22 research outputs found
Interest of the Characeae as bioindicators of water quality: the case of wetlands in Numidia (NE Algeria)
Characeae surveys and water physico-chemical studies have been performed during four years (2007-2011) on 41 wetlands of Numidia (NE Algeria). Among the 12 species inventoried in the region, four are rare in North Africa and one, Nitella batrachosperma, is new for Algeria. Comparison between Characeae communities and phosphate contents shows that (1) Characeae have nearly disappeared from habitats that contain high levels of orthophosphates (> 780 ÎŒg.l-1), (2) three species of Chara (C. globularis, C. gymnophylla and C. vulgaris) characterize medium-polluted habitats (213-780 ÎŒg.l-1), where they are often present as discontinuous populations, and (3) the Nitella (N. opaca and N. translucens) are good indicators of low water pollution ( 780 ÎŒg.l-1), (2) trois espĂšces de Chara (C. globularis, C. gymnophylla et C. vulgaris) caractĂ©risent les milieux moyennement polluĂ©s (213-780 ÎŒg.l-1) oĂč elles sont souvent prĂ©sentes sous forme de populations discontinues et (3) les Nitella (N. opaca et N. translucens) sont de bons indicateurs de faible pollution de lâeau (< 70 ÎŒg.l-1). En complĂ©ment de la simple prĂ©sence dâune espĂšce, lâĂ©tat physiologique des plantes est Ă prendre en considĂ©ration pour indiquer une population saine
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
Recent discovery of the small pillwort (<i>Pilularia minuta</i> Durieu, Marsileaceae) in Tunisia: Hope for an endangered emblematic species of Mediterranean temporary pools?
A AVALIAĂĂO DAS APRENDIZAGENS NA FORMAĂĂO INICIAL DE PROFESSORES: DISCURSOS DE PROFESSORES/FORMADORES
Dynamique de la végétation de mares temporaires en Afrique du Nord (Numidie orientale, NE Algérie)
The temporary ponds have been less studied in Northern Africa than in Mediterranean Europe. Moreover, no study is devoted to the ecology of these ponds in Numidia (North-Eastern Algeria). Thus to fill this gap, we have surveyed 26 temporary ponds and we have examinated the fluctuations of plant assemblages and hydrology. These samples were performed monthly (nine months) during the hydroperiod and along three annual cycles (1998-2001). The studied ponds are distributed along two transects of 90 km. We obtain a table of 539 relevés and 136 plant taxa. This table was submitted to an ACP and then to a Discrimin : Between analysis. This analysis allows to distinguish temporal and spatial effects : the first describes the succession of taxa, and the second the typology of ponds. Our results show that the temporal effect conveyied two periods (summer-autumn and winter-spring) with respectively Panicum repens and Ranunculus baudotii. The spatial effect permits to divide the twenty-six temporary ponds into three groups : group 1, Characeae and Juncus acutus ; group 2,
Callitriche obtusangula and Isoetes velata subsp. typica ; group 3,
C. obtusangula and Alisma plantago-aquatica.
An appendix includes a detailed description of these 26 temporary ponds, with some data related to plant richness and a focus about the most outstanding biogeographic elements present within the «afrotropical relict pocket » .La dynamique Ă©cologique des milieux endorĂ©iques temporaires mĂ©diterranĂ©ens a Ă©tĂ© peu Ă©tudiĂ©e en Afrique du Nord, et jamais en Numidie (NE algĂ©rien). Dans cette rĂ©gion, 26 mares temporaires ont fait lâobjet de suivis phytoĂ©cologiques et hydrologiques et la vĂ©gĂ©tation a Ă©tĂ© systĂ©matiquement Ă©chantillonnĂ©e chaque mois durant lâhydropĂ©riode, au cours de trois cycles annuels (1998-2001). Les stations Ă©tudiĂ©es sont distribuĂ©es le long de deux transects de 90 km environ. Une analyse inter-classes a Ă©tĂ© appliquĂ©e sur un tableau rassemblant 539 relevĂ©s et 136 espĂšces vĂ©gĂ©tales. Cette analyse a pour but de sĂ©parer deux effets, lâun temporel qui permet de dĂ©crire la succession des espĂšces, lâautre spatial qui est relatif Ă la typologie stationnelle. Les rĂ©sultats permettent de distinguer nettement deux pĂ©riodes dans lâannĂ©e (Ă©tĂ©/ automne et hiver/ printemps), dĂ©finies notamment par la prĂ©sence de Panicum repens dâune part et de Ranunculus baudotii dâautre part. La typologie aboutit Ă dĂ©finir trois groupes parmi les mares, dĂ©terminĂ©s successivement par : groupe 1, Characeae et Juncus acutus ; groupe 2, Callitriche obtusangula et Isoetes velata subsp. typica ; groupe 3, C. obtusangula et Alisma plantago-aquatica.
Une annexe comporte une description dĂ©taillĂ©e des 26 hydrosystĂšmes de mares temporaires et permet dâen percevoir la richesse floristique, incluant la prĂ©sence remarquable dâun Ă©lĂ©ment original reprĂ©sentatif dâune «poche relictuelle afrotropicale » .BĂ©lair GĂ©rard de. Dynamique de la vĂ©gĂ©tation de mares temporaires en Afrique du Nord (Numidie orientale, NE AlgĂ©rie). In: Ecologia mediterranea, tome 31,2005. pp. 83-100
Structure spatiale et statut dynamique dans une communauté végétale: cas d'une cocciféraie dunaire (Annaba, Algérie).
The quantity and the presence of thirty-six species are registred on a 4 kms transect in a dunary bush of the Kermes Oak (Annaba Algeria) . The spatial patterns are described and interpreted according to the series of degradation of the Kermes Oak and of the Oleo-Lentisc. The vegetal carpet appears to be structured by a superposition of scales of dynamic stages and mosaics or superpositions of ecologie associations . The article emphasizes the part that can be played by the description of the vegetal patterns in the interpretation of the contents of a floristic list.L'abondance et la prĂ©sence de trente-six espĂšces sont enregistrĂ©es sur un transect de 4 km dans une coccifĂ©raie dunaire (Annaba AlgĂ©rie). Les structures spatiales sont dĂ©crites et interprĂ©tĂ©es en fonction des sĂ©ries de dĂ©gradation du ChĂȘne KermĂšs et de l'OlĂ©o-Lentisque. Le tapis vĂ©gĂ©tal apparaĂźt structurĂ© par une superposition dâ Ă©cailles de stades dynamiques et de mosaĂŻques ou de superpositions de groupes Ă©cologiques. L'article souligne le rĂŽle que peut jouer la description des structures vĂ©gĂ©tales dans l'interprĂ©tation du contenu d'une liste floristique.Belair G. De, Chessel Daniel, Bencheikh-Lehocine M. Structure spatiale et statut dynamique dans une communautĂ© vĂ©gĂ©tale: cas d'une coccifĂ©raie dunaire (Annaba, AlgĂ©rie).. In: Ecologia mediterranea, tome 10 n°1-2, 1984. pp. 261-270
Contribution à la connaissance des orchidées de l'AurÚs (N.-E. de l'Algérie) : inventaire, cartographie, taxinomie et écologie
International audienceFrom various flora and vegetation studies of the AurĂšs Massif (northeast of Algeria), the orchids have been the subject of a specific inventory coupled with a phytoecological survey. After fourteen years, only nine species in fifteen localities have been recorded, including following taxa: Cephalanthera longifolia, Epipactis helleborine, Himanthoglossum hircinum subsp. hircinum, Ophrys luteasubsp. lutea, Ophrys scolopax subsp. apiformis, Ophrys subfusca subsp. subfusca, Ophrys tenthredinifera subsp. ficalhoana, Orchis olbiensis, Orchis purpurea subsp. purpurea. In addition to those ones, other species are reported in the literature in this massif or in the nearby massif of Belezma. These observations allowed us to confirm the taxonomy of some taxa which are still confused in the recent literature. The multidimensional analyses have revealed the station typology and some environmental variables that determine the distribution of these species in this region. Due to the alarming vulnerability of these sites and the threats, especially anthropogenic, to which they are subjected, a reflection to protect the habitats and their hosts seems to be urgent.Ă lâoccasion de diverses Ă©tudes de la flore et de la vĂ©gtation du assif de lâAurĂšs (N.-E. de lâAlgĂ©rie), les orchidĂ©es ont fait lâobjet dâun inventaire spĂ©cifique accompagnĂ© de relevĂ©s phytoĂ©ologiques conjoints. En quatorze annĂ©es, seulement neuf taxons rĂ©partis sur quinze localitĂ©s ont Ă©tĂ© inventoriĂ©s : Cephalnthera ongiflia, Epipactis helleborine, Himanthoglossum hircinum subsp. hircinum, Ophrys lutea subsp. lutea, Ophrys scolpax subp. apiformis, Ophrys subfusca subsp. subfusca, Ophrys tenthredinifera subsp. ficalhoana, Orchis olbiensis, Orchis purprea subp. purpurea. A ceux-ci sâajoutent dâautres espĂšces signalĂ©es dans la littĂ©rature pour ce mĂȘme massif ou dans le massif voisin de Belezma. Ces observations nous ont permis de confirmer la taxinomie de certains taxons qui demeurait assez couse dans la littĂ©rature rĂ©cente. Des analyses multidimensionnelles ont mis en Ă©vidence, dâune part la typologie des stations et dâautre art certaines variables environnementales dĂ©terminant la distribution de ces espĂšces dans cette rĂ©gion. En raison de la vulnĂ©rabilitĂ© alarante des sites visitĂ©s et des menaces, notamment anthropiques, auxquelles ils sont soumis, une rĂ©flexion sur la protecion des habitats et de leurs hĂŽtes apparaĂźt urgent
Contribution a la connaissance des orchidĂ©es de lâAurĂšs (N.-E. de lâAlgĂ©rie) : inventaire, cartographie, taxinomie et Ă©cologie
A contribution to the knowledge of orchids in the AurĂšs (N.-E. Algeria) : inventory, cartography, taxonomy and ecology.
From various flora and vegetation studies of the AurĂšs Massif (northeast of Algeria), the orchids have been the subject of a specific inventory coupled with a phytoecological survey. After fourteen years, only nine species in fifteen localities have been recorded, including following taxa : Cephalanthera longifolia, Epipactis helleborine, Himanthoglossum hircinum subsp. hircinum, Ophrys lutea subsp. lutea, Ophrys scolopax subsp. apiformis, Ophrys subfusca subsp. subfusca, Ophrys tenthredinifera subsp. ficalhoana, Orchis olbiensis, Orchis purpurea subsp. purpurea. In addition to those ones, other species are reported in the literature in this massif or in the nearby massif of Belezma. These observations allowed us to confirm the taxonomy of some taxa which are still confused in the recent literature. The multidimensional analyses have revealed the station typology and some environmental variables that determine the distribution of these species in this region. Due to the alarming vulnerability of these sites and the threats, especially anthropogenic, to which they are subjected, a reflection to protect the habitats and their hosts seems to be urgent.Ă lâoccasion de diverses Ă©tudes de la flore et de la vĂ©gĂ©tation du massif de lâAurĂšs (N.-E. de lâAlgĂ©rie), les orchidĂ©es ont fait lâobjet dâun inventaire spĂ©cifique accompagnĂ© de relevĂ©s phytoĂ©cologiques conjoints. En quatorze annĂ©es, seulement neuf taxons rĂ©partis sur quinze localitĂ©s ont Ă©tĂ© inventoriĂ©s : Cephalanthera longifolia, Epipactis helleborine, Himanthoglossum hircinum subsp. hircinum, Ophrys lutea subsp. lutea, Ophrys scolopax subsp. apiformis, Ophrys subfusca subsp. subfusca, Ophrys tenthredinifera subsp. ficalhoana, Orchis olbiensis, Orchis purpurea subsp. purpurea. A ceux-ci sâajoutent dâautres espĂšces signalĂ©es dans la littĂ©rature pour ce mĂȘme massif ou dans le massif voisin de Belezma. Ces observations nous ont permis de confirmer la taxinomie de certains taxons qui demeurait assez confuse dans la littĂ©rature rĂ©cente. Des analyses multidimensionnelles ont mis en Ă©vidence, dâune part la typologie des stations et dâautre part certaines variables environnementales dĂ©terminant la distribution de ces espĂšces dans cette rĂ©gion. En raison de la vulnĂ©rabilitĂ© alarmante des sites visitĂ©s et des menaces, notamment anthropiques, auxquelles ils sont soumis, une rĂ©flexion sur la protection des habitats et de leurs hĂŽtes apparaĂźt urgente.Beghami Yassine, VĂ©la Errol, BĂ©lair GĂ©rard de, Thinon Michel. Contribution a la connaissance des orchidĂ©es de lâAurĂšs (N.-E. de lâAlgĂ©rie) : inventaire, cartographie, taxinomie et Ă©cologie. In: Revue d'Ăcologie (La Terre et La Vie), tome 70, n°4, 2015. pp. 354-370
Menaces et conservation des zones humides dâAfrique du Nord : le cas du site Ramsar de Beni-Belaid (NE algĂ©rien)
New station of Pteris vittata L.(Pteridaceae) in Numidia (Eastern Algeria)
Les auteurs signalent une observation de Pteris vittata L. dans la Numidie algérienne. Cette découverte permet de faire le point sur sa répartition en Algérie