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Ain Shams University (2018)

Effect of Climate Changes on the Vegetation of Fayoum Protected Areas, Western Desert, Egypt

Ali, Aliaa Muhammad Refaat Khalil

Titre : Effect of Climate Changes on the Vegetation of Fayoum Protected Areas, Western Desert, Egypt

Auteur : Ali, Aliaa Muhammad Refaat Khalil.

Etablissement de soutenance : Ain Shams University

Grade : Master of Science (MSc) in Botany 2018

Résumé
Climate is the dominant determinant of the spatial distributions of plant species and vegetation in general. As the rate and magnitude of climate change accelerate, understanding the consequences becomes increasingly important. It becomes well known that rapid climate change affects current and future vegetation patterns. Since Protected Areas (PAs) have been established globally as vital areas for in situ biodiversity conservation, the effectiveness of PAs to conserve species distributions under climate change has been questioned. Unfortunately, climate change is likely to alter the species composition of PAs, with significant implications for conservation. For the last decades it has been recognized that species might move into, or out of, parks and reserves as climate changes. So, two PAs were selected ; namely, Qaroun PA (QPA) and Wadi El-Rayan PA (WRPA), located in Fayoum, Western Desert, Egypt, to study the effect of climate change on their vegetation. To do so, firstly, the vegetation ecology of the two PAs were studied using three types of analyses ; vegetation, soil, and multivariate analyses. That is to obtain an effective analysis of vegetation-environmental relationships and to provide us with deeper knowledge about the species compositions and the habitat diversity present in the both PAs. A total of 62 stands were chosen to represent the habitat diversity. Both methods of multivariate analyses were performed ; Classification of stands was done using Two-Way Indicator Species Analysis (TWINSPAN), while their ordinations were assessed using two methods ; Detrended Correspondence Analysis (DCA), and Detrended Canonical Correspondence Analysis (DCCA). The resulted vegetation groups lie under three main habitat types ; wetlands, low land desert, and plain desert, dominated by Phragmites australis, Alhagi graecorum, and Tamarix nilotica respectively. Secondly, these three dominant species were used to study and demonstrate the effect of climate change on their future potential spatial distribution which would, in turn, illustrate the spatial distribution of the whole habitat (vegetation) present in the study area. Species distribution models (SDMs) are one of the most important tools currently available to assess and demonstrate the potential impacts of climate change on species distribution. A total of 5 different SDMs were built using climate projections available from 1 General Circulation Model (GCM) under the higher Representative Concentration Pathways (RCP 8.5) for each of the three dominant plant species. Among these SDMs, there are 4 single models ; namely, (ANN, GBM, GLM, and RF) and 1 ensemble (consensus) model using the weighted average of the single models. SDMs were built for current climate (2016), 2050 (average climate for 2041–2060), 2070 (average climate for 2061–2080), and 2080 (up to 2100). The future potential distributions results of the three species show dramatic range contractions from their current potential distributions in both PAs. The results also indicate an overall range-shifting of the three species towards the north-west, losing their current potential habitat in both protected areas. This study can act as an early warning of climate change effects on valuable habitats and species present in only two protected areas in Egypt. The results can be further useful for conservation managers to start thinking of adapting policy that can reduce the extinction risk of this valuable species and habitats present in the protected areas.

Présentation étendue (EULC)

Page publiée le 4 avril 2020