Altitudinal variation in the age at maturity, longevity and reproductive lifespan of anurans in subtropical Queensland.

Abstract

Skeletochronology has been widely and successfully used to age temperate amphibians, enabling geographic comparisons of longevity and the age at maturity. To date, however, there have been very few similar studies conducted using skeletochronology in tropical or sub-tropical amphibians. In this study, we examined the applicability of skeletochronology for aging four sub-tropical anuran species (Litoria chloris, L. lesueuri, L. pearsoniana, and Mixophyes fleayi) that occur across a range of altitudes in southeast Queensland, Australia. We then used reliable estimates to examine altitudinal variation in longevity, age at maturity (AM), and potential reproductive lifespan (PRLS) for each species. Skeletochronology was successful in three of the four species. The age of L. lesueuri individuals from low altitude sites could not be reliably estimated due to extended activity seasons. On average, females were older than males in L. chloris, L. pearsoniana, and M. fleayi and were also older when breeding for the first time. There was, however, no significant difference in the PRLS between males and females within any of the three species. There were trends towards greater longevity and older AM in high altitude populations of all three species; however, there was no significant altitudinal variation in PRLS in any of the species. Our results suggest little intraspecific variation in the number of years that individuals of the four species are capable of breeding, regardless of gender, geographic location, longevity, and AM.