19 research outputs found

    Fecundity of The Pine Processionary, Thaumetopoea Pityocampa (Denis & SchiffermĂŒller, 1775) In The Case Of Reforestation In Moudjbara (Djelfa - Algeria)

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    A study of the fecundity of female populations of the pine processionary in the Moudjbara reforestation indicates that there are cyclical variations in the reproduction of this species. Descriptive analysis of pine processionary oviposition lengths showed greater significance for oviposition deposited on needles than for oviposition deposited on twigs. A very highly significant difference was noted between the lengths of the egg-laying supports from the Moudjbara reforestation (p=0.0001). The 195 pine processionary oviposition sites revealed a total of 37,272 eggs, with an average of 191 eggs per oviposition site. Analysis of the variance between the various categories of eggs showed a highly significant probability (p=0.0001). Three parasitoids were identified that emerged from oviposits collected at the Moudjbara reforestation site, with rates varying from year to year. T. embryophagum was encountered only sporadically in 2018, 2019 and 2021, with respective percentages not exceeding 2%. For the four pine processionary caterpillar populations studied, B. servadeii appeared to be more abundant than O. pityocampae. The number of B. servadeii adults observed reached 83.91% in 2020. Parasitoid activity was greater on eggs located at the ends of the clutch. It also appears that O. pityocampae mainly parasitizes the upper part of the egg, whereas B. servadeii shows a preference for the lower part

    Relation between site parameters and Aleppo Pine (Pinus halepensis Mill.) dendroecology in Senalba forest area (Djelfa, Algeria)

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    Aleppo Pine (Pinus halepensis Mill.) is a volunteering hardy species, very common in Mediterranean regions. This species has great economical, ecological and social values in Algeria. 120 sample plots were laid out on northern and southern slopes of Senalba forest area (Djelfa) located in a semi-arid region, to investigate the effect of altitude, aspect and soil depth on height, circumference at 1.30 m and annual ring growth. The results shown that aspect and altitude were the determining factors of Aleppo Pine growth. Three classes of fertility were distinguished in relation with dominant tree height and ageÀ partir de transects intĂ©grant les variations d’altitude et d’exposition, 120 placettes de Pin d’Alep (Pinus halepensis Mill.) de 800 mÂČ chacune ont Ă©tĂ© installĂ©es au niveau de quatre stations choisies dans le massif forestier de Senalba (Djelfa, AlgĂ©rie) situĂ© en rĂ©gion semi-aride. Chaque placette a fait l’objet des mesures dendromĂ©triques suivantes : circonfĂ©rence Ă  1.30 m, hauteur totale, hauteur dominante, surface terriĂšre, densitĂ©, Ăąge et accroissement moyen du cerne auxquelles ont Ă©tĂ© associĂ©es des caractĂ©ristiques stationnelles : altitude, exposition et profondeur du sol. L’analyse des donnĂ©es a mis en Ă©vidence que l’exposition et l’altitude sont les facteurs dĂ©terminants pour la croissance du pin. Trois classes de fertilitĂ© ont pu ĂȘtre distinguĂ©es Ă  partir du couple « Ăąge/hauteur dominante

    Health status of Aleppo pine stands (Pinus halepensis Mill.) in the natural Senalba forest (Djelfa - Algeria)

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    La prĂ©sente Ă©tude consiste en un diagnostic de l’état sanitaire des peuplements naturels de Pin d’Alep (Pinus halepensis Mill.) dans les massifs forestiers de Senalba Chergui et Gharbi situĂ©s dans la zone semi-aride de la rĂ©gion de Djelfa (AlgĂ©rie). L’échantillonnage adoptĂ© est le systĂ©matique stratifiĂ©, ce qui a conduit Ă  installer 80 placettes au niveau des versants nord et sud de chacun des massifs selon deux transects nord/sud et est/ouest. DiffĂ©rents paramĂštres dendromĂ©triques (hauteur et circonfĂ©rence des arbres dĂ©pĂ©ris Ă  1,30 m, Ă©paisseur de l’écorce, Ăąge) et stationnels (exposition, altitude, profondeur du sol, pH, taux de calcaire) sont mesurĂ©s. TraitĂ©es et analysĂ©es, ces donnĂ©es nous ont permis de conclure que le phĂ©nomĂšne de dĂ©pĂ©rissement touche majoritairement les peuplements situĂ©s sur le versant sud pour la forĂȘt de Senalba Chergui et ceux sur-ĂągĂ©s situĂ©s sur le versant nord de la forĂȘt de Senalba Gharbi. Les autres paramĂštres stationnels ou dendromĂ©triques n’ont pas d’effet significatif sur le phĂ©nomĂšne.This study aimed to analyse the health status of the natural Senalba Aleppo pine forest (Pinus halepensis Mill.) located in the semi-arid zone of Djelfa (Algeria). A stratified systematic sampling was adopted and 80 plots were set up along two transects established on south and north-facing slopes. Various dendrometric (tree height; circumference at 1.30 m; bark thickness; age) and site parameters (exposure; altitude; soil depth; calcareous rate; soil pH) were measured. Results showed that the decline process preferentially impacted the trees located on the southern slope of Senalba Chergui forest and old trees located on the northern slope of Senalba Gharbi forest. However, the other parameters have no significant effect on the process of decline

    Plant phenotype affects oviposition behaviour of pine processionary moth and egg survival at the southern edge of its range

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    Morphological traits of Aleppo pine (Pinus halepensis) needles in native and planted stands at the southern edge of its range influence oviposition behaviour of the pine processionary moth (Thaumetopoea pityocampa). Extreme environmental conditions result in a reduction in needle size of the host plant which corresponds to a lower rate of fecundity in the moth. Our results showed that egg batches were laid closer to the needle buds, especially on native trees with short needles, and this resulted in increased egg mortality. Number of eggs laid by the female moths did not vary between native and planted stands, nor did the number of parasitized eggs of the two common Hymenopteran parasitoids, Baryscapus servadeii and Ooencyrtus pityocampae. The observed differences in egg mortality are likely due to abiotic factors associated with the position of the egg batch on the needles. Thaumetopoea pityocampa eggs require a thermal niche for optimal development, and further measurements are required to determine the thermal threshold of these eggs. Understanding the role of climate in T. pityocampa populations will be an important factor for the survival of the Aleppo pine forests and protecting it from desertification

    DendroĂ©cologie du Pin d’Alep (Pinus halepensis Mill.) en fonction des paramĂštres stationnels dans le massif forestier de Senalba (Djelfa - AlgĂ©rie)

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    Relation between site parameters and Aleppo Pine (Pinus halepensis Mill.) dendroecology in Senalba forest area (Djelfa, Algeria). Aleppo Pine (Pinus halepensis Mill.) is a volunteering hardy species, very common in Mediterranean regions. This species has great economical, ecological and social values in Algeria. 120 sample plots were laid out on northern and southern slopes of Senalba forest area (Djelfa) located in a semi-arid region, to investigate the effect of altitude, aspect and soil depth on height, circumference at 1.30 m and annual ring growth. The results shown that aspect and altitude were the determining factors of Aleppo Pine growth. Three classes of fertility were distinguished in relation with dominant tree height and age.Á partir de transects intĂ©grant les variations d’altitude et d’exposition, 120 placettes de Pin d’Alep (Pinus halepensis Mill.) de 800 m ÂČ chacune ont Ă©tĂ© installĂ©es au niveau de quatre stations choisies dans le massif forestier de Senalba (Djelfa, AlgĂ©rie) situĂ© en rĂ©gion semi-aride. Chaque placette a fait l’objet des mesures dendromĂ©triques suivantes : circonfĂ©rence Ă  1.30 m, hauteur totale, hauteur dominante, surface terriĂšre, densitĂ©, Ăąge et accroissement moyen du cerne auxquelles ont Ă©tĂ© associĂ©es des caractĂ©ristiques stationnelles : altitude, exposition et profondeur du sol. L’analyse des donnĂ©es a mis en Ă©vidence que l’exposition et l’altitude sont les facteurs dĂ©terminants pour la croissance du pin. Trois classes de fertilitĂ© ont pu ĂȘtre distinguĂ©es Ă  partir du couple «ùge/hauteur dominante».Guit Brahim, Nedjimi Bouzid, Guibal FrĂ©dĂ©ric, Chakali Gahdab. DendroĂ©cologie du Pin d’Alep (Pinus halepensis Mill.) en fonction des paramĂštres stationnels dans le massif forestier de Senalba (Djelfa - AlgĂ©rie). In: Revue d'Écologie (La Terre et La Vie), tome 70, n°1, 2015. pp. 32-43

    Taxonomic notes on the ground beetles (Coleoptera: Carabidae) of Tunisia.

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    The objective of this study was to determine the species diversity of Carabidae found during expeditions to some provinces of Tunisia between 2012 and 2013. In total 105 species and subspecies within 59 genera belonging to 11 subfamilies of Carabidae are reported. Endemic elements are indicated and information on the Tunisian distribution of each species is also given.El objetivo de este estudio fue determinar la diversidad de especies de Carabidae encontradas durante las expediciones a algunas provincias de TĂșnez entre 2012 y 2013. En total se citan 105 especies y subespecies de 59 gĂ©neros pertenecientes a 11 subfamilias de Carabidae. Se indican los elementos endĂ©micos y se da informaciĂłn sobre la distribuciĂłn en TĂșnez de cada especie

    État sanitaire des peuplements de Pin d’Alep (Pinus halepensis Mill.) dans le massif forestier de Senalba (Djelfa, AlgĂ©rie)

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    Health status of Aleppo pine stands (Pinus halepensis Mill.) in the natural Senalba forest (Djelfa -Algeria). This study aimed to analyse the health status of the natural Senalba Aleppo pine forest (Pinus halepensis Mill.) located in the semi-arid zone of Djelfa (Algeria). A stratified systematic sampling was adopted and 80 plots were set up along two transects established on south and north-facing slopes. Various dendrometric (tree height ; circumference at 1.30 m ; bark thickness ; age) and site parameters (exposure ; altitude ; soil depth ; calcareous rate ; soil pH) were measured. Results showed that the decline process preferentially impacted the trees located on the southern slope of Senalba Chergui forest and old trees located on the northern slope of Senalba Gharbi forest. However, the other parameters have no significant effect on the process of decline.La prĂ©sente Ă©tude consiste en un diagnostic de l’état sanitaire des peuplements naturels de Pin d’Alep (Pinus halepensis Mill.) dans les massifs forestiers de Senalba Chergui et Gharbi situĂ©s dans la zone semi-aride de la rĂ©gion de Djelfa (AlgĂ©rie). L’échantillonnage adoptĂ© est le systĂ©matique stratifiĂ©, ce qui a conduit Ă  installer 80 placettes au niveau des versants nord et sud de chacun des massifs selon deux transects nord/sud et est/ouest. DiffĂ©rents paramĂštres dendromĂ©triques (hauteur et circonfĂ©rence des arbres dĂ©pĂ©ris Ă  1,30 m, Ă©paisseur de l’écorce, Ăąge) et stationnels (exposition, altitude, profondeur du sol, pH, taux de calcaire) sont mesurĂ©s. TraitĂ©es et analysĂ©es, ces donnĂ©es nous ont permis de conclure que le phĂ©nomĂšne de dĂ©pĂ©rissement touche majoritairement les peuplements situĂ©s sur le versant sud pour la forĂȘt de Senalba Chergui et ceux sur-ĂągĂ©s situĂ©s sur le versant nord de la forĂȘt de Senalba Gharbi. Les autres paramĂštres stationnels ou dendromĂ©triques n’ont pas d’effet significatif sur le phĂ©nomĂšne.Guit Brahim, Nedjimi Bouzid, Chakali Gahdab, Guibal FrĂ©dĂ©ric. État sanitaire des peuplements de Pin d’Alep (Pinus halepensis Mill.) dans le massif forestier de Senalba (Djelfa, AlgĂ©rie). In: Revue d'Écologie (La Terre et La Vie), tome 71, n°2, 2016. pp. 156-167
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