Sahel desert

Summer monsoon rains are responsible for tropical rain forests in Central Africa. The interface between this region and the Sahara Desert varies over time. When the boundary is relatively far north, rain falls on the Sahel desert region at the interface, crops grow, and the people do relatively well. When the boundary is more to the south, a condition that may last for several years, devastating droughts and even... 

Lahr, J. (1998) An ecological assessment of the hazard of eight insecticides used in Desert Locust control, to invertebrates in temporary ponds in the Sahel, Aquatic Ecology 32 (2), 153-162. 

Wliile most researchers in the field agree on the relative importance of biospheric feedbacks operating at high northern latitudes, the discussion becomes more interesting and diverse as the subtropics are concerned. Climate reconstructions and data on fossil pollen compiled by Jolly et al. (1998), Hoelzmann et al. (1998), Pe-tit-Maire (1996), and Anhuf et al. (1999) indicate that North Africa was much greener in the mid-Holocene than today. The Saharan desert was, presumably to a large extent, covered by annual grasses and low shrubs. The Sahel reached at least as far north as 23 °N, more so in the western than in the eastern part. 

A significant feature of the Sahel is the Sahel dust zone that develops predominantly from December to April each year. Characterized by frequent dust storms and high levels of atmospheric dust blown mostly from the Sahara desert, the Sahel dust zone is located in the latitudes of 10°N-16°N and extends for almost the entire width of Africa from east to west. 

Fixing the dry limit of savannas and dry forests in Africa is more difficult than in South America because of the gradual transition to desert. In South America, the transition between the tropical and temperate zones is occupied by chaco vegetation, which is a dry woodland (Bucher, 1982). If the Scholes and Walker criteria are followed, then much of the Sahel savanna zone (see later) falls outside their definition of savanna, because the growing season is too short. 

GiUet, H., Desert and Sahel, in Plant Ecology in West Africa, Lawson, G.W., Ed, John WUey, Chichester, 1986, 151. 

Charney, J. G. (1975). Dynamics of deserts and drought in the Sahel. Quarterly Journal of the Royal Meteorological Society, 707(428), 193-202. 

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