Body condition index of Bombina variegata variegata (Linneus,1758) in different habitats

Understanding how threatened amphibians respond to alternative environments, such as human made site and human exploited landscape is a crucial point of view for future conservation projects, primarily thought that these environments are growing both in number and importance. There are a lot of population traits for evaluating the population's status, such as the abundance, recruitment and survival rate, all methods very dispendious of an effort level. Here we investigated the influence of environmental variables on the physiological body condition of Bombina variegata (yellow-bellied toad) in three different habitat typologies, Natural, Mountain pasture and Agricultural, in the Province of Trento, Northern Italy. These habitats differ in their genesis, development and maintenance. The natural sites are unaffected by human impact, the Mountain pasture pond are semi-natural environments whose maintenance, however, depends on human intervention (periodic removal of substrate to prevent silting) and subject to cows trampling, in the end the agricultural sites are artificial cemented tank used by farmer as water reservoir. The species shows decreasing trend following the IUCN assessment but it has a fairly well distribution in the study area. We used the Scaled Mass Index (SMI), considering snout-vent length and body weight of toads, as a measure of the population's body condition. SMI was calculated for 932 male toads belonging to 9 populations that were monitored for 5 consecutive years. We found that toads in Natural Habitat had significantly better body condition than those in both Mountain pasture habitat (β = -0.559) and Agricultural one (β = -0.402), indicating that Natural habitat provided particularly higher quality habitat. SMI allows for the assessment of individuals persisting in disturbed environments, providing valuable information on environmental suitability, which is a primary objective of conservation.