Gundabooka National Park Report Compr
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Ecological Study of the Endangered Bristle-nosed bat (Mormopterus ‘species 6’) and Survey of Microchiropteran Bats in Gundabooka National Park Report for NSW National Parks & Wildlife Service Upper Darling Region Michael Pennay NSW Department of Environment & Conservation PO Box 733, Queanbeyan NSW 2620 2 Summary The primary aim of this study was to ascertain basic ecological information about the Endangered Bristle-nosed Bat (Mormopterus ‘species 6’) The Bristle-nosed bat is one of Australia’s least known microbats, known from only 22 specimens captured at scattered locations in the arid and semi arid regions of central Australia, Queensland and north-western New South Wales. Nothing is known of its ecology. It is listed as Endangered in NSW on the basis of its rarity (only 6 individuals known prior to this study) and Data deficient by the IUCN. Recent genetic investigations into the taxonomy of Australian molossids suggests that the Bristle-nosed bat is currently misplaced and in fact belongs in a monotypic genus separate from other Australian Mormopterus, further elevating the conservation significance of the species on the basis of genetic uniqueness (Reardon 2006). During a 10 day study in November 2005 10 Bristle-nosed bats were trapped at Gundabooka National Park in north-western NSW. Using radio transmitters the bats were tracked to locate roosts and monitor the foraging behaviour of the species. General behavioural and morphological observations including diet, flight patterns, airframe design and echolocation call were also recorded. Key Results · Three diurnal roosts were located including one maternity roost · The bats were found to roost communally, sometimes with other species · Roosts were all located in Bimbil Box and Inland Red Box tree hollows with tiny entrances amongst the fringing vegetation of a large dry creek channel (Yanda Creek) · Both foraging activity and roost locations were significantly biased in favour of riparian habitat along Yanda creek channel and avoiding the surrounding mulga shrublands. · The bats flew many kilometres in a night, roosts were up to 3.9 km from point of capture · Gundabooka NP was found to provide suitable habitat for an exceptional number of microbats including an additional 2 threatened species (Chalinolobus picatus and Saccolaimus flaviventris) Conclusions · The study demonstrated the species is readily captured using traditional methods in places where they occur. This suggests that the large number of survey sites where the species has not been found are probably genuine absences – supporting the argument that the species is rare · The species roosted in eucalypt tree hollows and foraged in the riparian zones – management actions that protect the retention of hollow bearing eucalypts around riparian zones will likely benefit the species · The species is not suitable for Anabat ultrasonic survey. The echolocation call was found to be indistinguishable from the common Little Broad-nosed Bat. · Of the listed key threatening processes in NSW six are likely to have some impact on the Bristle-nosed bat, these are in order of likely importance. Clearing of Native vegetation (loss of habitat), removal of dead wood (loss of habitat), alteration to natural flow regimes (loss of habitat), competition from Honey bees (loss of roosts), inappropriate use of fire (loss of habitat), lack of tree regeneration due to overgrazing by goats (loss of habitat). Predation by fox and cats is probably low due to the species use of small hollows and lack of ground based foraging. Other potential threats to consider may be; direct and indirect poisoning due to pesticide use for plague locust control and agricultural purposes. Competition from more disturbance tolerant bats. 3 4 Management recommendations The following suggestions should help the management of this species within Gundabooka National Park based on results of this research. 1. Protect known roosts and foraging habitat along riparian zones within the park especially maternity roosts · Protect hollow resources available in mature eucalypts fringing Yanda Creek and other areas within the reserve from fire · Monitor the reserve for infestations of Feral Honey bees and undertake control measures if hives become a problem · Avoid apiary activities within the park · Avoid the use of pesticides for Plague Locust control within 1km of riparian areas within the park · Continue goat control measures to reduce the overall pressure on regenerating vegetation within the park · Monitor and restrict illegal removal of timber for firewood from the Park · Continue fox and cat control. 2. Survey in other areas of the reserve and undertake on going monitoring of the species to ascertain population size and ecological requirements To assist with these recommendations a map of known and suspected habitat for this species within the park has been produced on the basis of this research (Figure 1). Care should be taken interpreting this map as seasonal use of the landscape may vary and areas not used in November may be important at other times of the year. 5 6 Figure 1. Known and suspected habitat of Mormopterus ‘species 6’ within Gundabooka National Park 7 8 Introduction Taxonomy Mormopterus ‘species 6’ was first recognised a distinct taxon in 1988 (Adams et al. 1988). It is widely recognised by biologists as being a distinct species on the basis of morphological and genetic characteristics however it has not yet been formally described, primarily due to the unresolved taxonomy of the genus Mormopterus in Australia (Reardon 2006, Reardon & Pennay in press). Recent work on the phylogeny of the family Molossidae by Reardon (2006) has revealed that the Australian bats under the genus Mormopterus are misplaced. They are not closely related to ‘true’ Mormopterus from Africa / Madagascar, home of the type species for the genus Mormopterus jugularis. In addition two of the Australian species currently placed under Mormopterus (norfolkensis and ‘species 6’) are both significantly distinct from other members of the Australian genus and each other. In fact they represent two divergent branches of separate monotypic genera. The norfolkensis bat has previously been described under the valid generic name Micronomus by Troughton, E. le G. in 1944 which is likely to be reinstated however the generic name for ‘species 6’ is presently undescribed. The importance of this information for land managers is that once this research is formally published it will further elevate the conservation significance of ‘species 6’ as it is believed to be more taxonomically and genetically unique than previously recognised, representing a monotypic genus. There are only three other Australian microchiropterans with this degree of genetic uniqueness (Ghost Bat Macroderma gigas, Orange Leaf-nosed Bat Rhinonicteris aurantia, and Greater Broad-nosed Bat Scoteanax rueppellii). Distribution The species is endemic to Australia, it was known prior to this study from only 22 specimens collected from scattered locations throughout the arid and semiarid regions of the Northern Territory, South Australia, Queensland and Northern New South Wales (Figure 2). Figure 2. Location of Mormopterus ‘species 6’ records. 9 Conservation Status The species was first discovered in New South Wales at Gundabooka National Park in 1997 when 3 individuals were caught (Ellis, 2001). A further individual were trapped at Bebo State Forest near Goondiwindi in 2001 (Pennay, 2002) and two individuals were captured nearby at Bonshaw the following year (DEC, 2004). A total to 6 individuals known for the State. In 2004 the species was listed as an Endangered species in NSW on the basis of its rarity and risk of extinction (DEC 2004). Nationally and Internationally its has been given ‘Data Deficient’ status (Duncan et al. 1999) Ecological knowledge Prior to this study nothing was known of the species ecology other than the capture locations and assumptions based on the habits of its nearest relatives (DEC 2004). Identification Mormopterus ‘species 6’ is superficially similar to other Mormopterus species, it possesses a ‘free tail’ not enclosed by the tail membrane common to all Molossids. However it is readily identified from other Mormopterus species on the basis of its lighter weight and dainty build (Figure 3). The average weight for adult Mormopterus ‘species 6’ caught at Gundabooka during this study was 5.5 grams whereas the average weight for other Mormopterus species that overlap in range with this species is approximately 8.5 grams. The forearm is also long (34mm) relative to its low weight. Other distinguishing features are stout bristles on the nose (Figure 4) and a distinctive large fleshy projection on the genitals of both male and females (Figure 5). All bats caught at Gundabooka had nostrils much darker than the skin on the muzzle however it is unknown if this is a reliable characteristic to assist with identification (Figure 3). Figure 3, Mormopterus ‘species 6’ ( right) compared with Mormopterus ‘species 3’ (left) is clearly much smaller with less robust features. Note the width of the snout and thickness of the ear margins. The dark nostrils seen in this bat were present in all M. ‘species 6’ caught at Gundabooka. 10 Figure 4. Detail of the face of Mormopterus ‘species 6’ showing the stout bristles on the nose (rostrum) which distinguish the species from other Mormopterus and form the basis of its common names “Bristle-nosed bat” or “Hairy-nosed Freetail bat”. Figure 5. Detail of the penis of a Mormopterus ‘species 6’ showing the fleshy projection extending from the tip of the penis, this projection is also found on female genitals, its function is unknown. 11 12 This Study Objectives The primary aim of this study was to ascertain basic ecological information about the Bristle- nosed Bat (Mormopterus ‘species 6’) to assist with conservation management of the species. Study Area The research was conducted in Gunadbooka National Park located approximately 50km south of Bourke in north-western NSW. Trapping was targeted around the location of the original captures of Mormopterus ‘species 6’ in 1997(Ellis 2001) in Yanda Creek (Figure 6).