Southeastern Spain is the driest region of Western Europe. Rainfall ranges between 200 and 300 mm/year. Near-desert landscapes, without trees and covered by shrubs, dominate the zone. According to the traditional view, these landscapes existed before any anthropogenic processes of degradation began. However, historical documents and place-names demonstrate that forests played an important role in this territory up to the 19th century and that a great diversity of fauna prevailed, including such forest species as bear, lynx, deer and roe deer. In this paper we will show how economic activities and demographic pressure on these fragile ecosystems changed them irreversibly in a short time. We develop a historical analysis of the relationships between human activities and the environment from the end of the Islamic period (16th century) up until the 20th century, focusing especially on agriculture, mining and demography. Keywords: Environmental history, Economic history, Arid zones, Southeastern Spain.