While resilience is a buffer to disturbance this buffer is provided through biological diversity, which acts as an insurance in this context. Biological diversity is also important in providing overlapping functions for restoring ecosystem capacity to generate essential ecological services. Loss of biodiversity reduces ecosystem resilience to change, and threatens the function of the system as a foundation for economic activity and human welfare. In a particular ecosystem many species may have similar functions, i.e., to a certain degree duplicating each other. A minimum composition of organisms has therefore, to be retained to secure that the relations between the primary producers, consumers, and decomposers be sustained to continue mediating the flow of energy, the cycling of elements and spatial and temporal patterns of vegetation.