Modern mediterranean-type ecosystems (MTEs) are shaped by key ecosystem drivers that affect their function. The most important of these drivers are climate, topography, soils, and fire. There are important geographical, climatic, and fire histories that are crucial to understanding these systems. Mediterranean-type climate (MTC) is defined as a cool wet winter (winter-wet) and a warm dry summer, which is a unique pattern of seasonality and one that is rare globally. All of the MTC regions have nutrient-poor soils, particularly as related to nitrogen (N), and some also have extensive phosphorus-poor soils. There is considerable variation both within and between regions in their degree of nutrient impoverishment of soils. Through these shared ecosystem drivers, selection has operated within each ecosystem to shape the communities and the organisms within them. This has resulted in the communities and organisms displaying similar structures and processes.