WILD FRUIT-TREES AND SHRUBS OF SOUTHERN AFRICA - GEOGRAPHIC-DISTRIBUTION OF SPECIES RICHNESS

Fruit trees and shrubs dominate the edible flora of Africa. Does their geo graphic distribution differ significantly from that of the woody flora in general? Based on analyses of macro-scale geographic variatio ns in the species richness (hereinafter SR) of southern Africa's trees and shrubs, there is a west-to-east trend of increasing edible-fruit- providing SR that is similar to that of woody plants as a whole and ir t accord with changes in climate and vegetation. Distinct from this pa ttern, the percentage of edible fruit-providing species increases nort hwards and towards the interior of Africa, with an unexpected broad su bcontinental zone of relatively high percentages of edible fruit speci es separating rich nutritional resource areas (high edible SR) from nu tritional deserts (low edible SR). This is consistent with humans and other. wide-ranging vertebrates (e.g., elephants) dispersing edible fr uit species into normally less than ideal (nutritional) environments d uring cyclical and/or episodic periods of wetter climate.