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National recovery plan for the Pygmy Bluetongue Lizard (Tiliqua adelaidensis)

Compiled by Tim Milne, Flinders University of SA
Mark Hutchinson and Sylvia Clarke, South Australian Museum Adelaide SA, November 2000

Note: This publication has been superseded by the Recovery plan for Pygmy Bluetongue Lizard Tiliqua adelaidensis 2012

Pygmy Bluetongue Lizard (Tiliqua adelaidensis)

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Contents


Summary

Current Species Status:

Endangered (Cogger 1993; Endangered Species Protection Act, 1992; 1991 Schedule of the SA National Parks and Wildlife Act 1972); to be listed as Critically Endangered for the next IUCN Red Data Book (H. G. Cogger, pers. comm., 1996). Former range probably extended from Adelaide to Peterborough, approximately 200 km to the north. Now known from 10 subpopulations in native grassland along a line of hills in the North Mount Lofty Ranges, from just south of Burra north to about Peterborough.

Known patches of prime habitat which support the species amount to less than 500 ha. Population size is uncertain, but preliminary estimates extrapolated from the best-known population suggest that there may be in excess of 5500 wild pygmy bluetongues.

The principle reason for the species' rarity is believed to be ploughing of native grassy understorey, which has altered soil compaction and friability, destroyed lizards directly and converted stable perennial grassland into frequently disturbed cropland or improved pasture dominated by introduced annuals. The species is endangered due to its small population size, fragmentation and lack of protection of its grassland habitat.

Habitat Requirements and Limiting Factors:

The only refuges used by pygmy bluetongues are spider holes. Lizard abundance is correlated with hole density and depth. The habitat at all sites is native grassland or grassy woodland, although all sites show considerable floristic degradation due to weed invasions.

Overall Objective:

To achieve down-listing of the species from Endangered to Vulnerable within 10 years based on IUCN (1994) criteria, with at least 6 secure sub-populations each supporting a minimum of 500 adult individuals.

Specific Objectives:

  1. Establish permanent agreements with landholders within three years to ensure that sites supporting pygmy bluetongues are recognised, made safe from threatening processes and can be accessed for future study.
  2. Establish guidelines within five years for the management of habitat remnants (eg fire regimes, grazing levels) for the management of habitat remnants so that more of the existing populations can be expanded to acceptable levels (>500 individuals).
  3. Establish local community involvement with the species' conservation within three years.

Criteria:

  1. 6 secure sites containing a minimum of 3000 pygmy bluetongues
  2. Stable or increasing populations.
  3. Active participation by local people in the species' conservation

Actions Needed:

  1. Ensure existing habitat is protected from future degradation by establishing agreements with landowners where possible.

Research Actions:

  1. Confirmation of existing demographic data
  2. Field study of limiting microhabitat and macrohabitat factors
  3. Experimental field study to establish optimum habitat management procedures
  4. Establish genetic composition of bluetongue populations

Recovery Actions:

  1. Establish permanent monitoring areas
  2. Increase both community involvement with, and awareness of, the species
  3. Implement appropriate management procedures based on findings of Actions 2-5..
  4. Develop methods for expanding existing populations and establishing new populations.

Estimated Costs of Recovery ('000s)

Actions

2

3

4

5

6

7

8

9

TOTAL

Year

TC

OT

TC

OT

TC

OT

TC

OT

TC

OT

TC

OT

TC

OT

TC

OT

TC

OT

1

37.0

34.1

18.0

15.6

31.1

18.4

5.0

-

15.8

13.7

7.0

3.5

4.1

3.5

-
-

118.0

88.8

2

22.0

19.1

18.0

15.6

28.0

15.6

6.0

5.0

15.8

13.7

7.0

3.5

4.1

3.5

-
-

100.9

76.0

3

22.0

19.1

18.0

15.6

28.0

15.6

-
-

15.8

13.7

7.0

3.5

4.1

3.5

-
-

94.9

71.0

4

-
-

14.5

12.6

28.5

16.1

-
-

16.9

14.7

7.0

3.5

4.1

3.5

4

-

75.0

50.4

5

-
-
-
-
-
-
-
-

16.9

14.7

7.0

3.5

4.1

3.5

4

-

32.0

21.7

Total

81.0

72.3

68.5

59.4

115.6

65.7

11.0

5.0

81.2

70.5

35

17.5

20.5

17.5

8

0

420.8

307.9

NOTE : the contribution from the South Australian Government is from the South Australian Museum, not the Department of Environment and Natural Resources.

Biodiversity benefits:

The Lomandra effusa/Lomandra multiflora dura grassland which is habitat for the pygmy bluetongue is classified as an endangered plant association in South Australia. Actions addressed as part of this Recovery Plan will lead to preservation of this habitat.


INTRODUCTION

Prior to its re-discovery, Tiliqua adelaidensis, the pygmy bluetongue lizard, was regarded as one of the most seriously endangered of Australia's reptile species, if not actually extinct (Cogger 1992, Ehmann 1992, Hutchinson 1992). Schomburgk's remark 'kommt nur auf sandigem, steinigem terrain vor' ('found only in sandy, stony terrain'; Richard Schomburgk, quoted by Peters, 1863) was the only published first-hand information available on its ecology. The discovery of the species near Burra, South Australia (Armstrong & Reid 1993, Armstrong et al. 1993), following the first sighting of the species for 33 years, presented an opportunity for urgently needed study of the species which had previously been known from only 20 museum specimens, mostly collected last century (Ehmann 1982, Shea 1992). The following is a summary of unpublished data collected by the authors as part of the Research Plan for the pygmy bluetongue adopted for funding by the Australian Nature Conservation Agency in 1994.

Description

Tiliqua adelaidensis is the smallest member of the genus Tiliqua, which consists of seven lizard species commonly known as bluetongues. It is a moderate sized skink with short limbs, a relatively heavy body and large head. Its colour varies from grey brown to orange brown, and may or may not include a series of black flecks along the back and flanks. It has a total length of less than 20 centimetres.

Past and Present Distribution

Very little information exists on the past distribution of T. adelaidensis, with the few known localities extending from the Adelaide Plains to the North Mount Lofty Ranges (Ehmann 1982, Hutchinson 1992). Prior to this study, only 20 specimens were known, of which half have no precise capture data, whilst some localities may only be addresses of the consigners of the specimens (Armstrong et al 1993). The relative abundance of pygmy bluetongues in European collections in the 19th century (11 of the 20 specimens) suggests that the species was formerly common, and has undergone a marked decrease in distribution (Shea 1992).

The pygmy bluetongue is now known from ten spatially discrete subpopulations, ranging from south of Burra to south of Peterborough (see figure 1). Preliminary estimates of population size suggest that the total number of pygmy bluetongues is 5500 (figure 2), with most sites supporting fewer than 500 individuals. This estimate is based upon lizard numbers within plots extrapolated against the area of prime grassland habitat within each site. The estimates given are a minimum count, as the boundary zone of poor habitat around each population would support additional pygmy bluetongues, although at a lower density. The total population estimate is still preliminary, and a need for greater precision exists. More accurate sub-population estimates will be addressed as part of the Recovery Plan.

Figure 2 : Estimated lizard numbers at known sites

Name of site

No. of lizards found

Area searched (000's m )

Density (lizards/ha.) ± 95%

Area of prime habitat (Ha.)

Estimated minimum adult population

Site 1

208

25.4

81.9

17

1392

Site 2 (W)

53

11.8

44.9

24

1078

Site 3 (H1)

11

2.7

40.7±36.3

9

366

Site 4 (T)

13

3.6

36.1

5

180

Site 5 (PR)

24

10.4

23.1

16

370

Site 6 (SC)

36

20

18.5± 7.8

19

352

Site 7 (EB)

13

7.7

16.9

32

541

Site 8 (MB)

8

5

16

15

240

Site 9 (T)

29

20

15 ±7.2

55

825

Site 10 (H2)

2

1

10

21

210

Habitat

The vegetation of all known sites is degraded remnant native grassland or grassy woodland. The soil is rather heavy sandy loam (red-brown earth). The exact original nature of this grassland is unclear, as copper mining and farming near the site since 1845 may have resulted in the removal of trees and shrubs for both industrial and domestic use. Similar hilly areas in the district support Allocasuarina verticillata (drooping she-oak) low open woodland over a ground cover of native grasses (Stipa spp., Danthonia spp.) and mat-rush or 'irongrass' (Lomandra spp.) similar to that recorded in the survey area. Jessup (1948) concluded that at least some of the area had probably been essentially treeless prior to European settlement. The Lomandra dura - Lomandra effusa grassland habitat in which all pygmy bluetongues have been found is listed as not conserved and 'very rare and endangered' (Davies 1982, Lang 1995).

Natural History

Pygmy bluetongues use empty spider burrows as refuges, basking sites and ambush points. The holes are circular in cross section, up to about 20 mm in diameter, and lack any sign of excavated soil at the entrances. The average depth of holes is approximately 25 centimetres, ranging from 10 to 75 cm. These holes appear indistinguishable from holes inhabited by mygalomorph and lycosid spiders. However, adult lizards are found in the deeper holes which are probably made by mygalomorphs. Lizards have been found in holes which had the lids of trapdoor spiders still attached. The lizards make no obvious external modifications to the holes, except for a slight bevelling of the edges caused by their coming and going. Burrow entrances are used as vantage points from which lizards are able to make short forays after any prey detected nearby. The lizards are extremely sensitive to both movement and noise, making it difficult to observe them basking outside their burrows unless approached extremely carefully. Only one adult lizard is found in each burrow.

Lizards bask with the back legs or tip of the tail remaining in the entrance of the burrow. From this position, the lizards can back rapidly into their burrows if disturbed. The hole dwelling behaviour of the pygmy bluetongue, initially an obstacle, has become a key factor facilitating its study. Use of an Olympus optic fibrescope permits direct observation of lizards in their burrows and their sedentary nature enables regular monitoring of all animals in a given area. This permits several types of study not normally possible with small vertebrates, such as direct-count censussing and assessment of age structure, and being able to locate given animals almost at will.

The diet of the pygmy bluetongue consists mainly of medium sized invertebrates. Ehmann (1982), examined stomach contents of specimens then in the South Australian Museum collection, recording cockroaches, ants, a spider, grasshopper and beetle, and some plants (Dianella seed, possible chenopod material). Dissections of lizards found dead during the duration of this project have revealed remains of noctuid larvae, acridoid grasshoppers, beetles, and several leaves and flowers of the herb Medicago. Scat analysis has shown the diet to consist of grasshoppers, snails, small spiders and beetles. Wild lizards accepted grasshoppers and mealworms offered as bait, and captive animals thrive on an omnivorous diet, including mealworms, crickets, chopped fruit and vegetables and raw egg (T. Morley per. comm.). This evidence suggests that pygmy bluetongues take a wide variety of invertebrate animals as food, but will also occasionally feed on plant matter.

Population Dynamics

Mating season is in spring (September and October), as spring-collected males have enlarged turgid testes and a dead female collected at this time had yolked ovarian follicles (Hutchinson and Milne 1994). Pitfall trapping has indicated that males are more active than females during spring, possibly because they are searching for a mates at this time (Hutchinson and Milne 1994). Females have been observed with newly born young from late January until late March, with the bulk of births taking place in February. Litter size is 1-4. At birth, pygmy bluetongues are approximately 45mm snout-vent length (SVL)and weigh approximately 1.5 grams. Juveniles remain in the parental burrow for up to 12 weeks, and then move out to smaller burrows of their own

By the start of spring (September), juveniles are between 60 and 70mm SVL and weigh between 4 and 8 grams. By the end of summer (April), at approximately one year of age, SVL is from 75mm to 85mm and weight from 6 to 10g. Males are capable of reproduction in the next spring season, and females may also reproduce at this age, although some females take another year to become reproductively active. Only females of length greater than 100mm have been observed to have four young, and to reach this size of maximum reproductive potential would take four years according to current growth rate estimates. It is estimated that less than 10% of juveniles survive until adulthood. Pygmy bluetongues are known to live to at least six years of age, based upon skeletochronology and survival of animals caught in 1992 as full grown adults.

Captive breeding

The Zoological Gardens of Adelaide has attempted to breed the species in captivity from a captive population of six specimens. This has, to date, been unsuccessful, due in part to the necessity of keeping the animals on display for publicity reasons and to the high level of aggression displayed by the captive lizards. In 1996, a new display has been created that is larger, and thermostatically heat controlled. It will be on display from August 1996, along with updated information about the pygmy bluetongue. At this stage, captive breeding is not regarded as essential for the short-term survival of the species. However, taking the longer term view, it is prudent to continue efforts to establish captive breeding as insurance against future degradation of the species' status in the wild. The removal of small numbers of individuals from the wild at this time, when some populations, at least, appear to be relatively large, is a justifiable part of the Recovery Plan.

The second aspect of the Zoo's involvement, raising public awareness, remains a vital aspect of the recovery of the species. The pygmy bluetongue is a small, cryptic animal unlikely to be encountered by more than a handful of people. By means of its well-designed display, the Zoo can ensure that the public is continually reminded of the lizard's existence and its precarious status.

Reasons for Decline / Threatening Processes

The initial impression that lizards require unploughed areas has been reinforced by the absolute correlation at all known sites between the presence of lizards and absence of ploughing. Observations at these sites show that lizards barely penetrate into patches of ploughed land adjacent to known bluetongue sub-populations. Native grassland similar to that in which the species occurs at Burra once extended south onto the Adelaide plains, but being prime agricultural land, was one of the first areas in South Australia to be cleared and ploughed. Ploughing permanently alters the vegetation and ground cover, converting a native, largely perennial flora into an introduced, largely annual one. In addition, ploughing would destroy the burrows, killing lizards directly and leaving the survivors without shelter and at the mercy of predators. The fact that most specimens were collected last century may simply be correlated with the fact that this was when most of their habitat was being converted to agriculture.

The presence of a relatively large number of apparently unploughed native grasslands that contain no pygmy bluetongues (see figure 1: closed squares indicate native grassland patches that do not contain pygmy bluetongues) suggests that other threatening processes may have contributed to the endangered status of this animal. Preliminary observations suggest that the degree of ground cover is correlated with the presence/absence of pygmy bluetongues. Ground cover is affected by several land use practices, including fertilising, seeding, fire and degree of grazing. These potential threatening processes require further study in order to propose management actions for pygmy bluetongue habitat.

Conservation status

The IUCN (1994) has proposed a series of criteria for determining the conservation status of species. These require detailed historical information to be fully assessed, information that is lacking for the pygmy bluetongue. Nevertheless, it is possible to arrive at a reasonable assessment of the species' status according to IUCN guidelines, as follows:

A. Population reduction.

  1. Recent declines in populations. No recent (within 10 years) population reductions known. Over the last 100 years, however, total range occupied by the species has been greatly reduced, possibly by as much as 95%.
  2. Projected declines in populations. Over the next 10 years populations could be reduced if current land use practices change. If no such change occurs, population reductions seem unlikely.

B. Extent of occurrence

The table above lists a preliminary estimate of 1.06 km² for the total area of prime habitat known to support pygmy bluetongues. Pygmy bluetongues also occur in lower densities on the less optimal peripheries of these habitat patches, so that the total area could be two to three times the somewhat arbitrary estimate of the area of prime habitat.

  1. The populations are severely fragmented.
  2. At present there is no indication of ongoing decline.
  3. The populations do not show evidence of extreme fluctuations.

C. Population size estimates

The total population is estimated at about 5000 adults.

  1. No continuing declines are currently known.
  2. The populations are fragmented, with most thought to contain fewer than 500 adults.

D. Population is restricted in that

  1. Although the total number of adults is thought to be about 5000,
  2. The area of occupancy is acutely restricted (to 2-3 km²), and there are only 16 locations known to support populations. The pygmy bluetongue is therefore prone to the effects of human activities (or stochastic events whose impact is increased by human activities) within a very short period of time in an unforeseeable future.

The pygmy bluetongue in most of these attributes at least meets the criteria for Vulnerable. Its very limited extent of occurrence and severe fragmentation of populations within that area (B1) qualify the species for Critically Endangered status. However, Critically Endangered implies imminent extinction, and given the current stability of populations and land use, such an assessment would be an overstatement. This very small and fragmented area does however mean that the species could very quickly be wiped out should the current situation change. As this eventuality cannot be guaranteed against at present, we recommend ranking the pygmy bluetongue as Endangered until such time as land usage in the area can be guaranteed.


Strategy for recovery

The Recovery Plan should focus on both the protection and management of these remaining areas of habitat such that the remaining sub-populations are viable. If this can be achieved, it would be unnecessary to attempt to translocate or re-establish the species as threats to the species' survival will have been nullified, and populations will be effectively managed so as to be stable or increasing.

At present the known populations are only conserved by the good will of the landowners. Long-term survival of the pygmy bluetongue in the wild will clearly depend on permanent, binding agreements ensuring that its habitat will not be degraded.. Although a primary threat to the species survival is ploughing, other processes (spread of fertiliser and pesticides, varying grazing and fire regimes) may have crucial effects that are presently undocumented. Before any agreements can be developed, threatening processes and correct management practices will need to be better understood than they are at present. In addition, landowners who will be asked to accept any restrictions on the use of their property need to be well-informed and willing before such restrictions can be reasonably imposed. On this last point, an important consideration will be to provide incentives for landowners to become involved in establishing sanctuaries for pygmy bluetongues on their properties

Initial investigation focussed on the species' ecology and distribution, and the early stages of the Recovery Plan should be spent verifying this data in order to predict long term population trends. Publicity during the Recovery Plan should focus primarily upon the local community in the Burra area. A genuine community involvement in the species must be developed in order for landholders to realise the importance of adopting management recommendations from the research conducted above. The Recovery Team should include local residents, including owners of land with populations of pygmy bluetongues

The criteria set to gauge the success of the recovery strategy are based upon effectively managing a realistic goal of 6 subpopulations which contain a total in excess of 3000 individuals. The area required to achieve such a goal is in the vicinity of 100 to 200 hectares total. 6 subpopulations are needed to help alleviate the effect of stochastic environmental and catastrophic events. If research can demonstrate the 6 subpopulations are relatively stable in number, then the species should be classified as vulnerable according to IUCN (1994) criteria.

Recovery Team

A recovery team was formed in 1993 to monitor the effectiveness of the preliminary research phase, and to eventually oversee the implementation of the Recovery Plan. This team presently includes:

Dr. Mark Hutchinson South Australian Museum

Ms Sylvia Clarke Project Officer

Dr. Tim Milne

Mr. Terry Morley Adelaide Zoo

Ms. Lee Heard DENR

Mr. Peter Copley DENR

Mr. Tim Croft DENR

Ms. Anne Duncan (until 25/2/00) ANCA, Endangered Species Unit

Dr. C. Michael Bull Flinders University of SA

Ms. Vicki-Jo Russell Threatened Species Network (SA)

It is envisaged that this recovery team will expand during execution of the Recovery Plan to include representatives from the Burra Community School, and local landholders.


RECOVERY OBJECTIVES AND CRITERIA

Overall Objective:

To achieve down-listing of the species from Endangered to Vulnerable within 10 years based on IUCN (1994) criteria, with at least 6 secure sub-populations each supporting a minimum of 500 adult individuals.

Specific Objectives:

  1. Establish permanent agreements with landholders within three years to ensure that sites supporting pygmy bluetongues are recognised, made safe from threatening processes and can be accessed for future study.
  2. Establish guidelines within five years for the management of habitat remnants (eg fire regimes, grazing levels) for the management of habitat remnants so that more of the existing populations can be expanded to acceptable levels (>500 individuals).
  3. Establish local community involvement with the species' conservation within three years.

Criteria:

  1. 6 secure sites containing a minimum of 3000 pygmy bluetongues
  2. Stable or increasing populations.
  3. Active participation by local people in the species' conservation

Actions Needed:

  1. Ensure existing habitat is protected from future degradation by establishing agreements with landowners where possible.

This action is contingent on the following:

Research Actions:

  1. Confirmation of existing demographic data
  2. Field study to establish limiting microhabitat and macrohabitat factors
  3. Experimental field study to establish optimum habitat management procedures
  4. Establish genetic composition of bluetongue populations

Recovery Actions:

  1. Establish permanent monitoring areas
  2. Increase both community involvement with, and awareness of, the species
  3. Implement appropriate management procedures based on findings of Actions 2-5..
  4. Develop methods for expanding existing populations.

Employee and field Costs:

It is recommended that one full time Research Officer conduct the bulk of all actions, with a Technical Assistant working part-time with this Officer during the busy spring-summer months. The costs given under each action below give an approximation of the amount of time that this Research Officer and assistant should spend upon each action.

A permanent base for accommodation in the Burra area is recommended for the duration of the Recovery Plan. A great proportion of the field costs ($100/wk) will be set aside for this accommodation. Vehicular costs are for the researchers own vehicle, and are calculated at 400km/week at 49c/km.

An optic fibrescope has become an essential item for research on the pygmy bluetongue. The existing unit is showing signs of deterioration after two and a half years of regular use. Purchase of a replacement fibrescope is a highest priority item during the first twelve months of the Recovery Plan. The estimated cost ($15,000) is listed under the first Action, but this instrument is clearly essential for the completion of all Recovery Plan aims.

Estimated contributions of the South Australian Museum (SAM) and Flinders University School of Biological Sciences are calculated as follows. SAM: Financial administration of other contributions will not be charged for by the Museum. The chief researcher for the project will spend an average of 2 days per month on matters related to the pygmy bluetongue recovery plan, valued at 10% of salary, $4600.

Action 1: Ensure existing habitat is protected from future degradation by establishing agreements with landowners where possible.

This single action is likely to ensure that the pygmy bluetongue will survive in the wild indefinitely. Before a clear strategy towards achieving this action can be enunciated, two major groups of action must be undertaken.

Therefore, this one action will need to be advanced through a series of component actions for which detailed strategies can be outlined and which are presented below.

Actions

Action 1: Ensure existing habitat is protected from future degradation by establishing agreements with landowners where possible

Aim:

To put in place permanent heritage-style agreements with owners of land supporting at least six pygmy bluetongue populations.

Justification:

No pygmy bluetongues occur in reserves, making conservation on private land essential. The significant populations are all small areas of commercial farming properties, making it possible to identify relatively small areas of these farms which could be prioritised for managing pygmy bluetongues.

Methods:

Costs for 1.2 appear in the relevant Action sections below. Methods 1.3 and 1.4 imply that landowners will have to forego some actions on some parts of their properties. Minimally it is likely to be necessary to fence designated pygmy bluetongue areas, and it may be that some opportunity costs requiring compensation will be identified. Funds must be available to meet these costs. Some can come from State government sources, but some other funding would ensure that there were sufficient funds available to avoid delays. The current WWF/NHT Grassy Ecosystem Grants Partnership is a model of how this could work.

NOTE : ALL COSTS GIVEN IN '000s

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

 

0

0

50

50

50

           

Action 2:Confirmation of existing demographic data

Aim:

To confirm and quantify the basic ecology of the species, and increase confidence that all extant populations are known.

Justification:

Verification of existing data relating to population dynamics, ecology and distribution.

Methods:

Costs:

NOTE : ALL COSTS GIVEN IN '000s

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

SAM

37

22

22

10

10

OTHER contribution (yearly):

Research Officer 30% workload 10.5
Technical Assistant 10% workload 3.0
Field Costs = 16 weeks @ $150/week 2.4
Vehicular costs = 16 weeks @ $200/week 3.2
TOTAL (years 2,3 19.1
Year 1 19.1
Purchase of optic fibrescope 15.0
TOTAL 34.1

Action 3: Field study of limiting microhabitat and macrohabitat factors

Aim:

To examine and quantify habitat characteristics controlling the abundance of pygmy bluetongues.

Justification:

The patchy nature of pygmy bluetongue distribution may result from several habitat variables. It is important to establish which variables correlate most strongly with pygmy bluetongue densities; only then can we develop causal explanations for the presence/absence and differences in density of the species. Sound knowledge of what constitutes optimal habitat will help to more accurately estimate population sizes. There is also the potential to increase population size if these controlling factors can be manipulated.

Methods:

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

SAM

2.4

2.4

2.4

2.0

 

OTHER

15.6

15.6

15.6

12.6

 
OTHER contribution (years 1-3):
Research Officer 20% workload 7.0
Technical Assistant 10% workload 3.0
Field Costs = 16 weeks @ $150/week 2.4
Vehicular costs = 16 weeks @ $200/week 3.2
TOTAL 15.6
OTHER contribution (year 4)
Research Officer 20% workload 7.0
Field Costs = 16 weeks @ %150/week 2.4
Vehicular costs = 16 weeks @ $200/week 3.2
TOTAL 12.6

Action 4: Experimental field study to establish optimum habitat management procedures

Aim:

To find appropriate management practices which ensure the maintenance of secure, viable populations.

Justification:

For effective management of land on which pygmy bluetongues are found, experimental manipulations are required to gauge the effect of different management options.

Methods:

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

SAM

2.7

2.4

2.4

2.4

 

OTHER

18.4

15.6

15.6

16.1

 

BCS

10.0

10.0

10.0

   

BCS=Burra Community School

OTHER contribution (years 1-3):

Research Officer 20% workload 7.0
Technical Assistant 10% workload 3.0
Field Costs = 12 weeks @ $150/week 1.8
Vehicular costs = 12 weeks @ $200/week 2.4
Botanical consultant : 2 weeks @ $700/week 1.4
TOTAL 15.6
OTHER contribution (year 4)
Research Officer 30% workload 10.5
Field Costs = 12 weeks @ $150/week 1.8
Vehicular costs = 12 weeks @ $200/week 2.4
Botanical consultant : 2 weeks @ $700/week 1.4
TOTAL 16.1
Fencing costs (year 1): three 50m by 50m quadrats: Cost per quadrat:
1 roll cyclone 0.15
1 roll fencing wire 0.13
5 strainers 0.1
5 strutting poles 0.05
100 posts 0.50
TOTAL 0.93 x3 2.79

Action 5: Establish genetic composition of bluetongue populations

Aim:

To carry out a study of genetic variation within and between populations..

Justification:

The pygmy bluetongue is apparently divided into several disjunct populations. Genetic study will demonstrate the degree of genetic variation remaining within each population and may also suggest whether gene flow between populations is occurring.

To hedge against any catastrophe that may decimate known populations of pygmy bluetongues, genetic profiles of known populations should be created. These profiles should assist in making management decisions in case relocation, re-introduction or re-stocking of grassland becomes necessary. DNA microsatellite allelic variation will also be useful in clarifying aspects of reproductive behaviour, as mothers and young can be screened to generate comparative data bearing on whether females mate with more than one male and whether there is evidence of mate fidelity (as occurs in T. rugosa).

Methods:

Analysis of DNA microsatellite sequences.

Techniques are already being developed for the related species Tiliqua rugosa and Egernia stokesii by the Environmental Biology Unit of the South Australian Museum. Preliminary comparisons will be initiated later this year to investigate whether primers now available for amplifying several microsatellites in T. rugosa will amplify homologous sequences in the pygmy bluetongue. On the basis of previous experience, it is expected that some T. rugosa sequences will also be suitable for T. adelaidensis, but that searches for additional microsatellites will also be necessary.

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

SAM

1.0

1.0

     

Flinders

4.0

       

OTHER

 

5.0

     

Recovery Actions

Action 6: Establish permanent monitoring sites

Aims :

To monitor population fluctuations at known sites over an extensive period.

Justification:

Monitoring sites are required to guarantee that population sizes are remaining stable, and management practices are successful. The opportunity to directly monitor a small vertebrate, rather than being forced to make estimates via a capture-mark-recapture study, is unique.

Methods:

In the first year of the Recovery Plan, one monitoring hectare per site should be established at each of six sites. Within these hectares, bluetongue burrows should be marked and mapped, and a total count for each quadrat obtained. At yearly intervals, the quadrats should be re-examined and a census count obtained. This action should be continued yearly for five years. After this time, dependent on results, quadrats could be censused at greater intervals, potentially by a friends' group or similar volunteer body.

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

 

16

16

16

18

18

OTHER contribution Years 1-3:
Research Officer 10% workload 3.5
Technical Assistant 20% workload 6.0
Field Costs = 12 weeks @ $150/week 1.8
Vehicular costs = 12 weeks @ $200/week 2.4
TOTAL 13.7
OTHER contribution years 4,5
Research Officer 30% workload 10.5
Field Costs = 12 weeks @ $150/week 1.8
Vehicular costs = 12 weeks @ $200/week 2.4
TOTAL 14.7

Action 7 : Increase both community involvement with, and awareness of, the species

a) In the local community

Create a locally based pygmy bluetongue friends' group including landholders, school representatives and other interested people

Aims :

To involve people in the Burra area in active participation in the conservation of an endangered animal unique to their region.

Justification:

A friends' group will help the pygmy bluetongue in two ways. The first is by voluntary contribution to research and conservation efforts. The second is by raising the local awareness of the species, so that it is regarded as a unique and important part of Burra's heritage. If this can be achieved, then landowners will be more receptive towards future management proposals for native grassland areas.

Methods:

Formalise as a 'friends group' the system of informal contacts (personal approaches, mail outs etc.) currently being used to inform local people of progress in the conservation research on the pygmy bluetongue. The nature of this organisation will evolve; guidelines on the role, limitations and possible funding requirements of this group should develop over time. An early priority for this group will be to provide a forum for discussion of the nature and scope of agreements which could be developed to secure areas supporting important populations of pygmy bluetongues.

The Burra area school owns land which is home to pygmy bluetongues. Discussions with the school have indicated that they are keen to utilise publicity associated with the pygmy bluetongue to promote their high school agricultural course. The school also intends to have each year in the school involved in some way with the pygmy bluetongue project. This involvement should range from simple identification of the bluetongues for the younger years up to a full involvement with management experiments for the year 11 and 12 students.

b More broadly at the state and national level

Justification:

The conservation issues concerning both reptiles and grassland communities receive relatively little exposure. Native grassland has traditionally been poorly recognised as a habitat of conservation value, and reptiles suffer from poor public perception of their worth. The pygmy bluetongue is an ideal vehicle to promote these conservation issues.

Methods:

The Zoological Gardens of Adelaide will continue its primary role in publicity of the species through display of captive animals in the reptile house. Information boards accompany this display, explaining the research and recovery steps required to ensure the survival of the species. The Zoo has also contributed greatly through the design and printing of an information brochure titled 'The pygmy bluetongue lizard - Identification and Importance.' This brochure will be re-printed during the first year of the Recovery Plan for distribution to interested parties.

Publication of research and conservation findings should be sought in both professional and popular journals.

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

 

7.5

7.5

7.5

7.5

7.5

OTHER contribution (yearly):
Research Officer 10% workload 3.5

Action 8: Implement appropriate management procedures based on findings of Actions 2-5.

Aims :

To implement appropriate management strategies such that bluetongue populations are demonstrably secure.

Justification:

In order to satisfy criteria that the number and extent of pygmy bluetongue populations can be considered secure, there must be appropriate management of native grassland areas to minimise threatening processes.

Methods:

Management of pygmy bluetongue populations will depend upon results obtained in actions 2-6. By the end of year 3 of the project, these management strategies can be proposed and implemented. Management options may include controlling levels of grazing, topdressing, seeding, ploughing, fire and other factors that potentially effect bluetongue numbers. Management requirements will be incorporated into suitable heritage agreements which will restrict threatening activities within bluetongue sites. The co-operation of landholders may also be sought if specific management requirements are discovered (as compared to the abstaining from certain practices under the terms of a heritage agreement).

Costs:

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

SAM

0.6

0.6

0.6

0.6

0.6

OTHER

3.5

3.5

3.5

3.5

3.5

OTHER contribution (yearly):
Research officer 10% workload 3.5

Action 9 : Develop methods for expanding existing sub-populations and establishing new populations.

Aim:

To find and potentially implement mechanisms by which both the number of lizards and extent of occurrence of lizards within each sub-population can be increased.

Justification:

At several sites, pygmy bluetongues are present but in comparatively low densities (see Figure 2). At others, lizards at high density in good quality grassland extend into adjacent disturbed areas at low densities. In both situations it may be possible to improve the quality of habitat of these low density populations. This would lead to an increase in the density and area of occupation of lizards in a sub-population. One grassland reserve exists in the Burra area at Mt Cone, but it lacks pygmy bluetongues. The possibility of establishing a population in this reserve should be investigated.

Methods:

The methods by which existing sub-populations may be expanded are dependent upon findings from Research Actions 2-4. These methods should be implemented in years 4 and 5 of the Recovery Plan. These methods should lead directly to a plan for establishing a new colony at Mt Cone.

Costs:

The Research Officer should seek assistance from the friends' group created as part of the Recovery Plan for this task, and the costs of this action should be part of the workload of this Research Officer during years 4 and 5 of the Recovery Plan. At this point, no further funding requirements are anticipated for this task.

Costs

Year 1

Year 2

Year 3

Year 4

Year 5

OTHER

2.0

2.0

10

10

10

SAGovt

5.0

5.0

5.0

5.0

5.0

FG

     

4.0

4.0

FG = Pygmy bluetongue friends group contribution

Friends group contribution (years4,5): 200 hours volunteer work @ $20/hr. = $4000


REFERENCES:

ARMSTRONG, G. & REID, J. (1993) The rediscovery of the Adelaide pygmy bluetongue, Tiliqua adelaidensis (Peters, 1863). Herpetofauna 22, 3-6.

ARMSTRONG, G., REID, J. R. W. & HUTCHINSON, M. N. (1993) Discovery of a population of the rare scincid lizard Tiliqua adelaidensis (Peters). Records of the South Australian Museum 36, 53-55.

COGGER, H. G. (1975) 'Reptiles and Amphibians of Australia.' (A. H. & A. W. Reed, Sydney). (Fifth edition, 1992)

COGGER, H. G., CAMERON, E. E., SADLIER, R. A. & EGGLER, P. (1993) 'The Action Plan for Australian Reptiles'. Australian Nature Conservation Agency Endangered Species Program No. 124. ANCA, Canberra.

DAVIES, R. (1982) 'The Conservation of Major Plant Associations in South Australia.' Conservation Council of South Australia: Adelaide.

EHMANN, H. (1982) The natural history and conservation status of the Adelaide pygmy bluetongue lizard Tiliqua adelaidensis. Herpetofauna 14, 61-76.

EHMANN, H. (1992) 'Encyclopaedia of Australian Wildlife. Reptiles.' (Angus & Robertson/National Photographic Index of Australian Wildlife, Sydney).

JESSUP, R. W. (1948) A vegetation and pasture survey of Counties Eyre, Burra and Kimberley, South Australia. Transactions of the Royal Society of South Australia 72, 33-68.

PETERS, W. (1864) Eine Übersicht der von Hrn. Richard Schomburgk an das zoologische Museum eingesandten Amphibien, aus Buchsfelde bei Adelaide in Südaustralien. Monatsberichte der K. Preussisches Akademie Wiss. Berl. 1863, 228-236.

SHEA, G. M. (1992). The systematics and reproduction of bluetongue lizards of the genus Tiliqua (Squamata : Scincidae). Unpublished doctoral dissertation. Department of Veterinary Anatomy, University of Sydney.


Implementation schedule

Action  Action description  Responsible Party  Feasibility  Funding Source  Estimated Costs ($000's/year) 
Total 

2

Confirmation of existing demographic data

SAM

100%

OTHER

SAM

34.1

2.9

19.1

2.9

19.1

2.9

   

72.3

8.7

3

Field study to establish limiting microhabitat and macrohabitat factors

SAM

100%

OTHER

SAM

15.6

2.4

15.6

2.4

15.6

2.4

12.6

1.9

 

59.4

9.1

4

Experimental field study to establish optimum habitat management procedures

SAM

BCS

100%

OTHER

SAM

BCS

18.4

2.7

10.0

15.6

2.4

10.0

15.6

2.4

10.0

16.1

2.4

10.0

 

65.7

9.9

40.0

5

Determine genetic composition of bluetongue populations

SAM

100%

OTHER

FU

SAM

4.0

1.0

5.0

1.0

     

5.0

4.0

2.0

6

Establish permanent monitoring sites

SAM

100%

OTHER

SAM

13.7

2.1

13.7

2.1

13.7

2.1

14.7

2.2

14.7

2.2

70.5

10.7

7

Raise community awareness of the species

SAM

ZOO

BCS

FG

100%

OTHER

SAM

ZOO

3.5

3.5

3.5

3.5

3.5

3.5

3.5

3.5

3.5

3.5

17.5

17.5

8

Implement appropriate management procedures

SAM

90%

OTHER

SAM

3.5

0.6

3.5

0.6

3.5

0.6

3.5

0.6

3.5

0.6

17.5

3.0

9

Develop methods for expanding existing populations

SAM

FG

70%

OTHER

SAM

FG

     

4.0

4.0

8.0

       

OTHER

88.8

76.0

71.0

50.4

21.7

307.9

       

TOTAL

118.0

100.9

94.9

75.0

32.0

420.8

DENR= SA Department of Environment and Natural Resources Contribution, SAM=South Australian Museum contribution, ZOO=Zoological Gardens of Adelaide contribution, FU=Flinders University, BCS=Burra Community School, FG = pygmy bluetongue friends group contribution.


Appendix. Experimental designs for Recovery actions

Experimental design for 3.2

The experimental protocol would be to use eight 50 m by 50 m plots configured as follows: two quadrats of 25 additional burrows/quadrat, 2 quadrats of 100 additional burrows/quadrat, 2 quadrats for spider removal (see 2.2 below) and 2 control quadrats. Quadrats will be located in a 4 by 2 arrangement, with at least 100 metres between quadrats. Treatments will be randomly assigned to each quadrat. Counts of the number of lizards found in burrows in each quadrat should be made at the commencement of the experiment. The experiment should be replicated within at least two sites. At the end of the trial period (running for two complete seasons would be desirable), all lizards within the quadrats should be captured, measured and weighed. A repeated measures analysis of variance could be used to test the null hypothesis that treatment has no effect on lizard increase within the quadrats. By capturing all individuals, any adverse effect of overpopulation can be noted, by statistical comparison of condition indices (eg weight per length) between quadrats and sites.

For management purposes, if the number of artificial burrows increases the number of bluetongues found in an area without decreasing the condition of the individual lizards within that area, then obviously this will be a mechanism by which to increase the size of lizard populations within known sites. In particular, this may be a task in which a friends' group (see Action 7) could participate.

Experimental design for 4.2 to 4.5:

Ideally, three 50 m by 50 m quadrats should be used in each manipulation and another 3 control quadrats of the same size should be established, with an initial count of pygmy bluetongue numbers taken in each quadrat. Only one set of control quadrats would be required for all manipulations. Treatments should be randomly assigned to regularly distributed blocks located at least 100 metres from one another. Yearly surveys of both pygmy bluetongue numbers and vegetation within each quadrat should be conducted. The effect of each treatment on the number of pygmy bluetongues could be assessed by statistical comparison of initial and final counts of lizards by paired t-tests. Vegetation should be assessed by 5 transects within each area, and five 1 m by 1 m quadrats at regular intervals along each transect. Whilst the effect upon lizard numbers of the different treatments is the primary objective of this experiment, the effect on vegetation should also be noted. This may assist in future management decisions made concerning endangered native grasslands within the Mid-North of South Australia that do not contain pygmy bluetongues.

Property and copyright in this document vests in the director, Environment Australia.
The Commonwealth disclaims responsibility for the views expressed.