2020-2022: SSAR Roger Conan Grant

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Unraveling the origin of the common wall lizards (Podarcis muralis) in Romania

The aim of this study is to ascertain the origin and population structure of Podarcis muralis in Romania and ultimately to explain their current distribution and range margin. We will generate sequences of the mitochondrial DNA (mtDNA) gene cytochrome b of samples from Romania and analyze them together with published data from across the while species’ native range. The main goal is, to identify the biogeographic and evolutionary processes shaping the genetic diversity of P. muralis at its north-eastern range margin. 

The north-eastern range margin of this species is shaped by both natural processes and human-mediated dispersal. The uniqueness and geographic distribution of the mtDNA haplotypes, as well as the large distribution gap between localities of P. muralis in Romania, suggests that natural dispersion is likely to have followed the Danube River (including rafting on natural materials or on boat transport). However, inference is currently limited by the poorly known phylogeography of the species in this region, in particular along the Danube itself (Romanian – Bulgarian border). In fact, better knowledge on the current distribution and demography of the isolated populations is necessary to determine their native status, in particular given recent evidence that the Ukrainian non-native populations partly originate from a geographically distant location.

This information is very important for guiding conservation actions. Non-native P. muralis can form hybrid populations with native populations, increase the risk for secondary introductions and may carry parasites that are transmittable to local fauna. Therefore, regional conservation activities are primarily concerned with identification of non-native lizards, and development of conservation recommendations and strategies that involve controlling the pathway of any invasions.

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Results

The origin of the common wall lizards (Podarcis muralis) populations in south-eastern Europe (namely in Bulgaria and Romania), representing the north-eastern range border of this species, was addressed using mitochondrial DNA. We compared cytochrome b sequences from Bulgaria and Romania with those from the contiguous range in Central Europe that are available from previous studies. We recorded five main haplogroups in Bulgaria and Romania, belonging to the Central Balkan clade. However, haplogroup III was recorded in more localities than previously found. Additionally, signs of haplotype admixture were identified in several populations along the Danube River. The presence of the Southern Alps haplotype in one population from Otopeni, Bucharest (Romania) and its close phylogenetic relationships to north Italy populations suggests human-mediated introductions of this wall lizard clade in Romania. Our results confirm that P. muralis can have non-native lineages and admixture through active human-mediated transport.

More information in our manuscript