Heterogeneity, Dynamism, and Diversity of Natural Systems.- The Concept of Disturbance.- Role and Effects of Disturbances in Natural Systems.- The Disturbance Regime.- Disturbances and Coexistence of Species.- Classification Criteria for Disturbance Events.- Categories of Natural Disturbances.- Anthropogenic Threats.- Nomenclature and Taxonomy of Threats.- Threat Regime.- Threat Quantification and Ranking.- Threat Mapping.- Including Threats in...