Bats of a semi-arid environment in south-eastern Australia: biogeography, ecology and conservation

Abstract

A total of 2075 captures of 11 taxa of bats was recorded during an extensive survey of the vertebrate fauna of the semi-arid Mallee region of Victoria. A further two species, Pteropus scapulatus and Saccolaimus flaviventris, are known from previous records, thus bringing the total to 13 taxa known from the region. There was a marked seasonality in activity patterns and in reproduction. Activity, as revealed by trap captures, peaked over the spring to early autumn months when daytime temperatures are high and nights are mild. Births occurred from October to December, lactating females were recorded from November to February, and juveniles were trapped between December and late February, with minor variation in timing between species. Morphometric measurements revealed that females were generally larger and heavier than males. There was a high level of overlap of species between broad vegetation types. Woodland habitats, especially Riverine Woodland, tended to have a higher frequency of capture and a greater species richness of bats per trapping event than did Mallee Shrubland. The assemblage of bats in the Mallee region, Victoria, like those in other semi-arid regions of southern Australia, includes species that are widespread in Australia (e.g. Chalinolobus gouldii and Nyctophilus geoffroyi), together with species that primarily occur in semi-arid and arid environments (e.g. N. timoriensis, Scotorepens balstoni and Vespadelus baverstocki). This region, which includes mesic riverine habitats, also supports a group of species that are characteristic of temperate south-eastern Australia (e.g. C. morio, V. regulus and V. vulturnus). In comparison with assemblages from temperate and tropical environmental regions, those from the semi-arid region tend to have a lower species richness with fewer families represented, a higher level of insectivory, and a smaller modal body size. The conservation status of bats from the Mallee region, Victoria, is believed to be secure, although the status of N. timoriensis warrants further attention.

Geographic Variation in the Echolocation Calls ofVespadelusspp. (Vespertilionidae) from New South Wales and Queensland, Australia

“…Populations of species in semi-arid western NSW (Riverina and north-west NSW) consistently had smaller forearms than those towards the coast. A pattern for species to be smaller in semi-arid compared to mesic regions has been reported elsewhere (Lumsden and Bennett, 1995;Young and Ford, 1998), although small forearms are not found in Vespadelus from the largely dry South Australia (Queale, 1997). It is interesting to note that one of our inland (low rainfall) collection sites, the Riverina, could be considered mesic because it is a large inland river and wetland system surrounded by extensive semi-arid lands (Law and Anderson, 1999).…”

Influence of season, habitat, temperature, and invertebrate availability on nocturnal activity of the New Zealand long‐tailed bat (Chalinolobus tuberculatus)

“…This observation contradicts the assertions of Dwyer (1962) and Daniel (1990), that C. tuberculatus hibernates continuously for 4 to 5 months through winter. Other studies from northern temperate regions suggest that foraging is curtailed at temperatures below 10-12°C (Anthony et al 1981;Wilkinson & Barclay 1997); in southern Australia, c. 5°C has been the threshold below which activity ceases (Taylor & Savva 1990;Lumsden 1993;Lumsden & Bennett 1995). Chalinolobus morio was more active than other bats in colder weather in southern Australia, perhaps because reduced competition at these times allows them to build up fat reserves (Taylor & Sawa 1990).…”

The echolocation calls, habitat relationships, foraging niches and communities of Pilbara microbats

“…Their biological relevance for Australian microbats has been well documented (e.g. McKenzie and Rolfe 1986;Lumsden and Bennett 1995;Law et al 1998;McKenzie and Muir 2000;Young and Ford 2000;Williams and Dickman 2004;Milne et al 2005a,b). To determine whether spatial autocorrelation caused by proximity between landward sites should to be treated as a factor infl uencing composition (e.g.…”