Small wetlands lost: a biological conservation hazard in Mediterranean landscapes

Abstract

In Spain, it is estimated that 60% of wetlands have disappeared in the last 50 years. The present study aimed to describe the relationships between loss of wetlands and land-use change in Azuaga County, Central-western Iberian Peninsula where during the period 1896-1996, 94% of the original wetlands disappeared. Forest, scrub, holm oak dehesas and olive groves have become fragmented or disappeared completely, having been substituted by eucalyptus plantations in areas of low productivity and by dry cultivation of herbaceous crops, mainly cereals, in more productive areas. These substitutions have resulted in a homogeneous, coarse-grained landscape with low diversity and high dominance. The type of land-use has depended on the evolution of demographic processes, with high human immigration rates toward the end of the nineteenth century and beginning of the twentieth century, and high emigration rates during the 1960s and 1970s. The mechanization of agriculture and transition from closed to market economy in the second half of the twentieth century also played an essential role in the landscape changes described.