 This perspective is relevant to the second part of the IPBES definition of biodiversity (above), where “biodiversity” is to include various measures of “change” in distribution, abundance etc. This perhaps reflects the ecology perspectives in which “biodiversity” is equated with various ecological indices and calculations, such as dissimilarity or relative abundance. Sometimes it is not at all clear how the key idea of “biodiversity loss”—complementarity—applies in such cases. This issue is addressed further in the section below on ecology and ecosystems framings.