Life-history traits in green toad (Bufo viridis) populations: indicators of habitat quality

Abstract

Five life-history traits (age and size at maturity, longevity, potential reproductive life span, age-dependent growth rate) were investigated in four Bufo viridis Laurenti, 1768 (= Pseudepidalea viridis (Laurenti, 1768)) populations that inhabited localities at similar altitude (60–100 m above sea level) and latitude (50°N–51°N, Germany), but that differed in habitat quality (i.e., human land use within a radius of 1 km around the breeding site). The age of 374 males and of 127 females collected during the breeding period was estimated using skeletochronology on phalange bones. We tested the hypothesis that sex and habitat quality account for detectable amounts of local variation in life-history traits. Significant sexual size dimorphism was present in all populations. Gender-specific variation in size was mainly accounted for by age, but also to a minor extent by habitat quality. In males, age at maturity varied between 1 and 3 years and was the only life-history trait that was significantly related to the intensity of human land use. In contrast, land-use indices covaried significantly with female longevity (6–15 years) and potential reproductive life span (5–12 years). Our pilot study suggests that, in B. viridis, life-history traits derived from the local age structure may be useful as indicators of habitat quality.