aridland

Aridland is a term used in geography to describe regions characterized by an arid climate with limited precipitation, high evaporation, and sparse vegetation. The term encompasses deserts as well as semi-arid steppes and savannas where moisture availability constrains plant and animal life.

Climate and geography: Aridlands experience low annual rainfall, often less than 250 millimeters in hyper-arid zones and up to 500 millimeters in semi-arid zones. Evapotranspiration exceeds precipitation most of the year. They lie in subtropical and continental interiors, and can be influenced by cold highland or warm coastal conditions. Köppen climate classifications include BWh, BWk, BSh, and BSk. Rainfall is often seasonal or episodic, with long dry spells and occasional intense storms; dust and sandstorms may occur.

Soils and ecosystems: Soils are frequently aridisols, prone to salinization and erosion. Vegetation is sparse, composed of drought-tolerant species such as succulents, cacti, sagebrush, and grasses; animals adapted to water scarcity and temperature extremes include reptiles, small mammals, and birds. In some aridlands, microhabitats around oases or river corridors support higher biodiversity.

Human use and challenges: Aridlands have supported nomadic and pastoral livelihoods for millennia; agriculture is possible with irrigation, but water scarcity and soil degradation pose risks. Rapid climate change can intensify aridity, increase drought frequency, and expand desertification. Management approaches include water-efficient irrigation, land restoration, rangeland management, and protected areas.