Plant Biodiversity in the Semi-arid Zone of Tunisia
摘要
Plant biodiversity which is a base for supporting ecosystems brings not only contribution to our life as resource materials, but also various ecosystem services such as environmental adjustment functions. Plants in arid and semi-arid zones are very sensitive to climate change. For example, if there is a slight decrease in the amount of rain, the landscape is changed like a desert. On the other hand, vegetation with high biodiversity has plasticity to climate change. Therefore, it is important to manage the biodiversity in semi-arid zones to prevent desertification. In Tunisia, arid and semi-arid zones are distributed in the central and southern parts of the country. Field survey was carried out in November 2008 and November 2009. Field survey was conducted in the semi-arid zone of Tunisia wherein 17 study sites were set in locations with diverse vegetation types. Plant species composition and coverage were measured in 5 × 5 m quadrat. Results showed that the number of species richness ranges from two to twenty-two. The lowest species richness was found to be in steppe that is dominated by Stipa tenacissima or Halocnemum strobilaceum. The highest species richness was measured at steppe dominated by Retama raetam. We use diversity indexes (Shannon’s H’ and Simpson’s 1 D) to rate the important factors for biodiversity conservation.