10 research outputs found
Bellis prostrata Pomel (Asteraceae), a new species for Morocco
Investigations conducted in temporary
wetlands of the coastal Meseta of W Morocco
(Benslimane region) lead to the discovery of
Bellis prostrata in a small endoreic temporary
pool (ca. 1 ha) of the quartzitic-limestone
plateau of Benslimane
Short and long term dynamics of Mediterranean temporary pool (Morocco occidental) and implication for conservation
La conservation des mares temporaires implique la connaissance, à la fois de leur fonctionnement et de leurs dynamiques temporelles, à court et long terme. La thèse, réalisée sur une mare temporaire du plateau gréso-quartzitique de Benslimane, s'organise en trois volets. (1) Le premier concerne la relation entre le pollen de surface et la végétation hydrophytique locale, dans le but d'établir un référentiel actuel pour l'étude paléoécologique de la mare. Les résultats obtenus montrent que la zonation de la végétation de la mare est correctement reconstruite à partir des enregistrements polliniques. Trois taxons clés (Isoetes velata-type, Myriophyllum alterniflorum, Ranunculus-type) peuvent être utilisés pour reconstituer la structure végétale passée. (2) Le second volet concerne l'histoire de la mare, en associant les données de la littérature et les données paléoécologiques obtenues à partir d'un sondage. Les résultats permettent de dater l'origine de la mare entre 1 million et 700 000 ans avant aujourd'hui. Ils témoignent de la conservation de la topographie régionale, par bilan sédimentaire négatif, jusqu'à environ 5000 cal. BP. A cette époque, le changement du fonctionnement morphogénétique de la mare, probablement lié au développement des pratiques agro-pastorales, a entraîné le comblement progressif de la mare. L'intensification des activités humaines constitue à moyen terme la principale menace concernant les mares du plateau de Benslimane, et par voie de conséquence, sur la préservation du plateau lui-même, que les mares protègent de l'érosion. (3) Le dernier volet apporte enfin un éclairage sur les processus mis en jeu dans la régénération de la végétation après micro-perturbations. Les résultats montrent une restauration rapide des microsites perturbés par dispersion proximale et effet de bordure. Toutefois, la dynamique de recolonisation reste liée aux conditions hydrologiques localesConservation of temporary pools implies the knowledge, about both their functioning and their temporal dynamics, on the short and the long term. The thesis, dealing with a temporary pool of the limestone-quartzite Benslimane plateau, is organised in three sections. (1) The first one concerns the relationship between the surface pollen and the hydrophytic vegetation, in order to establish a modern reference for the paleoecological study of the pool. The results show that the vegetation zonation is correctly reconstructed from the pollen records. Three key taxa (Isoetes velata-type, Myriophyllum alterniflorum, Ranunculus-type) may be used for reconstructing the past vegetation structure. (2) The second section deals with the pool history, by combining data from literature and palaeoecological data obtained from a sediment profile. Results allow dating the origin of the pool between 1 million and 700,000 years before today. They attest the conserv ation of the regional topography, by negative sedimentary balance, until ca. 5000 cal. BP. Then, the change of morphogenetic functioning of the pool, probably related to the development of agro-pastoral practices, resulted in the progressive filling of the pool. In the medium term, the intensification of human activities constitutes the main threat concerning the Benslimane pools, and consequently, on the conservation of the whole plateau, protected from erosion by pools. (3) The last section finally highlights the processes implied in the regeneration of the vegetation after micro-disturbances. The results show a fast restoration of the disturbed microsites by proximal dispersal and border effect. However, the recolonisation dynamics remains dependent on local hydrological conditions
Dynamiques temporelles à court et long terme dune mare temporaire méditerranéenne et implications pour la conservation (Maroc occidental)
La conservation des mares temporaires implique la connaissance, à la fois de leur fonctionnement et de leurs dynamiques temporelles, à court et long terme. La thèse, réalisée sur une mare temporaire du plateau gréso-quartzitique de Benslimane, s'organise en trois volets. (1) Le premier concerne la relation entre le pollen de surface et la végétation hydrophytique locale, dans le but d'établir un référentiel actuel pour l'étude paléoécologique de la mare. Les résultats obtenus montrent que la zonation de la végétation de la mare est correctement reconstruite à partir des enregistrements polliniques. Trois taxons clés (Isoetes velata-type, Myriophyllum alterniflorum, Ranunculus-type) peuvent être utilisés pour reconstituer la structure végétale passée. (2) Le second volet concerne l'histoire de la mare, en associant les données de la littérature et les données paléoécologiques obtenues à partir d'un sondage. Les résultats permettent de dater l'origine de la mare entre 1 million et 700 000 ans avant aujourd'hui. Ils témoignent de la conservation de la topographie régionale, par bilan sédimentaire négatif, jusqu'à environ 5000 cal. BP. A cette époque, le changement du fonctionnement morphogénétique de la mare, probablement lié au développement des pratiques agro-pastorales, a entraîné le comblement progressif de la mare. L'intensification des activités humaines constitue à moyen terme la principale menace concernant les mares du plateau de Benslimane, et par voie de conséquence, sur la préservation du plateau lui-même, que les mares protègent de l'érosion. (3) Le dernier volet apporte enfin un éclairage sur les processus mis en jeu dans la régénération de la végétation après micro-perturbations. Les résultats montrent une restauration rapide des microsites perturbés par dispersion proximale et effet de bordure. Toutefois, la dynamique de recolonisation reste liée aux conditions hydrologiques localesConservation of temporary pools implies the knowledge, about both their functioning and their temporal dynamics, on the short and the long term. The thesis, dealing with a temporary pool of the limestone-quartzite Benslimane plateau, is organised in three sections. (1) The first one concerns the relationship between the surface pollen and the hydrophytic vegetation, in order to establish a modern reference for the paleoecological study of the pool. The results show that the vegetation zonation is correctly reconstructed from the pollen records. Three key taxa (Isoetes velata-type, Myriophyllum alterniflorum, Ranunculus-type) may be used for reconstructing the past vegetation structure. (2) The second section deals with the pool history, by combining data from literature and palaeoecological data obtained from a sediment profile. Results allow dating the origin of the pool between 1 million and 700,000 years before today. They attest the conserv ation of the regional topography, by negative sedimentary balance, until ca. 5000 cal. BP. Then, the change of morphogenetic functioning of the pool, probably related to the development of agro-pastoral practices, resulted in the progressive filling of the pool. In the medium term, the intensification of human activities constitutes the main threat concerning the Benslimane pools, and consequently, on the conservation of the whole plateau, protected from erosion by pools. (3) The last section finally highlights the processes implied in the regeneration of the vegetation after micro-disturbances. The results show a fast restoration of the disturbed microsites by proximal dispersal and border effect. However, the recolonisation dynamics remains dependent on local hydrological conditions.MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF
Our System IDCBR-MAS: from the Modelisation by AUML to the Implementation under JADE Platform
This paper presents our work in the field of
Intelligent Tutoring System (ITS), in fact there is still the problem
of knowing how to ensure an individualized and continuous
learners follow-up during learning process, indeed among the
numerous methods proposed, very few systems concentrate on a
real time learners follow-up. Our work in this field develops the
design and implementation of a Multi-Agents System Based on
Dynamic Case Based Reasoning which can initiate learning and
provide an individualized follow-up of learner. This approach
involves 1) the use of Dynamic Case Based Reasoning to retrieve
the past experiences that are similar to the learner�s traces (traces
in progress), and 2) the use of Multi-Agents System. Our Work
focuses on the use of the learner traces. When interacting with the
platform, every learner leaves his/her traces on the machine. The
traces are stored in database, this operation enriches collective
past experiences. The traces left by the learner during the
learning session evolve dynamically over time; the case-based
reasoning must take into account this evolution in an incremental
way. In other words, we do not consider each evolution of the
traces as a new target, so the use of classical cycle Case Based
reasoning in this case is insufficient and inadequate. In order to
solve this problem, we propose a dynamic retrieving method
based on a complementary similarity measure, named Inverse
Longest Common Sub-Sequence (ILCSS). Through monitoring,
comparing and analyzing these traces, the system keeps a
constant intelligent watch on the platform, and therefore it
detects the difficulties hindering progress, and it avoids possible
dropping out. The system can support any learning subject. To
help and guide the learner, the system is equipped with combined
virtual and human tutors
Unravelling the impact of anthropogenic pressure on plant communities in Mediterranean temporary ponds
International audienceIdentifying the respective role of environmental, landscape and management factors in explaining the patternsin community composition is an important goal in ecology. Using a set of 32 temporary ponds in northern Morocco westudied the respective importance of local (within the pond) and regional (density of ponds in landscape) factors and theimpacts of different land uses on the plant species assemblages, separating pond and terrestrial species. The mainhypotheses tested were that (1) species assemblages respond to both local and regional environmental factors, (2)anthropogenic pressure has a negative influence on the number of pond species, and that (3) human activities differ in theirimpact on pond biodiversity. The results showed that (1) local factors explain most of the variation in plant communitycomposition, and (2) land use impacts the communities through changing local environmental conditions, leading to a lossof typical pond species. Aside from recreation, all other activities (grazing, drainage, agriculture and partial urbanisation)significantly reduced the number of pond species. The conservation strategy for rare pond species should focus onmaintaining networks of oligotrophic ponds, while allowing only low-impact activities
Bellis prostrata Pomel (Asteraceae), a new species for Morocco. Contribuciones a la flora vascular de Marruecos: Bellis prostrata Pomel (Asteraceae), una nueva especie para Marruecos
Bellis prostrata Pomel (Asteraceae), una nueva especie para Marruecos Key words.North Africa, endemic species, conservation, temporary wetland. Palabras clave. Norte de África, especie endémica, conservación, humedales temporales