The least‐cost path analysis of landscape genetics identifies two dispersal routes for the threatened Kaiser's mountain newt (Caudata: Salamandridae)

Abstract

Variation in landscape features plays an important role in shaping the distribution of species in natural populations. These can influence population connectivity, gene flow, genetic drift, and ultimately the genetic structure and diversity of isolated populations. In this study, we aimed to identify the impact of landscape heterogeneity on the dispersal patterns of the threatened Kaiser's mountain newt, Neurergus kaiseri.We integrated population genetics and geospatial data to predict the rates and patterns of genetic differentiation as well as to identify potential movement corridors among populations. For this purpose, we used two mitochondrial DNA markers and combined data on genetic subdivision (θ ST ) and least-cost path (LCP) analyses from 15 fragmented highland streams and spring-ponds representing the entire species distribution area. Five possible dispersal routes used in this study were straight-line, stepping-stone, least cost slope, stream likelihood and combination least cost slope/ stream likelihood. Genetic and LCP analyses indicated that two clades in the northern and southern distribution range have experienced two differing dispersal routes. The newts identified through the northern populations with high genetic diversity have dispersed with stepping-stone movements. In contrast, the southern populations are more isolated and dispersal might be facilitated by aquatic corridors in the least cost slope. We suggest that this study allows new implications for the conservation priorities of N. kaiseri by estimating the potential dispersal activity of the species in the face of climate change and ongoing habitat destruction relating to human activities in the southern Zagros mountains of Iran.

Historic range dynamics in Kaiser's mountain newt (Neurergus kaiseri): Insights from phylogeographic analyses and species distribution modeling

“…The results of the biogeographical analysis in this study also highlight that both dispersal and vicariance events have participated in the evolution of different species of the genus Neurergus, although the role of vicariance seems to be more prominent (Figure 4). The presence of two clades across the northern and southern distribution range of N. kaiseri has been displayed by various mitochondrial and nuclear markers (Farasat et al, 2016;Goudarzi et al, 2019;Khoshnamvand et al, 2019;Vaissi & Sharifi, 2021). In this study, the presence of two lineages was also confirmed using a bimodal curve in MMD analysis (Figure S2).…”

“…The presence of two clades across the northern and southern distribution range of N. kaiseri has been displayed by various mitochondrial and nuclear markers (Farasat et al., 2016; Goudarzi et al., 2019; Khoshnamvand et al., 2019; Vaissi & Sharifi, 2021). In this study, the presence of two lineages was also confirmed using a bimodal curve in MMD analysis (Figure ).…”

“…Data of two mitochondrial (mt‐DNA) genes including 127 control region (D‐loop: Farasat et al., 2016) and 72 NADH dehydrogenase 2 (ND2: Vaissi & Sharifi, 2021) sequences from 15 populations in the entire species range were obtained from GenBank (NCBI) and used for phylogenetic analysis (Figure 1). Details of the sequence data, outgroups, and their accession numbers are provided in Table .…”

“…Although, various phylogenetic studies have shown the existence of two northern and southern lineages in the N. kaiseri (Farasat et al., 2016; Goudarzi et al., 2019; Khoshnamvand et al., 2019; Vaissi & Sharifi, 2021). However, in this study based on ND2 and D‐loop sequences, Bayesian inference (BI) in MrBayes v 3.2.2 (Ronquist, Huelsenbeck, & Teslenko, 2011) was used for the construction of the phylogenetic tree.…”

Phylogenetic climatic niche evolution and diversification of the Neurergus species (Salamandridae) in the Irano‐Anatolian biodiversity hotspot

“…These investigations have cast a spotlight on the profound implications of climatic niche divergence in the speciation dynamics of this taxon. Despite the extensive body of prior literature exploring various facets of the Neurergus , spanning from ecological and distributional inquiries (e.g., Barabanov & Litvinchuk, 2015 ; Heydari et al., 2021 ; Mawloudi et al., 2019 ; Schneider & Schneider, 2010 ; Sharifi et al., 2013 ; Sharifi & Assadian, 2004 ) to investigations into habitat suitability (e.g., Ashrafzadeh et al., 2019 ; Cemal Varol et al., 2016 ; Malekoutian et al., 2021 ; Sharifi et al., 2017 ; Vaissi, 2021a , 2022 ), conservation strategies (e.g., Rastegar‐Pouyani et al., 2015 ; Sharifi et al., 2008 ; Sharifi & Assadian, 2004 ), and phylogenetic elucidations (e.g., Afroosheh et al., 2019 ; Farasat et al., 2016 ; Goudarzi et al., 2019 ; Hendrix et al., 2014 ; Khoshnamvand et al., 2019 ; Malekoutian et al., 2020 ; Özdemir et al., 2009 ; Steinfartz et al., 2002 ; Vaissi, 2021b ; Vaissi & Sharifi, 2021 ), there remains a significant knowledge gap concerning the impact of climate change on phylogenetic clades and niche evolutionary processes within the Neurergus .…”