Zeycan HELVACI

Dr. Zeycan HELVACI

orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 May 2020 in Journal of Zoological Systematics and Evolutionary Research
Verified
Journal Article
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PCPascale Chevret
Pascale Chevret
SRSabrina Renaud
Sabrina Renaud
ZHZeycan HELVACI
Zeycan HELVACI
RURainer Ulrich
Rainer Ulrich
JQJean‐Pierre Quéré
Jean‐Pierre Quéré
JMJohan R. Michaux
Johan R. Michaux
Water voles from the genus Arvicola display an amazing ecological versatility, with aquatic and fossorial populations. The Southern water vole (Arvicola sapidus) is largely accepted as a valid species, as well as the newly described Arvicola persicus. In contrast, the taxonomic status and evolutionary relationships within Arvicola amphibius sensu lato had caused a long‐standing debate. The phylogenetic relationships among Arvicola were reconstructed using the mitochondrial cytochrome b gene. Four lineages within A. amphibius s.l. were identified with good support: Western European, Eurasiatic, Italian, and Turkish lineages. Fossorial and aquatic forms were found together in all well‐sampled lineages, evidencing that ecotypes do not correspond to distinct species. However, the Western European lineage mostly includes fossorial forms whereas the Eurasiatic lineage tends to include mostly aquatic forms. A morphometric analysis of skull shape evidenced a convergence of aquatic forms of the Eurasiatic lineage toward the typically aquatic shape of A. sapidus. The fossorial form of the Western European lineage, in contrast, displayed morphological adaptation to tooth‐digging behavior, with expanded zygomatic arches and proodont incisors. Fossorial Eurasiatic forms displayed intermediate morphologies. This suggests a plastic component of skull shape variation, combined with a genetic component selected by the dominant ecology in each lineage. Integrating genetic distances and other biological data suggest that the Italian lineage may correspond to an incipient species (Arvicola italicus). The three other lineages most probably correspond to phylogeographic variations of a single species (A. amphibius), encompassing the former A. amphibius, Arvicola terrestris, Arvicola scherman, and Arvicola monticola.

1 January 2019 in Hittite Journal of Science and Engineering
Verified
Journal Article
Open access
BGBulent Gozcelioglu
Bulent Gozcelioglu
ZHZeycan HELVACI
Zeycan HELVACI
ECErcument Colak
Ercument Colak

3 July 2024 in Mammalia
Verified
Journal Article
Closed access
ZHZeycan HELVACI
Zeycan HELVACI
This study examines the population structure, ecological niche, and vulnerability to climate change of the woolly dormouse Dryomys laniger in Türkiye. Integrating genetic data with species distribution modeling, the research predicts suitable habitats for D. laniger under current and future climate change scenarios until the year 2100. Using an ensemble of two machine learning models, this study finds that by 2040, the range of D. laniger will be reduced significantly, particularly in southern populations. Eastern areas emerge as a potential refuge, showing slight expansion and colonization. The low genetic diversity in this eastern population indicates the need for long-term adaptability of D. laniger. Due to the unique adaptive potential of each population, this research highlights the importance of region-specific management plans to ensure the long-term survival of this species, which appears to be vulnerable to habitat fragmentation.

3 September 2025 in Biology
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ZHZeycan HELVACI
Zeycan HELVACI
EÇErcüment Çolak
Ercüment Çolak
Scarturus williamsi (Williams’ jerboa) is a medium-sized, semi-fossorial rodent endemic to steppe ecosystems across Anatolia, Iran, and Azerbaijan, with specialized habitat requirements in semi-arid continental environments. This study integrates a mitochondrial DNA analysis with species distribution modeling to assess the species’ evolutionary structure and vulnerability to future climate change. The phylogeographic analysis and species distribution modeling reveal the evolutionary history and climate vulnerability of Scarturus williamsi across Anatolia and adjacent regions. The mitochondrial DNA analysis of 98 individuals demonstrates exceptional haplotype diversity (Hd = 0.9896), with 90 unique haplotypes and complete regional isolation, indicating pronounced population structuring across five evolutionary lineages: Central Anatolia, Eastern Anatolia, Aegean, Black Sea, and Azerbaijan–Iran. The Iran–Azerbaijan lineage exhibits the deepest evolutionary divergence, while Eastern Anatolia functions as the primary Anatolian refugium and Central Anatolia as the secondary refugial center. The strong isolation by distance (r = 0.735, p < 0.001) across ~2500 km explains 54.0% of the genetic variation, with the hierarchical structure reflecting greater Iran–Turkey isolation than intra-Turkish differentiation. The species distribution modeling identifies the Mean Temperature of Driest Quarter (bio9) and the Mean Diurnal Range (bio2) as primary habitat determinants, with bimodal preferences reflecting highland versus steppe adaptations. Climate projections reveal severe vulnerability with habitat losses of 63.69–98.41% by 2081–2100 across emission scenarios. SSP3-7.0 represents the most catastrophic scenario, with a severe habitat reduction (98.41% loss), while even optimistic scenarios (SSP1-2.6) project a 60–70% habitat loss. All scenarios show accelerating degradation through mid-century, with the steepest losses occurring between 2041 and 2080. Projected eastward shifts face constraints from the Anatolian Diagonal, limiting the climate tracking capacity. Despite occupying open landscapes, S. williamsi exhibits exceptional sensitivity to climate change, with Anatolian refugial areas representing critical diversity centers facing substantial degradation. Results provide baseline genetic structure and climate vulnerability information for understanding climate impacts on S. williamsi and Irano–Anatolian steppe fauna.

31 March 2023 in Hittite Journal of Science and Engineering
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Journal Article
Open access
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ZHZeycan HELVACI
Zeycan HELVACI
This research focuses on species distribution modelling (SDM) to have an idea of distribution of Anatolian spiny mouse, Acomys cilicicus in the Last Glacial Maximum (LGM), the mid-Holocene and present by using coordinates along Silifke which is the only location the species found. Three ensembled species distribution models (generalized additive mod-els, maximum entropy and boosted regression trees) were used to project Anatolian spiny mouse environmental suitability. Results indicate that current distribution of A. cilicicus populations shifted east to west since during the Last Glacial Maximum and apparently eastern part of the Mediterranean region of Turkey is potential refugia for this species.

15 October 2025 in Zoologischer Anzeiger
Verified
Journal Article
Closed access
ZHZeycan HELVACI
Zeycan HELVACI