The planet’s biodiversity is remarkable. No fewer than 1.5million species have been named and described; at least threetimes this and possibly many more await discovery (Novotny etal. 2002). This biodiversity provides incalculable benefit tohumanity. Most directly, it comprises a vast genetic storehouseof medicines, foods and fibers (Myers 1983). Strong evidencesuggests that biodiversity endows stability to ecosystems(Naeem and Li 1997), sheltering humanity from disease andnatural disasters. Moreover, these ecosystems yield services ofsubstantial economic value (Costanza et al. 1997), althoughmostof these remain significantly undervalued. Least tangibly but noless importantly, all of the world’s societies and cultures valuespecies for their own sake, over and above any utilitarian purpose(Wilson 1984).