Roost site selection and roosting behaviour in lesser short‐tailed bats(Mystacina tuberculata)in comparison with long‐tailed bats(Chalinolobus tuberculatus)inNothofagusforest, Fiordland

Abstract

I studied the roosting ecology of the lesser short-tailed bat (Mystacina tuberculata) during the summer months of 1997-2000 in lowland Nothofagus rainforest, Fiordland, New Zealand. Structural characteristics of communal day-roost trees and cavities were compared with those of randomly available trees and cavities, and those used by a sympatric population of long-tailed bats (Chalinolobus tuberculatus). I radio-tracked 29 M. tuberculata to 20 communal roost cavities located in 16 trees. Twelve of 21 characteristics measured differed significantly between roost and random sites. M. tuberculata selected roosts in more open parts of the forest, in some of the largest red beech (Nothofagus fusca) trees and cavities available. Characteristics of trees used by the two bat species were similar. Both species roosted in large diameter, old age red beech. However, 11 of the 12 roost cavity characteristics varied significantly between bat species. Roost cavities used by M. tuberculata were significantly lower to the ground, had more entrances, and had larger entrance and internal dimensions than C. tuberculatus roosts. Nevertheless, roosts of both species were well insulated and exhibited stable internal temperatures. M. tuberculata roosting groups were dominated by females and young, and group size averaged 310 ± 88.1 bats (n = 40). Roosts were occupied for an average of 5.6 ± 6.9 days (n = 23). Group size was significantly larger than in C. tuberculatus, and roost residency time significantly longer. Differences in roost use and roosting behaviour between the two species should be considered when undertaking conservation management actions such as identifying trees for retention through logging cycles, or designating reserves.

Habitat use and nocturnal activity of lesser short‐tailed bats(Mystacina tuberculata)in comparison with long‐tailed bats(Chalinolobus tuberculatus)in temperate rainforest

“…Radio-tracking lesser short-tailed bats in concurrent studies revealed that all maternity roost trees discovered to date were within the Knobs Flat study area and that the Plato Creek area was used only by foraging bats (O'Donnell et al 1999;Christie 2003a;Sedgeley 2003). However, we are uncertain whether high activity levels at Knobs Flat simply reflected increased commuting rates close to roosts or not.…”

“…Nevertheless, this seems largely to be the case, with both long-tailed bats and lesser short-tailed bats demonstrating little overlap, and little flexibility, in their habitat use. Differences between lesser short-tailed and long-tailed bats in wing ecomorphology (Norberg & Rayner 1987;Jones et al 2003;O'Donnell 2005), echolocation (Parsons 2001), nocturnal activity patterns (O'Donnell 2000b(O'Donnell , 2005; this study), roost site selection (Sedgeley & O'Donnell 1999a,b;Sedgeley 2003), diet (Arkins et al 1999;O'Donnell 2005) and morphology (O'Donnell et al 1999;Lloyd 2005;O'Donnell 2005) suggest that differences between the species range across the full gambit of behaviours. Some caution should still be used when making definitive statements about habitat selection in New Zealand bats.…”

“…Resource availability is believed to be a primary limiting factor of bat populations, so changes in foraging and roosting habitats that lead to changes in food density will affect bat populations (Findley 1993;Gerell & Lunberg 1993). Current logging in private indigenous forests may continue to threaten bat populations in local areas (Molloy 1995;Sedgeley & O'Donnell 1999a;Sedgeley 2003). The national distributions of both bat species are still poorly known, therefore forests targeted for tree removal need to be thoroughly surveyed for bats before tree removal is contemplated.…”

Roost site selection by lesser short‐tailed bats(Mystacina tuberculata)in mixed podocarp‐hardwood forest, Whenua Hou/Codfish Island, New Zealand

“…forest in the Eglinton Valley, Fiordland, South Island. Research focused on interspecific differences in roost use during summer months Sedgeley & O'Donnell 1999a,b;Sedgeley 2003). Both species were highly selective of roost sites, using trees and cavities that had distinctive structural and microclimatic characteristics relative to those potentially available.…”

Assessment of the short-term success of a translocation of lesser short-tailed bats Mystacina tuberculata

“…obs.) but is unlikely to compete with short-tailed bats due to little ecological overlap (Arkins et al 1999, Sedgeley 2003. The size of the C. tuberculatus population is unknown.…”