The Action Plan for Australian Bats
Identification of threats and the development of methods and actions to mitigate these is essential before successful management programs can be applied to threatened species. One of the aims of the Action Plan is therefore to identify threatening processes affecting Australian bats and recommend national priorities for conservation action.
Threatening processes are any natural or anthropogenic processes which either have a direct negative impact on individual animals or which change the habitat in such a way that the continued existence of a species is jeopardised. Natural processes which affect individual animals or taxa are part of evolutionary processes and are not considered here.
Threatening processes affecting Australian bats operate at many levels and include both factors that cause the death or reproductive failure of individuals as well as those which affect populations, whole species or many species simultaneously. Understanding threats may be complicated since many bat species could be affected by several threatening processes and these may interact in complex ways. Examples include broadscale habitat destruction and modification; roost destruction and disturbance; shooting and electrocution to protect crops; pesticide poisoning; mortality caused by collision with powerlines, fences and cars; and infection with parasites or diseases. Adverse social and cultural attitudes towards bats within the human community may also be considered a threat to some species.
In some species the effects of threatening processes may be readily apparent e.g. species which form large roosts where population size can be easily measured. However, in other species where roosts are dispersed, population size can be more difficult to define or measure due to lack of historical information and/or difficulty of survey.
Each species outline and taxon summary in this Action Plan addresses what is known about threats to each species. A broader national picture of threatening processes affecting Australian bats can be obtained by examining the numbers of species affected by similar threats. Table 4.1 summarises the confirmed and potential threats which have been identified in each species recovery outline and taxon summary (i.e. for threatened, near threatened and data deficient bats, hereafter referred to as ‘threatened’), and shows the numbers of species affected by each threat.
In a similar way, a broad picture of the national priorities for conservation actions for Australian bats can be obtained by examining the numbers of species with similar types of actions identified. Table 4.2 is a summary of the types of actions identified in each species recovery outline and taxon summary. The table shows the numbers of species for which each action has been identified.
The review of Table 4.1 highlighted that the following processes were major threats affecting many Australian bats:
- habitat loss (affecting 21 of 36 species);
- roost disturbance (affecting 13 of 36 species); and
- forest harvesting (affecting 11 of 36 species).
A suite of other threats affecting small numbers of species is also identified: collapse, closure and re-working of old mines; crop protection activities; pathogens and pollutants; introduced predators; changes to fire regimes; over-collection; and collision with human infrastructure.
Also highlighted by this review is the general lack of knowledge about Australian bats. It is of great concern that for many bat species knowledge is insufficient to confidently identify reasons for decline or current threats. For seven species, no threats, confirmed or potential, can be identified.
|Habitat clearing, (includes fragmentation and modification)||Roost disturbance||Forest harvesting||Collapse, closure and/or reworking of mines||Change to fire regimes||Introduced predators||Pollutants||Over-collection||Crop protection activities (includes shooting, electrocution, and roost harassment)||Pathogens (includes diseases and tick infestation)||Collision with human infrastructure (fences and powerlines)|
|Saccolaimus saccolaimus nudicluniatus||P||P|
|Rhinolophus philippinensis (large form)||P||C||C||P|
|Rhinonicteris aurantius (Pilbara form)||P|
|Nyctophilus timoriensis (South-eastern form)||C||P||P|
|Lower risk (nt and cd)|
|Dobsonia moluccensis magna||P||P|
|Nyctophilus timoriensis (Central form)||P|
|Miniopterus schreibersii (Southern form)||P||P||P|
|Pteropus sp. (Moa Island)||P|
|Pteropus melanotus natalis||P||P|
|Rhinolophus philippinensis (small form)||P||P||P|
|Hipposideros diadema inornatus||P|
|Mormopterus loriae cobourgiana|
|Mormopterus sp.(form sp. 6. in Adams et al. 1988)|
C = confirmed threat or cause of decline
P = likely/suspected/inferred/possible threat or cause of decline
4.3.1 Habitat loss (including clearing, fragmentation and modification)
Habitat loss is a major threat affecting more than half (21 out of 36 species) of the threatened species in Australia. While bats are not necessarily dependent on large areas of uncleared habitat for their roosting habitat, they range over relatively large areas and thus require large areas of habitat for foraging (Lunney et al. 1988, Lumsden et al. 1994, Pavey 1995). Habitat loss has resulted from activities such as agricultural clearing, urban settlement, industrial development, forestry activities, development of transport and utility corridors and tourism and recreation developments. In addition to the direct loss of habitat there are additional threats which can be associated with agricultural clearing and urban and industrial development: disturbance/destruction of roosts, mortality associated with structures such as powerlines and barbed wire fences, and the expansion of range of introduced predators.
Using satellite imagery Graetz et al. (1995) estimate that 20% of the Australian continent has been cleared or thinned since European settlement. Contrary to common belief, broadscale clearing has actually increased in the last fifty years, with as much land cleared in the last fifty years as was cleared in the 150 years before 1945. Serious concern remains about continuing patterns of clearance (Department of Environment, Sport and Territories 1995, State of the Environment Advisory Council 1996).
As a response to concern about clearing of native vegetation, there are currently national programs under the Natural Heritage Trust e.g. the Bushcare program, which aim to expand revegetation activities, conserve and improve the management of remnant bush and reverse the long term decline in the quality and extent of Australia’s native vegetation. The protection of highly significant native vegetation is also pursued through the National Reserve System Program. State agencies also have legislation and funding programs which encourage retention of habitat and protection of wildlife on private land (e.g. Land for Wildlife (Victoria)).
4.3.2 Roost Disturbance
Roost disturbance affects 13 out of the 36 threatened species. Disturbance is usually in the form of regular human visitation, or visitation at inappropriate times such as during the maternity season or hibernation. Most susceptible species are cave dwellers or species which roost and breed in abandoned mines. The funding of management actions to protect roosts and prevent disturbance could be extremely effective in improving the conservation of bats in Australia.
4.3.3 Forest harvesting
This threat affects 11 of the 36 threatened species. Of the area of Australia covered by forests at the time of European settlement 40% has been modified by logging (State of the Environment Advisory Council 1996). The mechanisms through which logging can cause impact on bats can be summarised as:
- direct mortality;
- destruction of roost sites;
- reduced feeding opportunities through clearing of habitat;
- direct reduction in food abundance through effects on insect populations; and
- alteration of habitat structure which may impact on foraging abilities and affect chance of predation (Law 1996).
Despite the number of studies on the impact of forestry activities (relative to other threatening processes), the question of the extent of impact remains unanswered, partly because of the methodological problems associated with study of these highly mobile animals. In addition, management practices for mitigation of the effect of logging on wildlife, including bats, are presently being implemented by most State forestry agencies, but there are few studies of their efficacy. Such research is essential to ensure management regimes can be adapted as necessary to meet the requirements of forests-dependent fauna.
4.3.4 Collapse, closure or re-working of old mines
This is a particular type of roost disturbance/destruction which has been identified as a threat for 9 threatened bat species. A total of 29 species of Australian bats are known to use abandoned mines as daytime roosts, and 21 of these use them as maternity sites. Bats also use abandoned mines as dispersal stopover points and in a few cases the range of species has been extended (Hall et al. 1997, Hall and Richards 1998). Many of the bat species which use abandoned mines are rare and threatened and often there are large congregations of animals at these sites. The closure of mines for public safety considerations, or the collapse, destruction or re-working of abandoned mines can thus threaten the population viability of bat species now dependent on these sites following the destruction of natural roosts or because their range has now been extended to include them. On-ground management actions to protect roosts of threatened bat species are needed by mining companies, State conservation and other land management agencies.
4.3.5 Crop protection activities
‘Crop protection activities’ refers to a group of threats which apply specifically to two species, Pteropus poliocephalus (VU) and Pteropus conspicillatus (LR nt). These bats are well known for the damage they inflict on commercial fruit crops and have often been regarded as ‘pest species’ in the past. Losses to the fruit industry have been estimated by commercial growers at 20 million dollars per annum (Tidemann et al. 1997). As a result, these species have long been the subject of crop damage mitigation activities, primarily culling, by commercial fruit growers. Crop damage mitigation techniques also include harassment and disturbance of roosts, and use of crop protection devices such as ‘Fyre Foxes’ (networks of electric wires above orchards used to stun or kill flying foxes) and exclusion netting. Little research into the effectiveness of these techniques or their impact on bat populations.
The need to develop non-lethal techniques to protect fruit crops from Pteropus poliocephalus and Pteropus conspicillatus has been identified in this Action Plan. These should be developed and implemented in conjunction with the fruit growing industry. Further research on effective exclusion techniques (such as netting) and use of non-lethal electric currents and olfactory deterrents are suggested approaches. Incentives for encouraging the use of non-lethal techniques may also need to be considered. Queensland Department of Primary Industries are currently reviewing exclusion techniques for protection of fruit crops in that State.
All animals, bats and humans included, host an enormous range of micro-organisms, most of which usually have little effect on their hosts. If, however, animals are already stressed by starvation or some other factor, serious disease or death may result. Only a few animals will be affected in wild populations most of the time, but during unusual climatic events (eg, reduced food supply in El Nino years), localised or widespread outbreaks of disease may occur. Many diseases which are generally non-fatal in their usual hosts, may have serious consequences if transmitted to or through another species.
In the past decade three viral diseases have been traced to Australian bats - two have caused fatalities to humans and the other has caused illness. All three viruses have been fatal to domestic animals:
- Hendra virus (also known as equine morbillivirus, bat paramyxovirus no.1) caused the deaths of two people after they caught the disease from horses that were suspected to have caught it from bats;
- Ballina virus (also known as Australian bat lyssavirus) killed two people via bat-bites; and
- Menangle virus (also known as bat paramyxovirus no. 2) caused deaths of pigs and illness in humans.
In Australia very little is known about bat diseases, simply because the research has not been done. Preventive vaccination is only available currently for Ballina virus (because of its very close affinity to classic rabies). The infectivity of Australian bat diseases to people is unknown, although probably low. Many people have been bitten by many bats over many years and contamination with faeces and urine is constant for people who work with these animals. Although only recently discovered, it is likely that these diseases have been present in the Australian bat population for some time and it is highly likely that more remain to be discovered.
Proper diagnostic testing is the only way to ascertain the cause of an animal’s malaise. Accurate identification of species, age etc. are also very important if a complete epidemiological picture is to be obtained. People who wish to avoid any risk of disease should avoid contact with bats and their roosts altogether. Few people have died from bat diseases in Australia but the health risk should be taken seriously by all concerned with bat conservation.
The threat of bat diseases is not just of a disease affecting individual animals or humans, but of the perception of personal risk by the public, leading to a reduced concern for the conservation of bats. Bats living in close proximity to humans may be at risk of persecution by people concerned about health risks. The issue of public health has now become a real issue to be addressed wherever there is likely to be contact between bats and humans. It should be noted that the Health Departments in Queensland and New South Wales consider that bats and the viruses that some of them carry are an extremely low public health risk. Well-targeted education programs are needed to convey this message to the public, together with information on the ecosystem benefits of bats.
|Survey||Ecological research||Assess threats||Taxonomy (including genetics and examination of museum specimens)||Protect roosts from disturbance||Long term monitoring||Habitat management/ protection||Management of roosts in man-made structures||Develop species identification||Develop survey techniques||Develop non destructive deterrents||Research into pathogens||Develop National recovery Plan|
|Saccolaimus saccolaimus nudicluniatus||Y||Y||Y||Y|
|Rhinolophus philippinensis (large form)||Y||Y||Y||Y||Y|
|Rhinonicteris aurantius (Pilbara form)||Y||Y||Y||Y|
|Nyctophilus timoriensis (South-eastern form)||Y||Y||Y|
|Dobsonia moluccensis magna||Y||Y||Y||Y|
|Nyctophilus timoriensis (Central form)||Y||Y||Y||Y|
|Miniopterus schreibersii (Southern form)||Y||Y||Y||Y|
|Pteropus sp. (Moa Island)||Y|
|Pteropus melanotus natalis||Y||Y|
|Rhinolophus philippinensis (small form)||Y||Y||Y||Y||Y|
|Hipposideros diadema inornatus||Y||Y||Y||Y||Y|
|Mormopterus loriae cobourgiana||Y||Y||Y||Y|
|Mormopterus sp.(form sp. 6 in Adams et al. 1988)||Y||Y||Y||Y|
|Total numbers of species||31||30||23||21||18||10||7||5||3||3||2||1||1|
Y = action identified for this species
The review of the taxon summaries and recovery outlines (Table 4.2) highlighted that the following actions were of high national priority for Australian threatened bats:
- Survey (recommended for 31 out of 36 species);
- Ecological research (30 out of 36 species);
- Assessment of threats (23 out of 36 species);
- Taxonomy (21 out of 36 species); and
- Roost protection (18 out of 36 species).
4.4.1 Survey and ecological research
Survey of distribution and abundance of bats has been identified as an important action to assist the recovery of threatened species. It needs to be carried out in a strategic way to ensure effective conservation of bat species and efficiency of effort. Action could perhaps be taken on a regional and/or taxonomic basis or on the basis of common threats or management problems and priorities could be determined by a national advisory group. Data from surveys could be aggregated into a national bat atlas held by an appropriate national organisation such as the Environmental Resources Information Network (ERIN) or the Australian Biological Resources Study (ABRS). This would greatly assist in future reviews of the Action Plan.
Geographic information systems and modelling techniques should be used to ‘fine tune’ the target areas for survey and associated ecological studies. Surveys should employ a wide range of technology and be carried out with appropriate standardised methodologies. A national library of echolocation calls held by ERIN or ABRS would also assist surveys, which are increasingly relying on this method to identify species.
Possible regional groups for surveys and ecological research include:
Far North Queensland and Cape York Peninsula: this appears to be the highest priority region in terms of both numbers of species and numbers of threatened species. Species include:
- Dobsonia moluccensis magna (LR[nt]),
- Nyctimene cephalotes (DD),
- Rhinolophus philippinensis (large form)(EN),
- Rhinolophus philippinensis (small form)(DD),
- Hipposideros semoni (EN),
- Saccolaimus mixtus (DD),
- Saccolaimus saccolaimus nudicluniatus (CR), and
- Murina florium (LR[nt]).
Arid inland eastern Australia:
- Taphozous troughtoni (CR),
- Mormopterus sp. (form sp. 6 in Adams et al. 1988) (DD),
- Chalinolobus dwyeri (VU),
- Chalinolobus picatus (LR[nt]), and
- Nyctophilus timoriensis (Central form) (LR[nt]).
- Pteropus melanotus natalis (DD) and
- Pipistrellus murrayi (EN).
- Macroderma gigas (LR[nt]),
- Hipposideros diadema inornatus (DD),
- Hipposideros stenotis (DD),
- Taphozous kapalgensis (DD), and
- Saccolaimus saccolaimus nudicluniatus (CR).
- Macroderma gigas (LR[nt]),
- Hipposideros stenotis (DD),
- Rhinonicteris aurantius (Pilbara form) (VU) and
- Vespadelus douglasorum (DD).
Other groups based on similar threats and possible management approaches include:
Species which roost in abandoned mines, where collapse, closure and re-working is a threat. This group includes:
- Macroderma gigas (LR[nt]),
- Rhinolophus philippinensis (large form) (EN),
- Rhinolophus philippinensis (small form) (DD),
- Hipposideros semoni (EN),
- Rhinonicteris aurantius (Pilbara form) (VU) and
- Taphozous troughtoni (CR).
‘Forest’ species of eastern Australia. This group includes:
- Mormopterus norfolkensis (DD),
- Chalinolobus dwyeri (VU),
- Chalinolobus picatus (LR[nt]),
- Kerivoula papuensis (LR[nt]),
- Murina florium (LR[nt]),
- Myotis macropus (LR[nt]),
- Nyctophilus timoriensis (South-eastern form)(VU),
- Scoteanax ruepellii (LR[nt]) and
- Scotorepens sp.(DD).
Flying foxes with similar management problems. This group includes:
- Pteropus conspicillatus (LR[nt]) and
- Pteropus poliocephalus (VU).
4.4.2 Assessment of threats
Assessment of threats has been identified as an action for 23 out of 36 threatened species, reinforcing the concern that little or nothing is known about threatening processes for many Australian bats. Assessment of threats should be an integral part of all ecological studies carried out on threatened species, including development of management actions to mitigate threats.
Resolution of taxonomic problems is an action required for 21 out of 36 threatened bat species. Further, Chapter 2 (Table 2.1) identified at least 25 bat taxa requiring taxonomic clarification at the species level. It is a real possibility that such taxonomic research may identify further species which are threatened. Identification of taxonomic units is thus an integral part of ensuring the effective conservation of bats in Australia and there is a need for this to be recognised by conservation agencies and for adequate resources to be provided to rectify the problem.
4.4.4 Roost protection
Protection of roosts from disturbance has been recommended as an action for 18 out of 36 species. It is important to note that many of these species are in high categories of risk (CR, EN, VU), which indicates that despite the priority for information gathering actions such as survey, research and taxonomy, there are management actions which can be undertaken immediately to protect threatened species. Priority for funding such management actions, however, should not be overshadowed by the priority for these other actions.
4.5.1 Habitat clearance
The loss of habitat is probably the most serious issue affecting long-term conservation of Australian bats. The problem of habitat clearance however is a nationwide problem and its effect is obviously not restricted to bats.
- Funding for programs such as Bushcare, which are designed to halt the clearance of land and revegetate cleared land, should be maintained at current levels as a minimum and, ideally, be increased.
4.5.2 Survey and Research
- High priority should be given to survey and ecological research necessary to clarify the distribution, abundance and conservation status of Australian bats, in particular threatened, near threatened and data deficient species.
- Identification of threats and development of management prescriptions for their mitigation should be an integral part of all ecological studies.
- Forestry agencies should be encouraged to carry out further research on the impact of logging on tree-dwelling bats. In particular, studies should identify:
- the sensitivity of bat species to different intensities of logging (e.g. clearfelling vs selective logging);
- the impact of forest fragmentation on bats at a landscape scale;
- which species are affected by current forestry practices;
- the effectiveness of current management prescriptions; and
- improvement or modification to existing management actions if required.
- A national atlas of Australian bats should be developed and maintained, using existing and incoming data.
- A national library of echolocation calls should be established to assist in ecological research and survey.
- High priority should be given to providing adequate resources to resolve taxonomic problems of Australian bats. This needs to be recognised by conservation agencies with fauna management responsibilities as an integral part of ensuring the effective conservation of bats in Australia.
4.5.4 Protection of roost sites
- On-ground management actions to protect roosts of threatened, near threatened and data deficient bats species should be given high priority for funding by State conservation and other land management agencies.
4.5.5 Development of non-lethal techniques for protection of fruit crops
- Non-lethal techniques to protect fruit crops from Pteropus poliocephalus and Pteropus conspicillatus, should be developed and implemented in conjunction with the fruit growing industry. This will require further research on effective exclusion techniques (such as netting) and use of non-lethal electric currents and olfactory deterrents. Incentives for encouraging the use of non-lethal techniques may also need to be considered.
- A national education program should be developed to address the public health risks associated with contact with bats as well as the important ecological role of bats and the need to ensure their conservation.
4.5.7 Conservation of bat fauna in mines proposed for closure, destruction or re-working
- Guidelines for management and conservation of bat fauna in mines proposed for closure, destruction or re-working should be developed by State conservation agencies in consultation with the mining industry and government departments responsible for mining and workplace health and safety. Such guidelines could identify potential species in different areas and include options for protection of roosts and prevention of roost disturbance, such as the installation of bat gates and erection of fencing to prevent human access.
4.5.8 National coordination
In many cases the distribution of bat species, and hence responsibility for their management, extends across Commonwealth, State and Territory jurisdictions. Achievement of recovery of threatened species and management of other species would be facilitated by the existence of a national advisory group.
- A national bat advisory group should be established to advise on the implementation of this Action Plan. In particular:
- advise on priorities for survey, research and taxonomy;
- set standards for survey and monitoring;
- facilitate establishment of an Australian bat atlas and call library;
- facilitate communication between researchers and managers;
- advise on / coordinate national issues eg. handling protocols required due to Australian bat Lyssavirus and other emerging viral diseases; and
- identify and facilitate projects of broader national significance ( e.g. education, public awareness).
Department of Environment, Sport and Territories 1995. Native vegetation clearance, habitat loss and biodiversity decline. Biodiversity Series, Paper No. 6. Biodiversity Unit, Department of Environment, Sport and Territories, Canberra.
Graetz R.D., Wilson M.A. and Campbell S.K. 1995. Landcover disturbance over the Australian continent, a contemporary assessment. Biodiversity Series, Paper No. 7. Biodiversity Unit, Department of Environment, Sport and Territories, Canberra.
Hall L. Richards G.C., McKenzie N. L. and Dunlop N. 1997. The importance of abandoned mines as habitat for bats. pp 326–334 in P. Hale and D. Lamb (Eds) Conservation Outside Nature Reserves. Centre for Conservation Biology, University of Queensland, Brisbane.
Hall L.S. and Richards G.C. 1998. Issues concerning bat distribution on minesites in Australia. pp. 125–137 in C.J.Asher and L.C.Bell (Eds) Fauna Habitat Reconstruction after Mining Workshop. Australian Centre for Mining Environmental Research, Kenmore.
Law B.S. 1996. The ecology of bats in south-east Australian forests and potential impacts of forestry practices: a review. Pacific Conservation Biology 2, 363–374.
Lumsden L., Bennett A., Silins J. and Krasna S. 1994. Fauna in a remnant vegetation-farmland mosaic: movements, roosts and foraging ecology of bats. Report to Australian Nature Conservation Agency, Canberra (unpublished).
Lunney D., Barker J., and Leary T. 1988. Movements of banded bats (Microchiroptera: Vespertilionidae) in Mumbulla State Forest near Bega, New South Wales. Australian Mammalogy 11, 167–169.
Pavey C.R. 1995. The foraging ecology of a guild of insectivorous bats (Rhinolophoidea) in eastern Australia: a test of resource partitioning theory. PhD thesis. University of Queensland, Brisbane (unpublished).
State of the Environment Advisory Council. 1996. Australia, State of the Environment 1996. Report to the Commonwealth Minister for the Environment. CSIRO, Canberra.
Tidemann C., Kelson S. and Jamieson G. 1997. Flying fox damage to orchard fruit in Australia – incidence, extent and economic impact. Australian Biologist 10, 177–184.
1 Biodiversity Group, Department of the Environment and Heritage
2 Australian Bird and Bat Banding Scheme
3 Department of Veterinary Anatomy and Pathology, University of Queensland
4 School of Resource Management and Environmental Science, Australian National University
5 Vision, Touch and Hearing Research Centre, Department of Physiology and Pharmacology, University of Queensland
6 State Forests of NSW