Iulian Gherghel

Refining Climate Change Projections for Organisms with Low Dispersal Abilities: A Case Study of the Caspian Whip Snake

Climate warming is one of the most important threats to biodiversity. Ectothermic organisms such as amphibians and reptiles are especially vulnerable as climatic conditions affect them directly. Ecological niche models (ENMs) are increasingly popular in ecological studies, but several drawbacks exist, including the limited ability to account for the dispersal potential of the species. In this study, we use ENMs to explore the impact of global climate change on the Caspian whip snake (Dolichophis caspius) as model for organisms with low dispersal abilities and to quantify dispersal to novel areas using GIS techniques. Models generated using Maxent 3.3.3 k and GARP for current distribution were projected on future climatic scenarios. A cost-distance analysis was run in ArcGIS 10 using geomorphological features, ecological conditions, and human footprint as “costs” to dispersal of the species to obtain a Maximum Dispersal Range (MDR) estimate. All models developed were statistically significant (P<0.05) and recovered the currently known distribution of D. caspius. Models projected on future climatic conditions using Maxent predicted a doubling of suitable climatic area, while GARP predicted a more conservative expansion. Both models agreed on an expansion of suitable area northwards, with minor decreases at the southern distribution limit. The MDR area calculated using the Maxent model represented a third of the total area of the projected model. The MDR based on GARP models recovered only about 20% of the total area of the projected model. Thus, incorporating measures of species’ dispersal abilities greatly reduced estimated area of potential future distributions.

Going west – A subtropical lineage (Vincetoxicum, Apocynaceae: Asclepiadoideae) expanding into Europe ☆

Vincetoxicum sensu lato is a tropical lineage comprising two clades that have reached high northern latitudes. Of the temperate clades, one is restricted to the Far East, the other one (Vincetoxicum s. str. Clade) extends into Europe, but their ranges overlap in Central China and Japan. Three species invasive in North America, V. hirundinaria, V. nigrum and V. rossicum, are members of the Vincetoxicum s. str. Clade. We explore the prerequisites for the range expansion in the Vincetoxicum s. str. Clade performing Bayesian and Maximum Likelihood phylogenetic analyses on sequences of the nuclear internal transcribed spacer (ITS) region, the nuclear external transcribed spacer region (ETS), and five plastid markers. The resulting phylogeny is used to conduct biogeographic analysis using BioGeoBEARS to reconstruct ancestral species ranges. Moreover, we map the known occurrences of two rare characters in Asclepiadoideae, the possession of phenanthroindolizidine alkaloids and reported cases of autogamy onto our phylogeny. Finally, we have conducted ecological niche modelling using Maxent on a total of 220 spatially unique occurrences of nine Vincetoxicum s. str. species spanning more than 4,000 km along the east-west gradient to learn about the climatic conditions along the presumed migration route. Our results indicate a north-westward migration in Vincetoxicum s. str. along the Asian mountain chains to Europe. Climatic preferences of the nine species sampled are dissimilar, except for the common exposure to at least one month of subfreezing temperatures, indicating a rather wide climatic tolerance for the clade as a whole. The three species invasive in North America belong to the northern Eurasian subclade and show the rare combination of phenanthroindolizidine alkaloids and autogamy.

Landscape as a determinant of dispersal patterns and population connectivity in a newt species

Landscapes and their structure are important in shaping the distribution of species and the composition of communities. Since a landscape contains elements that are less permeable to dispersal, species use corridors of habitat suitable to movements that maintain the genetic flow among populations. Corridors have been widely used in conservation biology, but less often to study the connectivity between species’ allopatric ranges. In this study, we analyzed the distribution and connectivity patterns of the Danube Crested Newt (Triturus dobrogicus), a species found in the Danube river basin and whose range is separated by the Carpathian Mountains in two regions, eastern and western. Despite the geographical barrier and clear morphological differentiation between the populations of the two regions, recent genetic analyses suggest maintenance of genetic flow. The aims of our study were (1) to estimate the dispersal ability of the Danube Crested Newt and the connectivity (via corridors) between populations and (2) to identify possible pathways used by the species to cross the Carpathian Mountains barrier. We found that the landscape facilitates a higher population connectivity in the western range than in the eastern range of the species. Moreover, we identified two major migration pathways, along the Iron Gate Canyon and the Timis – Cerna Gap, that may connect all known occurrences from the two regions separated by the Carpathian Mountains. As an alternative dispersal hypothesis, we also discussed the possibility that the Danube Crested Newt is passively dispersed by water, down the Danube river flow direction. Our study provides support for the assertion that even when a species’ distribution is separated in two ranges by a geographical barrier, connectivity between populations via corridors can persist.

Annual Reproduction in Female Adders (Vipera berus) from a Montane Environment

Abstract European vipers are typical capital breeders and most studies have revealed that females usually reproduce once every two or three years and that, in some cases, females reproduce once during their lifetime. This paper presents evidence, based on monitoring marked snakes in consecutive years, that several female adders (Vipera berus) from a montane environment from the Northern Romanian Carpathians reproduced annually (2007–2008), and also gives preliminary data on other female reproductive traits. Reproductive females and their offspring were smaller and lighter than V. berus individuals from most previously studied populations. Maternal traits were not significantly correlated with litter and offspring characteristics.

New Records for the Aesculapian Snake (Zamenis longissimus) (Reptilia: Colubridae) in Romanian Moldova

Abstract The Aesculapian snake (Zamenis longissimus) is a widespread colubrid species, being present in much of central and southern Europe, with isolated populations occuring as far east as Iran. In Romania, the species is known from most of the country’s regions, although it has been reported from very few areas from the Moldova region (eastern and north–eastern Romania). Here we present three new records for Z. longissimus in Romanian Moldova, including the first record for the species in Botoșani County, the north–easternmost region of Romania.

Ecology and biogeography of the endemic scorpion Euscorpius carpathicus (Scorpiones: Euscorpiidae): a multiscale analysis

Abstract We present a first analysis of the ecology and potential distribution of Euscorpius carpathicus (Linnaeus, 1767), a scorpion species endemic to southern Romania, and report on the overwintering habitat selection of this species. Using field data, literature review, species distribution modelling, and habitat selection models, we document the broad scale distribution and ecology of E. carpathicus, as well as habitat selection in the foothills of the Curvature Carpathians, including exclusive microhabitat selection of riverine clay banks. In contrast with other species of the genus that inhabit cracks in cliffs or walls, E. carpathicus has adapted to cracks in clay.