Movement patterns within an urban population of fire salamanders highlight the importance of conserving small habitat patches

Abstract

Movement is an ecological process that affects individual fitness and population dynamics of species. Understanding movement patterns is crucial for the effective conservation of amphibian populations isolated by urban development. Here, we conducted a capture-recapture study over 6 years in a population of the fire salamander (Salamandra salamandra) inhabiting a 7.3-ha patch of forest and disturbed land-use types in an urbanised catchment north-west of Budapest, Hungary. We investigated relationships between movement distances and environmental, spatial and demographic parameters in order to understand how this species is able to persist in a relatively small and isolated habitat patch. We found that most movement was aggregated around a permanent stream and that movement distances were generally ≤200 m, with maximum distances of 925 and 707 m for males and females, respectively. Movement patterns within the population were best modelled using a negative exponential function characterised by infrequent long-distance movement. Males had substantially larger home range sizes than females and were predicted to have larger movement distances. Mean movement distances were predicted to be larger in disturbed areas in the upper stream catchment which included residential areas, compared with smaller movements in more natural forest near the stream. There was a positive relationship between mean movement distance and body condition. Our results suggest that this local population persists in a relatively small habitat patch because it provides a stable breeding site and suitable foraging and shelter microhabitats. Conservation of the local population requires protection of the structure, connectivity and quality of forest and stream habitats, and preventing urban development in the surrounding catchment.

Larval development and habitat usage of stream-breeding Fire salamanders in an urban environment

“…In our study area, this could mean that larvae are almost completely washed out from a relatively short 485-m long stream segment; however, the presence of numerous pools likely prevented larval flushing from the stream. These larval dispersal distances also correspond fairly well with the observed distances moved by adult males, females and juvenile salamanders in the study area (Kiss et al 2022), and suggest that the population is largely restricted to the stream environment and adjoining terrestrial habitats. A similar finding was made for stream-adapted salamanders in another population within central Europe (Hendrix et al 2017).…”

“…This indicates that the upper two thirds of the stream were preferred by females for larval deposition. Our parallel studies showed that the most favourable habitat conditions for adults were found in the same areas (Kiss et al 2021(Kiss et al , 2022. However, the distribution of larvae in stream sections may also be facilitated by the fact that females may visit several habitats when laying larvae as part of a risk-spreading strategy (Caspers et al 2015).…”

“…This stream catchment collects the groundwater of the surrounding, mainly urbanised area. The stream valley flowing through a patch of oak-hornbeam forest is partly surrounded by buildings and roads (see map in Kiss et al 2021Kiss et al , 2022.…”

“…Szabó 1959, Dely 1967, population structure and dynamics of adult fire salamanders (e.g. Kiss et al 2021Kiss et al , 2022. Only one study has examined the effect of density on fire salamander larval development (Csilléry & Lengyel 2003).…”

“…A geographically as well as genetically isolated population (Vörös et al 2016) occurs in an urbanised catchment within the Buda Hills northwest of Budapest, where a short, forested stream provides suitable habitats for fire salamander larvae and adults (Kiss et al 2021(Kiss et al , 2022. We conducted a six-year study on this local population (see Kiss et al 2021Kiss et al , 2022, during which we conducted larval surveys over four years.…”