Lichen Hill

Just outside Alexander Bay is a small hill - sticking out in orange among the dull greys, browns and whites of the sand and stone in the southern Namib desert. Passers-by will usually just keep on going, not knowing the uniqueness that lies hidden there. To be absolutely honest, there is no place like that anywhere in the whole wide world...

Although the hill seems orange in colour, there are actually no flower-bearing plants on the hill. Every now and then you may see a few conophytums, lithops or other desert plants, but the majority of the hill is covered in a layer of rod-like structures – 10cm thick. Laymen will be excused thinking of these structures as plants, strictly speaking these are neither plants nor animals. These are lichens.  They are symbionts, composed of microscopic algae and fungi. Fungi do not have chlorophyll and do not photosynthesize to produce their own food. A lichen`s fungal part is thus fed by its photosynthesizing algal part. The algal part on the other hand benefits from the association because the fungus are better in finding, soaking up and retaining water and nutrients than they are.  The fungus also provide the resulting lichen shape and the reproductive structures. This type of symbiosis where two organisms live together in synchronised harmony to the benefit of both, is called mutuality. 

What makes the 50ha hillock near Alexander Bay so singular is the diversity and density of the lichen species. As stated by a survey more than 30 different lichen species exist here.

The most probable reason for this is the offshore sea fog. Even though lichens are found mainly in desert-like environments, they cannot live without water. The warm inland at Alexander Bay causes regular strong sea breezes during the daytime, often bringing with it the offshore fog. And this seems to bring the ideal circumstances for lichens to flourish.