Why are frogs and toads especially diverse in humid tropical regions?

Frogs and toads are most diverse and abundant in humid tropical regions due to their specific physiological and morphological requirements. Because amphibians typically possess moist, gas-permeable skin, they rely heavily on cutaneous respiration, which necessitates environments that prevent desiccation.12

In humid tropical rainforests, these animals can remain active throughout the year, whereas in temperate zones, they must often enter periods of dormancy to survive cold or dry conditions. The tropical environment provides a complex, resource-rich habitat that allows for high levels of niche partitioning; species utilize a wide variety of sites for calling and egg-laying, which minimizes interspecific competition.32

Furthermore, while many amphibians require water for their larval stages, the consistent moisture of the tropics supports diverse reproductive strategies, including the ability to lay eggs in damp terrestrial sites like bromeliads or moist soil. The abundance of food, such as insects and other invertebrates, further supports the high density and diversity of species found in these regions.341