MORE bad news to set amphibians鈥� eyes bulging. The catastrophic declines in frog and salamander populations in recent years may be even more widespread than had been feared 鈥� and the devastation seems to extend to reptiles.
Steven Whitfield of Florida International University in Miami and colleagues studied data on ground-dwelling reptiles and amphibians collected over the past 35 years at the La Selva Biological Station in Costa Rica. The counts show a steady decline in the numbers of reptiles and amphibians in native forest, while numbers increased in abandoned cacao plantations (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0611256104).
Fungal diseases or pesticide contamination, blamed for amphibians鈥� decline elsewhere, are unlikely to be behind the declines at La Selva, since they would affect abandoned plantations as well as native forest. The researchers suggest the cause may be a change to a warmer, wetter climate, which reduces tree growth and may lead to a thinner layer of leaf litter, in which the animals live. Cacao plantations produce a heavier layer of this leaf litter.
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Pesticides and fungus have been blamed for the decline in Costa Rica鈥檚 mountain amphibians (New 杏吧原创, 3 March, p 17).
