Biodiversity Hotspots

Because biodiversity is not distributed evenly across the planet, and because conservation resources are always limited relative to the scale of the challenge, ecologists have developed the concept of a biodiversity hotspot as a way of identifying which regions of the world most urgently deserve conservation priority. The concept was first proposed by the British ecologist Norman Myers in 1988, and has since become one of the most widely used frameworks in global conservation planning.

For a region to qualify as a biodiversity hotspot, it must satisfy two specific criteria together, not just one. First, the region must show exceptionally high endemism, meaning it must be home to a large number of endemic species -- species found naturally nowhere else on Earth. This criterion is deliberately about endemism rather than simple species richness alone, because a region can hold enormous numbers of species yet lose comparatively little of the world's total biodiversity if most of those species also occur safely elsewhere; a hotspot, by contrast, holds species that would be lost from the planet altogether if that specific region were destroyed, which is what makes its conservation especially urgent. Second, the region must also be under serious and demonstrable threat, typically shown by having already lost a very substantial proportion -- for the original Myers criterion, at least 70 per cent -- of its original natural vegetation cover to human activity. A region with high endemism but little active threat, or a heavily threatened region with comparatively ordinary, widely-shared biodiversity, does not qualify as a hotspot under this definition; it is specifically the combination of high, irreplaceable endemism together with severe ongoing threat that marks a region out. …