Ahmed Aidoud - Academia.edu (original) (raw)
Papers by Ahmed Aidoud
ISBN : 978-9973-856-33-3The long term ecological surveillance observatoires network (Réseau d'... more ISBN : 978-9973-856-33-3The long term ecological surveillance observatoires network (Réseau d'Observatoires de Surveillance Ecologique à Long Terme, ROSELT/OSS) of the Sahara and Sahel Observatory (OSS) consists of a cluster of observatories which span circum-Saharan Africa and share a common focus on the issue of desertification. Since its inception, the network has been addressing the challenge of improving the collective knowledge on desertification; a scourge that has complex linkages with the issues of biodiversity and climate change. Over the last ten years, OSS has put in place standardised protocols of data collection and processing in the circum-Sahara with a view to apprehending the trends characterising the evolution of the ROSELT/OSS observatories' ecological and socio-economic systems. In this part of Africa, where rainfall decrease is chronic in the Sahel and spreading to North Africa, population growth and land use change—due to overgrazing or the conversion o...
Revue D Ecologie-la Terre Et La Vie, 2016
Long-term monitoring of Gray-leaved Sagebrush (Artemisia herba-alba Asso.) steppe in southern Ora... more Long-term monitoring of Gray-leaved Sagebrush (Artemisia herba-alba Asso.) steppe in southern Oran Region (Algeria): factors and indicators of change.-The Gray-leaved Sagebrush (Artemisia herba-Alba Asso.) steppes in the Southern Oran region in Algeria are rangelands of great pastoral interest. 40 years long-term dynamics of these steppes has been studied since 1975 using a diachronic monitoring (i) in permanent site considering five reference years and (ii) in 30 sites in the rest of the sagebrush steppe in 1975-76 and 2013-2015. Results generally show degradation with changes in the community composition and species dominance with appearance or extension of indicator species reflecting changes in land-use and environmental conditions. The increase in ephemeral species may explain the increase in the beta diversity, while the gamma diversity decreased underlying a trend toward banalization of the plant community composition. Unlike the rest of the pre-existing sagebrush steppe, in the monitoring site, following a series of rainy years, sand which had been fixed would have played an important role in the recovery of the vegetation cover.
Annales de l'Institut national agronomique El Harrach, Jun 1, 1989
HAL (Le Centre pour la Communication Scientifique Directe), 2009
HAL (Le Centre pour la Communication Scientifique Directe), May 25, 2019
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), 2009
ABSTRACT
Revue forestière française, 2010
Science et changements planétaires / Sécheresse, Sep 15, 2006
... par les États, malgré de grands écarts de production dus aux variations pluviométriques [75 .... more ... par les États, malgré de grands écarts de production dus aux variations pluviométriques [75 ... des sols, à la surexploitation des ressources voire aux changements climatiques [20, 94]. ... K, Ismaili M, Fikri-Benbrahim S, Tribak A. Problèmes de dégradation de l'environnement par la ...
Revue D Ecologie-la Terre Et La Vie, 2018
Springer eBooks, 2004
ABSTRACT Natural and semi-natural ecosystems of the Maghreb have been subject, for several centur... more ABSTRACT Natural and semi-natural ecosystems of the Maghreb have been subject, for several centuries, to grazing and cultivation as dominant land-uses. Living in a Mediterranean climate which is generally arid, plant, animal and human populations developed diverse adaptive strategies to cope with such rough conditions. Forests and rangelands have been undermined by erratic droughts that seem to be becoming more frequent. During the last two or three decades, vegetation and soil resources, in particular those of arid lands, have been marked by a rapid and severe degradation. The major changes observed were the regression of perennial plants (ligneous and grasses) and sand encroachment that are recognised to be relevant indicators of desertification in North Africa and the Middle East rangelands. A brief overall view of the Maghreb is given and illustrated by an example from the steppe rangelands dominated by alfa-grass (Stipa tenacissima L.) as a case study. The basic results of long term monitoring of what was originally a typical and dense steppe of the arid High Plains of Algeria have shown that alfa steppes have nearly disappeared from pediment surfaces since the 1980s. Causes are multiple but overgrazing remains in the present case, the main and direct origin of degradation because of diverse social and economic reasons, human population and need increases and increases in sheep grazing pressure. Irreversible changes were assessed using a grazing gradient approach. The gradient was represented by a transect starting from a long-term ungrazed exclosure, representing the pre-existing system and ending at free grazed rangelands. The monitored alfa stand showed, at the beginning of the study, a high homogeneity of vegetation and soil features. Vegetation pattern was a mosaic with individual tussocks and interstitial bare soil. The long term monitoring showed significant changes of the dominant species phytomass, plant composition and diversity and soil characteristics. The results, showing a regressive trend of the principal attributes of the vital ecosystem, could be generalized to all steppe habitats that had been originally dominated by alfa-grass. The aim of this work is to improve knowledge about extent, causes and mechanisms of desertification in order to direct restoration and rehabilitation actions.
Sciences, eaux & territoires, 2011
années de suivi * Reconstitué d'après les pollens retrouvés dans la tourbe. ** Le cadastre de Par... more années de suivi * Reconstitué d'après les pollens retrouvés dans la tourbe. ** Le cadastre de Parigné de 1811 mentionne que l'étang du marais est « presqu'entièrement recouvert d'une croûte flottante assez épaisse pour que les bestiaux y puissent pâturer ». ➊ La laîche paniculée (Carex paniculata).
Ecologia mediterranea, 2011
La désertification des parcours pastoraux steppiques arides constitue une des problématiques fond... more La désertification des parcours pastoraux steppiques arides constitue une des problématiques fondamentales de développement dans le sud de la Méditerranée. Elle pose avec acuité les questions de restauration et de gestion de ces écosystèmes qui ont été, dans la plupart des cas, soumis au surpâturage depuis des décennies. Divers modèles ont été développés pour expliquer la dynamique des écosystèmes arides dont l’origine, les causes et les mécanismes des changements sont souvent peu ou pas connus. Le suivi à long terme et la connaissance de l’histoire d’un écosystème dégradé ont été souvent avancés comme le meilleur moyen de comprendre ces changements et surtout de définir les références pour le pilotage des actions de réhabilitation de cet écosystème. Dans le cas présent, le système préexistant est une steppe aride dans laquelle, l’Alfa (Stipa tenacissima L.) a été l’espèce dominante et dont a été montré le caractère «clef de voûte» vis-à-vis de la composition spécifique et des conditions édaphiques. Trente-cinq années de surveillance ont permis d’évaluer le fonctionnement de cet écosystème au niveau de la production primaire utilisable par les troupeaux et de faire ressortir l’importance des fluctuations dues au climat par rapport aux changements de végétation et de sol, induits par le surpâturage ovin. Les résultats de ce travail permettent de discuter les modèles dynamiques existants et d’avancer des propositions quant aux opérations de réhabilitation et les nouveaux modes de gestion préconisés dans les parcours steppiques d’Algérie.
HAL (Le Centre pour la Communication Scientifique Directe), Nov 21, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Oct 13, 2012
HAL (Le Centre pour la Communication Scientifique Directe), Nov 21, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), 2009
http://www.eurolimpacs.ucl.ac.uk/oldsite/docstore/Deliverable\_312.pdfRapport de recherch
HAL (Le Centre pour la Communication Scientifique Directe), Jan 28, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), 2014
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), 2009
Functional assessment enables the user to predict the functioning of a wetland area without the n... more Functional assessment enables the user to predict the functioning of a wetland area without the need for comprehensive and expensive empirical research The FAPs therefore provide a methodology that can be used by both experts and non-experts to assess wetland functioning relatively rapidly. The volume includes an electronic version of the FAPs on CD which automates aspects of the assessment once the initial recording stage is completed. It is anticipated that the FAPs will be used by a range of individuals or organisations concerned with wetland management who wish to gain a better understanding of the processes, functions, services or benefits and potential of the wetlands for which they have responsibility
ISBN : 978-9973-856-33-3The long term ecological surveillance observatoires network (Réseau d'... more ISBN : 978-9973-856-33-3The long term ecological surveillance observatoires network (Réseau d'Observatoires de Surveillance Ecologique à Long Terme, ROSELT/OSS) of the Sahara and Sahel Observatory (OSS) consists of a cluster of observatories which span circum-Saharan Africa and share a common focus on the issue of desertification. Since its inception, the network has been addressing the challenge of improving the collective knowledge on desertification; a scourge that has complex linkages with the issues of biodiversity and climate change. Over the last ten years, OSS has put in place standardised protocols of data collection and processing in the circum-Sahara with a view to apprehending the trends characterising the evolution of the ROSELT/OSS observatories' ecological and socio-economic systems. In this part of Africa, where rainfall decrease is chronic in the Sahel and spreading to North Africa, population growth and land use change—due to overgrazing or the conversion o...
Revue D Ecologie-la Terre Et La Vie, 2016
Long-term monitoring of Gray-leaved Sagebrush (Artemisia herba-alba Asso.) steppe in southern Ora... more Long-term monitoring of Gray-leaved Sagebrush (Artemisia herba-alba Asso.) steppe in southern Oran Region (Algeria): factors and indicators of change.-The Gray-leaved Sagebrush (Artemisia herba-Alba Asso.) steppes in the Southern Oran region in Algeria are rangelands of great pastoral interest. 40 years long-term dynamics of these steppes has been studied since 1975 using a diachronic monitoring (i) in permanent site considering five reference years and (ii) in 30 sites in the rest of the sagebrush steppe in 1975-76 and 2013-2015. Results generally show degradation with changes in the community composition and species dominance with appearance or extension of indicator species reflecting changes in land-use and environmental conditions. The increase in ephemeral species may explain the increase in the beta diversity, while the gamma diversity decreased underlying a trend toward banalization of the plant community composition. Unlike the rest of the pre-existing sagebrush steppe, in the monitoring site, following a series of rainy years, sand which had been fixed would have played an important role in the recovery of the vegetation cover.
Annales de l'Institut national agronomique El Harrach, Jun 1, 1989
HAL (Le Centre pour la Communication Scientifique Directe), 2009
HAL (Le Centre pour la Communication Scientifique Directe), May 25, 2019
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), 2009
ABSTRACT
Revue forestière française, 2010
Science et changements planétaires / Sécheresse, Sep 15, 2006
... par les États, malgré de grands écarts de production dus aux variations pluviométriques [75 .... more ... par les États, malgré de grands écarts de production dus aux variations pluviométriques [75 ... des sols, à la surexploitation des ressources voire aux changements climatiques [20, 94]. ... K, Ismaili M, Fikri-Benbrahim S, Tribak A. Problèmes de dégradation de l'environnement par la ...
Revue D Ecologie-la Terre Et La Vie, 2018
Springer eBooks, 2004
ABSTRACT Natural and semi-natural ecosystems of the Maghreb have been subject, for several centur... more ABSTRACT Natural and semi-natural ecosystems of the Maghreb have been subject, for several centuries, to grazing and cultivation as dominant land-uses. Living in a Mediterranean climate which is generally arid, plant, animal and human populations developed diverse adaptive strategies to cope with such rough conditions. Forests and rangelands have been undermined by erratic droughts that seem to be becoming more frequent. During the last two or three decades, vegetation and soil resources, in particular those of arid lands, have been marked by a rapid and severe degradation. The major changes observed were the regression of perennial plants (ligneous and grasses) and sand encroachment that are recognised to be relevant indicators of desertification in North Africa and the Middle East rangelands. A brief overall view of the Maghreb is given and illustrated by an example from the steppe rangelands dominated by alfa-grass (Stipa tenacissima L.) as a case study. The basic results of long term monitoring of what was originally a typical and dense steppe of the arid High Plains of Algeria have shown that alfa steppes have nearly disappeared from pediment surfaces since the 1980s. Causes are multiple but overgrazing remains in the present case, the main and direct origin of degradation because of diverse social and economic reasons, human population and need increases and increases in sheep grazing pressure. Irreversible changes were assessed using a grazing gradient approach. The gradient was represented by a transect starting from a long-term ungrazed exclosure, representing the pre-existing system and ending at free grazed rangelands. The monitored alfa stand showed, at the beginning of the study, a high homogeneity of vegetation and soil features. Vegetation pattern was a mosaic with individual tussocks and interstitial bare soil. The long term monitoring showed significant changes of the dominant species phytomass, plant composition and diversity and soil characteristics. The results, showing a regressive trend of the principal attributes of the vital ecosystem, could be generalized to all steppe habitats that had been originally dominated by alfa-grass. The aim of this work is to improve knowledge about extent, causes and mechanisms of desertification in order to direct restoration and rehabilitation actions.
Sciences, eaux & territoires, 2011
années de suivi * Reconstitué d'après les pollens retrouvés dans la tourbe. ** Le cadastre de Par... more années de suivi * Reconstitué d'après les pollens retrouvés dans la tourbe. ** Le cadastre de Parigné de 1811 mentionne que l'étang du marais est « presqu'entièrement recouvert d'une croûte flottante assez épaisse pour que les bestiaux y puissent pâturer ». ➊ La laîche paniculée (Carex paniculata).
Ecologia mediterranea, 2011
La désertification des parcours pastoraux steppiques arides constitue une des problématiques fond... more La désertification des parcours pastoraux steppiques arides constitue une des problématiques fondamentales de développement dans le sud de la Méditerranée. Elle pose avec acuité les questions de restauration et de gestion de ces écosystèmes qui ont été, dans la plupart des cas, soumis au surpâturage depuis des décennies. Divers modèles ont été développés pour expliquer la dynamique des écosystèmes arides dont l’origine, les causes et les mécanismes des changements sont souvent peu ou pas connus. Le suivi à long terme et la connaissance de l’histoire d’un écosystème dégradé ont été souvent avancés comme le meilleur moyen de comprendre ces changements et surtout de définir les références pour le pilotage des actions de réhabilitation de cet écosystème. Dans le cas présent, le système préexistant est une steppe aride dans laquelle, l’Alfa (Stipa tenacissima L.) a été l’espèce dominante et dont a été montré le caractère «clef de voûte» vis-à-vis de la composition spécifique et des conditions édaphiques. Trente-cinq années de surveillance ont permis d’évaluer le fonctionnement de cet écosystème au niveau de la production primaire utilisable par les troupeaux et de faire ressortir l’importance des fluctuations dues au climat par rapport aux changements de végétation et de sol, induits par le surpâturage ovin. Les résultats de ce travail permettent de discuter les modèles dynamiques existants et d’avancer des propositions quant aux opérations de réhabilitation et les nouveaux modes de gestion préconisés dans les parcours steppiques d’Algérie.
HAL (Le Centre pour la Communication Scientifique Directe), Nov 21, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), Oct 13, 2012
HAL (Le Centre pour la Communication Scientifique Directe), Nov 21, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), 2009
http://www.eurolimpacs.ucl.ac.uk/oldsite/docstore/Deliverable\_312.pdfRapport de recherch
HAL (Le Centre pour la Communication Scientifique Directe), Jan 28, 2010
International audienc
HAL (Le Centre pour la Communication Scientifique Directe), 2014
National audienc
HAL (Le Centre pour la Communication Scientifique Directe), 2009
Functional assessment enables the user to predict the functioning of a wetland area without the n... more Functional assessment enables the user to predict the functioning of a wetland area without the need for comprehensive and expensive empirical research The FAPs therefore provide a methodology that can be used by both experts and non-experts to assess wetland functioning relatively rapidly. The volume includes an electronic version of the FAPs on CD which automates aspects of the assessment once the initial recording stage is completed. It is anticipated that the FAPs will be used by a range of individuals or organisations concerned with wetland management who wish to gain a better understanding of the processes, functions, services or benefits and potential of the wetlands for which they have responsibility