Degradation or destruction of large natural environments, as well as environments partially modified or cultivated by man (including forests, rangelands, wetlands and aquatic ecosystems), designated wilderness areas, and culturally important landscapes (whether natural, modified, cultivated or built environments). This diversity of environments provides habitats for a variety of species and supports a range of activities of value to man (including timber, agriculture, livestock, and fish production).
The natural environment contains a number of terrain-discrete habitats. They include forests, mountains, plains, marsh or wetlands, desert, tundra, reefs, islands and many more, some of which are subdivisions of the above. Each habitat has any or all of the following: humans and human artefacts, animals, insects, plants, minerals, specific climate and other characteristics. There are food chains and other elements of ecosystems characteristic to each habitat. When one of the ecosystems is under attack as a result of natural or man-made disaster it is extremely difficult to calculate the ripple effects throughout nature. When two or more ecosystems are being degraded the probabilities of synergistic destructiveness multiply.
Ecosystems in many regions are threatened , despite their biological richness and their promise of material benefits. This has been documented with examples from ecosystems including forests (temperate, tropical, mangrove), coral reefs, savannas, arid zones and grasslands.