Regional Conference on Plant Genetic Resources in West and Central Africa

This Conference was convened by IPGRI and held at IITA-Ibadan, Nigeria during 26-30 April 2004.

The Desert Margins Program presented a collective paper by all country coordinators entitled 'Elements of agro-biodiversity conservation and use in the desert margins of Sub-Saharan Africa'. This report presented some preliminary findings of the DMP's in-depth studies at its benchmark sites in each member country, where scientists carefully describe the current state of biodiversity, and monitor changes over time as human pressures on the land change. This information is vital for guiding policies and practices to protect native biodiversity.

These studies were finding that, in contrast to other arid and semi-arid areas of Africa, there are relatively few species that are endemic to the Sahel (i.e. originated there and nowhere else). Many bio-geographers consider the Sahel to be a transition zone between the Soudano-Zambezian and the Saharo-Sindian zones of endemism.

The low biodiversity of the Sahel is probably for two main reasons:

• Large fluctuations in climate associated with drought/recovery cycles, preventing the stable evolution of types adapted to a fixed set of conditions; and

• The relatively homogeneous soil, which does not provide selective pressure for genetic diversification.

Other arid or semi-arid systems such as the Karoo-Namib in Southern Africa and the horn of Africa are more diverse in terms of soil and stable in terms of climate, and are correspondingly more biodiverse as well.