Influences of Physiographic Factors, Vegetation Patterns and Human Impacts on Aeolian Landforms in Arid Environment

摘要

During the last few decades, the inland and coastal aeolian landforms of southern Kuwait showed severe land degradation and deterioration of plant cover due to human impacts such as spring camping, offroad driving and overgrazing. This study aimed to quantify the edaphic conditions and vegetation composition of the main types of aeolian landforms in the southern desert of Kuwait and to investigate the effects of vegetation, climate, physiography and impacts of anthropogenic activities on the features and stability of aeolian sand deposits and subsequently land degradation and vegetation loss. This study classified the southern aeolian deposits into four main landforms: inland active sand sheets, inland stable sand sheets, coastal stable sand sheets and coastal stable sabkhas. These landforms are mostly influenced with soil texture, moisture content, organic matter, salinity, vegetation cover, wind strength and intensity of land use. A total of 46 plant species in 23 families was found in these landforms. Poaceae species dominated the vegetation of inland active and stable sand sheets; however Asteraceae and Chenopodiacea species dominated the vegetation of coastal stable sand sheets and coastal sabkhas. Therefore, the growth of these species in hot deserts is adaptive to the accumulation of wind-borne sediments within or around their canopies. Annuals and perennial herbs were the dominant growth forms in the aeolian landforms. The Shannon-diversity of the plant species was lower at inland stable sand sheets than at inland active sand sheets, coastal stable sand sheets and coastal stable sabkhas. The dominant perennials were Cyperus conglomeratus , Stipagrostis ciliata and Moltkiopsis ciliata at inland aeolian landforms, and Zygophyllum qatarense , Salsola imbricate , Suaeda aegyptiaca , Cyperus conglomeratus and Launaea mucronata , Suaeda vermiculata , Lycium shawii and Halocnemum strobilaceum at coastal aeolian landforms. The dominant annuals were Schismus barbatus at inland aeolian landforms and Polycarpaea repens , Schismus barbatus , and Cornulaca aucheri at coastal aeolian landforms. Deterioration of plant cover, decline in sub-shrubs and shrubs, lacking of trees and severe land degradation in the inland and coastal aeolian landforms of southern Kuwait are attributed to human impacts. Effective management plan for human activities and restoration program for degraded aeolian landforms may include prohibitions of human activities that adversely affect native plant communities, planting of certain native perennial species efficient in trapping sands and stabilization of aeolian landforms, such as Poaceae species and Chenopodiaceae species. In addition, awareness programs and participation of local inhabitants are crucial measures to guarantee successful of restoration plan.