**2. The 'bandoneon desert'. Concepts and nature of the Sahara**

It is fascinating to see that the old concept of an extension of one large ecosystem on the cost of another – here the advancing/encroaching desert into the savannas is still taken as valid. The alarm of Stebbing [19] of an advancing desert in the Niger-Nigeria border region was rapidly disproved by a common French-English – Forester expedition [20]. More than half a century later, Tucker et al. [21] presented the model of an expanding and retracting Sahara, which he considered as desert for the whole in the scale of years. Their conclusions were based on interpreted vegetation changes with help of satellite images; however, without any differentiation between permanent and short-time plant cover. Another less meaningful approach was presented by Thomas and Nigaru [22], who claimed a 10% expansion of the Sahara/desert since 1920 both to the North and to the South. The authors based

**65**

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example…*

their conclusion on changes in precipitation as they defined ecosystems/landscapes

Thus, we have to deal with a variety of methods and concepts in the analysis of landscapes/ecosystems in northern and western Africa. We take the term 'landscape' we take in a broad sense as a characteristic part of the earth's surface, which is defined by various features such as vegetation, relief or the intensive human impact, which developed in time, and which is visibly different from neighbouring

**A.** Field observation and subsequent definition of landscape – or vegetation

**B.** The characterisation of recognised landscapes and definition of leading

**C.** A difference in the concept of consistent or transition zones. 'Sahara' as the transition from the Mediterranean to the 'Sahel' [24] or the 'Sahel' as transition

**D.** Reduction of landscapes/ecosystem (and climate too) to a single feature such as rainfall. It is the main cause of confusion on the dynamics of the large

impedes often a neutral recognition. Mostly, the terms 'Sahara' and 'desert' are

Thus, it is necessary to explain clearly the terms in order to avoid confusion and to define them from direct observation in the field – or at least from clear descriptions.

A vegetation map of northern and western Africa was established in order to explain clearly the large vegetation types and their repartition. It is based on direct observation during several expeditions (see the small included map) and on published vegetation maps [27]. It deals with the physiognomic units such as forest, shrub-land or grass-land and gives the main floristic components. There is no differentiation between natural formation, near to nature formation or cultural units; however, their dynamics are shortly discussed. Here, we will concentrate on the South-Mediterranean steppe, on the Sahara and on the Sahel to give a background to the discussion about limits, their dynamics and their regeneration potential. Block diagrams and designs will support it. Thus, we will try to avoid the various confusions on terms such as 'steppe or prairie'. The map is to document visible units and their limits and to work as a modern model when reconstructing the past. The question of limits might be regarded as an academic one. However, it is an assess-

**3.1 The southernmost formation of the Mediterranean realm is the 'steppe'**

For both the statement of Cole [28] is still valid: 'Most discussed and least

The term 'steppe' is freely used in literature – comparable to the term 'savanna'.

**E.** A main problem is the emotional component in the term 'desert', which

aftermath of the colonisation with Chevalier [23] as an example.

features of their vegetation or geomorphology.

from the 'Sahara' to the (real) savannas [25].

ecosystems in northern and western Africa [26].

used as synonyms – see [24].

**3. What are we talking about?**

ment of resource areas-mainly of pasture.

types. This was the procedure at the beginning of the twentieth century in the

*DOI: http://dx.doi.org/10.5772/intechopen.87030*

exclusively by mean annual precipitation.

regions.

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example… DOI: http://dx.doi.org/10.5772/intechopen.87030*

their conclusion on changes in precipitation as they defined ecosystems/landscapes exclusively by mean annual precipitation.

Thus, we have to deal with a variety of methods and concepts in the analysis of landscapes/ecosystems in northern and western Africa. We take the term 'landscape' we take in a broad sense as a characteristic part of the earth's surface, which is defined by various features such as vegetation, relief or the intensive human impact, which developed in time, and which is visibly different from neighbouring regions.


Thus, it is necessary to explain clearly the terms in order to avoid confusion and to define them from direct observation in the field – or at least from clear descriptions.
