Plant-mammal interactions: lessons for our understanding of nature, and implications for biodiversity conservation

摘要

Over the last few millennia, natural ecosystems have been transformed, polluted or degraded to varying degrees, as a result of human activities. With the advent of increasingly more sophisticated remote-sensing technologies and with the use of models and geographical information systems, we can have revealing pictures, assessments and even projections of the degree of transformation of the natural ecosystems of the Earth (e.g. Alcamo et al. 1998; Sala et al. 2000). Evaluations of the contemporary patterns of land-use and land-cover change at global, regional and national levels have been undertaken by several national and international projects, and the images and statistics they provide are appalling. This is particularly evident and currently very much publicized in the case of tropical forests. For example, a recent assessment at the global scale indicates that the current rate of tropical deforestation may be of the order of 15.4 million hectares per year, most of it concentrated in the tropics of the New World, where the most extensive tracts of forest still remain (Whitmore 1997).