Nothing but Sand
Human encroachment, agriculture, livestock grazing and climate changes have dramatically increased the conversion of fragile grasslands to deserts worldwide. A major impact of desertification is loss of biodiversity and decreased capacity to produce crops. Ironically, droughts are common in these arid and semi arid lands and well-managed lands can recover if damage during droughts can be minimized.
Did you know?
Desertification has its greatest impact in Africa where two thirds of the continent is desert or drylands. Source: United Nations Convention to Combat Desertification.
Environmental engineering Associate Professor John Albertson is studying the combined effects of rainfall dynamics and grazing on African savanna desertification or woody encroachment. In a recent Global Change Biology journal article, Albertson presented an analysis of long term dryland vegetation dynamics that characterizes and classifies the ecosystem’s response to climate and land use conditions,and may help decision makers more effectively and sustainably manage land resources.
Albertson’s team found that both high grazing intensity and lower rainfall can lead to frequent and prolonged periods of degraded grasslands. Further, once grass reaches a degraded condition, woody vegetation strongly suppresses recovery even if later rainfall is high. This research suggests that the widely projected increase in rainfall variability caused by global climate shifts will likely lead to decreased grass cover -- and ultimately to higher risk of desertification, if land use guidelines are not adopted.
John Albertson website: http://www.cee.duke.edu/faculty/albertson/index.php