Quelques aspects floristiques et pédologiques de l’incidence écologique des reboisements du mont Ventoux

Work was carried out on the southern slopes of the mountain in four forest types ( Quercus ilex ; Q. pubescens ; Cedrus atlan- tica ; Pinus nigra ssp. austriaca) . Renewal of the forest cover reduces the Mediterranean nature of the environment, so that mesophytic species increase their range horizontally or down wards at the expense of previously established xerophytic species. This ultimately leads to a change in the vegetation series. The soils are all rendzinas, and show different responses to the four forest types. Q. pubescens is the most effective at improving the soil and increasing the humus content ; P. nigra on the other hand produces a humus rich in lignin which gives rise to a very acid mor humus and instigates degradation of the soil. The effects of Q. ilex and C. atlantica are intermediate between these two

A contribution to the knowledge of orchids in the Aurès (N.-E. Algeria): inventory, cartography, taxonomy and ecology

À l’occasion de diverses études de la flore et de la végétation du massif de l’Aurès (N.-E. de l’Algérie), les orchidées ont fait l’objet d’un inventaire spécifique accompagné de relevés phytoécologiques conjoints. En quatorze années, seulement neuf taxons répartis sur quinze localités ont été inventoriés : 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 s’ajoutent d’autres espèces signalées dans la littérature pour ce même 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 littérature récente. Des analyses multidimensionnelles ont mis en évidence, d’une part la typologie des stations et d’autre part certaines variables environnementales déterminant la distribution de ces espèces dans cette région. En raison de la vulnérabilité alarmante des sites visités et des menaces, notamment anthropiques, auxquelles ils sont soumis, une réflexion sur la protection des habitats et de leurs hôtes apparaît urgente.From various flora and vegetation studies of the Aurès 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

Michel Thinon, L’analyse pédoanthracologique : aspects méthodologiques et applications / Pedoanthracology - Methodological aspects and applications. Thèse de Doctorat en Sciences (spécialité Ecologie) soutenue le 4 juin 1992 à l’Université d’Aix-Marseille III

Thinon Michel. Michel Thinon, L’analyse pédoanthracologique : aspects méthodologiques et applications / Pedoanthracology - Methodological aspects and applications. Thèse de Doctorat en Sciences (spécialité Ecologie) soutenue le 4 juin 1992 à l’Université d’Aix-Marseille III. In: Ecologia mediterranea, tome 17,1991. p. 178

L'analyse pedoanthracologique - Aspects methodologiques et applications

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : TD 20537; TD 20537 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Quelques aspects floristiques et pédologiques de l’incidence écologique des reboisements du Mont Ventoux

Work was carried out on the southern slopes of the mountain in four forest types (Quercus ilex ; Q. pubescens ; Cedrus atlan-tica ; Pinus nigra ssp. austriaca) . Renewal of the forest cover reduces the Mediterranean nature of the environment, so that mesophytic species increase their range horizontally or downwards at the expense of previously established xerophytic species. This ultimately leads to a change in the vegetation series. The soils are all rendzinas, and show different responses to the four forest types. Q. pubescens is the most effective at improving the soil and increasing the humus content ; P. nigra on the other hand produces a humus rich in lignin which gives rise to a very acid mor humus and instigates degradation of the soil. The effects of Q. ilex and C. atlantica are intermediate between these two.Thinon Michel. Quelques aspects floristiques et pédologiques de l’incidence écologique des reboisements du Mont Ventoux. In: La Terre et La Vie. Supplément n°1, 1978. Écologie du Mont Ventoux, sud de la France. pp. 67-109

V - Etude du matériel anthracologique [Les sondages Ib-Nord des Baou de Saint- Marcel à Marseille]

Thinon Michel. V - Etude du matériel anthracologique [Les sondages Ib-Nord des Baou de Saint- Marcel à Marseille]. In: Documents d'Archéologie Méridionale, vol. 3, 1980. pp. 93-94

Michel Thinon, L’analyse pédoanthracologique : aspects méthodologiques et applications / Pedoanthracology - Methodological aspects and applications. Thèse de Doctorat en Sciences (spécialité Ecologie) soutenue le 4 juin 1992 à l’Université d’Aix-Marseille III

Thinon Michel. Michel Thinon, L’analyse pédoanthracologique : aspects méthodologiques et applications / Pedoanthracology - Methodological aspects and applications. Thèse de Doctorat en Sciences (spécialité Ecologie) soutenue le 4 juin 1992 à l’Université d’Aix-Marseille III. In: Ecologia mediterranea, tome 17,1991. p. 178

Calcite crystals, starch grains aggregates or... POCC? Comment on 'calcite crystals inside archaeologial plant tissues'

International audienceThe microscopic objects presented by F.O. Freitas and P.S. Martins as ‘recrystallized calcite crystals’ and ‘starch grain aggregates’ are both compound crystals, end products of the transformation of plant calcium oxalate crystals into calcite in wood fires. These calcareous silty particles are the major component of the wood ashes familiar to archaeologists. Petrographic microscope remains the more efficient tool for this kind of research

Calcite crystals, starch grains aggregates or... POCC? Comment on 'calcite crystals inside archaeologial plant tissues'

International audienceThe microscopic objects presented by F.O. Freitas and P.S. Martins as ‘recrystallized calcite crystals’ and ‘starch grain aggregates’ are both compound crystals, end products of the transformation of plant calcium oxalate crystals into calcite in wood fires. These calcareous silty particles are the major component of the wood ashes familiar to archaeologists. Petrographic microscope remains the more efficient tool for this kind of research