14 research outputs found
The recent expansion of an avian invasive species (the Cattle Egret Ardea ibis) in Algeria
This study identifies new information on the recent distribution of an invasive bird species, the Cattle Egret Ardea ibis, in Algeria. Breeding and wintering distributions as well as breeding numbers were obtained from large-scale surveys in 1999 and 2007, and from historical data. Between 1999 and 2007, the total number of colonies found increased from 51 to 87, and most were located in the northern part of the country. The breeding distribution area, confined to the coastal areas in the 1970s, has shifted further south, and reached the northern part of the Sahara since the 2000s. Most colonies were established during the period 1980-1995. The oldest colonies were generally larger than the recent ones. The number of colonies increased by 83% between 1999 and 2007 in the 12 administrative units (wilayas) surveyed. The number of breeding pairs increased from 7765 in 1999 to 28544 in 2007, corresponding to an annual population growth rate of 17.7%. The changes in distribution and population dynamics since the 1970s and the potential factors affecting these changes are discussed
Structure de l'habitat et biologie de reproduction du HĂ©ron garde-bĆuf, Bubulcus ibis, dans une colonie de la vallĂ©e de la Soummam (Petite Kabylie, AlgĂ©rie)
The Cattle Egret, Bubulcus ibis, is a new breeding bird in the Soummam Valley region
(Petite Kabylie, Algeria). The location of each of 511 nests was determined in relation to the
chronology in time of colony site occupation. This allowed an assessment to be made of
preferential nest site selection. The regular monitoring of 58 marked nests provided data on
reproductive parameters.
The nesting season lasted from the end of March to the end of July. The mean clutch size
(2.77 ± 0.56, N = 64), the mean fledging success ( 1 .69 ± 0.87, N = 64) and the breeding
success (57 . 3 %) are low compared to other breeding areas in the Mediterranean. Losses of
eggs and chicks were due mainly to high winds (Sirocco).
The first Cattle Egrets arriving at the colony in March selected the highest trees, and the
highest nest supports close to the trunk. With new arrivais during the course of the season, a
graduai decrease was observed in the height of the nests which were progressively built away
from the trunk. This selective behaviour is a new aspect observed during nesting of Cattle
EgretsLa caractĂ©risation de l'emplacement de 511 nids de HĂ©rons garde-bĆufs, Bubulcus ibis. implantĂ©s dans une colonie de la vallĂ©e de la Soummam (Petite Kabylie, AlgĂ©rie), a permis d'Ă©tablir la chronologie d'installation et les
modalitĂ©s du choix initial et prĂ©fĂ©rentiel du site d'implantation du nid. Le suivi rĂ©gulier de 58 nids prĂ©alablement marquĂ©s a permis de calculer de paramĂštres relatifs au succĂšs reproducteur. La reproduction du garde-bĆufs a lieu de la fin-mars Ă la fin-juillet, avec un pic d'installation
noté en mai. La taille moyenne des pontes (2,77 ± 0,56, N = 64), le nombre moyen d'envol par nid (1,69 ± 0,87, N = 64) et le succÚs de reproduction (57.3 %) sont relativement faibles, comparés à ceux notés dans d'autres régions méditerranéennes. Les pertes subies par les pontes et les
nichées sont dues, principalement, à l'action du vent (Sirocco) qui entraßne des chutes. Les individus nicheurs installent préférentiellement leurs nids sur les arbres les plus hauts, à la hauteur la plus élevée et dans la position la plus proche du tronc principal. Ce comportement de
sélection est un nouvel aspect observé pendant la nidification de l'espÚce
DYNAMIQUE DES POPULATIONS ET MODALITES DâINFESTATION DE POLLINIA POLLINI COSTA, 1857 (HOMOPTERA, ASTEROLECANIIDAE) SUR LâOLIVIER OLEA EURPAEA L. DANS LA REGION SEMI-ARIDE DâARRIS (BATNA, NORD-EST DâALGERIE)
Le suivi dĂ©mo-Ă©cologique de la cochenille Pollinia pollini est rĂ©alisĂ©e dans une oliveraie de la rĂ©gion semi-aride dâArris (Nord-est AlgĂ©rie) durant une pĂ©riode dâune annĂ©e, allant de janvier Ă dĂ©cembre 2015. LâĂ©tude du mode dâinfestation de lâolivier Olea eurpaea par la cochenille est basĂ©e sur des dĂ©nombrements des diffĂ©rents stades de dĂ©veloppement de lâespĂšce sur les rameaux. Ces dĂ©nombrements sont rĂ©alisĂ©s suivant les orientations de lâarbre (Nord, Est, Sud, Ouest et Centre) et suivant le mode dâinstallation de la cochenille sur les rameaux (Ă la surface des rameaux, aux aisselles des rameaux et des feuilles ou Ă lâintĂ©rieur du bois). Ce travail montre que P. pollini Ă©volue en une seule gĂ©nĂ©ration annuelle. La parution des larves du premier stade commence Ă la troisiĂšme dĂ©cade de mars et se poursuit jusquâĂ la mi-aoĂ»t. Les larves du deuxiĂšme stade apparaissent Ă la troisiĂšme dĂ©cade dâavril et enregistrent leur pic en juillet. Les femelles adultes, qui sont prĂ©sentes le long de la pĂ©riode dâĂ©tude, enregistrent leurs effectifs maximaux en octobre et en novembre. LâĂ©tude de lâabondance globale de P. pollini en fonction des orientations montre que lâespĂšce sâinstalle prĂ©fĂ©rentiellement dans les parties Nord, Est et Ouest de lâarbre, avec des proportions relativement proches allant de 20 % Ă 22 %. Le suivi de lâemplacement de P. pollini sur les rameaux de lâolivier montre que la cochenille sâinstalle dans trois emplacements diffĂ©rents. Elle prĂ©fĂšre sâinstaller aux aisselles des rameaux et des feuilles (43,23 %), Ă la surface des rameaux (29,15 %) et Ă lâintĂ©rieur du bois (27,62 %)
Using self-organizing maps to investigate environmental factors regulating colony size and breeding success of the White Stork (Ciconia ciconia)
We studied variations in the size of breeding colonies and in breeding performance of White Storks Ciconia ciconia in 2006â2008 in north-east Algeria. Each colony site was characterized using 12 environmental variables describing the physical environment, land-cover categories, and human activities, and by three demographic parameters: the number of breeding pairs, the number of pairs with chicks, and the number of fledged chicks per pair. Generalized linear mixed models and the self-organizing map algorithm (SOM, neural network) were used to investigate effects of biotic, abiotic, and anthropogenic factors on demographic parameters and on their relationships. Numbers of breeding pairs and of pairs with chicks were affected by the same environmental factors, mainly anthropogenic, which differed from those affecting the number of fledged chicks per pair. Numbers of fledged chicks per pair was not affected by colony size or by the number of nests with chicks. The categorization of the environmental variables into natural and anthropogenic, in connection with demographic parameters, was relevant to detect factors explaining variation in colony size and breeding parameters. The SOM proved a relevant tool to help determine actual dynamics in White Stork colonies, and thus to support effective conservation decisions at a regional scale
BIODIVERSITY OF XYLOPHAGOUS INSECTS AND THEIR ROLE IN THE Cedrus atlantica FORESTS DECLINE IN THE NATIONAL PARK OF BELEZMA â BATNA- (ALGERIA)
De tous les ennemis des forĂȘts, les xylophages sont certainement les plus dangereux car la rĂ©ussite de leur attaque entraine nĂ©cessairement la mort de tout ou partie du sujet atteint. Peu nĂ©fastes en temps normal, ils peuvent prendre, Ă la faveur de circonstances particuliĂšres, un dĂ©veloppement inquiĂ©tant et provoquer de graves dommages. Il nâest pour sâen convaincre, que de rappeler les catastrophes les plus rĂ©centes survenues dans les cĂ©draies du Parc National de Belezma.Dans cette aire protĂ©gĂ©e, le dĂ©pĂ©rissement du cĂšdre de lâAtlas dans le parc national de Belezma (Batna, AlgĂ©rie), sâest probablement dĂ©clenchĂ© depuis les annĂ©es 2000. Câest un phĂ©nomĂšne complexe dont les facteurs responsables sont amplement diversifiĂ©s. Les quelques observations et Ă©tudes rĂ©alisĂ©es ont permis de conclure que parmi les causes de ce phĂ©nomĂšne ; les insectes xylophages jouent un rĂŽle primordial dans la rĂ©gression de ces Ă©cosystĂšmes atteignant des cĂšdres en cours de dĂ©pĂ©rissement ou dĂ©jĂ dĂ©pĂ©ris.  Cette étude porte sur lâune des plus importantes cĂ©draies du parc national de Belezma, celle du Djebel Boumerzoug situĂ© sur le territoire de la commune de Oued El ChaĂąba, Condorcet, oĂč lâimpact des xylophages et les bouleversements dans le climat est dâautant plus forts que cette essence forestiĂšre sensible Ă la sĂ©cheresse ce qui la rend sensible aux attaques des ravageurs.Nos investigations nous ont permis dâidentifier 11 insectes xylophages appartenant Ă 3 familles : Scolytidae, Buprestidae et Cerambycidae. Les Buprestidae et Cerambycidae sont majoritaires avec des taux total dâapparitions respectivement de 65,94% et 21,47%. La famille restante est celle de Scolytidae reprĂ©sentĂ© par un taux global dâapparition relativement faible; de 12,59%. Ainsi, nous avons observĂ© que les positions de galeries montrent une certaine synchronisation des attaques, oĂč celles des Buprestidae viennent juste aprĂšs celles de Scolytidae mais en prĂ©cĂ©dant les Cerambycidae.Cette Ă©tude montre quâun diagnostic des attaques sur l'arbre attaquĂ© mĂȘme tardif, est indispensable car, au-delĂ de l'individu, c'est le peuplement qui est menacĂ©. Le diagnostic des attaques sur quelques individus est un des Ă©lĂ©ments de base de la lutte prĂ©ventive contre une Ă©pidĂ©mie
Cattle egrets ardea ibis use human-made habitat in a newly colonised area in northern Algeria
The Cattle Egret Ardea ibis is a species of Indo-African origin (Kushlan and Hafner 2000) whose biological plasticity is certainly one of the key causes of its worldwide expansion (Franchimont 1986a, Hancock and Kushlan 2005), making it a good model species with which to study the factors that allow colonisation of new environments by invasive birds. We studied the use of natural and human-made feeding habitats by Cattle Egrets in a newly colonised area in the Soummam Kabylie region (36°43'N, 05°04'E), northern Algeria, where the species has bred since 1993, to better understand the relationships between habitat features and the distribution of populations during the entire biological cycle. Until the nineteenth century, the species was breeding in localised areas in northern Algeria (Heim de Balsac and Mayaud 1962). More recently, it started breeding and wintering in a much larger area (Isenmann and Moali 2000, Si Bachir et al. 2008), including semiarid and arid areas in the Sahara (Siegfried 1971, Hancock and Kushlan 2005). Assuming that in North Africa artificial habitats such as crops and orchards are more stable and resource-rich environments than natural habitats (Boukhemza et al. 2000, Kushlan and Hafner 2000, Hancock and Kushlan 2005), we hypothesised that man-made agroecosystems promote the expansion of the species in the recently colonised subhumid and semiarid regions
Structure de lâhabitat et biologie de reproduction du HĂ©ron garde-boeufs, Bubulcus ibis, dans une colonie de la vallĂ©e de la Soummam (Petite Kabylie, AlgĂ©rie)
The Cattle Egret, Bubulcus ibis, is a new breeding bird in the Soummam Valley region (Petite Kabylie, Algeria). The location of each of 511 nests was determined in relation to the chronology in time of colony site occupation. This allowed an assessment to be made of preferential nest site selection. The regular monitoring of 58 marked nests provided data on reproductive parameters.
The nesting season lasted from the end of March to the end of July. The mean clutch size (2.77 ±0.56, N = 64), the mean fledging success (1.69 ±0.87, N = 64) and the breeding success (57.3 %) are low compared to other breeding areas in the Mediterranean. Losses of eggs and chicks were due mainly to high winds (Sirocco).
The first Cattle Egrets arriving at the colony in March selected the highest trees, and the highest nest supports close to the trunk. With new arrivals during the course of the season, a gradual decrease was observed in the height of the nests which were progressively built away from the trunk. This selective behaviour is a new aspect observed during nesting of Cattle Egrets.La caractĂ©risation de lâemplacement de 511 nids de HĂ©rons garde-bĆufs, Bubulcus ibis, implantĂ©s clans une colonie de la vallĂ©e de la Soummam (Petite Kabylie, AlgĂ©rie), a permis dâĂ©tablir la chronologie dâinstallation et les modalitĂ©s du choix initial et prĂ©fĂ©rentiel du site dâimplantation du nid. Le suivi rĂ©gulier de 58 nids prĂ©alablement marquĂ©s a permis de calculer des paramĂštres relatifs au succĂšs reproducteur. La reproduction du garde-bĆufs a lieu de la fin-mars Ă la fin-juillet, avec un pic dâinstallation notĂ© en mai. La taille moyenne des pontes (2,77 ± 0,56, N = 64), le nombre moyen dâenvol par nid (1,69 ±0,87, N = 64) et le succĂšs de reproduction (57,3 %) sont relativement faibles, comparĂ©s Ă ceux notĂ©s dans dâautres rĂ©gions mĂ©diterranĂ©ennes. Les pertes subies par les pontes et les nichĂ©es sont dues, principalement, Ă lâaction du vent (Sirocco) qui entraĂźne des chutes.
Les individus nicheurs installent prĂ©fĂ©rentiellement leurs nids sur les arbres les plus hauts, Ă la hauteur la plus Ă©levĂ©e et dans la position la plus proche du tronc principal. Ce comportement de sĂ©lection est un nouvel aspect observĂ© pendant la nidification de lâespĂšce.Si bachir Abdelkrim, Hafner Heinz, Tourenq Jean-noĂ«l, Doumandji Salaheddine. Structure de lâhabitat et biologie de reproduction du HĂ©ron garde-boeufs, Bubulcus ibis, dans une colonie de la vallĂ©e de la Soummam (Petite Kabylie, AlgĂ©rie). In: Revue d'Ăcologie (La Terre et La Vie), tome 55, n°1, 2000. pp. 33-43
Effect of large-scale environmental variables and human pressure on distribution patterns of exotic continental fish in east Algeria
This study aims to identify large-scale environmental variables that explain the distribution of continental exotic fish across five bioclimatic regions in east Algeria (160,000 kmÂČ), North Africa. Fish communities were sampled at 39 sites from 2007 to 2010. Seven environmental variables were investigated: habitat type, altitude, latitude, longitude, bioclimatic region, minimum and maximum air temperatures and human pressure. The common carp (Cyprinus carpio Linnaeus, 1758) and the silver carp (Hypophtalmichthys molitrix Valenciennes, 1844) were the most widespread exotic species. Almost all exotic fishes were distributed over desert and sub-humid bioclimatic scales. Reservoirs represent the type of habitat that houses the greatest exotic species richness. The distribution pattern of exotic fishes was mainly predetermined by the type of habitat. Alien ichtyofauna colonizes primarily man made hydrosystems regardless of environmental variables or the degree of human pressure, making these habitats more vulnerable to invasion
DYNAMIQUE DES POPULATIONS DâOULEMA MELANOPUS LINNE, 1758 (COLEOPTERA ; CHRYSOMELIDAE) SUR SIX VARIETES DE BLE DUR (TRITICUM DURUM DESF.) DANS LA REGION DES HAUTES PLAINES DE LâEST ALGERIEN
La dynamique des populations du CriocĂšre des cĂ©rĂ©ales Oulema melanopus L. (Coleoptera ; Chrysomelidae) est suivie sur six variĂ©tĂ©s de blĂ© dur Triticum durum Desf. (Bousselam, Waha, Mohamed Ben Bachir, Megress, Setifis et Tadjdid), durant trois annĂ©es (2012, 2013 et 2014) dans les Hautes plaines de lâEst AlgĂ©rien (SĂ©tif), oĂč lâespĂšce est considĂ©rĂ©e comme ravageur primaire des cĂ©rĂ©ales. Pour chaque variĂ©tĂ©, et sur 40 plantes Ă©chantillonnĂ©es, un total de 5 talles, sur un ensemble de 200 talles par variĂ©tĂ© et par relevĂ© sont examinĂ©es. Ces relevĂ©s, dâune semaine Ă dix jours, sont explorĂ©s durant les quatre stades phĂ©nologiques de la plante hĂŽte : fin tallage, montaison, Ă©piaison, maturation. LâannĂ©e 2013 est considĂ©rĂ©e comme la plus favorable au dĂ©veloppement dâO. melanopus par rapport aux deux annĂ©es 2012 et 2014. Le stade montaison est le stade oĂč les effectifs les plus Ă©levĂ©s sur toutes les variĂ©tĂ©s sont notĂ©s. La variĂ©tĂ© Tadjdid est la plus colonisĂ©e par O. melanopus, en particulier durant les stades ââfin tallageââ et ââmontaisonââ. La variation des effectifs en fonction des variĂ©tĂ©s Ă©tudiĂ©es est significative (P< 0,01) en 2012 et en 2014, Ă trĂšs hautement significative en 2013 (P< 0,0001). La variation des effectifs en fonction des stades phĂ©nologiques est hautement significative (P< 0,001) en 2012 et trĂšs hautement significative (P< 0,0001) en 2013 et 2014. La variation des abondances en fonction de lâeffet combinĂ© ââVariĂ©tĂ© x Stade phĂ©nologiqueââ est significative (P< 0,01) en 2012, hautement significative (P< 0,001) en 2013 et trĂšs hautement significative (P< 0,0001) en 2014. Les rĂ©sultats permettront dâeffectuer un meilleur choix des variĂ©tĂ©s rĂ©sistantes au CriocĂšre des cĂ©rĂ©ales et dâorienter les programmes de lutte contre ce ravageur dans les Hautes plaines de lâEst AlgĂ©rien
Spatiotemporal diversity, structure and trophic guilds of insect assemblages in a semi-arid Sabkha ecosystem
The current study highlights some knowledge on the diversity and structure of insect communities and trophic groups living in Sabkha Djendli (semi-arid area of Northeastern Algeria). The entomofauna was monthly sampled from March to November 2006 using pitfall traps at eight sites located at the vicinity of the Sabkha. Structural and diversity parameters (species richness, Shannon index, evenness) were measured for both insect orders and trophic guilds. The canonical correspondence analysis (CCA) was applied to determine how vegetation parameters (species richness and cover) influence spatial and seasonal fluctuations of insect assemblages. The catches totalled 434 insect individuals classified into 75 species, 62 genera, 31 families and 7 orders, of which Coleoptera and Hymenoptera were the most abundant and constant over seasons and study stations. Spring and autumn presented the highest values of diversity parameters. Individual-based Chao-1 species richness estimator indicated 126 species for the total individuals captured in the Sabkha. Based on catch abundances, the structure of functional trophic groups was predators (37.3%), saprophages (26.7%), phytophages (20.5%), polyphages (10.8%), coprophages (4.6%); whereas in terms of numbers of species, they can be classified as phytophages (40%), predators (25.3%), polyphages (13.3%), saprophages (12%), coprophages (9.3%). The CCA demonstrated that phytophages and saprophages as well as Coleoptera and Orthoptera were positively correlated with the two parameters of vegetation, especially in spring and summer. While the abundance of coprophages was positively correlated with species richness of plants, polyphage density was positively associated with vegetation cover. The insect community showed high taxonomic and functional diversity that is closely related to diversity and vegetation cover in different stations of the wetland and seasons