130 Hotspots 15.7% of the global land surface, their original habitat covering only 2.3% Between them, they are estimated to hold at least 150,000 plant species as endemics (50% of the world’s total), and an overall 22,022 terrestrial vertebrate species (77% of the world’s total) including 11,980 species as endemics (42% of the world’s total) The list of biodiversity hotspots sensu Myers/CI is therefore dynamic, and additional updates are expected as knowledge improves on the distribution of species and on habitat loss, and as landuse changes worldwide The 2004 update highlighted two regions (Queensland Wet Tropics and Taiwan) that came close to meeting the hotspots criteria, and mentioned three others (Angola Escarpment, rainforests of eastern Australia, and southeastern China) likely to be considered in future revisions (Mittermeier et al., 2004) Roberts et al (2002) extended the concept of biodiversity hotspots sensu Myers/CI to marine systems, by identifying areas of high levels of endemism and of high threat across the world’s tropical reefs Using data on the distribution of 3235 species of reef fish, corals, snails, and lobsters, they mapped species endemism across a 50,000 km2 degree grid by calculating the sum in each cell of the reciprocal of the range size of each species They then identified 18 multitaxa centers of endemism from areas that were in the top 10% of the cells for at least two taxa Finally, 10 of these regions considered under high threat were identified as marine biodiversity hotspots Threat was assessed using a map-based indicator of risk to coral reefs from coastal development, marine pollution, overexploitation, and inland pollution (Bryant et al., 1998) Biodiversity Hotspots sensu lato The concept of biodiversity hotspots as areas with high concentration of species was (possibly) first proposed by Prendergast et al (1993) (who cited Myers (1988) as the source for the term, but then used it in a different sense) Their analysis was based on the distribution of butterflies, dragonflies, aquatic plants, breeding birds, and liverworts in Britain, and hotspots were defined as the top 5% cells (10 km2) with the highest species richness for each taxon Later in that same year, Pomeroy (1993) independently applied the term hotspots to refer to African countries with a high diversity in plant species, after controlling for variation in country area using the species–area relationship The concept of hotspots was extended to areas with high concentrations of rare species by Williams et al (1996), who distinguished between ‘‘richness hotspots’’ (the top 5% sites in terms of diversity) and ‘‘rarity hotspots’’ (the top 5% sites in richness of rare species, defined as the 25% species with the smallest ranges) BirdLife International’s Endemic Bird Areas are a global application of the concept of rarity hotspots: there are 218 regions where the distributions of two or more restricted-range bird species (with ranges smaller than 50,000 km2) overlap (Stattersfield et al., 1998) The concept of hotspots was further extended to refer to concentrations of threatened species (Dobson et al., 1997), dubbed elsewhere as ‘‘threatspots’’ (Troumbis and Dimitrakopoulos, 1998) The term hotspots has since become a common way of designating areas with high richness of all, rare, or threatened species, either in absolute terms (Orme et al., 2005; Ceballos and Ehrlich, 2006; Grenyer et al., 2006), or after controlling for variation in the area of the analyzed units (e.g., Veech, 2000; Guilhaumon et al., 2008) The concept of hotspot continues to expand as it is applied to other facets of biodiversity, for example, through the designation of hotspots of functional diversity (Lucifora et al., 2011), or hotspots of beta diversity (Harborne et al., 2006) There is however one key aspect in which hotspots sensu lato remain conceptually distinct from hotspots sensu Myers/CI: the former apply to peaks of diversity along a particular axis of diversity or of threat, whereas the latter highlights areas that have both high endemism and high threat The two approaches can meet if hotspots sensu lato are defined as concentrations of species that are simultaneously threatened and spatially rare Biodiversity Hotspots in the Literature A review of the usage of the term ‘‘biodiversity hotspots’’ in scientific journals illustrates how the various concepts have permeated the literature A Web of Science search (June 2011) for publications on biodiversity and hotspots (search term: Topic ¼ ((hotspotà OR hot-spotà OR hot spotÃ) AND biodiversity) in four journals (three high impact journals, Nature, Science, and Proceedings of the National Academy of Sciences USA; and the highest impact journal on biodiversity conservation, Conservation Biology) yielded 180 articles Of these, 23 were excluded: 17 for not using the term ‘‘hotspot’’ at all; four for being news articles without references; and two for using the term in a different sense from biodiversity hotspots (pollution hotspots, Grimm et al., 2008; groundwater recharge hotspots, Herbert et al., 2010) The remaining 157 articles were analyzed Testifying the extent to which it has become a glamorous concept in the literature, a third of these articles (51/157) used the term hotspots in the title The concept was used in four (partially overlapping) main ways (Figure 3): hotspots sensu Myers/CI; hotspots sensu lato; following other definitions; and without being defined These are discussed below Biodiversity Hotspots sensu Myers/CI The concept of biodiversity hotspots sensu Myers/CI has had substantial impact in the scientific literature Indeed, the 2000 Nature paper (Myers et al., 2000, now with over 3500 citations) is not only the most cited publication on biodiversity hotspots (Figure 4), but also one of the most cited studies in Ecology (was the most cited paper in Environment and Ecology in the 1998–2008 period; Thomson Reuters (2008)) Analysis of a sample of articles provides a deeper perspective of the way in which the concept of hotspots sensu Myers/CI has permeated the literature (Figure 3) Out of 157 articles analyzed, 99 (63%) used the term hotspots in this sense, including 88 who use it exclusively in this way The dominant usage (2 in of the 99 papers) was to highlight the value of the paper’s study area as a global biodiversity hotspot (e.g., Bossuyt et al (2004) and Delibes-Mateos et al (2008)) Conversely, in a separate search for conservation articles focusing on five regions classified as biodiversity hotspots sensu Myers/CI, more than half