The formation of agriculture in Africa is a response to neolithic era Sahara dessication and what seems like a greater population strain as a result of the adoption pastoralism.
I did conceive of an OTL that reaches back to the Green Sahara period from before the most recent one but thought it would be far too long and "boring".
It centers around small clusters of people who survive in the Sahara highlands around wadis, wells and fossil water sources subsisting on North African date palms, honey and Ammotragus lervia.
The intensive reliance on food and material resources is the impetus for trade and resource consolidation creating complex stratified systems that would be very dynamic once greening occurred again.
I focus on Phoenix dactylifera for a number of reasons
1. It's already native to North Africa
2. It's an indicator species of ground water/high water tables
3.it's a very big water dependant species but dense enough to be very efficient and act as a "nurse tree" for other crops
4. Leaves can be fodder for sheep and it's pollen is useful to bees
5. Most importantly it sprouts vegetatively and so like everywhere else it's less a matter of domestication and more so adventageously propagating mutants that happen produce more or more consistently
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Bees and apiculturists pursuits are very worthwhile and supportive of non-deforesting caloric intake.
Just have flower fodder and it thrives, this limits cutting down olive and other trees that OTL are given a sacred status amongst desert people's like North African olive, saharan Myrtle, Saharan "acacia", etc...
We have a great body of work about Okiek foraging communities that were in fact gardening apiculturists who traded honey with herders and it is seen as a transitional trade good between Herders and "hunters"
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Ammotragus lervia aka the Barbary goat was actually contained in caves and feed during the first of a two part greening OTL in the Neolithic Saharan. It was abandoned with dessication but it can still theoritically persist in a slash and take tree fodder system.
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Part of me would love to have giraffes because they were recorded in stone carvings and cave paintings as being lead by ropes or chains in Saharan art. They'd be perfect in this agroforestry system but to maintain genetic diversity the amounts of energy and labour is just too much.
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Anyways with Barbary goats you'd really be able to take advantage of green grasslands and with higher stocking be able to really some damage on populations of non-human hominids elsewhere.
The spread of disease from them could collapse wild life like rinderpest did in 19th century East and South Africa and destroy the subsistence economies of Eurasian neanderthals and others leaps and bounds.
Having a stratified society in Oasis would dramatically shift once water availability broadens but you know some aspects would persist, maybe for the better or worse but what ev's
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Oh and early ceramic culture, use of pitch in waterproofing, maybe early exploitation of surface copper in the air used as luxury goods for early trade?
Sky's the limit, just do research and do this ATL right or else I'm gonna read you to bits and pieces