively the native flora. The results highlighted the potential of species and community traits for the bioassessment of river integrity.

Keywords : species traits; community traits; exotic species; flora; rivers; Central and South Portugal.

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