We provide the first comprehensive inventory of the non-native plants on Madagascar since Perrier de la Bâthie's effort 80 years ago, and evaluate the characteristics and importance of this biota. Using botanical databases (especially the Tropicos Catalogue of the Vascular Plants of Madagascar), published plant lists, field observation, and relevant literature, we inventory 546 introduced species that have naturalized, as well as 611 other introduced species that only exist in cultivation. We also list 211 species with unclear status, eight native species that have had different genetic stock introduced, and three endemics that have naturalized outside their native range. Of the naturalized species, 101 display invasive behaviour. Highly represented families include Fabaceae (224 confirmed introduced species), Myrtaceae (143), Poaceae (71), Cactaceae (52), Asteraceae (50), and Solanaceae. (33). Humans have been bringing plants to Madagascar since they colonized the island, mainly for their utility. A number of plants with native varieties but which also have long histories of human use and transport are ripe for further historical biogeographical research (including Eragrostis, Panicum, Sorghum, Dioscorea, Ziziphus, and Adansonia). The introduced flora is similar in composition to other tropical regions; its numerical size appears to confirm that poorer countries experience relatively fewer plant introductions. Madagascar's introduced species deserve more attention, not just through the rubric of invasion biology, but as plants that build new ecologies and that sustain human communities. (Résumé d'auteur

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Abstract:In 1997, a study was initiated by IRD, Bolivia to analyse the dynamics of floods in the Bolivian Amazon, which commonly affect an area of 100 000 to 150 000 km 2 for about 4 months of the year. This region is characterized by vast isolated areas with difficult access and is continuously covered by clouds in the wet season. For these reasons, this hydrological study depends heavily on the use of remote sensing, and particularly radar data, for flood monitoring and the identification of areas at risk of inundation. This article presents preliminary results obtained in the Trinidad area, around the Mamoré River, using LANDSAT, ERS and RADARSAT radar data from dry, wet and flood seasons (collected between 1996 and 1998), and water level and, hydrometeorological data obtained from the upper and lower parts of the Mamoré basin. After characterizing the annual flood cycle within the study area, a TM colour composite (to map the vegetation) and a radar colour composite (multi-temporal), are used to evaluate the potential contribution of microwave data (RADARSAT and ERS) for mapping the extent of flooding at both the regional (all the flood plain) and the local scale (around the city of Trinidad).

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Cet article examine l’émergence de la notion de justice environnementale au niveau local et son articulation avec les politiques globales s’inspirant du développement durable. Ce rapide tour d’horizon montre que les acteurs qui se réclament de la justice environnementale n’emploient pas les mêmes mots, ou alors n’y mettent pas le même sens, et de manière générale s’abstiennent de les définir avec précision. Il s’agit en effet d’une notion plurielle, qui peut être éclairée par les penseurs qui se sont intéressés à l’environnement ou à la nature pour y fonder une éthique, et les théoriciens de la justice sociale. L’application des politiques environnementales « justes » pose un certain nombre de problèmes d’ordre géographique, tels l’identification et la cartographie des injustices, l’articulation des différentes échelles et des acteurs impliqués, et la définition des espaces concernés.

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