azziz HIRCHE | Université des Sciences et Technologie Houari Boumediene (USTHB) (original) (raw)

one by azziz HIRCHE

NOVA Editions, 2013

The arid Algerian High Plateaus, a key area with pastoral activity, covers 27 million hectares. T... more The arid Algerian High Plateaus, a key area with pastoral activity, covers 27 million hectares. This steppe undergoes significant degradation in the eighties. The combination of severe drought, the most important of the century, showing a peak between 1982 and 1987 and an exponential increase in livestock had a catastrophic impact on pastoral resources. Vegetation cover, which was generally greater than 30% before 1980 is now less than 15%. Phytomass, which exceeded 1t.ha-1.year-1 in 1980, is now less than 450 kg.ha-1.year-1. This desertification has in turn greatly undermined the fodder potential of the steppe. The fodder production, which earlier exceeded an average of 150 Uf. ha−1.year−1, can currently provide about 30–40 Uf. ha−1.year−1. In response to this deterioration, the Algerian government, from the seventies defined a strategy to manage and restore the ecosystems. It had several technical solutions to combat it. The first was to increase pastoral and agricultural production; the second was to reduce the livestock; the third was to combine the two. Only the first approach was chosen. Several options were considered. The main ones were planting, collecting water for livestock and agriculture and finally installing exclosures. Agro-forestry plantations were performed on 217,549 ha with different species, particularly the genus Atriplex, Medicago and Opuntia. Small hydraulic entities were also build to irrigate 410,000 ha and to increase the planted area. The exclosures were established on 3 million hectares. We will discuss the relevance and success rate of these works from a holistic perspective. The economical and biological impacts (biodiversity, production...) will be assessed. The result is that the government's strategy is not clear, and sometimes seems at odds with the objectives of the combat against desertification. Worse yet, we will show that in some cases, the Algerian government seems paradoxically to be supporting the steppe degradation.
Keywords: Rangelands, Steppe, Overgrazing, Exclosures, Plantations, Desertification

Algeria is faced with the desertification, a crucial environmental problem. This land degradation... more Algeria is faced with the desertification, a crucial environmental problem. This land degradation occurs mainly in the Algerian steppes, the most widespread rangelands in the country and even in North Africa. This pastoral land was severely degraded during two decades. The main vegetation was constituted by Stipa tenacissima a keystone species. It reached 2/3 of the landscape in 1978 and occupies in 2012 only 1/10 of the original area. The vegetation covers close to 40% in the seventies and is generally less than 20% nowadays. The increase of both population and livestock leads to a high pressure on this fragile ecosystems aggravated by the huge drought in the eighties (1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988). It results a tremendous soil degradation and sand encroachment. This study tries to assess the sandstorms as a proxy of soil degradation. It appears that a correlation is generally observed and the paroxysm of the drought period, correspond to the maximum of soil deflation and sand cover. It is interesting to note that the recent decrease of sandstorms seems to be correlated to a rainy years and a lesser livestock pressure.

Geoecology and Desertification, from physical to human factors: Proceedings of the International Symposium in memory of Prof Juan Puigdefabregas (EcoDesert) Almeria February 20-22, 2019, 2020

The Sahel region is often studied in the context of desertification or land degradation. Most stu... more The Sahel region is often studied in the context of desertification or land degradation. Most studies using NOAA GIMMS images shows in this region a globally re-greening trend. What’s about Algeria in particular and Maghreb in general ?

Environmental Monitoring and Assessment, 2010

This study aims to monitor the arid Algerian High Plateaus, a key region for pastoral activities ... more This study aims to monitor the arid Algerian High Plateaus, a key region for pastoral activities which has suffered harsh and widespread degradation from the eighties. This area is not sufficiently known by the international scientific community. For this purpose, we considered phytoecological inventories and the-A. Hirche (B) · M. Salamani

SJSS. SPANISH JOURNAL OF SOIL SCIENCE, 2017

ABSTRACT Land degradation is one of the most important environmental threats facing the internati... more ABSTRACT
Land degradation is one of the most important environmental threats facing the international
community. In North Africa, many semiarid and arid regions are suffering significant land degradation,
which can be an impediment to sustainable development. Therefore; land degradation is monitored
in a regional context for a better understanding of its causes and consequences. One of the main
consequences is a notable increase in sand encroachment with negative environmental implications.
For this reason, the dynamics of sands between south-eastern Morocco and the wilaya of Nâama,
south-western Algeria, was studied. Sand samples gathered from six distinctive areas were subjected to
physicochemical, colorimetric (redness index), morphoscopic (circularity), and geochemical analysis,
and studied statistically using an analysis of variance (ANOVA), wind direction data, ternary plots
and a hierarchical cluster of trace elements (K, Rb, Fe, Ti, Ca and Sr). In all areas, a clear dominance
of the sand fraction appeared showing percentages ranging from 89 to 96%. Sampled areas were all
carbonated, and the pH was alkaline, with close values ranging from 8.4 to 9. The mean circularity
values ranged from 0.67 in Merzouga (Morocco) to 0.80 in El Aguer (Algeria). The lowest value
of the redness index was noted in Merzouga with a mean value of 4. The Algerian areas showed
an almost similar redness index with a value of 6 but the highest value was noted in Saadana with
a value of 11. Geochemical approaches, based on ternary plots and dendrogram cluster indicating
the abundance of major elements (Fe, Ca and K), were used as indicators of wind transport. Results
suggested the existence of a Regional Wind Action System (RWAS) implicated in the transport of
sand from south-eastern Morocco and its redistribution towards south-western Algeria. Merzouga
was connected to all areas but particularly to nearby Saadana and Kasdir in the Algerian territory.

two by azziz HIRCHE

Papers by azziz HIRCHE

The Egyptian Jjournal of Environmental changes, 2020

Ce travail porte sur la région de Djelfa, dont les parcours sont emblématiques des steppes arides... more Ce travail porte sur la région de Djelfa, dont les
parcours sont emblématiques des steppes arides
d’Algérie. Il s’articule autour de deux parties. La
première est consacrée à la réactualisation de
la carte d'occupation des terres de 2001 (étude
diachronique) à partir des images satellitaires
OLI de Landsat 8 (2001-2015), appuyée par des
observations de terrain. Dans la deuxième partie,
sera établi un bilan pastoral des ressources de la
wilaya. Son corollaire est la possibilité d’établir
une gestion rationnelle des parcours qui fait
l’objet de la présente étude

PONTE International Journal of Sciences and Research, 2019

The green dam is one of Algeria's greatest environmental achievements. However, few studies have ... more The green dam is one of Algeria's greatest environmental achievements. However, few studies have focused on this area and particularly on its dynamics. This study intends to follow the evolution of the green dam since its establishment. We have chosen a typical region where this reforestation was initiated, the forest of Moudjbara, located in Djelfa (department). A visual classification of Landsat satellite images 1972, 1987; 2003 and 2016 coupled with field surveys was carried out. To limit the exogenous variations, the sun-synchronous satellite images were chosen in autumn. Phytoecological surveys based on mixed sampling were performed. In terms of area, reforestation (after planting) reached about 6 500 ha in 1987 and 7985 ha in 2003 while in 2016 it reached 8500 ha, occupying nearly one third of the total study area. Nevertheless, crops, especially in areas where reforestation has declined, are increasing. Phytosanitary status is a concern but natural forests seem less affected with 1.2 nests per tree in natural forest and 1.85 in reforestation. The comparison between original and reforested forest formations shows that biodiversity is greater in natural forests and the difference between reforestation areas and natural forest decrease with time. The similarity index between the natural forest and reforestation areas for the year 2002 is estimated at 63% reaching 76% in 2018 for perennial species. The most notable changes are observed in the nearby steppe, which is undergoing advanced degradation. The crops which occupied only 1.29% of the study area in the beginning of the study currently cover 12% of the territory. This work shows that reforestation has relatively maintained their original areas, although crops areas are growing. Contrariwise, the phytosanitary quality and the biodiversity of the reforestation areas are less satisfactory compared to natural ones. The rangelands are Vol. 75 | No. 4/ undergone deep changes, which weaken their long-term future and question the survival of livestock farming in these zones.

La revue Liaison Énergie-Francophonie, 2017

Selon l’évaluation des écosystèmes pour le millénaire (Board, 2005), les zones sèches corresponde... more Selon l’évaluation des écosystèmes pour le millénaire
(Board, 2005), les zones sèches correspondent aux zones
hyper arides, arides, semi-arides et subhumides sèches
(Fig.1). De façon générale, elles sont caractérisées par
(Hori et al., 2011) :
􀁲􀀁 une pluviométrie faible, et irrégulière ;
􀁲􀀁 une amplitude thermique journalière, mensuelle et
annuelle importante ;
􀁲􀀁 des sols généralement peu structurés, peu profonds,
souvent sablo-limoneux et pauvres en matière
organique ;
􀁲􀀁 une +ore à tendance xérophytique.

Revue terre et vie, 2017

Spatial and temporal changes in steppic landscapes of Algeria. Case study of the Méchéria region.... more Spatial and temporal changes in steppic landscapes of Algeria. Case study of the Méchéria
region.— Economic activities in the arid steppes of Algeria are largely based on sheep husbandry using
rangelands. The recent "regreening" observed in the arid and semi-arid rangelands surrounding the Sahara desert is
challenging the desertification caused by the increasing grazing pressure. To the question about the reality of
desertification, this work tries to answer by a diachronic and landscape approach. We compared the land cover
map carried out in 2014 to the other two maps performed in 1978 and 2006. The remotely sensed changes in the
landscape units show a fragmentation in the preexisting steppe landscapes with various degradation stages.
Steppes of Stipa tenacissima lost 94 % of their area since 1978; those of Lygeum spartum after increasing by 4 %
from 1978 to 2006, decreased by 13 % from 2006 to 2014. The L. spartum steppe had disappeared from its
original places (80 % of cases) but encroached on new lands mainly at the expense of S. tenacissima (60 % of the
current surface). Currently, two types of steppes dominate 80 % of the total rangelands; those of L. spartum with
35 % and of Atractylis serratuloides with 33 %. The spreading A. serratuloides steppe over 22 % of the total
surface during the last 8 years is considered to be an indicator of overgrazing and one of the basic evidences that
land degradation is still relevant in these rangelands in spite of their regreening mainly due to a high precipitation
amount since 2007

Sécheresse, 2007

La désertification des zones arides prend une ampleur sans cesse croissante. Si la plupart des au... more La désertification des zones arides prend une ampleur sans cesse croissante. Si la
plupart des auteurs s’accordent à reconnaître le rôle potentiel du climat dans les
phénomènes de dégradation du milieu, la tendance climatique n’est pas toujours
facilement perçue et reste encore controversée. Dans ces régions, la pluviométrie
constitue un facteur prépondérant dans la caractérisation climatique. Ce travail se
propose de répondre à la question suivante : en zones arides algériennes la
pluviosité a-t-elle subi une péjoration, c’est-à-dire une tendance à la baisse ? Nous
nous proposons d’étudier la tendance de deux stations sahariennes - El Oued et
Touggourt -, d’une station présaharienne - Biskra - et de quatre stations steppiques des
Hautes Plaines - Djelfa, Saida, Méchéria et El Bayadh (ex-Geryville) sur des séries
pratiquement séculaires. Il en ressort une alternance de séquences sèches et
pluvieuses non périodiques, qui dépassent rarement trois à quatre ans. Aucune
tendance nette n’est observée dans les stations sahariennes et présahariennes. En
revanche, celles du Sud oranais montrent un net assèchement, surtout durant ces trois
dernières décennies, tant par la baisse des quantités de pluie que par l’augmentation
des séquences sèches. Un gradient d’assèchement semble se dessiner des régions
orientales vers les régions occidentales ; mais ces résultats trop fragmentaires pour
être généralisables nécessitent d’être confirmés par des études ultérieures avec un
réseau plus dense de stations et des séries d’observation plus longues.

Journal of arid Land , 2018

The steppic regions of North Africa are submitted since 1960 to an increasing desertification tre... more The steppic regions of North Africa are submitted since 1960 to an increasing desertification trend, including the degradation of traditional pastures used by local populations. The initially dominating species (Artemisia herba-alba, Lygeumspartum, Stipatenacissima) declined and were progressively replaced by grazing-tolerant species (Atractylisserratuloides, Salsolavermiculata). The anthropogenic or climatic determinism of such an evolution is controversial. We propose here a climate statistical analysis in order to detect putative rainfall changes in the last century in the Algerian steppes. We selected nine meteorological stations representative of the bioclimate diversity of the studied region, and covering the entire 20th century: 2 Saharan stations (El Oued and Touggourt), 3 pre-Saharan stations (Biskra, Laghouat and Ain Sefra) and 4 steppe stations located in the arid High Plains (Djelfa, Saida, Méchéria and El-Bayadh).Previous studies proposed that only the southwestern steppe region (south of Oran region) experimented significant rainfall changes for the last century. Most of them however concern restricted territories and limited periods, and none integrate the last decade (2004-2014) that was one of the rainiest. Our work is designed for integrating all the longest time series of meteorological data available for the steppe regions of Algeria including the last decade. Our results confirm the spatial rainfall distribution (significant rainfall changes only recorded in the southwestern region) evidenced by previous studies, and reveala rainfall decreasing gradient from northeastern to southwestern Algeria. Moreover, they reveal a significant rainfall decreasing trend in the southern Oran region, marked by two particular periods of drought in 1980-1985 and 1999-2003. However, overall, except for the southwestern region, rainfall has not declined since the beginning of the century. While less marked in other regions, these droughts appear to have affected the whole Algerian steppe territories. Our study consequently implies that the climate did not play a leadinginfluence of the ongoing degradation of the vegetation cover of steppe landscapes. Such a vegetation evolution then appears to be have been controlled more by human activities than by climate forcing.

Books by azziz HIRCHE

ROSELT/DNSE/OSS/; Observatoire du Sahara et du Sahel, 2015, 2015

....Dans cette optique, l’OSS a initié la conception et le développement de ce guide technique pr... more ....Dans cette optique, l’OSS a initié la conception et le développement de ce
guide technique pratique destiné à apporter aux techniciens en charge de la
collecte de données un support pratique et de les appuyer sur le terrain.
Ainsi, ce guide permettra aux agents techniques de terrain de :
• Contrôler le concept de surveillance écologique dans ses dimensions
scientifique et technique.
• Maîtriser les protocoles et les techniques de collecte de données écologiques
au niveau des sites d’observation.
• S’approprier les procédures d’analyse et de traitement des données collectées
au niveau des observatoires et en particulier le calcul d’indicateurs.
- 13 -
Guide Technique Écologie
Ce travail passe par les étapes suivantes :
• Identification du kit de données à collecter : analyse, intégration et
harmonisation des méthodes existantes développées dans le cadre de
ROSELT/OSS et du DNSE pour aboutir à un protocole opérationnel et
scientifiquement consistant, au moindre coût.
• Identification de la démarche technique pratique de calcul et production
des indicateurs : indicateurs de la désertification, de la biodiversité, des
changements climatiques.