What Do We Know About the Succulent Karoo?

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Contents
1. Title: What do we know about the Succulent Karoo?
2. Background
3.1 Introduction
3.2 Description of the succulent karoo
3. Physical environment
4.3 Soil
4.4 Climate

4. Patterns
5.5 Diversity
5.6 Endemism
5.7 Flora

5. Growth form and water relations
6. Current activities in the succulent karoo
7. My idea.

What do we know about the Succulent Karoo?

Introduction
Stretching from Namibia down the west coast of South Africa, the Succulent Karoo is a vast, semi-arid desert, with mountain ranges, ancient rock formations, wild coastlines and clouds of stars arching overhead at night. The succulent karoo is home to more than 6,300 plant species, almost half of which occur nowhere else in the world, it is a secret land of weird and wonderful succulent plants which is the richest on the planet, among which run an eclectic mix of insects, reptiles, scorpions and arachnids, all adapted to the arid conditions of the region, where moisture is largely gained from dense sea fogs. The region has one of the highest species densities and levels of endemism at both local and regional scales(Hilton-Taylor 1996). This review will be focused mainly on the biodiversity (flora & fauna) of the succulent karoo, considering its environmental condition Description of the succulent Karoo

The succulent Karoo covers an area of about 111.212 km, some 5.35% of southern Africa. Succulent Karoo boundaries are roughly congruent with those of the western domain, a regional centre of endemism. The succulent Karoo can be distinguished on the bases of the low (a mean of 253 mm per year) but reliable and seasonal rainfall(Cowling, Rundel et al. 1998). More than 40% of the rainfall occurs during the winter season, with a large portion of the area receiving more than 60% in the winter. Within the succulent Karoo there is a small area that can receive rainfall at any time of the year, while the eastern extremes have autumn and summer rainfall with peaks in March and November. Fog plays an important role in supplementing precipitation from rain. Measures from southern coastal section have indicated that precipitation from fog can amount to 300 mm per annum. The minimal temperatures are sufficiently high to prevent frosts and if frost occurs, it is never serve. Geology and topography of the succulent Karoo are quite diverse. The altitudes range from sea level to 1900 m. However, most if the area is below 800 m. The succulent Karoo can be divided into a number of smaller areas which are differentiated by their geology, topography, total amount of rainfall received and season of rainfall (Hilton-Taylor, 1994). These differences also results in different floristic for each area. These areas are named Southern Namib Desert, Gariep centre, Namaqualand Rocky hills, Kamiesberg, Sandveld, Vanrhynsdorp centre (or Knersvlakte), Western Mountain Karoo and Roggeveld, Tanqua Karoo and Worcester-Robertson Karoo and little Karoo.

Physical environment
Soil
Great diversity of soil types can be found within the succulent Karoo. As in the Namaqualand, the soils can be broadly grouped onto three categories(Desmet 2007), which are: Weakly structured grey, yellow or red medium grained sands of the Sandveld and Bushmanland derived from fluvial deposits. These soils contain about 3% of clay and these sands are usually underlain by silica or calcium rich hardpans. Shalow, undefferented and free drainind red and yellow, variably grained sand to loamy soils of the Kamiesberg and Richtersveld derived weathering of the underlying parent material. As well as red, base rich, granite-derived colluvial soils rich in clay of the inland margin of the coastal plain under the Hardveld. These soils have a dorbank underlying them(Desmet 2006). The distinctive pock marked patterning of the landscape remain irrespective of termite activity on large circular termitaria due to the changes in soil...
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