期刊名称：Journal of Environmental Science and Water Resources
印刷版ISSN：2277-0704
出版年度：2015
卷号：4
期号：3
页码：071-091
出版社：Wudpecker Journals
摘要：The aim of the present work is to study the effects of dam on the vegetation of arid region in terms of species composition, life form, chorotype and economic uses in relation to type of wadi. Multivariate techniques and species diversity indices have been used to differentiate vegetation groups and to assess the effect of dam on the vegetation types in the study area. Two wadis were selected in the same area (Wadi Sissed with dam and Wadi Al - Arg without dam). Eighteen stands were selected in the study regi on. Life forms, global geographical distribution and economic uses of the recorded species were determined. Two hundred and twenty three species belong to 49 families and 150 genera were recorded along the two wadis: 66 annuals and 157 perennials. The fami ly Asteraceae has the highest contribution, followed by Poaceae and Fabaceae. Saharo - Arabian elements are the most represented chorotype, followed by the Sudano - Zambzian, Irano - Turanean and Mediterranean elements. The life form spectrum indicated that chamaephytes and therophytes were the most represented. The economic uses of the recorded species could be arranged descendingly as follows: grazing . medicinal . fuel . human food . other uses. The application of TWINSPAN and DECORANA techniques to the v egetation data led to the recognition of 4 vegetation groups (communities): three vegetation groups are represented Wadi Sissed which has a dam (I: Aerva javanica, III: Typha elephantine, IV: Pluchea dioscoridis and one vegetation group is represented Wadi Al - Arg without dam (II: Tamarix nilotica) which divided into three sub - groups ( A: Tamarix nilotica , B: Cynodon dactylon and C: Mentha longifolia - Nasturtium officinale ). The present study can conclude that the construction of dams may effect on the vegetat ion
关键词：Multivariate analysis; Diversity; chorotype; plant communities; Saudi Arabia
