Global distribution and conservation of rare and threatened vertebrates

Abstract

Global conservation strategies commonly assume that different taxonomic groups show congruent geographical patterns of diversity, and that the distribution of extinction-prone species in one group can therefore act as a surrogate for vulnerable species in other groups when conservation decisions are being made. The validity of these assumptions remains unclear, however, because previous tests have been limited in both geographical and taxonomic extent. Here we use a database on the global distribution of 19,349 living bird, mammal and amphibian species to show that, although the distribution of overall species richness is very similar among these groups, congruence in the distribution of rare and threatened species is markedly lower. Congruence is especially low among the very rarest species. Cross-taxon congruence is also highly scale dependent, being particularly low at the finer spatial resolutions relevant to real protected areas. 'Hotspots' of rarity and threat are therefore largely non-overlapping across groups, as are areas chosen to maximize species complementarity. Overall, our results indicate that 'silver-bullet' conservation strategies alone will not deliver efficient conservation solutions. Instead, priority areas for biodiversity conservation must be based on high-resolution data from multiple taxa.

The conservation status of the world’s reptiles

“…While for some taxa, the distribution of predominant threats significantly overlaps areas of high species richness (e.g., amphibians, Hof et al, 2011), other studies have shown incongruence between threat distribution and endemic or threatened species richness (e.g., Grenyer et al, 2006;Lee and Jetz, 2008;Orme et al, 2005); however, the latter has traditionally been favoured as a selection tool for conservation priority areas. Similarly, distributions of different threat types may not always spatially overlap (Hof et al, 2011), so that effective mitigation strategies have to be developed in a spatially explicit context in order to reduce extinction risk of species.…”

“…The assessment of biodiversity value often relies on the distribution patterns of certain indicator taxa (e.g., birds), and the effectiveness of the resulting prioritisation mechanism greatly depends on the degree to which such distribution patterns are congruent with those of other taxa. However, cross-taxon congruence varies with given metrics of biodiversity (Grenyer et al, 2006). While reptilian species richness broadly mirrored species richness patterns observed in mammals, amphibians and birds (BirdLife International, 2008a;Schipper et al, 2008;Stuart et al, 2004), additional areas rich in reptiles (e.g., around the Gulf of Guinea and southern Africa) or threatened reptiles (e.g., islands such as Hispaniola, Sri Lanka, New Caledonia) were highlighted in our assessment and may be overlooked if conservation priorities are set based on patterns in a small number of nonreptilian taxa alone.…”

Reconsidering the Loss of Evolutionary History: How Does Non-random Extinction Prune the Tree-of-Life?

“…The spatial congruence in taxonomic richness across taxonomic groups has been well described globally (Grenyer et al 2006 ), with the richest areas of the world found in highly productive environments at low latitudes and in mountainous regions . Similarly, there is a geographical pattern in the distribution of rare and threatened taxa, which has been shown at the global scale for vertebrates (e.g.…”

“…Similarly, there is a geographical pattern in the distribution of rare and threatened taxa, which has been shown at the global scale for vertebrates (e.g. Grenyer et al 2006 ), and at various scales for plants (e.g. Zhang and Ma 2008 ;Daru et al 2013 ).…”

“…Zhang and Ma 2008 ;Daru et al 2013 ). However, hotspots of richness and rarity or threat do not necessarily coincide (Grenyer et al 2006 ). For example, vertebrate richness peaks on the Neotropical mainland, but bird rarity concentrates on oceanic island archipelagos, the diversity of rare mammal species peaks on continental shelf islands and rare amphibian species are more centered on continental landmasses (Grenyer et al 2006 ).…”