The fast–slow continuum of longevity among yellow-bellied toad populations (Bombina variegata): intrinsic and extrinsic drivers of variation

Abstract

Yellow-bellied toad populations (Bombina variegata) show a wide fast–slow continuum of the life-history trait longevity ranging from 5 to 23 years. We investigated populations in Germany (n = 8) and Austria (n = 1) to determine their position within the continuum of longevity and the potential drivers of adult survival at the local and the continental scale. Intrinsic and extrinsic factors considered were local weather, nutritional state, allocation of ingested energy to somatic growth, pathogen prevalence, and geographical clines (latitude, altitude, and longitude). Capture-mark-recapture (CMR) monitoring and direct age assessment by skeletochronology allowed for reliable estimates of longevity and adult survival. Raw and corrected recapture rates as well as a probabilistic estimate of the lifespan of the eldest 1% adults of a cohort (CMR data) were used as surrogates for adult survival and thus longevity in a population. Additionally, survival rates were calculated from static life tables based on the age structure (skeletochronological data) of eight populations. Populations in Germany were short-lived with a maximum lifespan of annual cohorts varying from 5 to 8 years, whereas the population in Austria was long-lived with a cohort longevity of 13 to 23 years. We provide evidence that annual survival rates and longevity differ among years and between short- and long-lived populations, but there was no decrease of survival in older toads (i.e. absence of senescence). Variation of weather among years accounted for 90.7% of variance in annual survival rates of short-lived populations, whereas the sources of variation in the long-lived population remained unidentified. At the continental scale, longevity variation among B. variegata populations studied so far did not correspond to geographical clines or climate variation. Therefore, we propose that a population’s position within the fast–slow continuum integrates the response to local environmental stochasticity (extrinsic source of variation) and the efficiency of chemical antipredator protection determining the magnitude of longevity (intrinsic source of variation).

Tastier than thought? Telemetric research reveals predation on the poisonous yellow‐bellied toad Bombina variegata

“…Although known variations in longevity among populations are reported to have been caused by various factors, mainly anthropogenic ones (Cayuela et al, 2022), the predation levels reported here can influence local populations strongly enough to cause differences in demography among them. This is in line with a new hypothesis that relates demographic differences among toad populations to variations in predation caused by different levels of chemical defense (Hantzschmann et al, 2019).…”

Compensatory recruitment allows amphibian population persistence in anthropogenic habitats

“…The characteristics of each surveyed population (i.e., study period, duration, number of individuals captured, and number of captures performed during the study period) are set out in SI Appendix, Table S1. The capture-recapture sampling protocol was the same for all 67 populations and has been described in previous studies (31,53,60,61). Briefly, several capture sessions were performed each year during which individuals were caught by hand or by using dipnets.…”