Where the rare species are

Prioritizing geographic areas for conservation attention is important - time and money are in short supply but endangered species are not - and difficult. One popular perspective highlights areas with many species found nowhere else (Myers et al. 2000). Another identifies areas that contain species with fewer close relatives elsewhere (Faith 1992). One might characterize the first as focusing on geographic, and the second on phylogenetic, rarity. To the extent that geographically rare species are at greater risk of extinction (Gaston & Fuller 2009), and that phylogenetically rare species contribute disproportionally to overall biodiversity (Crozier 1997), it would seem reasonable to formally integrate the two approaches. In this issue, Rosauer et al. (2009) do just that; their elegant combined metric pinpoints areas missed out when the two types of rarity are looked at in isolation.