No single explanation for biodiversity in Madagascar. Duke Today, October 10, 2014. No single “one-size-fits-all” model can explain how biodiversity hotspots come to be, finds a study of more than 700 species of reptiles and amphibians in Madagascar.By analyzing the distribution of Madagascar’s lizards, snakes, frogs and tortoises, researchers find that each group responded differently to environmental fluctuations on the island over time. The results are important because they suggest that climate change and deforestation in Madagascar will have varying effects on different species.