Publications archive - Publications
Key departmental publications, e.g. annual reports, budget papers and program guidelines are available in our online archive.
Much of the material listed on these archived web pages has been superseded, or served a particular purpose at a particular time. It may contain references to activities or policies that have no current application. Many archived documents may link to web pages that have moved or no longer exist, or may refer to other documents that are no longer available.
Gregory J. Hollis
Environment Australia, October 1997
Note: This publication has been superseded by the National Recovery Plan for the Baw Baw Frog Philoria frosti
The following personnel are referred to in the recovery action:
An understanding of what constitutes natural or abnormal fluctuations in the Baw Baw Frog population can only be achieved by monitoring the relative abundance of populations over time, to establish the extent of population stability. For amphibians, the length of monitoring time should be at least one generation (Pechmann and Wilbur 1994). The longevity of the Baw Baw Frog is currently unknown, but given the size of the species, may be over 10 years. Previous surveys and studies on the Baw Baw Frog have shown that a census of calling males (audio strip transects) conducted during the breeding season (Oct. - Dec.) is the most practical means by which a population estimate (or relative abundance index) can be obtained. Following the methodology described by Malone (1985a) and Hollis (1995), censuses will be undertaken from a sample of selected discrete breeding units that encompass the species geographic range (including National Park, Alpine Resort and State Forest areas), and have been censused in previous surveys in 1983, 1984, 1993, 1994, 1995 and 1996. In addition to calling male censuses, details of habitat and micro-habitat at each frog calling site will be collected as well as the mapping of breeding habitat within each area surveyed. Automatic recording apparatus will be used to record calling activity at the beginning of the breeding season so as to determine the commencement of the calling activity. Due to the limit number of years for which survey monitoring data is available for the Baw Baw Frog (1983, 1984, 1993-1997- at completion of this seasons survey), statistical analyses are not suitable for determining significance levels of trends that are present in the data. Analyses will be restricted to a comparison of totals of calling males within and between breeding units over different years surveyed.
Under the supervision of NRE (A), censuses will be undertaken during the peak in calling activity (usually November) by B or E and C, with assistance from D and F where appropriate, for a period of approximately 4-6 weeks (30 - 40 working days). Any dead, moribund or diseased frogs encountered during this survey will be collected and forward to a microbiologist (E) for analysis and determination of possible contribution of disease to the population. Breeding habitat mapping will be conducted during calling male censuses and after the completion of the breeding season. Persons B or E will have a good knowledge of the biology and ecology of the Baw Baw Frog and be familiar with the methodology used to conduct the survey.
Previous systematic surveys of the Baw Baw Frog (Malone 1985a; Hollis 1995; G. Hollis unpubl. data) and historical records (Atlas of Victorian Wildlife) show that the locality of several records are in montane forest habitats at elevations between 1100-1300 m. However, most survey and research studies on the Baw Baw Frog have previously concentrated on elevations above 1300 m due to restricted access to lower elevations, and the perception that most of the population occurs on the plateau proper. A significant portion of Baw Baw Frog habitat is potentially in montane forest (largely in State Forest), an area that has received no survey attention to date and which is targeted for clearfell timber harvesting and associated extensive road works in the near future. This area has received little or no timber harvesting in the past due to its limited access. A survey of montane forest between 1100-1300 m a.s.l. is required urgently to assess the status of the species and to describe and map potential habitat in this area. Under the supervision of NRE (A), the survey will be undertaken during the breeding season (Oct.-Dec.) by survey teams consisting of B or E and C, with assistance from D and F where appropriate. Any dead, moribund or diseased frogs encountered during this survey will be collected and forward to a microbiologist (E) for analysis and determination of possible contribution of disease to the population. Persons B or E will have a good knowledge of the biology and ecology of the Baw Baw Frog and be familiar with the methodology used to conduct the survey. Partial funding is required from ESP for pre-survey planning and mapping prior to this survey being conducted.
To investigate population viability and possible threats to the Baw Baw Frog, information about the population demography of the species is required. Demographic information about the species, including growth, age at sexual maturity and longevity, is currently unknown. In studies conducted on the species over the past two seasons (1994 and 1995), 50 toe-clips (phalanges) have been collected from breeding adult males and females across the distribution of the species. In addition to these, 35 toe-clips and femurs have been collected from adults and juveniles in the Museum of Victoria, providing in total, 85 samples. Skeletochronology is now used as a standard procedure with which to provide demographic information. The Baw Baw Frog is considered to be a suitable species for application of this procedure, and considering the rarity of the species, skeletochronology is the only practical short-term means by which this information can be obtained. Samples will be processed by B under the supervision of an histologist (E), using equipment and facilities provided by a university. Both analysis and interpretation of results will take approximately 2.5 months. Funding is required from ESP to fund the sample preparation and analysis component of this work.
Examination of long and short-term climate records is required to assess whether the observed decline in the Baw Baw Frog population can be attributed to fluctuations in climatic variables. Considering the relatively short interval over which the population appears to have declined (< 10 years), fluctuations in climate, including seasonal and daily variation in precipitation and temperature, may explain the decline and should be examined immediately. Climatic records will be collected from NRE (Erica, dating back to 1932), from a data-logger that has been on the Baw Baw Plateau since 1994, and from CSIRO and the Bureau of Meteorology. Data examination will be undertaken by B, with assistance from E for 3 months. Assistance is required from ESP to fund this examination.
Although the fundamental characteristics of the breeding habitat of the Baw Baw Frog have been described previously (Malone 1985a; Hollis 1995), detailed knowledge about floristic and structural breeding attributes that are important to the current P. frosti population are not known. Initial work carried out on embryo and larval survivorship has shown that vegetation structure is very important to the species (see 1.4.2). Knowledge of the key habitat variables associated with the current distribution of breeding localities will provide a benchmark for future comparisons. It will also be important for land management decisions, and will allow the development of experimental design to further investigate the decline of the population. Data collection will be undertaken by B and E over a period of 2 weeks (full-time). A further two weeks (full-time) will be required for botanical identification by E, and 2 months (full-time) for data entry, analysis and interpretation by B and E (Statistical consultation). Data collection will be conducted during the 1997 field season and data analysis will be conducted during the 1998 field season. Funding is required from ESP for data entry, analysis and statistical consultation.
Absence of knowledge of floristic and structural habitat attributes of breeding sites that are important to the current P. frosti population.
that current breeding site attributes are located randomly across the species range and distribution of breeding vegetation types.
The treatments in this assessment will be 1995-1997 P. frosti breeding sites and randomly selected sites in vegetation communities known to be used by the species for breeding. Data will be collected at three different scales at each site, including 1m2 (oviposition site), 10m2 and a sub-catchment scale.
|1m2 (oviposition site) Scale||10m2 Scale||Sub-catchment Scale|
|% cover (Braun blaunquet) of each plant species within the height classes (0-0.1, 0.1-0.3, 0.3-1.0, 1.0-2.5, 2.5-5.0, 5.0-8.0, 8.0-15.0, 15.0-27.0, 27.0-41.0.41-55.0 m)||% cover (Braun blaunquet) of each plant species within the height classes (0-0.1, 0.1-0.3, 0.3-1.0, 1.0-2.5, 2.5-5.0,5.0-8.0, 8.0-15.0, 15.0-27.0, 27.0-41.0.41-55.0 m)||AMG|
|% cover of litter (visual & line transect)||% cover of litter (visual & line transect)||Sub-catchment drainage direction|
|% cover of logs/sticks (visual & line transect)||% cover of logs/sticks (visual & line transect)||Breeding unit perimeter/area ratio|
|No. of fallen logs/sticks (categories 1-5,5-10,10-40,40-100,>100 cm diameter)||% cover of rocks (visual & line transect)||Linear distance to nearest adjacent vegetation communities (m)|
|% cover of rocks (visual & line transect)||Maximum rock height||Aspect|
|Maximum rock height||Average rock height||Breeding unit drainage direction|
|Average rock height||Aspect||Drainage network density within (100 m radius and) (500 m radius)|
|Aspect||Slope (clinometer)||Disturbance (man/other)|
|slope (highest to lowest point/distance)||Vegetation community type|
|Soil type (depth, colour, texture)||Disturbance (man/other)|
|Oviposition site temperature (surface/15 cm depth)||Altitude (m)|
|Oviposition site ambient temperature|
|Oviposition site ambient/15 cm depth differential|
|Oviposition site PH|
|Oviposition site Conductivity|
|Oviposition site micro-habitat (8 categories)|
Each site will only be visited once. Oviposition site variables will be collected in the breeding season only.
It is envisaged that approximately 60-80 breeding sites will be described across the species current distribution. Replicates for the extant sites will be the number of calling males present at each breeding site across all sites sampled. For comparison, data will be collected at a further 40 randomly selected sites across the species distribution and range of breeding habitat types. The selection of sites will be random after stratification by vegetation type and region. Sites chosen have to be within one of the known breeding habitat types used by the species (Sub-alpine wet heathland, Montane riparian thicket, Montane wet forest, Cool temperate mixed forest).
For the extant frog breeding sites it is assumed that each calling male site is independent. Sites used for comparison will be randomly chosen.
The data will be analysed by a method of vegetation ordination using Non-metric Multi-dimensional Scaling (NMDS). This method provides a dissimilarity index between variables across all sites sampled. A description of this method and its advantages over alternative multi-variant analysis methods is presented in Minchin (1987). Data will be entered and manipulated using the program DECODA (Minchin 1991).
Acceptance or rejection of the null hypothesis will determine whether or not the current P. frosti population is selecting breeding sites at random within breeding vegetation community types. This will greatly assist in comparisons made between historic and current breeding habitat usage, and may elude to habitat and distribution characteristics associated with the decline of the species. For management purposes, it will provide information that will allow for the identification of the species current core habitat and distribution.
The diet of the Baw Baw Frog is currently unknown. Knowledge of the species diet will provide information about food preferences, habitat use, foraging habitats and movement, and may also provide insight into reasons for the decline in the population. From Baw Baw Frog specimens preserved at the Museum of Victoria, stomachs and intestines will be removed by B. The contents of stomachs will then be flushed, examined and the prey types identified and quantified. It is expected that this will take 2 months. Funding is required from ESP to identify and quantify prey items.
Recruitment to the terrestrial stage (from oviposition) in the Baw Baw Frog was estimated by Malone (1985a) to be approximately 8.1% in 1983 and 1984. Embryonic and larval stages of amphibian development are considered by amphibian biologists to be the most susceptible stages to external influences. A research exercise will be designed to investigate whether recruitment rates have changed since the frog population has declined. It will be conducted by B and C at intervals over the breeding and post breeding season period (Nov. - Apr.), for two years so that effects of seasonal variation are considered. The development and survivorship of selected egg masses, from locations representing a range of breeding habitat types of the species, will be monitored and quantified through to metamorphosis. The field work component will involve 8 weeks each year. Data analysis will be conducted by B over a period of 2 months following final data collection. Funding is required from ESP to conduct this research exercise.
The impact of predation on the Baw Baw Frog population by introduced predators such as the Fox, Dog and Cat is unknown. To assess whether predation by these introduced animals represents a threat to the Baw Baw Frog, predator scats (primarily Fox and Dog) will be collected from the Baw Baw Plateau and amphibian prey remains identified. Scats will be collected systematically, by conducting scat censuses along tracks and roads of known length and width. Scats found opportunistically will also be collected. Scats will be collected during spring, summer and autumn periods by B and C, with assistance from D and F, to detect any seasonal differences in predation. Collection of scats will be undertaken for 2 weeks in each season, totalling 6 weeks field work. Prey identification will be undertaken by E for $8 per scat. Funding is required from ESP to fund the prey identification process.
The role of captive husbandry for Baw Baw Frog conservation purposes may become increasingly important if the factors responsible for the decline in the Baw Baw Frog population continue to operate. Captive husbandry techniques will be developed by E over a period of 12 months, with the aim of increasing embryonic and larval survivorship over and above that which occurs in the wild. Two to three egg masses, each consisting of approximately 70 - 90 eggs, will be raised in controlled conditions through to metamorphosis. A proportion of metamorphlings (to be determined by the Recovery Team) will be released at egg collection sites pending an assessment of quarantine procedures. The remaining metamorphlings will be retained for 12 months and released pending an assessment of quarantine procedures. Any reintroductions into collection sites will comply with the IUCN guidelines. A small percentage of embryos, larvae or metamorphlings may be used for approved experimental work. To minimise the possibility of exposure of frogs to exotic pathogens during the husbandry trials, and the subsequent release of contaminated frogs at completion, special measures will be put in place to ensure that raising of eggs, larvae and frogs are undertaken in isolated and sterile conditions.
The Baw Baw Frog Philoria frosti has undergone significant decline. Indications are that the species is now extinct from some former sites and has declined to levels subject to the complications of stochasticity and small population dynamics throughout its distribution. It is now suggested that such populations may require assistance to ensure that they do not decline further while efforts to identify and counter the causal agent/s continues. Captive rearing of wild eggs may prove a useful tool in increasing recruitment to such populations until they are capable of self maintenance.
Funding is required from ESP for this action
The provision of information to park visitors about the ecology of sensitive flora and fauna, and their protection, is an important component of the conservation and protection of Baw Baw Frog habitat on the Baw Baw Plateau. Likewise, continued monitoring of the impact of recreational activities on the environment is necessary to provide feedback on the effectiveness of management actions. Increasing numbers of park users in recent years have resulted in an increase in the number of camp fire sites across the plateau. Also, many of these camp fire sites have been established within sensitive and rare vegetation communities, including Baw Baw Frog breeding habitat - wet sub-alpine heathland. Surveys for campfire sites, and ash removal, will be undertaken across the Baw Baw Plateau by D. Leaflets and park interpretation signs detailing information on sensitive communities and species, including the Baw Baw Frog, and 'fuel stoves only' use , will be constructed and made available to park users. The recovery of existing, and incidence of new, camp fire sites will be monitored during population surveys (Action 3.2) to assess their potential impact on the habitat and biology of the Baw Baw Frog.
The Department of Natural Resources and Environment, with assistance from volunteer groups (Australian Trust for Conservation Volunteers and Friends of the Baw Baw National Park), will undertake annual works to upgrade and maintain existing tracks on the Baw Baw Plateau. This will include construction of board-walks over sensitive wetlands, general track clearing and drainage works. The ARC will also be conducting maintenance works of walking and nordic trails in the Mt Baw Baw Alpine Resort, including the closure and revegetation of a number of trails. It will also be involved in a project to relocate sections of the 1 km village trail from sensitive wetland areas, including the installation and replacement of board-walk decking. These works will help to protect the breeding and non-breeding habitat of the Baw Baw Frog by preventing soil erosion, sedimentation of aquatic habitats and help to allow existing damaged vegetation communities to recover. No funding assistance is required from ESP. Costing estimates for 1997 - 2000 are projected from the 1996 budget.
A site specific project involving the construction of a 500 m board-walk through a badly degraded section of the walking/ski trail from Gwinear Flat to Mustering Flat is planned to be undertaken by the Department of Natural Resources and Environment. Sources of funding are being investigated.
Assessment of the potential benefits of walking and ski track maintenance and will be indirectly assessed and monitored by examination of relative abundance indices obtained from the annual survey of the species (Action 3.1).
The presence of feral cattle on the Baw Baw Plateau represents a potential threat to breeding and non-breeding habitats of the Baw Baw Frog. An attempt to eradicate cattle from the plateau in 1989 was only partially successful, with an unknown number still remaining. With the aid over 100 volunteers from bushwalking clubs, naturalist groups and 'friends of' groups, a systematic survey of the distribution of cattle on the Baw Baw Plateau will be conducted over a period of three days, under the supervision and guidance of staff from the Department of Natural Resources and Environment. This will provide information on the distribution and movement of cattle and will be followed by a program to eradicate the cattle by NRE and ARC.
During the annual monitoring survey of the Baw Baw Frog (Action 3.1), the distribution of deer, and extent of damage to breeding habitat by trampling, will be monitored to determine if further management actions are required to control deer.
Incursions of introduced plants (mainly Rubus spp.) along the alpine walking track between Mt Erica car par and Mt Erica will be controlled by D. Incursions of introduced plants within the Mt Baw Baw Alpine Resort will be controlled by the ARC.
The distribution of the Salix cinerea on the Baw Baw Plateau is extensive and numbers of plants in wetland systems are increasing (G. Hollis pers. obs.). Although the impact of this species on Baw Baw Frog habitat is unknown, large infestations of S. cinerea may potentially alter the structural attributes of Baw Baw Frog habitat. Control of this introduced plant on the Baw Baw Plateau will involve on-ground poisoning of individual trees with a non-residual base chemical agent to ensure that there is no impact on the environment. Under the supervision of NRE personnel (D), Australian Trust for Conservation Volunteers (ATCV) (F) will be used for a period of two weeks per year, over a three year period, to undertake this work. Funding is required from ESP for the purchase of suitable chemical control agents and to cover food and travel costs of the ATCV. Costing estimates for 1997 - 2000 are projected from the 1996 budget.
The potential benefits of control and/or eradication of cattle and introduced weeds to the Baw Baw Frog and its habitat will be indirectly assessed and monitored by examination of relative abundance indices obtained from the annual survey of the species (Action 3.1).
Given the relatively pristine habitat of the Baw Baw Frog, and the unexplained nature of its decline, increased UV-B radiation as a possible threat to the species should be investigated. Field work will be undertaken by E to measure and monitor seasonal levels of UV-B radiation reaching different habitats and micro-habitats used by the Baw Baw Frog in the first field season. To determine the potential susceptibility of the Baw Baw Frog to UV-B radiation, larval and embryonic life stage of the Baw Baw Frog will be examined for the presence of the DNA UV-B repair enzyme (photolyase). Sympatric amphibians (Crinia signifera, Geocrinia victoriana and Litoria ewingii/ Litoria verreauxii alpina) will also be examined for comparison. If levels of UV-B radiation vary significantly between different habitats utilised by the Baw Baw Frog, field experiments will be undertaken by E to measure the effects of UV radiation on embryonic and larval development of the Baw Baw Frog, and other amphibians present on the Baw Baw Plateau (Crinia signifera and Geocrinia victoriana and Litoria verreauxii alpina) during a second season of field work. This action will be carried out in collaboration with other proposed amphibian research projects investigating declines in high altitude species and the influence of increased levels of UV radiation (e.g. Pseudophryne corroboree - Osborne 1996). Funding is required from ESP to fund the field and analysis expenses of the project.
In southern and temperate regions of Australia it has been estimated that UV-B radiation over the past two decades has increased on average by approximately 2%. In alpine and sub-alpine regions, levels of UV-B radiation are higher than at lower altitudes. Increases in UV-B radiation, due to the depletion of the ozone layer, has been admitted to the list of plausible hypotheses that might explain the global phenomena of declining and disappearing amphibian populations in some areas. Increases in UV-B radiation might explain the decline of the P. frosti population.
Radio-tracking undertaken within the Mt Baw Baw Alpine Resort in 1995/96 showed that adult Baw Baw Frogs also utilise adjacent vegetation types to those used by the species for breeding purposes. Breeding occurs within wet habitats in sub-alpine wet heathland, montane riparian thicket and montane wet forest. During the non-breeding season, frogs also move into vegetation types adjacent to breeding habitats, including sub-alpine woodland and montane wet forest away from seepages. Most radio-tracking, however, was conducted in sub-alpine habitats as apposed to montane habitats at elevations between 1000 and 1300 m. Further radio-tracking is required within these lower elevation habitats to determine the extent of possible movement by adult frogs in State Forest. Radio-tracking will be undertaken during both breeding and non-breeding seasons, with emphasis on non-breeding season movement. It is envisage that approximately 12 adult frogs will used for radio-tracking. Techniques and methodology used will follow those used during radio-tracking of the species in 1995/96. This action will be funded by NRE (Forests Branch).
A Reference Group to advise on issues arising within the Baw Baw Frog research program has been operating for several years. With the status of the species now recognised, requirement for an intensive recovery effort established, and some commitment of funds and resources from organisations involved, recovery actions can be implemented to attempt to prevent extinction of the species. A Recovery Team will be formed to facilitate this process, and will include all required skills, particularly in frog ecology, population genetics, captive breeding, land management and utilisation, and project management, The Recovery Team will be responsible for implementing the Recovery Plan, including the detailed planning required for the program, such as the identification of actions, targets, responsibilities and time-lines for their completion. The Recovery Team will also monitor and assess implementation of the Recovery Plan, and will need to address administrative issues relating to the recovery effort, including the issue and management of contracts for components of the program, and obtaining relevant permits to enable work to proceed. The major cost for management of the recovery program (salaries for project planners) will be met by NRE. Other participating agencies will be responsible for their own costs.
Regular review and evaluation of implementation of the recovery effort is essential, especially in a program such as this where there is a high degree of uncertainty. Reviews and evaluations are required to determine if objectives are being met, to rapidly identify and solve problems, and to revise objectives. Regular informal reviews should occur at recovery team meetings, and a major formal review and evaluation (possibly utilising an external facilitator) held annually. NRE will meet the cost of holding the annual review. Participating agencies will be responsible for their own costs.