VICTORIAN HERPETOLOGICAL SOCIETY INC. (VHS) - RECENTLY PUBLISHED PAPER
Notes on a field trip to the lower Mornington Peninsula (Victoria, Australia) with comments on the wider significance of some observations.
BY RAYMOND T. HOSER AND ROBERT VALENTIC.
This paper first appeared in MONITOR - Journal of the Victorian Herpetological Society, 7 (2), September 1996, pp. 24-34. What follows is a text only version of the same article (no italics), no illustrations, etc.. Please download the entire article if desired. If the paper is cited later, please cite it as coming from MONITOR.
On 17th October 1995, both author's went to the lower Mornington Peninsula in search of the Swamp Skink Egernia coventryi with a view to photographing a specimen. Besides locating four specimens of this species, a number of observations were made that have either been rarely reported in the literature or have significance for the conservation strategy of the Swamp Skink.
DETAILS OF THE FIELD TRIP:
Tootgarook Swamp area - Melways reference map 169, F7. Lat. 38( 23' Long. 144( 52'. The area is adjacent to an area known as Truemans Road Recreational Reserve.
Overcast and with occasional sunny breaks. There had been a northerly wind just prior to arrival in the area at about 12:30 hrs.(a weak cold change had arrived about one hour earlier at about 11:30 hrs. - but apparently was weak and did not appear to get to Melbourne on this day). The search in the area went from about 12:30 to 14:20 hrs. Air temperature at the time was estimated at about 15(C but may have been up to 5(C hotter or colder as no thermometer was used - but temperature had dropped sharply an hour earlier from well over 20(C.
OBSERVATIONS (IN ORDER):
Egernia coventryi - Young specimen found under hard debris and immediately adjacent to drainage ditch (RH). The drainage ditch referred to here and later in these notes runs along a road called Hiscock Road. The swamp and adjacent areas referred to are to the immediate south of Hiscock Road (right hand side if heading east from Truemans Road).
About five Garden Skinks Lampropholis delicata - all adult and found under cover (RH/RV) - all in grassy area (paddock).
Metallic Cool-skink Pseudemoia metallica - Adult gravid female - Under sheet of embedded tin (RH) - in grassy area (paddock)
Two adult Swampland Cool-skinks Pseudemoia rawlinsoni - basking on grass swards above ground level at edge of dense Melaleuca thickets bordering swamp (RV).
Blotched Bluetongue - Tiliqua nigrolutea - Adult - Basking in grasses at edge of swamp(RV). Had two ticks in one ear and no evidence of mites (see Eastern Bluetongue below).
White-lipped Snake Drysdalia coronoides - Large Greenish adult - coiled amongst dense grass swards at edge of swamp, adjacent to dense Melaleuca thickets(RV).
Eastern Bluetongue - Tiliqua scincoides - Adult - With mites (brown) as indicated by white droppings and ticks in ears and elsewhere - close inspection revealed mites under scales which were raised, under vent, etc, etc. - found at edge of swamp in grassy area - active(RV/RH).
Drysdalia coronoides - Adult - male - opaque eyes, due to imminent sloughing - olive in dorsal colour - basking in grass tussock in swampy area in a tight coil (RV). Snake had a number of small to medium ticks on it.
Drysdalia coronoides - Adult - female - gravid - brownish red in colour - active near grass tussock in swampy area or at edge of swamp (RV).
Lampropholis delicata (RV) - adjacent to drainage ditch under cover.
Lampropholis delicata (RH) - Adjacent to drainage ditch under cover.
Egernia coventryi (RH) active in pile of twigs and branches overhanging water in a drainage ditch.
Young specimen Egernia coventryi (RV) - under sheet of tin in drainage ditch - there was about two inches of clearance under the tin with grasses in this space (flattened) which itself was above about 2 inches of water in the canal. The lizard was in the grasses,(young specimen).
Drysdalia coronoides - Juvenile - born last summer - Reddish in colour. Under sheet of tin on mound of dirt adjacent to drainage ditch(RH). Had opaque eyes
Egernia coventryi (RV) - basking atop grasses adjacent to pile of twigs where above E. coventryi was observed by RH five minutes earlier. This specimen was a very large and possibly gravid adult. Shortly after termination of search at 14:20 hrs., storm clouds came over and it started to rain at about 14:35 hrs.
The Pseudemoia rawlinsoni, Tiliqua nigrolutea, three of the Drysdalia coronoides and Tiliqua scincoides, all came from a pristine swamp habitat or immediately adjacent to it. All the Egernia coventryi, Lampropholis delicata, Pseudemoia metallica and one Drysdalia coronoides all came from a heavily grazed and highly disturbed paddock, in or adjacent to a drainage ditch. All vegetation in the area was introduced species and all ground cover in the form of rocks, tin, etc. was man-made.
That Tiliqua scincoides and Tiliqua nigrolutea are sometimes sympatric around Melbourne is known. For example Michael Kearney (Pers. comm. 1995) has noted both species at the One Hundred Acres Bushland Reserve at Park Orchards. RV has noted both species together at the following locations:- Plenty Gorge, near South Morang (basking 2 metres apart); Greensborough (2 sites); Fitzimmons Lane, adjacent to Yarra River at Templestowe at Westerfolds Park; Campbellfield, at Merri Creek (both sheltering under single piece of tin - a relatively notable find as T. nigrolutea are not common in dry basalt habitats). However there has been little study as to preferences of habitat or micro-habitat between the two species where they occur together. In the Tootgarook swamp both lizards were found in close proximity in identical circumstances. There is clearly a need for investigation to see whether these species directly compete for resources or occupy somewhat different ecological niches where they occur together.
The presence of reptile mites Ophionyssus natricus on the T. scincoides is notable. RV has observed reptiles in several Melbourne or near Melbourne locations with these parasites. These include: three sites along the Merri Creek, near Campbellfield, Somerton, and Donnybrook, Koroit Creek at Altona and Rockbank Golf Course, Rockbank. All areas are basalt plains and heavily disturbed habitat. At all sites, RV found T. scincoides with mites and at Rockbank Tiger Snakes Notechis scutatus also had mites. On 26th May 1993, RV found an adult T. scincoides in torpor under a sheet of tin in Plenty, near Greensborough. This was the first reptile found by RV in the north-eastern suburbs to carry mites, even though RV has inspected the area regularly over the preceding 12 years. Peter Comber (Pers. comm. 1995) found these same parasites on a Carpet Snake Morelia spilota sub.sp. near Mount Hope, Victoria, Lat. 36( 03' Long. 144( 07'. This find is notable due to it's distance from major population centres such as Melbourne. While it is possible that the T. scincoides found above (at Tootgarook) was a released captive specimen, this is thought to be unlikely. Furthermore later inspection of photos of one of the E. coventryi found at Tootgarook showed it to have mite infestation. The evidence of these lizards and other mite infested reptiles found elsewhere (also cited above), appears to indicate that wild reptiles are not always able to rid themselves of these parasites. Investigation is required to see if the mites found on wild reptiles in Victoria are naturally occurring or have at some stage originated from captive reptiles, with wild populations originally not carrying these parasites. If the latter is the case, then there may be potential for health problems for some wild reptiles in the longer term. This may ultimately result in population declines through the blood sucking actions of the mites and their acting as a vector for diseases.
The presence of E. coventryi in highly disturbed habitat (above) is thought to have resulted from migration of animals from adjacent areas of habitat, known to support these lizards (the nearby swamp). It is also noted that specimens of this species are highly territorial and aggressive to one another (Taylor, 1995), possibly leading to specimens being forced from optimal habitat to seek refuge in suboptimal habitat in adjacent areas. Our finding of specimens in highly altered adjacent habitat concurs with those of Taylor (1995) who noted that E. coventryi moved into an area where a pipeline was constructed before a revegetation program was completed. That E. coventryi is able to invade areas of apparently suboptimal habitat indicates a degree of resilience in this species in terms of it's ability to cope with human induced changes to habitat. The invasion of areas of apparently suboptimal habitat would also indicate that more specimens are bred each year in the nearby swamp, than the swamp can maintain (in terms of the territorial requirements of the lizard). This could mean a forced mortality in these lizards as specimens are pushed into less than optimal areas where risks of predation, and so on are increased. Taylor (1995) also noted the high mortality of new born skinks in the Tootgarook Swamp area. From a conservation point of view, it would seem that deliberate removal of specimens from an area such as Tootgarook Swamp would not in all likelihood adversely affect the population, the net result being only that fewer specimens would be forced out of the swamp by competing lizards and less young lizards would be attacked by others of the same species. Taylor (1995) indicated a substantial population of these lizards in the area. This is confirmed by our observations.
Furthermore on 15th October 1995, Michael Kearney (pers. comm. 1995) observed more than 15 specimens (mostly adults) at Tidal River, Wilson's Promontory National Park, Lat. 39( 02' Long 146( 19'. All the lizards were basking, with some retreating to burrows. The lizards were in tussock grass in brackish swamp habitat adjacent to Tidal River, which is an estuarine creek with dense Melaleuca and understory. On 5th January 1993, RV observed an adult E. coventryi basking on a Melaleuca trunk about 1.4 metres above ground level adjacent to Darby River, Wilsons Promontory National Park, Lat. 38( 59' Long. 144( 11'. Neil Davie (pers. comm. 1995) has also noted unconfirmed reports of this species occurring in relatively large numbers near Angelsea golf course, Lat. 38( 25' Long. 144( 11'. Danny Goodwin (pers. comm. 1995) has noted a number of specimens from adjacent to a council depot in Melaleuca swampland near Little Yarra Road, Yarra Junction, Victoria Lat. 37( 46' Long 145( 37'.
Ehmann (1992) also describes the species as 'abundant'. Cogger et. al. (1993) describes the species as either 'rare or insufficiently known', while Taylor (1995) describes the species as 'threatened'. In a 1992 internal DCNR Report (not cited here) herpetologist Peter Robertson stated that there were only nine locality records for Victoria. Rawlinson (1971) cited six known Victorian localities as Ballarat area, Warnambool area, Rosedale area, Mallacoota area, Kentbruck area and Boneo area. A booklet titled Threatened fauna in Victoria - 1995(CNR, 1995) lists E. coventryi as 'rare' according to a formula that is not strictly in line with that used by the IUCN.
While it is conceded that this lizard's distribution is believed to be restricted to southern Victoria and further that it may be disjunct within this area, we do not believe there is any evidence of major decline in this species. The lack of records for this species is in line with many other species of small and innocuous skinks found throughout Australia, which to date have attracted relatively little attention. We believe it is likely that E. coventryi may be more common than is currently thought by many authorities and that the alleged rarity of the species may have more to do with it's being overlooked rather than a fundamental rarity.
Furthermore some populations of this species are within National Parks and reserves and appear secure. The evidence provided by Taylor (1995) and ourselves above, would indicate that collection of small numbers of lizards from healthy swamp populations would not threaten those populations. While not necessarily advocating the collection of these or any other lizards from the wild, current protection laws in Victoria do nothing more than restrict collection of the species. In view of the small and innocuous nature of the lizard, any such legal restriction is unlikely to have any realistic impact on the long term status of the species. Few people are ever going to want to collect the lizard. However by according the lizard some sort of status as rare, threatened or even endangered, the State Wildlife authorities do run the risk of inadvertently devaluing the status of species of reptile or other animal that really are endangered and under much more serious threat.
We are concerned that unnecessary effort may be devoted to 'protecting' this lizard while species under greater need for help may expire through lack of resources devoted to their protection. For example it would be ludicrous to put E. coventryi in a class alongside that of the Victorian Spotted Tree Frog Litoria spenceri, which clearly does appear to be endangered, is declining rapidly for reasons that are not entirely clear and under far greater threat (Ehmann, et. al. 1992; Gillespie, 1992; Marc Hero, et. al., 1991; Tyler, 1992; Watson, et. al. 1991).
As a final note, Kearney observed these lizards basking at Wilson's Promontory in a sunny break on a cloudy day when the air temperature was estimated at about 14( C. Our own observations (above) also indicated activity at relatively cool temperatures and below 18( C. A statement by Taylor (1993) that these skinks are only active at temperatures in excess of 18( C, does not appear to be strictly corroborated by observations reported here.
CNR (1995), Threatened Fauna in Victoria - 1995, Department of Conservation and Natural Resources, Heidelberg, Victoria, Australia. 13 pp.
Cogger, H. G., Cameron, E. E., Sadlier, R. A. and Eggler, P. (1993), The Action Plan for Australian Reptiles, Australian Nature Conservation Agency, Canberra, ACT, Australia. 261 pp.
Ehmann, H. (1992), Encyclopedia of Australian Animals - Reptiles, The National Photographic Index of Australian Wildlife/Angus and Robertson, Pymble, NSW, Australia. 510 pp.
Ehmann, H., Ehmann, J. and Ehmann, N. (1992), 'The rediscovery of the endangered Spotted Tree Frog (Litoria spenceri) in New South Wales and some subsequent findings.' Herpetofauna 22(2):21-24.
Gillespie, G. R. (1992), 'Survey for the Spotted Tree Frog (Litoria spenceri) in Victoria, February-March 1992', Victorian Naturalist 109(6):203-211.
Marc Hero, J., Littlejohn, M., and Marantelli, G. (1991), Frogwatch Field Guide to Victorian Frogs, Department of Conservation and Environment, East Melbourne, Victoria, Australia. 112 pp.
Rawlinson, P. A. (1971), 'The reptiles of west Gippsland', Proc. Roy. Soc. Vict. 84: 37-52.
Taylor, M. (1994), 'Rescue Plan for a Colony of Swamp Skink.' Proceedings 1994, ARAZPA/ASZK Conference:282-286.
Taylor, M. (1995), 'Back to the swamp - Completion of the Swamp Skink Project', Thylacinus 20 (1): 15-17.
Tyler, M. J. (1992), Encyclopedia of Australian Animals - Frogs, The National Photographic Index of Australian Wildlife/Angus and Robertson, Pymble, NSW, Australia. 124 pp.
Watson, G. F., Littlejohn, M. J., Hero, J. M. and Robertson, P. (1991), Conservation status, ecology and management of the Spotted Tree Frog (Litoria spenceri). Arthur Rylah Inst. for Environmental Research. Technical Report Series. 116: 40 pp.
Raymond Hoser has been an active herpetologist for about 30 years and published over 150 papers in journals worldwide and also nine books.
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