Role of water temperature on the embryonic period of Bufotes variabilis: linking amphibian development and survival to climate change

Amphibian populations have been declining at a global scale for the last several decades, with about one-third of all amphibian species considered globally threatened. Climate change is often regarded as one of the most important factors driving amphibian population declines since amphibian development are strongly influenced by temperature. Temperature can play especially important roles at early life-history stages, where it is known to profoundly influence embryonic development and survival have important fitness consequences for later life. According to estimates, Iran is projected to experience an increase of nearly 2.6 °C in mean temperatures and a 35%decline in precipitation. In order to test the influence of water temperature on embryonic development and survival of the green toad Bufotes variabilis, 200 eggs were raised separately at two different water temperatures (17 and 20 °C) during 3 days. The experimental results showed that the water temperature had a significant effect on development stage (p≥0.001) and hatching time (p≤0.05) but the effect of water temperature on the percentage of hatching or survival was non-significant (p> 0.05). Theresults showed a longer of hatching time (2.5±0.57 days) and slower development stage (19.92±0.05) with decreasing temperatures and a higher percentage of hatching (90%±5.1) performance to high temperatures. In contrast, shorter of hatching time (1.5±0.57 days) and faster development stage (20.88±0.13) with increasing temperatures and a lower percentage of hatching (87%±6.83) performance of B. variabilis to high temperatures.

Keywords:

Temperature , Amphibian , Bufotes variabilis , Hatching