Monday, May 23, 2011

Lazarus species - hope springs eternal

What happens when a species everyone thought was extinct is rediscovered? Reports from 2005 that the ivory-billed woodpecker may persist in a Louisiana swamp produced an outpouring of energy but still no confirmed sightings. And usual surprises when we go looking for species is that they are missing from where we'd expect them rather than vice-versa. Nevertheless, one of the most pure symbols of hope for biodiversity must surely be those rare occasions when someone stumbles upon a species long since thought to be extinct. These Lazarus species - a name which refers the the Gospel account of Jesus raising Lazarus from the dead - number in the tens, not hundreds, and may well represent some of the Earth's most threatened species.

It seems appropriate that we begin the Global Amphibian Blitz with a tribute to one such 'risen' species - Holdridge's toad - which, not seen since 1986, made its home in a tiny chunk of montane rainforest about 20 km from the Costa Rican capital. With the combined impact of climate and a fungus called chytridiomycosis impacting countless frog species in this part of the world, few expected that over two decades later Juan Abarca and colleagues would find one very much alive.

Holdridge's toad observed by Victor Acosta Chaves
We expect the Global Amphibian Blitz will produce observations of rare species. And we expect that some of these observations may be from unexpected places outside of a species' known range. We also expect that recent extinctions may sadly prevent some species from being located where they once were. What we dare not expect but can't help but hope is to place another amphibian alongside Holdridge's toad on that short list of Lazarius species.
Abarca J, Chaves G, García-Rodríguez A, Vargas R (2010) Reconsidering extinction: Rediscovery of Incilius holdridgei (Anura: Bufonidae) in Costa Rica after 25 years. Herpetological Review 41, 150-152.

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