The Shrublands and shrub-dominated woodlands biome includes oligotrophic systems occurring on acidic, sandy soils that are often shallow or skeletal. Classically regarded as ‘azonal’ biomes or ‘pedobiomes’ (i.e. biomes determined by soils), they are scattered across all landmasses outside the polar regions, generally (but not always) closer to continental margins than to interior regions and absent from central Asia.

Productivity and biomass are low to moderate and limited by soil fertility. The effect of nutrient poverty on productivity is exacerbated in tropical to mid-latitudes by water deficits occurring during either winter (tropics) or summer (temperate humid and Mediterranean climates) and by low insolation and cold temperatures at higher latitudes. Trophic networks are simple but the major functional components (photoautotrophic plants, decomposers, detritivores, herbivores, and predators) are all represented and fuelled by autochthonous energy sources.

Shrubs are the dominant primary producers and possess a diversity of leaf and root traits as well as mutualistic relationships with soil microbes that promote the capture and conservation of nutrients. Recurrent disturbance events exert top-down regulation by consuming biomass, releasing resources, and triggering life-history processes (including recruitment and dispersal) in a range of organisms.

Fire is the most widespread mechanism, with storms or mass movement of substrate less frequently implicated. Storage effects related to re-sprouting organs and seed banks appear to be important for maintaining plant diversity and hence structure and function in shrublands exposed to recurring fires and water deficits.