Acidity analysis (pН) of spawning reservoirs as the ecological niche parameter of anurans of the Middle Volga

Acidity level of spawning reservoirs of the Middle Volga region (n = 35), for 6 spices of anurans was considered as one of ecological niche parameters. The majority of species spawn at рН = 6,5-9,3. Spawning does not occur in reservoirs with рН less than 7,3 for Rana ridibunda, with рН more than 8,04 for Bombina bombina. Similar niches on acidity level have Вombina bombina with Rana arvalis and Bufo viridis with Rana ridibunda, the greatest distinctions were observed for Pelobates fuscus and Rana lessonae.