Die natiirlichen Grundwasseraustritte in der Naukluft und ihrer Umgebung (Namibia): Hydrogeologische Situation und okologische Bewertung

摘要

The investigation took place in the karstified Naukluft- and Tsaris Mountains, located in central Namibia. The 31 inspected springs showed a widespread range, from small water filled pools, without vegetation to large spring brooks, stretching for miles, and fringed by a forest. All analysed water samples fulfilled the namibian standards and were declared suitable for drinking water. It was ascertained that all examined springs are fed by groundwater coming out of aquifers just below the surface and having a little ability of retention. In addition to this there are at least two groundwater levels which are not connected with each other. Bioindicators (Odonata) were used in order to find a correlation between the test results, local factors and the distribution of these organisms. The potential diversity of the Odonata consists of 9 Zygoptera- and 21 Anisoptera species. During the fieldwork 25 of these species were identified in the investigation area which can be deemed to be an isolated habitat. The physico-chemical properties of the spring waters seemed to be no limiting factor for the distribution of the Odonata. The realization of a hydrogeological, climatical and biological monitoring could be helpful to strengthen the expressiveness of the results of this study.