human impactsThe ecosystems of the Chilean Winter Rainfall-Valdivian Forests face severe pressure from human activities and development. Chile has one of the fastest growing economies in Latin America and is still strongly dependent on natural resources. Most of the major threats are concentrated in the Mediterranean subunit in the southern part of the hotspot, where a high percentage of the Chilean population lives today. Habitat degradation and forest clearing began in the 16th century with the arrival of Spanish colonists. In subsequent years, huge areas of deciduous and evergreen forests were burned in the south. Forest cutting for timber and fuel wood continued well into the 20th century. Since the 1970s, the establishment of large-scale pine and eucalyptus plantations have spurred the clearing of 20,000 km² of native vegetation in the southern portion of the hotspot including the diverse forests of the Coast Range. These man-made forests are valuable for soil stabilization and halting erosion, but they fragment remaining stands of native vegetation. This splintering slows gene flow among plant species and acts as a barrier to many habitat-specialist animals.Other major threats to the integrity of Chilean ecosystems include accidental and intentional forest fires. Unlike the other Mediterranean-type climate zones, fires are not a major natural part of the ecosystem in the Chilean Winter Rainfall-Valdivian Forests, and plant and animal species are not adapted to its effects. Between the 1970s and 1990s, an estimated 360-600 km² were burned each year in this region. The Monterey pine (Pinus radiata) is a non-native, fire-adapted species that is often planted on Chilean tree plantations; fires here can easily spread to vulnerable native forests. Overgrazing by domestic animals has also contributed to the heavy degradation of matorral vegetation below the treeline. Grazing by goats and European rabbits, introduced in the early 1900s, threatens native vegetation in the drier parts of the north. Throughout the hotspot, invasion by introduced weedy species and perennial shrubs, assisted by forest fires and overgrazing, is crowding out native vegetation. The illegal trade and export of native species, particularly reptiles, is also a problem in some cases. As is the situation in nearly all of the world's hotspots, other threats include various forms of urbanization. Two examples from the Chilean Winter Rainfall-Valdivian Forests region are the development of coastal areas for tourism and the construction of highways and hydroelectric complexes. In total, about 30 percent of the hotspot's original vegetation remains in pristine condition, much of it in the winter-rainfall deserts subunit.
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© Jim Sanderson
The delicate biodiversity of central Chile is being heavily impacted by habitat loss and degradation.
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