Effects of historical forest contraction on the phylogeographic structure of Australo‐Papuan populations of the red‐legged pademelon (Macropodidae: Thylogale stigmatica)

Abstract

Geographic patterns of genetic variation are strongly influenced by historical changes in species habitats.Whether such patterns are common to co-distributed taxa may depend on the extent to which species vary in ecology and vagility. We investigated whether broad-scale phylogeographic patterns common to a number of small-bodied vertebrate and invertebrate species in eastern Australian forests were reflected in the population genetic structure of an Australo-Papuan forest marsupial, the red-legged pademelon (Macropodidae: Thylogale stigmatica). Strong genetic structuring of mtDNA haplotypes indicated the persistence of T. stigmatica populations across eastern Australia and southern New Guinea in Pleistocene refugial areas consistent with those inferred from studies of smaller, poorly dispersing species. However, there was limited divergence of haplotypes across two known historical barriers in the northeastern Wet Tropics (Black Mountain Barrier) and coastal mideastern Queensland (Burdekin Gap) regions. Lack of divergence across these barriers may reflect post-glacial recolonization of forests from a large, central refugium in the Wet Tropics. Additionally, genetic structure is not consistent with the present delimitation of subspecies T. s. wilcoxi and T. s. stigmatica across the Burdekin Gap. Instead, the genetic division occurs further to the south in mideastern Queensland. Thus, while larger-bodied marsupials such as T. stigmatica did persist in Pleistocene refugia common to a number of other forest-restricted species, species-specific local extinction and recolonization events have resulted in cryptic patterns of genetic variation. Our study demonstrates the importance of understanding individualistic responses to historical climate change in order to adequately conserve genetic diversity and the evolutionary potential of species.

Pleistocene climate fluctuations influence phylogeographical patterns in Melomys cervinipes across the mesic forests of eastern Australia

“…Radiation of Melomys in Australia was estimated here to have occurred within the last 1.6 Myr, possibly corresponding with glacial cycles and associated shifts in vegetation prevalent in the late Plio‐Pleistocene (Hopkins et al ., ; Kershaw, ) and matches the timing of diversification observed in other taxa (e.g. Joseph & Moritz, ; Schneider et al ., ; Norman et al ., ; Krosch, ; Macqueen et al ., ). Frequent shifts in vegetation allowed range expansions in some taxa and caused range contractions and local population extinctions in others (Aplin, ; Martin, ; Lukoschek et al ., ; Bowman et al ., ; Byrne et al ., ).…”

“…Other studies have identified divergence across the BG (e.g. Hoskin et al ., ; Hugall et al ., ; O'Connor & Moritz, ; Moussalli et al ., ; Chapple et al ., ) but few have found divergent lineages that either abut or show a geographical disjunction to the north or south of, rather than centred on, this large dry corridor (but see Keleman & Moritz, ; Eldridge et al ., ; Macqueen et al ., ). This pattern of vicariant isolation and divergence, followed by dispersal and subsequent secondary contact probably occurred during a warm, wet period when closed forest was more widespread across the BG.…”

Habitat and introduced predators influence the occupancy of small threatened macropods in subtropical Australia

“…We considered this distance was a suitable compromise to maximize detection of predators which frequent areas on and close to roads (Meek, Ballard, Fleming, & Falzon, 2016) and medium-sized mammals which are likely to prefer vegetative cover (MacQueen, Seddon, & Goldizen, 2011;Norton et al, 2015). We considered this distance was a suitable compromise to maximize detection of predators which frequent areas on and close to roads (Meek, Ballard, Fleming, & Falzon, 2016) and medium-sized mammals which are likely to prefer vegetative cover (MacQueen, Seddon, & Goldizen, 2011;Norton et al, 2015).…”

Lines in the land: a review of evidence for eastern Australia's major biogeographical barriers to closed forest taxa

“…Solid lines indicate some of the previous published locations of the LB – 1: MacQueen et al . (), 2: Ford (), Eldridge et al . (); 3: Edwards & Melville ().…”

“…Furthermore, patterns in an agamid lizard that inhabits adjacent dry woodland exhibit the expected inverse effect of expansion of drier habitat in this region with evidence for stepping‐stone historical population expansion (Edwards & Melville, ). In contrast, some birds (Joseph, Moritz & Hugall, , ; Joseph & Moritz, ; Nicholls & Austin, ) and mammals (MacQueen et al ., ; Bryant & Fuller, ) show no apparent influence of the BMC on population structure (even when they were significantly structured by other nearby barriers), implying that responses to this barrier were species specific and over‐generalisation of patterns and effects may be inappropriate.…”