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Wageningen University (2013)

Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria

Niane, A.A.

Titre : Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria

Auteur : Niane, A.A.

Université de soutenance : Wageningen University and Research center

Grade : Doctoral thesis ( PhD thesis) 2013

Résumé partiel
Rangelands represent 70% of the semi-arid and arid Mediterranean land mass. It is a natural habitat for millions of people whose livelihood depends on animal husbandry. The revolutionary developments in the animal husbandry and veterinary medicines resulted in exponential increases in human and livestock population living on and from dry lands. To respond to population growth, urbanization and transportation means and expanded road networks, land reform and rural development policies forced to adopt semi to fully sedentary lifestyles with disintegrated traditional community structures and organizational frameworks. Under these demographic changes coupled with national and international border crossing restrictions, there was an escalation in opportunistic cultivation, and excessive exploitation of the scarce and slowly renewable vegetation cover resulting in a steep decline in the primary production components of the rangeland ecosystems. In an attempt to stop and reverse the degradation process, large-scale re-vegetation programs based on transplanting and reseeding with perennial shrubs, resting and grazing management systems were devised and implemented. This study aimed to evaluate the impacts of the rehabilitation programs on the above-ground vegetation cover and soil seed bank replenishment in the Syrian rangelands. The underlying assumption of the rehabilitation program is that with a well-established perennial plant cover and proper grazing management, top soil is stabilized, soil moisture, nutrients and seed bank are replenished, organic matter is accumulated and microorganisms’ activity is promoted resulting in greater abundance, species richness and diversity of annuals. To test the above hypothesis, field and controlled environment based studies were carried out with quantitative data collection and processing on plant species abundance, richness and diversity of above-ground vegetation and soil seed bank for fully protected rotationally and continuously grazed areas of 10 rangeland sites in northern Syria for three consecutive seasons. In addition to the use of frequentist statistical approaches for species diversity estimation in the studies, the Bayesian method was explored. Moreover, the crucial issues of seed quality in re-vegetation were tackled through a study on seed viability and longevity in Salsola vermiculata L., which is a highly palatable, well adapted and widely used species in the arid Mediterranean rangeland rehabilitation programs

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Page publiée le 12 janvier 2014, mise à jour le 20 décembre 2021