How does desertification reduce the productivity of dryland ecosystems?

Desertification is not the physical expansion of existing deserts, but rather the process by which natural or human-induced factors reduce the biological productivity of drylands, including grasslands and scrublands.1

Productivity in these ecosystems is reduced through several mechanisms:

• Climatic Stress: Arid and semiarid environments rely on sparse, variable rainfall. Extended droughts can rapidly diminish biological output.2
• Human Disturbance: Activities such as overgrazing, unsustainable irrigation, and the removal of native vegetation—particularly shrubs that help cycle nutrients and stabilize soil—significantly degrade ecosystem health.13
• Soil Degradation: In rain-fed croplands, the use of annual crops leaves soil exposed to erosion by wind and water. Unlike native perennial species, which have deep roots that bind the soil, annual cultivation leads to the loss of topsoil and vital nutrients.4
• Resource Scarcity: Consequences include the loss of forage for livestock, reduced woody biomass, and a decrease in groundwater stocks.2