|
Publications
on Bats (1997-2000)
|
|
|
Vardon,
M.J. and Tidemann, C.R. (2000). The black
flying-fox Pteropus alecto in north Australia: juvenile mortality
and longevity. Australian Journal of Zoology 48: 91-97. Vardon,
M.J. and Tidemann, C.R. (1999). The ecology
and management of flying-foxes in the Northern Territory. Australian
Biologist 12: 91-95. Vardon,
M.J. and Tidemann, C.R. (1999). Flying-foxes
(Pteropus alecto and P. scapulatus) in the Darwin
region, north Australia: patterns in camp size and structure.
Australian Journal of Zoology 47: 411-423. Vardon, M.J. and Tidemann, C.R. (1998). Reproduction, growth and maturity in the black flying-fox, Pteropus alecto (Megachiroptera: Pteropodidae). Australian Journal of Zoology 46: 329-344. Tidemann, C.R., Kelson, S. and Jamieson, G. (1997). Flying-fox damage to orchard fruit in Australia - incidence, extent and economic impact. Australian Biologist 10: 177-184. Tidemann, C.R. and Vardon, M.J. (1997). Pests, pestilence, pollen and protein: the need for community-based management of flying-foxes in Australia. Australian Biologist 10: 77-83. Tidemann, C.R., Vardon, M.J., Nelson, J.E., Speare, R. and Gleeson, L.J. (1997). Health and conservation implications of Australian bat Lyssavirus. Australian Zoologist 30: 369-376. Vardon, M.J., Simpson, B.K., Sherwell, D. and Tidemann, C.R. (1997). Flying-foxes and tourists: a conservation dilemma in the Northern Territory. Australian Zoologist 30: 310-315.
*
Australian Journal of Zoology (2000) 48: 91-97. Biology
and management of the grey-headed flying-fox, Pteropus poliocephalus* Abstract Pteropus
poliocephalus is endemic to coastal eastern Australia (20-28oS),
where infrequent, but extreme droughts and floods, commonly across
large parts of the range, cause major swings in the availability
of forage - primarily eucalypt blossom, supplemented with fruits
and leaves. It can establish camps in most types of closed vegetation
>3m in height and it can breed opportunistically. Nevertheless,
camp occupation is persistent in most areas in most years, and most
births coincide with the southern spring. Mean (±SD) age at recovery
of banded animals was 40.4 (±18.8) months; the oldest was 96 months
(30 recovered/1840 banded). Seventy-six percent of foraging records
(n = 433) were within 20 km of the camp of origin. Pteropus
poliocephalus has experienced a range reduction since European
settlement and it is widely believed to be vulnerable to extinction.
Possible causes of a decline are climate change, competition with
congenerics, habitat loss and modification, and pest control. Conservation
effort has been expended primarily on protective legislation, reservation,
and promotion of the benefits of P. poliocephalus as well
as other flying-foxes; the problems they cause (mostly off-reserve)
have been poorly addressed and monitoring has been inadequate. Collaborative
management by major stakeholders (=cost-bearers) would facilitate
both the development of cost-effective and benign methods for excluding
flocks from inappropriate areas, and monitoring of population status.
Measures developed to manage P. poliocephalus could inform
management of other flying-foxes for most problems are generic.
Dry season camps of flying-foxes (Pteropus spp.) in Kakadu World Heritage Area, north Australia * Christopher R. Tidemann, Michael J. Vardon, Ronald A. Loughland and Peter J. Brocklehurst Abstract We investigated camps of black Pteropus alecto and red-flying-fox P. scapulatus in the early dry season of 1992 (April-June) in Kakadu National Park, a World Heritage Area in the wet-dry tropics of north Australia. Fifteen camp-sites were located and two types of camps were defined: main camps containing >1000 animals and a significant component of young (P. alecto, n = 4; P. scapulatus, n = 2) and satellite camps of lesser size (P. alecto, n = 9; P. scapulatus, n = 3). The two species shared three camp-sites. All camps were in dense riparian vegetation (fresh and saltwater mangroves, paperbark forests, closed forest and bamboo), overhanging or adjacent to water inhabited by crocodiles, that would provide a protected microclimate and protection from predators. All camps were within 5 km or less of one or more unoccupied sites that were indistinguishable in landform or vegetation from camp-sites. In Kakadu NP riparian vegetation makes up about 6% of the park and is a non-limiting resource for flying-foxes roosting. We propose that the initial colonization of camp-sites is essentially random when roost vegetation is non-limiting and that factors such as predation by humans, cyclones and fires determine the persistence and size of camps at the local level. At a broader temporal and spatial scale, interaction between the seasonal availability of forage and reproductive cycles is known to influence the location, size and structure of Pteropus camps. We advance the hypothesis that colonies of flying-foxes could be moved to new camp-sites, a strategy that would facilitate resolution of the frequently problematic management of these animals. * Journal of Zoology London (1999) 247: 155-163. Back to Top of Page The ecology and management of flying-foxes in the Northern Territory * Vardon, M.J. and Tidemann, C.R. Abstract Flying-foxes (Pteropus alecto and P. scapulatus) are widespread and abundant in the Top End of the Northern Territory. This paper reports on recent studies which have focused on the collection of baseline data, particularly on habitat use and how this varies over the year and between the species. Seasonal patterns have emerged with the abundance of each species related to the phenology of food plants, the reproductive cycle, camp-site characteristics and climatic regimes. The challenge now is to integrate our knowledge of flying-foxes with the many and sometime conflicting values attributed to them by people in the Northern Territory. *Australian Biologist (1999) 12: 91-95 Back to Top of Page Flying-foxes (Pteropus alecto and P. scapulatus) in the Darwin region, north Australia: patterns in camp size and structure * Vardon, M.J. and Tidemann, C.R. Abstract Five camps of flying-foxes (Pteropus alecto and P. scapulatus) were monitored regularly in the Darwin region between July 1994 and December 1997. For both species there was a relatively consistent annual pattern in the size and age-sex structure of camps. P. alecto appeared to be a local migrant, with numbers in the north of the study area negatively correlated with numbers in the south, but the movement did not involve all animals. Following births in February there was a southward movement of adult P. alecto in March and a return movement northward in September-November. The extent of three vegetatin types surrounding camps had a significant effect (P<0.05) on camp size in P. alecto. Sex ratios varied between P. alecto camps, with a higher proportion of females being found in larger camps (P<0.001), while the proportion of juveniles varied over the year (P<0.05), but not between camps. Large numbers of P. scapulatus were annual migrants to the southern portion of the study region during July-October 1994-97, but relatively small numbers of the species were present at other times. When integrated with other published information, the pattern seen in this study supports the view that P. scapulatus undertakes regular long-range movements and uses habitat in time and space differently from P.alecto. * Australian Journal of Zoology (1999) 47: 411-423. Back to Top of Page Black flying-foxes, Pteropus alecto: are they different in North Australia? * Vardon, M.J. and Tidemann, C.R. Abstract The Black Flying-fox, Pteropus alecto, has a range exceeding 1.6 million km2 in Australia (Webb and Tidemann 1996) and is also found in Papua New Guinea and Indonesia (Mickleburgh, Hutson and Racey 1992). At present four subspecies of P. alecto are recognised but only one, P. alecto gouldi, is known from Australia (Mickleburgh et al. 1992). At a gross level there is very little genetic variation in the Australian population of the species (Webb and Tidemann 1996). It is widespread and common in north Australia where it forms colonies in the canopy of trees. It is shot in large numbers as an orchard pest (Vardon and Tidemann 1995) and in the Northern Territory it is ranked as the most damaging vertebrate pest on fruit (Lim, Bowman and Tidemann 1993). It is also killed for food by Aboriginal people (Vardon, Missi, Cleary and Webb 1997a). Yet despite these and other pressing management issues (Tidemann and Vardon 1997) little is known about the species, and what information that exists is scattered widely through the literature (eg. Andersen 1912; Ratcliffe 1931; Johnson 1964; Nelson 1965; Thomson 1991; Hall 1995). A similar situation exists for P. scapulatus (Vardon, Simpson, Sherwell and Tidemann 1997b). * Australian Mammalogy (1998) 20: 131-133. Back to Top of Page Reproduction, growth and maturity in the black flying-fox, Pteropus alecto (Megachiroptera: Pteropodidae) * M.J. Vardon and C.R. Tidemann Abstract This paper reviews the timing of reproduction, growth rates and age at maturity of the black flying-fox, Pteropus alecto. This species is found from Sulawesi, Indonesia, south to the central coast of Australia. In northern Australia at 12oS most young are born in January-March, in contrast to October-November at 27oS in eastern Australia, but a small percentage of young are born outside the major birth peaks in both areas. The birth peaks of P. alecto appear to be aligned with periods of maximum plant productivity, rather than day length. The plasticity of breeding season is likely to be an important factor enabling P. alecto to colonise areas from near the equator to 29oS. Individual growth rates were calculated for 27 P. alecto. The weight growth rate of these animals were 2.40 ± 3.14 g day -1 (mean ± s.d), while growth rate of the forearm was 0.19 ± 0.18 mm day -1 (mean ± s.d.). The growth rate of the forearm of females was significantly greater than for males (P=0.08). From the mean forearm lengths of animals trapped, separate growth curves were developed for juvenile males (n = 566) and females (n = 610); these indicate that growth rate of females is about 8% higher than that of males. Primiparous females had a forearm length of 171.1 ± 3.4 mm (mean ± s.d.) (n = 5), which is achieved 15-17 months after birth, but about a third of females with forearm lengths of 160-170 mm have suckled young. Males mature at an age greater than females due to their slower growth rate, a phenomenon known from other megachiropteran species. * Australian Journal of Zoology (1998) 46: 329-344. Back to Top of Page Chris Tidemann, Shannon Kelson and the late Graham Jamieson This
paper estimates the cost to the Australian fruit industry from damage
by flying foxes. Losses totaling about $20 million per annum were
estimated by commercial growers in Western Australia, the Northern
Territory, Queensland and New South Wales. Losses to banana growers
across these areas were estimated to be about $12 million and estimates
of losses to stonefruit and mango growers each exceeded $3 million
per annum. Total losses under $1 million were estimated by growers
of pomefruit, lychees and papaya respectively. Estimated rates of
damage varied substantially between locations and growing conditions,
unusually "bad bat seasons" were reported by growers of
susceptible fruit in most areas. * Australian Biologist (1997) 10: 177-184.
Christopher R. Tidemann and Michael J. Vardon Flying-fox management or conservation (we equate the two) in Australia is problematical, largely because these animals are very different things to different people. Flying-foxes are hunted as traditional food by Aborigines, while in cities on the east coast they are kept as pets. In fruit growing areas many are destroyed as pests, and most recently, flying-foxes have been found to carry viruses that have caused the deaths of three people. Against the resulting backdrop of disparate and conflicting community attitudes to flying-foxes is a confusing division of management responsibilities for these animals between numerous government agencies at the local, state and national levels. A worse situation is that flying-foxes live in large colonies, which makes them easy to destroy, and colony sites are invariably in habitats that are under continued threat from agricultural and urban development. If we are serious about biodiversity conservation at the national level, it is vital these issues be resolved because flying-foxes, by dispersing pollen and seeds, are pivotal to ecosystem maintenance. In this paper we review the issues and argue that, if flying-fox populations are to be maintained in perpetuity, all the stakeholders will need to be involved in a collaborative, proactive management process. * Australian Biologist (1997) 10: 77-83.
Health and conservation implications of Australian bat Lyssavirus * Christopher R. Tidemann, Michael J. Vardon, John E. Nelson, Richard Speare and Laurence J. Gleeson Australian bat Lyssavirus, first reported in mid-1996 from a Black Flying-Fox Pteropus alecto has now been isolated from two other species of flying-fox, a microbat and a human, who died of a rabies-like illness, infected animals have been identified from widely separated localities in four Australian states. It is not known definitely from which species of animal the human victim contracted the disease, which is (are) responsible for spreading it, nor whether it is an old disease or one that has recently entered Australia. The infectivity of Australian bat Lyssavirus to humans and other mammals is not known, but its close geonomic and antigenic relationship to classical rabies virus suggests that it is likely to be capable of causing fatal illness in most mammalian species. Its similarity to classical rabies also indicates that humans and other mammals will be protected by existing rabies vaccines. The discovery of Lyssavirus in Australian bats has highlighted the needs for professional and community groups involved with wild animals to work together to decrease the risks to human health and to lessen the impact on bats and other native species. Educating the public about the risks of contact with bats is the single most important safeguard in protecting humans from a bat-borne disease. Concurrently, people need to be informed of the important role of bats in maintaining biodiversity and ecosystem integrity to minimize public impact on bats. * Australian Zoologist (1997) 30: 369-376.
Michael J. Vardon, Boyd K. Simpson, David Sherwell, Christopher R. Tidemann Abstract
A small colony (1,000-5,000) of Little Red Flying-foxes, Pteropus scapulatus, usually resident at Mataranka Hot Springs in the semi-arid zone of the Northern Territory of Australia between October and February. In 1994-95 this changed markedly. More than 200,00 individuals were present and most did not depart until July. The colony generated a powerful smell and caused significant damage to the vegetation surrounding the Spring, resulting in conflict with tourist use of the area. Many methods were employed in attempts to shift animals, but none were successful. The situation is an extreme example of the problems caused by Australian Pteropus and highlights a general lack of information and effective management techniques for the genus and its habitats. Information on the sex ratio and breeding condition of females at the colony is presented. * Australian Zoologist (1997) 30: 310-315.
[Batatlas] [Publications on Bats (1990-1996)] [Myna Home Page] [Publications on Mynas and Other Woodland Birds] |
|
|
|
|