Edited by Sebastian Steinfartz and Sylvain Ursenbacher
Amy MacLeod and Sebastian Steinfartz
Traditionally, conservation management focuses efforts on taxonomic units. However, when the taxa used do not reflect biologically meaningful units, such methods should be reconsidered to avoid the loss of irreplaceable biodiversity. The Galápagos marine iguana (Amblyrhynchus cristatus) is listed as Vulnerable on the IUCN Red List of Threatened Species and is facing growing anthropogenic threats. Currently, management is based on a taxonomy which is questionable in the light of recent molecular data. As such, there is a danger that evolutionarily significant populations may be left vulnerable to extirpation. Herein, we apply molecular data to elucidate the population structure of this species across the Galápagos archipelago, and thus advise conservation management in the absence of a revised taxonomy. Applying a wealth of molecular data including 12 microsatellite loci and 1181 bp of the mitochondrial control region in over 1200 individuals, we delineate distinct populations and prioritize their management. Bayesian population structure analysis revealed 10 distinct population clusters, which we propose as management units (MUs). All MUs are significantly differentiated, with one unit on San Cristóbal Island being particularly distinct in terms of both microsatellite loci and mitochondrial data. Based on estimates of the genetic effective population size (Ne), we find the MUs comprised of populations occurring on Floreana, Española, Marchena, and San Cristóbal to be alarmingly small. In consideration of both Ne and anthropogenic threats, we recommend that conservation practitioners focus efforts on Floreana and San Cristóbal islands, and argue that better census size estimates of populations are urgently needed.
Publication of the Societas Europaea Herpetologica
Amphibia-Reptilia publishes high quality original papers, short-notes, reviews, book reviews and news of the Societas Europaea Herpetologica (SEH). The Societas Europaea Herpteologica (SEH) website is located at: www.seh-herpetology.org.
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Sebastian Steinfartz and Barbara A. Caspers
Finding a potential mate, that is an individual of the opposite sex, is a fundamental step for sexual reproduction in animal species. Signals involved in the context of mate attraction are mediated by acoustic, visual, and/or chemical signals. For amphibians in general, and especially for many newt and salamander species, chemical cues are known to play important roles in inter- and intraspecific communication. We therefore investigated the use of olfactory cues for sex recognition in terrestrial fire salamanders (Salamandra salamandra) that belong to the group of true salamanders within the Salamandridae. Specifically, we performed odor preference tests with adult salamanders of both sexes and tested whether substrate-borne chemical cues provide sex-specific signals. We found an overall preference for chemical cues of the opposite sex, i.e. males and females differed significantly in their preference for a specific sex. Females spent significantly more time in the compartment with the chemical cues of a male, whereas males did not show a significant preference, but in general more males preferred the compartment with the chemical cues of a female. Our results suggest that fire salamanders are capable to discriminate the sex of conspecific individuals based on pure chemical cues. We discuss our results in the light of the presence of dorsal glands in the males' cloaca of true salamander species, from which pheromones can be directly released onto the substrate.
Timm Reinhardt, Sebastian Steinfartz and Markus Weitere
The matching of life-history-events to the availability of prey is essential for the growth and development of predators. Mismatches can constrain individuals to complete life-cycle steps in time and in ephemeral habitats it can lead to mortality unless compensation mechanisms exist. Here we measured the performance of a population of European fire-salamanders (Salamandra salamandra) and their prey in ephemeral ponds. We analysed how short time inter-annual variability of yearly rainfall and temperature (two consecutive years, 2011 and 2012) affects matching of predator and prey and how two different weather scenarios influenced the predator’s population structure. A single species (larvae of the mosquito Aedes vexans) dominates the prey community here, which occurs in high quantities only in the beginning of the season. When the occurrence of prey and predator matched during a period of sufficiently high temperatures (as in 2011), initial growth of the salamander larvae was high and population size development homogeneous. At low temperatures during matching of predatory and prey (as in 2012), the initial growth was low but the salamander larvae developed into two distinctly different sizes. Further, some individuals in the large cohort became cannibalistic and initial size differences increased. As a result, the latest (smallest) cohort disappeared completely. Temperature measurements and estimation of maximal growth rates revealed that temperature differences alone could explain the different early development between years. Our data show that weather conditions (rainfall; temperature during early growth phase) strongly determined the performance of salamander larvae in ponds. Our data also add to the match-mismatch concept that abiotic growth conditions (here: low temperature) could prevent efficient conversion of prey- into predator-biomass despite high prey availability.
Ulrich Schulte, Daniel Küsters and Sebastian Steinfartz
We studied patterns of annual movement of individual adult fire salamanders (Salamandra salamandra) during the years 2001 and 2002 in Western Germany in a typical middle European habitat for this species. We tested whether salamanders inhabit small home ranges and move little during the activity period as predicted for a species that shows strong site fidelity to a limited area. Initially, 98 individuals were collected in their natural habitat and marked with passive integrated transponder (PIT) tags. Of those individuals 88 were released at the collection site for recapture during the activity periods of the years 2001 and 2002. Ten marked individuals were kept in captivity to test for the tolerance of PIT tags. We did not find any negative impact of PIT tags on marked individuals of S. salamandra, neither under captive nor natural conditions. Forty-seven of the marked individuals (corresponding to 53% of the 88 released ones) were recaptured at least once and 28 individuals (corresponding to 32%) were recaptured multiple times. The return rate of males (78%) was higher than for females (43%). Mean home range size (and standard deviation) was estimated to 494 ± 282 m2 for 4 individuals as the minimum convex polygon based on 5 to 6 recapture events for each individual per year and to 1295 ± 853 m2 for 3 individuals with 8 records over two years. Minimum distances moved inferred from individual recaptures increased during the activity period of both years with time, indicating that individuals have more of a tendency to disperse than to stay within a limited area. Our data suggest therefore that S. salamandra adults display site fidelity, but use a much larger area than hitherto documented for this and other terrestrial salamander species.
Sebastian Steinfartz, Max Sparreboom and Gunter Schultschik
The courtship of all four species of the salamandrid genus Neurergus is described. The display behaviour is similar in all species, but there are differences in the temporal organisation of tail-fanning. The behaviour of these newt species resembles that of other Old World aquatic salamandrids in its general pattern, with tail-fanning the principal movement during the display phase. The spermatophore transfer phase includes a behaviour pattern during which the male turns back side-on to the female after spermatophore deposition and arrests her in a position where her cloaca is situated over the spot where the spermatophore was put down by the male. This movement is similar to the behaviour pattern described as ‘brake’ in all species of Triturus. In cladistic terms this shared behaviour pattern forms a synapomorphy for the genera Triturus and Neurergus.