Ecology is a young science. It was defined as the total relationship between organisms and their environment, including other organisms. The alternation, fragmentation and finally loss, of natural habitats are the major causes of the increasingly rapid decline in overall biotic diversity. For communities and important processes, however, conditions may be altered long before any of the individual species actually disappear. From a conservation perspective this often means that even if all species survive locally, their densities may become reduced and their ecological situation changed due to a different pattern of interaction with surrounding communities or environmental conditions. Consequently, because of the need to study how changing spatial patterns affect the dynamics of fauna and flora, new interdisciplinary paradigms such as patch dynamics, landscape ecology and conservation biology have all developed and are currently trying to develop, guidelines for the preservation of biological diversity at different geographical and temporal levels.