Iberian steppes

Abstract

In Spain, the extensive, largely treeless areas in semi-arid environments are considered as steppes, dominated by small shrubs, with forbs and grasses (dwarf shrub steppes). The main factor for their occurrence seems to be climatic continentality and drought. The Iberian steppe vegetation contains plant species of South Mediterranean Irano-Turanian and of Mediterranean Saharo-Sindian af fi nities. The Mediterranean- Irano-Turanian element consists of eastern steppe species that spread through the Mediterranean basin, with many vicariances at generic level . The Mediterranean- Saharo-Sindian element of the Iberian steppes consists of plants derived from the Tertiary subtropical fl ora of the open African spaces. Plant endemism reaches 42% in the Iberian steppes. The steppes harbour steppe bird communities with highly endangered species. Steppe birds in general depend very much on the structure of the vegetation. Many bird species are seriously at risk, while processes, like agricultural intensi fi cation, abandonment of grazing, changes of land use, and construction activities, cause degeneration and destruction of many steppe areas.