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Um novo sesquiterpeno, aromadendrano-4β,10α,15-triol, foi isolado das folhas de Xylopia brasiliensis Spreng (Annonaceae), juntamente com quatro derivados de esqueleto aromadendrano e três esteróides. As estruturas dos metabólitos foram definidas por meio da análise dos respectivos espectros de RMN, incluindo experimentos bidimensionais, além de espectrometria de massas. Os sesquiterpenos aromadendranos diidroxilados apresentaram atividade antifúngica frente a Cladosporium cladosporioides.A new sesquiterpenoid, aromadendrane-4β,10α,15-triol, was isolated from the leaves of Xylopia brasiliensis Spreng (Annonaceae), together with four known aromadendrane derivatives and three steroids. The structures of these compounds were defined by analysis of their NMR spectral data, including bidimensional analysis, and mass spectrometry. The isolated aromadendranediol derivatives showed antifungal activity against Cladosporium cladosporioides.

Plant species richness in the Cape Verde archipelago is examined relative to island eco-geographical factors. Species-area and species-area-habitat relationships are analysed using the classical species-area model and the recently proposed species-choros model. The number of Xoristic zones (used to estimate the choros parameter) provides an adequate estimate of the potential habitat diversity, and the species-choros model achieved a better Wt with both total Xora and endemic species. In addition to area and habitat diversity, longitude also emerges as an important determinant of species diversity, whereas latitude, minimum distance to the nearest island, and total rural population do not display any correlation. As in other insular ecosystems, the species richness (about 140 per 100 km 2 ) is lower than in nearby mainland regions; the proximity to the desert areas of the Sahel can also be seen as related with this low value. The Xoristic heterogeneity in Cape Verde is high, as is usual in island ecosystems. In a comparative analysis of the species richness on the diVerent islands (using -values), Brava stands out as having the highest total Xora species densities, while for endemic Xora Brava and São Nicolau jointly occupy the leading position. The high diversity for both total and endemic species on Santo Antão, São Vicente, São Nicolau, Fogo and Brava reinforces their importance in conservation terms -in the case of most of them, something that is already recognized in the established network of protected areas.

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Channelization is often a major cause of human impacts on river systems. It affects both hydrogeomorphic features and habitat characteristics and potentially impacts riverine flora and fauna. Human-disturbed fluvial ecosystems also appear to be particularly vulnerable to exotic plant establishment. Following a 12-year recovery period, the distribution, composition and cover of both exotic and native plant species were studied along a Portuguese lowland river segment, which had been subjected to resectioning, straightening and two-stage bank reinforcement, and were compared with those of a nearby, less impacted segment. The species distribution was also related to environmental data. Species richness and floristic composition in the channelized river segment were found to be similar to those at the more 'natural' river sites. Floral differences were primarily consistent with the dominance of cover by certain species. However, there were significant differences in exotic and native species richness and cover between the 'natural' corridor and the channelized segment, which was more susceptible to invasion by exotic perennial taxa, such as Eryngium pandanifolium, Paspalum paspalodes, Tradescantia fluminensis and Acacia dealbata. Factorial and canonical correspondence analyses revealed considerable patchiness in the distribution of species assemblages. The latter were associated with small differences in substrate composition and their own relative position across the banks and along the river segments in question. Data was also subjected to an unweighted pair-group arithmetic average clustering, and the Indicator Value methodology was applied to selected cluster noda in order to obtain significant indicator species.

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