Which activity is listed as contributing to land degradation in southern Drylandia?

Which activity is listed as contributing to land degradation in southern Drylandia?

• A. Grazing
• B. Mining
• C. Urban development
• D. Tourism

Answer: (A)

In dryland ecosystems, vegetation is sparse and soils are fragile, so the land’s ability to recover after disturbance is limited. Grazing directly challenges this balance: when livestock feed heavily, plant cover is removed and many plants don’t have time to regrow before the next grazing cycle. The loss of cover exposes the soil to wind and rain, while the weight and movement of animals compact the soil, reducing its porosity and infiltration. With limited rainfall, soil moisture decreases further and organic matter declines, triggering a cascade of erosion, nutrient loss, and reduced productivity. This combination creates a persistent degradation cycle that is especially pronounced in southern Drylandia, where pastoral systems are common and stocking rates can exceed the land’s drought-era carrying capacity. While mining, urban development, and tourism can degrade land as well, their impact in this dryland context tends to be more localized or episodic rather than the widespread, sustained driver that grazing imposes on fragile dryland ecosystems.

In dryland ecosystems, vegetation is sparse and soils are fragile, so the land’s ability to recover after disturbance is limited. Grazing directly challenges this balance: when livestock feed heavily, plant cover is removed and many plants don’t have time to regrow before the next grazing cycle. The loss of cover exposes the soil to wind and rain, while the weight and movement of animals compact the soil, reducing its porosity and infiltration. With limited rainfall, soil moisture decreases further and organic matter declines, triggering a cascade of erosion, nutrient loss, and reduced productivity. This combination creates a persistent degradation cycle that is especially pronounced in southern Drylandia, where pastoral systems are common and stocking rates can exceed the land’s drought-era carrying capacity.

While mining, urban development, and tourism can degrade land as well, their impact in this dryland context tends to be more localized or episodic rather than the widespread, sustained driver that grazing imposes on fragile dryland ecosystems.