Life history modelling reveals trends in fitness and apparent survival of an isolated Salamandra salamandra population in an urbanised landscape

Life history theory provides a basis for understanding how amphibians persist within landscapes fragmented by urbanisation. To quantify the life history traits of a population susceptible to habitat disturbance, we implemented a capture-recapture study of an isolated population of the fire salamander (Salamandra salamandra) within an urbanised catchment of Budapest, Hungary. We estimated life history parameters to assess intraspecific differences in growth rates, body condition, apparent survival and superpopulation size. There was no apparent sexual dimorphism in the population. Relatively rapid growth rates were estimated post-metamorphosis to 7 years; growth then slowed, and the growth curve reached a plateau towards the asymptotic body length (males 195.6 mm; females 193.8 mm), with estimated longevity (> 20 years). The age structure was relatively stable with a high proportion of younger age classes (3-4 years) indicating adequate recruitment. There were no differences between male, female and juvenile body condition, although male and juvenile body condition was higher in spring/summer than in autumn. There were no differences in the probability of apparent survival (phi) between adult males and females, which were relatively high (annual phi similar to 0.7-0.8). Juvenile survival was estimated to be substantially lower (similar to 0.2). There was a positive relationship between the probability of apparent survival and body condition. The mean estimated superpopulation size for males, females and juveniles was 999.75, 853.94 and 533.61, respectively. Our results suggest that the S. salamandra population is demographically healthy, relatively large and persists despite the ongoing urbanisation in the local catchment, but requires monitoring to detect future habitat disturbances.

Automated summary

Life history theory is utilized to study the amphibian population of fire salamanders within an urbanised catchment in Budapest, Hungary. The population shows relatively stable age structure, rapid growth rates, and reaches a plateau in body length with a long lifespan. Despite ongoing urbanisation, the population remains healthy but requires monitoring for potential habitat disturbances.