Deserts and xeric shrublands
A terrestrial biome of low precipitation and sparse vegetation, where plant and animal communities persist under dry conditions.
Aridity: A persistent climatic deficit of water, measured by comparing precipitation with atmospheric demand for moisture. It defines dryland conditions more precisely than low rainfall alone.
Desert pulse-reserve paradigm: An ecological framework in which brief resource pulses are captured, stored, and later reused in deserts. It explains how irregular rainfall can sustain biological activity between storms.
Dryland restoration: The repair of degraded dryland ecosystems through measures that restore soil, vegetation, and ecological processes. Restoration must work with scarce water and slow vegetation recovery.
Semiarid climate: A climate with low precipitation but enough moisture to support more continuous vegetation than in hyperarid regions. Its greater water availability often supports grasslands or denser shrub cover near desert margins.
Sahara: The largest hot desert, spanning much of North Africa. Its enormous area contains sand seas, rocky plateaus, and diverse arid habitats.
Potential evapotranspiration: The amount of water that could evaporate and transpire if moisture were freely available. Comparing it with precipitation reveals the climatic water deficit that shapes these biomes.
Soil seed bank: The viable seeds present in soil and litter, often including seeds awaiting suitable conditions to germinate. Many annual desert plants persist through dry years as dormant seeds.
Desert agriculture: Crop and livestock production practiced in arid environments using adapted methods and limited water supplies. Agriculture in deserts depends on managing water availability and soil salinity.
Tundra: A cold biome with low-growing vegetation, frozen soils in many regions, and a short growing season. Tundra can appear sparse like a desert, but cold rather than water shortage chiefly limits growth.
Atacama Desert: A desert in western South America known for exceptionally low precipitation in many areas. Its extreme aridity illustrates how ocean and atmospheric circulation can suppress rainfall.