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Accueil du site → Doctorat → États-Unis → 2012 → Environmental Risk Assessment for Habitats of the Egyptian Northwestern Coastal Desert

University of Idaho (2012)

Environmental Risk Assessment for Habitats of the Egyptian Northwestern Coastal Desert

Halmy, Marwa

Titre : Environmental Risk Assessment for Habitats of the Egyptian Northwestern Coastal Desert

Auteur : Halmy, Marwa

Etablissement de soutenance : University of Idaho

Grade : Doctor of Philosophy (PhD) 2012

Résumé
The risk of habitat loss for a selection of important plant species in part of the northwestern coastal desert of Egypt was assessed and projected due to change in land use and climate. The change in land use/land cover (LULC) in the study area was assessed over 23 years using three Landsat Thematic Mapper scenes acquired in 1988, 1999, and 2011. A comparison of the performance of two ensemble techniques, random forest and boosted artificial neural networks (ANNs), for mapping LULC of the study area was conducted. Both techniques performed well using integrated satellite spectral data and ancillary geospatial data. However, random forest showed higher accuracy compared to boosted ANNs, while boosted ANNs showed better generalization and lower overfitting tendencies. The analysis of LULC distribution over the three mapped dates revealed that the landscape has been undergoing dynamic changes over the last three decades. The change analysis shows that the landscape has become patchier and less naturalized. The natural land cover (rangelands, coastal dunes, barren lands, and marsh areas) continues to suffer from dissection and attrition, while the artificial and semi-artificial land covers (resorts, built-up areas, quarries and croplands) are undergoing creation and aggregation. Based on the trend and the rate of change in land use over the study period, projected LULC change scenarios are developed using Markov Chain-Cellular automata approach. To understand how the change in land use and climate might influence the distribution of some important plant species, species distribution models were developed using random forest approach. The prediction of plant distribution under different scenarios of land use and climate change showed that land use change poses risk to all of the modeled species compared to climate change. The assessment of the combined impact of land use and climate change showed that modeled species are expected to suffer loss in habitat with the exception of Gymnocarpos decanderus. This study is the first to account for modeling plant species distribution and quantitatively assess the impact of change in land use and climate on the distribution of plant species in Egypt. The study can provide baseline data and guidelines for conservation efforts directed towards ameliorating the impact of human impact on important plant species in the northwestern coastal desert of Egypt.

Mots clés : African Studies ; Ecology ; Environmental Science ; African Studies ; Ecology ; Environmental Science ; Social Sciences ; Biological Sciences ; Health and Environmental Sciences ; Dried Lands ; Egyptian Coastal Desert ; Environmental Risk ; Habitats ; Land Use/Land Cover ; Species Distribution

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Page publiée le 16 novembre 2017, mise à jour le 9 mars 2019