The influence of teleconnections on the long-term dynamics of mass-breeding events in the threatened crested toad (Guanica, Puerto Rico)

Population decline and variability of neotropical amphibians have been related to climate change and variability. Between 1984 and 2007, the number of breeding adults of the threatened crested toad (Peltophryne lemur, Bufonidae) in a temporary pond in the Guanica dry forest (Southerwestern, Puerto Rico) was influenced by major droughts, tropical storms and hurricanes. Mass-breeding events (>200 individuals) occurred after daily rainfall >14 cm, and positively correlated with total rainfall during the wet season. The intensity of the wet season related to total annual rainfall that in turn was jointly affected by the ENSO (El Nino-Southern Oscillation) and NAO (North Atlantic Oscillation) indices. Negative annual rainfall anomalies were observed when negative ENSO index coincided with positive NAO index; positive rainfall anomalies occurred under the opposite conditions. After installing a water-level datalogger in the breeding pond in 2005, we correlated the number of breeding adults to rainfall, maximum depth, pond duration, and ponding timing. Mass breeding occurred during the rainy years 2005 and 2007, while fewer adults bred during the dry 2006. Reduced pond area and volume and short pond duration promoted unsuccessful development of toadlets. We highlighted the importance of climatic teleconnections on amphibian population dynamics in the Caribbean.