Rivers as barriers for high elevation amphibians: a phylogeographic analysis of the alpine stream frog of the Hengduan Mountains

Abstract

At high altitude, rivers may function as barriers for amphibians. We examined 21 populations of Scutiger boulengeri from the Hengduan Mountains with 1038 base pairs of mitochondrial cytochrome b gene sequences. The haplotypes of S. boulengeri formed three clades on the gene tree, and each clade was restricted to one mountain ridge separated by two major river systems, the Yalong River and the Dadu River. The vicariant pattern of the gene tree suggests that these rivers functioned as effective barriers during population differentiation. On the other hand, mountain ridges may have facilitated amphibian movement. Populations within the uninterrupted mountain ranges of clades II and III, revealed little genetic structure. The northern clade I, harboured a substantial amount of genetic variation, which might be the consequence of the rugged terrain and heterogeneous habitat of this area. Furthermore, one outgroup species, Scutiger glandulatus, formed the fourth clade and nested within S. boulengeri, suggesting that S. boulengeri is likely a paraphyletic species or a species complex.

Do rivers function as genetic barriers for the plateau wood frog at high elevations?

“…Using a phylogeographic analysis of mitochondrial DNA sequence data, Li et al (2009) recently investigated a high elevation megophryid frog species, Scutiger boulengeri within the Hengduan Mountains. They found three deeply diverged clades separated by two major rivers, and concluded that rivers function as dispersal barriers for this species.…”

“…If these rivers function as genetic barriers to S. boulengeri, do they have a similar impact on other high elevation amphibian species? Furthermore, Li et al (2009) used a phylogeographic approach, which examines the consequence of a long history as opposed to contemporary events. Whether such impact of rivers is detectable by examining contemporary gene flow is an interesting question.…”

Genetic diversity and historical demography of the narrow-range endemic Alpine toad, Scutiger liupanensis, in the Liupan Mountains of central China

“…A continuous fragment (947 bp) of mitochondrial cytochrome b (cyt b) was amplified by conducting a PCR (MyCycler TM , Bio-Rad), with forward (5'-CTT CCA TCC AAC ATC TCA GCA TGA TGA AA-3') and reverse (5'-ACA AGA CCA ATG CTT TAG TTA AGC TAC-3') primers (Li et al, 2009). A continuous fragment (644 bp) of mitochondrial cytochrome c oxidase subunit I (COI) was also amplified using PCR (MyCycler), with forward (LepF5'-ATT CAA CCA ATC ATA AAG ATA TTG G-3') and reverse (LepR5'-TAA ACT TCT GGA TGT CCA AAA AAT CA-3') primers (Hebert et al, 2004).…”

Diferenciação geográfica de Ecpleopus gaudichaudii (Squamata, Gymnophthalmidae) baseada em caracteres morfológicos e moleculares, e considerações sobre a descrição osteológica

“…A amostragem ainda é pequena para que haja um tratamento estatístico confiável sobre esse aspecto. A hipótese dos rios tem sido objeto de estudo desde Wallace (1852) e os resultados apresentados desde então são ambíguos, apoiando a hipótese em alguns casos (Ayres & Clutton-Brock, 1992;Lampert et al,(2003); Pellegrino et al, 2005;Li et al, (2009) ao passo que em outros não apresentam topologia compatível com o isolamento causado pelos rios (Gascon, Lougheed & Bogart, 1998;Patton & da Silva, 1998;Lougheed et al, 1999;Symula, Schulte & Summers, 2003). Nos casos relacionados aos rios da bacia amazônica, os rios são caracteristicamente meândricos o que pode torná-los pouco efetivos para atuar como uma barreira ao longo dos tempos.…”

“…Vários lagartos, cobras e anfisbenas endêmicas foram descobertas nessas regiões. Elas formam espécies irmãs de distribuição alopátricas vicariantes em margens opostas e dunas adjacentes (Rodrigues & Juncá, 2002 (Zhao et al, 2009, Li et al, 2009 …”