Temperature Induced Predation Impact of Mosquitofish (Gambusia affinis) on Growth, Development, and Survival of Larvae and Tadpole of Bufotes variabilis (Amphibia: Anura)

Resumo

There are increasing evidences documenting the negative impact of exotic species including mosquitofish, Gambosi affinis, in Iran. Meanwhile, recent climate change in freshwater ecosystems in arid and semi-arid regions such as Iran is expected to cause undesirable impact. We conducted experiments in 2 levels of temperature and predator density including: high temperature/high predator (HT/HP), high temperature/ low predator (HT/LP), low temperature/high predator (LT/HP), and low temperature/low predator (LT/LP) that carried out within 20 days. Larval growth rate was highest at the HT/HP (0.29 mm/day), development stage was slowest at the LT/HP treatment (Gosner: 28.33 ± 0.33), and survival rate was lowest at HT/HP treatment (0.00%). Except for the significant impact of predator density on survival, B. variabilis was tolerant of both predator density and increased temperature and there was no interaction between predator density and increased temperature in term of growth, development and survival. But, combined effects of temperature and predator density showed significant effects on growth, metamorphosis, and survival over time.