The demographic history of the New Zealand short‐tailed bat Mystacina tuberculata inferred from modified control region sequences

Abstract

Short-tailed bats Mystacina tuberculata were widespread throughout the forest that dominated prehuman New Zealand, but extensive deforestation has restricted them to scattered populations in forest fragments. In a previous study, the species' intraspecific phylogeny was investigated using multiple mitochondrial gene sequences. Six phylogroups were identified with estimated divergences of 0.93-0.68 Ma. In the current study, the phylogeographical structure and demographic history of the phylogroups were investigated using control region sequences modified by removing homoplasic sites. Phylogeographical structure in the North Island was generally consistent with an isolation-by-distance dispersal model. Coalescent-based analyses (i.e. mismatch distributions, skyline plots, lineage dispersal analysis and nested clade analysis) indicated that the three phylogroups found in central and southern North Island expanded before the last glacial maximum, presumably during interstadials when Nothofagus forest was most extensive. Genetic structure within a central North Island hybrid zone was consistent with range expansion from separate refugia following reforestation after catastrophic volcanic eruptions. Phylogeographical structure in the South Island was consistent with southern populations originating during rapid southward range expansion from refugia in northern South Island following postglacial reforestation of the South Island 10-9 kya.

Recent evolutionary history of New Zealand's North and South Island Kokako (Callaeas cinerea) inferred from mitochondrial DNA sequences

“…However, recently Ho et al (2005) showed that the rate of mitochondrial evolution is elevated and highly variable at these shorter divergence times and so cannot be expected to behave in clock-like manner. Nevertheless, these studies of forest-dependent species imply that little gene flow occurred between the two islands probably because the land bridge was likely to have been 'limited and intermittent' during the Pleistocene (Lloyd 2003a). Also these studies indicate that forested refugia existed in the South Island of New Zealand throughout the Pleistocene and thus allowed the survival of lineages distinct from those on the North Island.…”

“…For example, studies by Lloyd (2003aLloyd ( , 2003b found New Zealand's endemic Short-tailed Bat contains six distinct mitochondrial lineages that probably diverged in the mid-Pleistocene owing to allopatric fragmentation. The North Island lineages show evidence of population expansion and the mixing in the central region of the Island but the distribution remains consistent with an isolation-by-distance dispersal model.…”

“…Average nucleotide diversity between NI Kokako and SI Kokako was high (0.049) relative to only 0.006 within NI Kokako, and the phylogenetic analyses identified SI Kokako as a separate monophyletic clade. Studies of other forest-dwelling taxa from New Zealand, such as Short-tailed Bats (Lloyd 2003a), North Island and South Island kiwi (Baker et al 1995), and a cicada (Buckley et al 2001) have all revealed relatively large genetic distances between North and South Island clades and have estimated dates for divergence at between 0.89 and 0.9 million years ago. If we adopt the estimate divergence rate of the avian control region as 5% per million years, as suggested by Freeland and Boag (1999), then Kokako too would fit this pattern.…”

The conservation status of New Zealand bats, 2009

“…The geographic range and numbers of bats have declined significantly and in many areas declines are continuing (e.g. O'Donnell 2000a;Lloyd 2003aLloyd , 2005Pryde et al 2005Pryde et al , 2006. Declines result from a combination of threats, primarily predation and competition from introduced mammalian pests, habitat degradation, disturbance and, possibly, disease (see below).…”

“…The total population was estimated as being in the order of 40,000 individuals in eight populations in 2002 (Table 2; Lloyd 2003a, b). A small population in the Tararua Ranges, previously grouped with southern lesser shorttailed bats, has been re-assigned to this taxon on the basis of recent genetic analyses (Lloyd 2003a). We classified central short-tailed bats as Declining.…”