Edge populations can harbor unique genetic diversity shaped by historical isolation and play a key role in species' resilience and range expansion under ongoing climate warming. The Aesculapian snake (Zamenis longissimus) reaches the northern limit of its range in Central Europe, where isolated populations may provide key insights into the species' evolutionary potential and conservation priorities. In Bohemia (the western Czech Republic), only one reproducing population, in the vicinity of Stráž nad Ohří (SO), had previously been confirmed north of the species' continuous distribution. Here, we report two additional reproducing populations recently discovered through long-term monitoring: one at the Želinský meander (ZM) and another in Central Bohemia (CB). The ZM population is autochthonous, viable, and genetically remarkable, harboring two divergent mitochondrial haplotypes: the widespread Eastern phylogeographical clade haplotype E1 and a novel haplotype, W10, belonging to the Western clade. This represents the first confirmed record of a Western clade haplotype in the Czech Republic, and only the second known locality within the species' entire range where both clades coexist. In contrast, the CB population-founded by human-mediated translocation from SO-is expanding dynamically and is represented solely by E1, the only haplotype previously recorded in the country. Our study highlights the importance of incorporating genetic data into conservation planning and understanding species' evolutionary potential. The mitochondrial diversity uncovered at the ZM exemplifies how historical processes, isolation, and lineage mixing shape contemporary genetic structure. Preserving such populations, which retain unique evolutionary diversity, will be critical for maintaining the resilience of Z. longissimus in Central Europe. More broadly, disjunct northern populations may serve as reservoirs of genetic diversity, enhancing adaptive potential and supporting future range expansion under climate change. Recognizing and conserving this diversity is essential not only for local persistence but also for species-level resilience in a rapidly changing environment.

Association Zamenis z s 363 01 Stráž nad Ohří Czech Republic

Laboratory of Molecular Ecology Institute of Animal Physiology and Genetics Czech Academy of Sciences 277 21 Liběchov Czech Republic

Mining Museum Příbram 261 01 Příbram Czech Republic

Prague Zoo 171 00 Prague Czech Republic

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Meek M.H., Beever E.A., Barbosa S., Fitzpatrick S.W., Fletcher N.K., Mittan-Moreau C.S., Reid N.B., Campbell-Staton S.C., Green N.F., Hellmann J.J. Understanding local adaptation to prepare populations for climate change. BioScience. 2023;73:36–47. doi: 10.1093/biosci/biac101. DOI

Kelly E., Phillips B.L. Targeted gene flow for conservation. Conserv. Biol. 2016;30:259–267. doi: 10.1111/cobi.12623. PubMed DOI

Rehák I. Importance of reptiles to humans. In: Baruš V., Oliva O., editors. Reptiles—Reptilia, Fauna ČSFR. Volume 26. Academia; Praha, Czech Republic: 1992. pp. 50–53. (In Czech)

Böhme W., Koppetsch T. Snake names in the Greek-Roman antiquity: Old characterizations, identity in current zoology, and change of their original meaning in post-Linnean herpetology. Salamandra. 2021;57:475–501.

Salvi D., Mendes J., Carranza S., Harris D.J. Evolution, biogeography and systematics of the western Palaearctic Zamenis ratsnakes. Zool. Scr. 2018;47:441–461. doi: 10.1111/zsc.12295. DOI

The Reptile Database. [(accessed on 1 May 2025)]. Available online: http://www.reptile-database.org.

Musilová R., Zavadil V., Marková S., Kotlík P. Relics of the Europe’s warm past: Phylogeography of the Aesculapian snake. Mol. Phylogenetics Evol. 2010;57:1245–1252. doi: 10.1016/j.ympev.2010.09.017. PubMed DOI

Böhme W. Äskulapnatter (Elaphe longissima LAURENTI, 1768) In: Böhme W., editor. Handbuch der Reptilien und Amphibien Europas. Volume 3. Aula Verlag; Wiesbaden, Germany: 1993. pp. 331–372. (In German)

Edgar P., Bird D.R. Convention on the Conservation of European Wildlife and Natural Habitats. Standing Committee; Strasbourg, France: 2006. Action Plan for the Conservation of the Aesculapian Snake (Zamenis longissimus) in Europe; pp. 1–23. Council of Europe: Convention on the Conservation of European Wildlife and Natural Habitats.

Musilová R., Zavadil V., Kotlík P. Isolated populations of Zamenis longissimus (Reptilia: Squamata) above the northern limit of the continuous range in Europe: Origin and conservation status. Acta Soc. Zool. Bohem. 2007;71:197–208.

Musilová R., Zavadil V., Kotlík P., Moravec J. Zamenis longissimus (Laurenti, 1768)—užovka stromová. In: Moravec J., editor. Fauna ČR, Plazi—Reptilia. Academia; Praha, Czech Republic: 2015. pp. 304–333. (In Czech)

IUCN Red List of Threatened Species: Zamenis longissimus. [(accessed on 1 May 2025)]. Available online: https://www.iucnredlist.org/species/157266/49063773#assessment-information.

Peters G. Die Reptilien aus dem fossilen Tierbautensystem von Pisede bei Malchen. Wissensch. Zeitschr. Humboldt-Uni Math. Nat. R. 1977;26:307–326.

Szyndlar Z. Fossil snakes from Poland. Acta Zool. Cracov. 1984;28:1–156.

Böhme G. Zur Verbreitungsgeschichte der Herpetofaunen des jüngeren Quartärs im nördlichen Deutschland. Rana Sonderh. 1999;3:5–11.

Allentoft M.E., Rasmussen A.R., Kristensen H.V. Centuries-old DNA from an extinct population of Aesculapian snake (Zamenis longissimus) offers new phylogeographic insight. Diversity. 2018;10:14. doi: 10.3390/d10010014. DOI

Alkins D. Ph.D. Thesis. Bangor University; Bangor, UK: 2021. Habitat Selection of a Non-Native Snake: Implications for Future Management of Zamenis longissimus in Colwyn Bay, North Wales.

Clemens D.J., Allain S.J. First record of the Aesculapian snake (Zamenis longissimus) in South Wales. Herpetol. Bull. 2020;152:30–31. doi: 10.33256/152.3031. DOI

Major T. Ph.D. Thesis. Bangor University; Bangor, UK: 2024. The Ecology, Biogeography, and Taxonomy of Isolated Snake Populations.

Gomille A. Verbreitung und Lebensweise in Mitteleuropa. Chimaira; Frankfurt am Main, Germany: 2002. Die Äskulapnatter, Elaphe longissimi.158p. (In German)

Hartman L. Die Äskulapnatter im Taunus. Jahrbücher Nassau. Ver. Naturkunde. 2021;142:57–77.

Šolcová-Danihelková M. Occurrence of the Aesculapian Snake (Elaphe longissima Laur.) in the Karlovy Vary Region. Sborník Biol. Geol. Věd Pedagog. Fak. 1966;2:183–187. (In Czech)

Zavadil V., Musilová R., Jeřábková L., Moravec J. Užovka stromová—Výskyt v České republice. In: Moravec J., editor. Fauna ČR, Plazi—Reptilia. Academia; Praha, Czech Republic: 2015. pp. 333–335. (In Czech)

Horníková M., Lanier H.C., Marková S., Escalante M.A., Searle J.B., Kotlík P. Genetic admixture drives climate adaptation in the bank vole. Commun. Biol. 2024;7:863. doi: 10.1038/s42003-024-06549-z. PubMed DOI PMC

Management Plan for the Želinský Meander Natural Monument for the Period 2013–2022. [(accessed on 1 May 2025)]. Available online: https://drusop.nature.cz/ost/archiv/plany_pece/ug_file.php?FULLTEXT_UPLOAD=&RECORD_ID=25557. (In Czech)

Quitt E. Method of climatic regionalization of the western part of the Czechoslovakia. Sborník Českosl. Spol. Zem. 1968;73:118–129. (In Czech)

Quitt E. 1971: Climatic regions of Czechoslovakia. Stud. Geogr. 1971;16:1–73.

Kumar S., Stecher G., Li M., Knyaz C., Tamura K. MEGA X: Molecular Evolutionary Genetics Analysis across computing platforms. Mol. Biol. Evol. 2018;35:1547–1549. doi: 10.1093/molbev/msy096. PubMed DOI PMC

Zavadil V., Tejrovský V., Matějů J. Summary of the current knowledge on the distribution of the Aesculapian snake (Zamenis longissimus) in the Ústí nad Labem region. Sborník Muz. Karlov. Kraj. 2016;24:225–238. (In Czech)

Fritz U., Guicking D., Kami H., Arakelyan M., Auer M., Ayaz D., Fernández C.A., Bakiev A., Celani A., Džukić G., et al. Mitochondrial phylogeography of European pond turtles (Emys orbicularis, Emys trinacris)—An update. Amphibia-Reptil. 2007;28:418–426. doi: 10.1163/156853807781374737. DOI

Krása A. New locality of the Aesculapian snake in Povltaví. Herpetol. Inf. 2018;15–16:19. (In Czech)

Vaissi S., Kürşat Şahin M., Kurnaz M. Niche dynamics and climate change sensitivity in western Palearctic Zamenis ratsnakes (Reptilia: Colubridae) Amphibia-Reptil. 2024;46:33–50. doi: 10.1163/15685381-bja10209. DOI

Zahradníček P., Brázdil R., Štěpánek P., Trnka M. Reflections of global warming in trends of temperature characteristics in the Czech Republic, 1961–2019. Int. J. Clim. 2020;41:1211–1229. doi: 10.1002/joc.6791. DOI