The status of frogs in the Watagan Mountains area the Central Coast of

M. J. Mahony Department of Applied Science and Technology, The University of Newcasde, Callaghan, NSW 2308

ABSTRACT

The composition of frog communities and the numbers of the various species present have been studied for over 15 years in several habitats in the Watagan l\/lountains area of New South Wales, making it possible to document changes in these features over this period. The habitats studied include two ponds, three streams, one site with both ponds and a stream, and several ephemeral situations. Fifteen myobatrachid and 15 hylid species occur in the area. During the period of the study five species

have disappeared — three myobatrachids and two hylids. These are two species of Great Barred River Downloaded from http://meridian.allenpress.com/rrimo/book/chapter-pdf/2644388/rzsnsw_1993_039.pdf by guest on 30 September 2021 frog (Mixophyes balbus and M. iteratus) that breed in streams; one pond species — the Green and Golden Bell Frog {Utoria aurea), and two species that breed in ephemeral situations, Bibron's Toadlet {Pseudophryne bibroni) and an as yet undescribed species of tree frog. Although quantitative measures of abundance were not recorded over the entire period of the study, there was an apparent decline in the number of stream frogs, while the numbers of most species that breed in ponds and ephemeral situations appear to have remained unchanged. To understand the causes of the disappear- ances and declines there is a need to establish an active research programme involving experimental manipulations to eludicate the causes combined with the establishment of long-term monitoring sites and survey programmes.

INTRODUCTION The third question accepts that declines are real and asks whether all or just some frogs are In recent years there has been a growing threatened. The final question assumes that awareness, on a global scale, that certain biologists who report declines are not simply species of amphibians are facing a decline in being alarmist: why are the frogs disappearing distribution and abundance. This decline has and/or what is the cause of the decline? been precipitous in some cases, and a number of species have disappeared altogether (Blaustein The first two questions are very important, and Wake 1990). Indeed, the fact that some because some biologists who work on frogs go distinctive species disappeared so rapidly led so far as to suggest that the declines and dis- biologists to look carefully at populations of appearances are warnings of serious problems amphibians in a variety of habitats (Osborne in our environment, and indirecdy, an early 1989; McDonald 1990; Richards et al. 1993). warning about the continual survival of all life. Australian frogs have not been spared from the With this serious possibility it is necessary to global decline. Unfortunately, several of the provide empirical evidence that the reported continent's most distinctive species of frogs declines have indeed occurred. There are have disappeared or are in serious decline. The several ways to obtain these data — the ideal current decline and loss of amphibians in Aust- would be to have sites that have been monitored ralia is at a level which equals the catastrophic on a long-term basis with consistent quantitative declines that have occurred to mammals since data records. Unfortunately, in a country the European settlement. In the past 15 years six size of , and with the variety of species of indigenous Australian frop have habitats represented, this is not a likely option disappeared and a further 36 are believed to and there are no such sites currently being be in serious decline (Tyler 1991; Richards et monitored, although monitoring has begun in al. 1993). some critical habitats (see Richards et al. 1993). Another option is the re-examination of sites In general, the causes of the declines/ where concentrated studies of population disappearances are unknown. Several questions ecology have been conducted in the past, and are often directed to those who work on frogs examination of field notes for sites which have when they express concern over this pattern. been visited over periods of time that span the The first is related to an understanding of the first reports of declines. population dynamics of frogs: how can we be sure that these declines are not just natural In response to the third question, it appears population fluctuations? The second question that not all frogs are threatened. I will present is related and asks where is the baseline data evidence that some groups of frogs slaow no which show that populations have declined? evidence of decline in the study area. The

Herpetology in Australia 257 answer to the last question is that biologists currently do not know why frogs are declining. There are some possible causal agents that have been linked to declines in various parts of the world, such as acid rain, drought, or disease. However, these causes cannot be used to explain all declines (Pechman et al. 1991). The aim of this study was to examine the changes in populations of frogs in one small area of New South Wales. The Watagan Mountains between the Hawkesbury and Hunter Rivers on the central coast of New South Wales is an area that has been visited by herpetologists for over fifteen years. Although quantitative field methods for recording

abundance were not applied over this period, Downloaded from http://meridian.allenpress.com/rrimo/book/chapter-pdf/2644388/rzsnsw_1993_039.pdf by guest on 30 September 2021 there are detailed field notes for species occurrence and distribution records.

MATERIAL AND METHODS The "Watagan Mountains Area" is shown in Figure 1. On the east the area is bounded by a coastal plain about'20 to 25 kilometres wide, with several large coastal lagoons and lakes. To the west the area is bounded by Wollombi Brook, a tributary of the Hunter River. The area is between Latitude 33°00' and 33°20' south. While the whole area has not been Fig. 1. Map of the Watagan Mountain area. The six regularly extensively studied, many sites within it have visited sites are numbered and the major creeks and been investigated, including habitats in the rivers are shown. The 200 metre contour line is valleys, the main eastern and western slopes included. and the ridge tops. A range of habitats is found within the area, including subtropical rain- Observations in the area have involved visits forest gullies, wet eucalypt and dry eucalypt to several sites such as ponds, streams and a forests, dry heaths, and paperbark swamps. number of ephemeral ponds or soaks, on a This region has a high diversity of frog species, relatively consistent basis. Often four or five showing a variety of habitat preferences and visits were conducted in spring and summer, life history strategies, and it has received less regularly in the autumn, and a small considerable attention from herpetologists number of trips during winter. Consistent field over a long period of time, making it a suitable methods were used over the period of time that area in which to investigate the status of observations were made: at each site a list of various species. species present was determined by listening to male mating calls and by searches using head- Beginning in the spring of 1977 and continuing torches. Counts of the number of calling males for the spring, summer and autumn seasons of of different species were often recorded, the next nine years, several sites were routinely although not always. Sites were inspected and visited. Between 1987 and 1990 the area was evidence of reproduction (egg masses, pairs in visited only on three occasions. During the amplexus) were generally noted. Many site spring and summer of 1991-1992 the area was records were also obtained while spotlighting visited routinely once again. During the first along roads. This method was often used to nine years the reasons for trips were primarily locate ephemeral ponds and soaks in the forest for the purpose of genetic and systematic that were not visible from the road. studies (Mahony and Robinson 1988), and there was no thought that measures of abundance Brief habitat descriptions of the six sites that were necessary because there had been no alarm were routinely visited are: bells on the subject. However, field notes were Site 1 — valley (33°18'S compiled for distribution, and at times notes 15ri7'E): Ourimbah Creek drains a portion were added about the abundance of particular of the southern end of the area. The valley species. All location details for specimens floor has been cleared to varying degrees for collected for genetic studies were recorded. agriculture. Subtropical rainforest and wet

258 Herpetology in Australia times. This creek usually flows gently, but after rain can form a powerfiil torrent. The catchment of the creek has been selectively logged in the past decade. Site 3 — Pond A, Walkers Ridge Rd (33°08'S, 151°12'E): Two adjacent human- made ponds on the ridge top that drain a small section of road and the area surround- ing the ponds. These ponds have not dried out in the past fifteen years, although during drought have been reduced to puddles less than 3 metres in diameter and about 10 cm deep. Surrounded by heath vegetation and low eucalypt woodland, the ponds have large

areas of emergent vegetation, small shrubs Downloaded from http://meridian.allenpress.com/rrimo/book/chapter-pdf/2644388/rzsnsw_1993_039.pdf by guest on 30 September 2021 and grasses on their banks, and one has a large fallen tree trunk from the bank to the water. Site 4 — Boarding House Dam (33°00'S, 151°24'E): A dam constructed on the upper reaches of Congewai Creek forms a pond which feeds into a deeply dissected gully with subtropical rainforest and wet eucalypt forest vegetation. The bank of the pond is grassed on one side and the other is thick with reeds and emergent vegetation.

Fig. 2. Site 2. Wollumbi Brook at The Basin. This photo- Site 5 — Pond B, Mount Faulk Road graph, taken in 1980, shows a number of habitat (33°00'S, 151°26'E): A human-made circular features that make it a suitable site for a variety of pond, with dense vegetation on three-quarters frog species. Sandy banks, overhanging vegetation and a number of logs provide sites for calling and of the bank. It drains a section of road and the breeding. The dense streamside vegetation provides surrounding area. Surrounding vegetation is cover for winter torpor and foraging. A low level road predominantly wet eucalypt forest. This pond crossing forming a weir now occurs at this site, and much of the vegetation has been cleared. Photo: has not dried up even during drought. S. Donnellan. Site 6 — Gap Creek (33°01'S, 15r26'E): Subtropical rainforest and wet eucalypt forest eucalypt forest are found along the upper surround the creek which has a small waterfall reaches of the creek, and the valley sides have with a splash pool and rocky stream. This site wet or dry eucalypt forest depending on was not visited as often as the others, but was aspect. In paddocks at the end of the cleared routinely visited in the latter half of the study. section of the valley large ponds form follow- ing heavy rains. Attention was paid to the presence or absence of the introduced Mosquito Fish Site 2 — Wollombi Brook, The Basin Gambusia affinis (holbrooki) in all the habitats (33°06'S 151°13'E) Fig. 2: Subtropical rain- examined because I consider that it may be forest and wet eucalypt forest along the creek implicated in the decline of some frog species. extending into wet eucalypt or dry eucalypt forests on the valley sides, depending on RESULTS aspect. This site has changed markedly over the past 15 years. The site has been developed Thirty frog species were recorded with 16 as a camping area by State Forests of New belonging to the family Hylidae or "tree frogs", South Wales. Thick natural vegetation has and 15 species to the family Myobatrachidae been removed progressively along one section or "ground frogs" (Table 1). Two undescribed of the creek and gendy sloping areas away species of tree frogs occur in the area, they from the creek have been transformed into are referred to here as Litoria sp "A" and L. grassed areas and woodland. The flow of the sp "B", (see discussion for details). No species creek has been significandy altered by a weir. is endemic to the area, but a number reach Prior to this, a log bridge had been in place, the limit of their geographic distribudon in but had been invariably washed away during this area. Among the hylids, Litoria Moris and floods and the bridge re-sited a number of L. brevipalmata are at the southern end of their

Herpetology in Australia 259 Table 1. Frog species recorded in the Watagan Mountains Area, at the six regularly visited sites, and those that typically breed

1. 2. 3. 4. 5. 6. Wollombi Ourimbah Brook Boarding Species Creek The Basin Pond A House Dam PondB Gap Creek

Family Myobatrachidae Adelotus brevis X X X X X X Crinia signifera X X X X X Heleiporvs australiacus* Lechriodus fletcheri* X X X X Limnodynastes dumerilli greyi X X X Lim. peronii X X X Lim. ornatus X Mixophyes balbus X X X X M.fasciolatus X X X M. iteratus X X X X Pseudophryne australis* P. bibroni* Downloaded from http://meridian.allenpress.com/rrimo/book/chapter-pdf/2644388/rzsnsw_1993_039.pdf by guest on 30 September 2021 P. coriacea* Uperoleia fusca X X X U. laevigata X X X Family Hylidae Litoria aurea X L. brevipalmata X L. caerulea X L. chloris* X L. citropa X X L. dentata X X X L. fallax X X X X L. freycineti X X X L. sp A X X L. latopalmata X X X L. lesueuri X X X X X X L. peronii X X X X X L. phyllochroa X X X X L. tyleri X X X X L. sp B "heath frog"*

distributions, and L. citropa is at the northern end situations (Table 1). An example is L. lesueuri. of its distribution. Among the myobatrachids, It is most commonly found around pools Lechriodus fletcheri, Mixophyes iteratus, Pseudo- and gently flowing water on streams, and phryne coriacea and Uperoleia fusca are at the only occasionally found at ponds. Although southern limit of their distributions, while quantitative data on abundance are not Heleioporus australiacus and Pseudophryne presented, the numbers of this frog along australis are at the northern limit (Barker and streams greatly outweighs the numbers Grigg 1978; Cogger 1992). The remaining 20 observed around ponds. Similarly, M.fasciolatvs, species are widely distributed to the north and and Adelotus brevis are most commonly found south of the area. Two species never recorded along streams, but are also known from ponds, within the Watagan Mountains, but known and L. fallax and L. peronii are most commonly from a number of coastal lagoons and swamps found at ponds rather than streams. in the region, are L. jervisiensis and Paracrinia haswelli. Species restricted to stream habitats were, M. balbus, M. iteratus, L. citropa, and L. phyllochroa, At the six sites routinely visited there were while those found only at ponds were, L. distinct habitats associated with frogs, namely latopalmata, L. freycineti, Limnodynastes ornatus, streams and ponds. There are, however, a Lim. dumerilli, Lim. peronii, Uperoleia fusca and number of habitats not represented at any of U. laevigata. Only one species, Crinia signifera, the sites. There is a group of species which was found in all the habitats, although it typically typically breed in ephemeral pools and are prefers still or only slighdy flowing water. rarely found in permanent ponds or streams, these include the three species of Pseudophryne, Over the 15 year period that field observations Lechriodus fletcheri, H. australiacus, L. chloris, L. were made, changes in the distribution and sp A, and L. sp B. One of these species, L. chloris abundance of some species became apparent. may occasionally be associated with streams, Declines and disappearances of two species of where there are distinct pools. Some species Barred River frogs {Mixophyes balbus, M. are generalists and were found in a variety of iteratus) and the Green and Golden Bell Frog

260 Herpetology in Australia (L. aurea) were noted. Also Pseudophryne bibroni, the headwaters of Cedar Brush Creek (33°04'S, has become scarce in recent years. One species, 15ri6'E). Tadpoles of these species are large Litoria sp B (known by the common name as and powerful swimmers. They were common the "heath frog") is known from only one in Wollombi Brook, Boarding House Dam location in the area, and this species has not (Congewai Creek), Gap Creek and Watagan been observed in the past six years. All the Creek over a decade ago, but were not located other species recorded from the region have in 1991 or 1992. been detected regularly over the period of observations including the past two years. The third member of this genus, M. fasciolatus, Three species were encountered only rarely and is still found in the forests. It is the only one of usually in specific habitats or at specific times, the trio that breeds in ponds as well as streams. L. brevipalmata, L. sp A and H. australiacus. In the past two years this species has been detected on several occasions along streams and in ponds in moist forest, particularly DISCUSSION following summer rains. Although it is not as commonly encountered as in the past. Species that breed in streams Downloaded from http://meridian.allenpress.com/rrimo/book/chapter-pdf/2644388/rzsnsw_1993_039.pdf by guest on 30 September 2021 Since 1984 no specimen of the Great Barred Among the other species that breed specific- Frog M. iteratus has been found at any of the ally along streams there is no clear indication three stream sites which were routinely visited, of declines. Two species of tree frog, L. lesueuri and M. balbus has not been observed since and L. phyllochroa, are common along the 1986. Searches in the past two years have con- streams that have been regularly visited. Less centrated on the known habitats of these common is L. citropa, but this species was not species without any success. Mixophyes fasciolatus observed in large numbers at any time during has been located throughout the period. Each the period of observations. The species has species has a distinctive male mating call. It been observed and noted as breeding at two of would be difficult to overlook calling adult the stream sites, The Basin and Boarding males of M. iteratus, because the call is loud House Dam, in the past two springs. and carries for some distance. The adults are Changes to the stream-side vegetation, large (up to 110 mm) and can be easily caused by modification of the banks, clearing detected using a spotlight. The mating call of of trees, and visitor pressure have had a signifi- M. balbus is softer and may be overlooked. cant effect on the characteristics of the streams However, this is also a relatively large frog at these sites. Subde changes in the frog (up to 90 mm) and is readily detected by spot- communities at these sites have been observed lighting. over the period. For example, the construction of a low level road crossing and the subsequent Mixophyes iteratus was never observed in large formation of a pond behind this crossing at numbers at the sites where it was recorded, but The Basin has favoured species which prefer groups of males could be heard calling along still water in which to breed. Species such as L. stretches of streams, and their position on the fallax and L. peronii, once uncommon at the bank was easily located by spotlighting. On one site, are now common. occasion five males were found calling along a 50 metre stretch of Wollombi Brook at The A species that breeds in both streams and Basin. This population density is similar to that ponds is the Tusked Frog A. brevis. Over the reported by Straughan (1968) in several period of observations, its numbers have not locations in south-east Queensland. Apart shown any marked decline. from animals observed on stream banks, the only time that specimens were spotlighted was Species that breed in permanent ponds in subtropical rainforest within 20 metres of a stream. The preferred habitat in this area are Two species of "whistling tree frog" (the streams lined with subtropical rainforest and Litoria ewingi species group of Tyler and Davies wet eucalypt forest. No specimen of this species 1986) occur in the area. These species are L. was collected while spodighting along roads. verreauxi, and a species that is referred to here In contrast M. balbus was often caught in large as L. sp A. Genetic studies are currently in numbers during road spotlighting. They were progress to determine the specific status and particularly found in a number of moist relationships of this species. Litoria sp A is most sections of the forest (rainforest and wet likely to be confused in the field with L. eucalypt forest), in association with Lechriodus verreauxi. It is smaller than this species (23 mm fletcheri. Large calling choruses were not snout-vent length, SVL, compared to 30 mm common, and the only occasion that a group in L. verreauxi), has a higher pitched mating of 10 adults males were detected was along call, and can be distinguished by differences in

Herpetology in Australia 261 markings on the sides and thigh. These species was only observed by spotlighting in specific occur sympatrically at a number of sites in the habitats, where there is sandy soil on sandstone area, including Ourimbah Creek and Pond B. ridges that support heath vegetation. Breeding While L. verreauxi is common at most ponds sites are small soaks formed in eroded sand- and slow flowing streams in the area, and males stone drainage lines. Because its preferred call from late winter to summer, L. sp A has habitat is restricted, this species was not been encountered only after heavy rains in late commonly observed, however, following winter or spring, calling from around either summer rains it usually was detected at known ephemeral or permanent ponds. Another sites. Although quantitative data are not avail- member of this species group, L. jervisiensis able, the total population of this species at occurs at coastal ponds and lagoons to the east three locations appears to have diminished in of the area. recent years. Only small populations of breed- ing adults were observed in the summers of The Green and Golden Bell Frog L. aurea 1991 and 1992. The cause of the decline is not was recorded at one location in the area, at known, but two sites are near roads and it is Ourimbah Creek, and on only one occasion in possible that with an increase in traffic in Downloaded from http://meridian.allenpress.com/rrimo/book/chapter-pdf/2644388/rzsnsw_1993_039.pdf by guest on 30 September 2021 the spring of 1979. Calling males were observed recent years some animals are killed on the in large permanent ponds in paddocks that road. Road kills have been observed at one of were surrounded by long grass, and with an these sites. There are no exotic fish in the abundance of emergent vegetation. The breeding sites of this species. species has not been recorded at the site since that time. There have been a number of Another species which breeds in ephemeral reports of the disappearance of this frog from situations is the Red-crowned Toadlet P. known sites along the east coast (Tyler 1991), australis. Several breeding sites of this species and two closely related species from the southern are known in the southern half of the Watagan and northern tablelands of New South Wales Mountains and have been regularly visited have disappeared (Osborne 1986). The cause over the period of observations. The species is of the decline of these pond frogs is unknown, also known from a small number of sites in the but it is possible that the introduced Mosquito northern half of the area, but these sites have Fish may prey on the eggs and tadpoles of this not been regularly visited. Although never in frog. It is not known when the Mosquito Fish large numbers at the regularly visited sites, the was introduced to ponds at Ourimbah Creek, animals have been consistently recorded but it was present at this location in 1993. whenever rain has occurred. Among the other pond breeders there is no The Red-backed Toadlet Pseudophryne indication that numbers have declined markedly coriacea is found in the northern half of the over the period of observations. The two area, on top of the ridges and on the slopes species of Uperoleia occur sympatrically at most down to the valley floor. It occurs in relatively permanent ponds in the forest, similarly Lim. large numbers along small drainage lines and dumerilli and Lim. peronii are found in most in areas that flood after heavy rain. The permanent ponds and the latter also in swamps surrounding vegetation is usually moist and flooded areas. Limnodynastes ornatus is eucalypt forest or rainforest. There is no found only in the southern half of the area at evidence that its abundance has diminished Pond A. This pond has sandy soil nearby and over the period of observations. this seems to be favoured as a substratum for burrowing by this species. Among the tree Bibron's Toadlet P. bibroni was recorded on frogs L. fallax, L. freycineti, L. latopalmata, L. several of the ridges that run in a south-west peronii, L. tyleri and L. verreauxi are known from or westerly direction in the northern half of most ponds and there was no indication of the area. The vegetation on these ridges con- declines in populations over the period of the sisted of a mixture of wet and dry eucalypt study. Two of these species, L. fallax and L. forest, which in several areas have been clear- peronii, were also commonly encountered along felled and regrowth forest established. As with streams in situations where water flow was the other two species it was found around slow. ephemeral soaks or small drainage lines. This species has not been observed in the past Species that breed in ephemeral situations two years, despite specific searches in areas where it was formerly known. There are no The Great Burrowing Frog H. australiacus is apparent changes to the habitat at the sites known only from three locations in the area. apart from forestry harvesting that may None of these locations are at the six specific explain the decline/disappearance of this sites regularly visited (see Table 1). This species species. 262 Herpetology in Australia Two other species that breed in ephemeral immediate alarm for its continued persistence ponds have been recorded in consistent at these sites. However, this should not be a numbers over the period of the study. The cause for complacency as the locations in the Red-eyed Tree Frog L. chloris occurs through- region from which the frog is known have been out the forest and breeds in small soaks or subject to development in recent years. A puddles. At Gap Creek this species breeds in detailed study of vegetation associations, and rock pools above a small waterfall and in the the characteristics of known populations splash pool of the waterfall. This waterfall flows should be a matter of priority. Every effort strongly only after heavy rain, at other times it should be made to ensure that the exotic consists of a shower of drops. Fletcher's Rain- Mosquito Fish Gambusia affinis (holbrooki) is not forest Frog Lechriodus fletcheri was encountered introduced into these sites. mainly in the northern half, in areas of moist eucalypt forest and rainforest. In the past two A species which breeds in flooded areas and years successful breeding has been recorded in permanent ponds after heavy rains is the both species. There is an indication that their Bleating Tree Frog L. dentata. This species numbers have declined over the period of forms large breeding choruses, particularly in Downloaded from http://meridian.allenpress.com/rrimo/book/chapter-pdf/2644388/rzsnsw_1993_039.pdf by guest on 30 September 2021 observations. Both species are readily detected the valleys, and there was no indication of a by spotlighting along roads after rain during decline in its population in the area. In a the spring and summer months, and using this similar fashion the large Green Tree Frog L. method it is possible to gain some estimate of caerulea is known mostiy from the valleys, numbers in various parts of the forest. Where although it has been encountered in the forest clear-felling has occurred and plantations have on a small number of occasions. Breeding takes been established the number of frogs detected place in large ponds or flooded areas. is lower than in areas where no harvesting has Another species that breeds only in ephemeral taken place. situations is a species of tree frog known by the One of the most enigmatic frogs known from common name the "heath frog", and referred this area is the Green-thighed Tree Frog L. to here as L. sp B. In redefining L. jervisiensis, brevipalmata. Its biology remains largely White et al. (1980) drew attention to the differ- unknown. First described in 1972 (Tyler et al. ences between this species and the superficially 1972) with the type location Ourimbah Creek, similar "heath frog". A formal description of this species is known from less than ten sites this latter species has been presented (White et along the eastern seaboard from Ourimbah in al., in press). Two recent publications include the south to the Conondale Ranges in south- descriptions of L. jervisiensis but actually east Queensland. During the period of observa- describe and present photographs of the tions, this species was recorded only after "heath frog" (Hero et al. 1991; Cogger 1992). heavy rainfall in spring and summer. Calling The "heath frog" is much larger than the males gather in choruses usually around species considered here as L. jervisiensis (60 mm flooded areas, such as ponds in grassy areas or SVL in the "heath frog" compared to 23 mm at the base of paperbark trees. These areas SVL for L. jervisiensis). Although confusion form ephemeral ponds after heavy rain. On may surround the systematics and nomenclature no occasion have calling males been found of this species, there is no doubt that it associated with flowing streams. Another represents a distinctive species. This species reason why so little is known about this species was collected in the area at ephemeral ponds, is that males call for only a small number of on the ridge tops, in the period 1981 to 1984. nights following heavy rain, and outside this The species has not been located in the area period animals are rarely encountered. The since. mating call is distinctive and is available on The declines and disappearances of several audio tape (Grigg and Barker 1977). In the species of frogs from the east coast of Queensland last two years, two other populations have been over the past 15 years have been documented found in the region, one at a human-made (McDonald 1990, Richards et al. 1993). With pond in the forest on a ridge above the this as background and the reported worldwide Ourimbah Creek Valley (G. Schmida and H. decline of amphibians, a clear picture of the Ehmann, pers. comm.) and in the status of frogs along the east coast in New Valley approximately 40 km to the north of South Wales is currently needed. This paper Ourimbah Creek. The status of this frog is has concentrated on a small area where there difficult to ascertain. Measures of numbers in have been field observations over an extended populations and the location of populations period of time. Also during this period, field are difficult to obtain. The species has been observations were conducted throughout encountered in recent years and there is no much of the north east region of New South Herpetology in Australia 263 Wales, but at a much lower intensity. In the that focus field and laboratory studies on past two years we have observed that several of declining species. These studies will necessarily the species that have declined in the Watagan involve experimental manipulations of the Mountains have also declined from suitable presumptive causal agents of declines. Without habitats in the north east of the state. Both such an approach we may witness the continued species of Mixophyes that have declined and disappearance of frogs without understanding disappeared in the Watagan Mountains area the causes or knowing how to arrest them. have also declined markedly in the north-east. Similarly, Pseudophryne bibroni has declined in ACKNOWLEDGEMENTS many areas, particularly at high altitudes. The Over the period of this study assistance in Green and Golden Bell Frogs Litoria aurea, L. the field was provided by many people, in flavipunctata and L. castanea have all declined particular T. Daly, S. Donnellan and R. Knowles and in the latter two cases searches in the past who were present on many trips. two years have failed to locate any individuals. These declines are currently being studied. REFERENCES There is no apparent common pattern link- BLAUSTEIN, A. R. AND WAKE, D. B., 1990. Declining Downloaded from http://meridian.allenpress.com/rrimo/book/chapter-pdf/2644388/rzsnsw_1993_039.pdf by guest on 30 September 2021 amphibian populations: A global phenomenon. Trends ing those species which have declined. Thus Evol. Evol. 5(7): 203-04. declines are not restricted to all the species that BARKER, J. AND GRIGG, G. C., 1978. A Field Guide to Australian breed in a particular habitat, or all members of Frogs. Rigby Ltd.: . a taxonomic group. The species of Mixophyes COGGER, H. G., 1992. Reptiles and Amphibians of Australia. 5 th that breed in streams have disappeared in the Ed. Reed Books: Sydney. Watagan's area, yet other stream species GRIGG, G. C. AND BARKER, J., 1977. Frog calls of South East remain, and population numbers are apparently Australia. Tape recordings. unchanged. Not all species appear to be HERO, J-M., LITTLEJOHN, M. AND MARANTELLI, G., 1991. declining. Species that breed in ephemeral Frogwatch field guide to Victorian frogs. Victorian situations appear to be least effected, with the Department of Conservation and Environment: exception of the Bibron's Toadlet, and most Melbourne. species that breed in permanent ponds appear MAHONY, M. J. AND ROBINSON, E. S., 1988. Nucleotide organizer region (NOR) location in karyotypes of Aust- to be unaffected, with the exception of the ralian ground frogs (Family Myobatrachidae). Genetica Green and Golden Bell Frog and its close 68: 119-27. relatives. MCDONALD, K. R., 1990. Rheobatrachus Liem and Taudactylus Straughan and Lee (Anura: Leptodactylidae) in Research is required to determine the causes Eungella National Park, Queensland: Distribution and of the declines documented and to ensure the decline. Trans. R. Soc. S. Aust. 114: 187-94. long term persistence of all species. Action is OSBORNE, W., 1986. Frogs of the Canberra region. Bogong required to establish long-term monitoring 7(3): 10-12. sites which cover the range of habitats where OSBORNE, W., 1989. Distribution, relative abundance and frogs are found. Surveys are necessary for conservation status of corroboree Frogs, Pseudophryne those species that are known or suspected to corroboree Moore (Anura: Myobatrachidae). Aust. Wild. have declined and or disappeared from some Res. 16: 537-47. areas. These two approaches will enable the PECHMAN, J. F. K., SCOTT, D. E., SEMLITSCH, R. D., CALDWELL, J. P., VITT, L. J. AND GIBBONS, J. W., 1991. first two questions posed in the introduction to Declining amphibian populations: the problem of be answered. They will provide necessary base- separating human impacts from natural fluctuations. line data on which to measure changes in Science 253: 892-95. community composition and population RATCLIFFE, D., 1980. The Peregrine Falcon T. Calton and A. density. They will also be necessary to measure D. Poyser. the effectiveness of ameliorative steps. How- RICHARDS, S. J., MCDONALD, K. R. AND ALFORD, R. A., 1993. ever, monitoring and surveys alone will be Declines in populations of Australia's endemic tropical rainforest frogs. Pacific Cons. Biol. 1: 66-77. ineffective in arresting declines or ascertaining TYLER, M. J., MARTIN, A. A. AND WATSON, G. F., 1972. A the causes of declines. A major problem with new species of Hylid frog from New South Wales. Proc. monitoring programmes in the past is that they Linn. Soc. NSW. 97(1): 82-86. have failed to detect even major catastrophic TYLER, M. J., 1991. Declining amphibian populations — A changes in numbers of organisms before they global phenomenon? An Australian perspective. Alytes had become so large that there was no way to 9(2): 43-50. ignore them. Such was the case with the WHITE, A, W., WHITFORD, D. AND WATSON, G. F., 1980. pesticide DDT, which had been in widespread Re-description of the Jervis Bay tree frog Litoria jervisiensis (Anura: Hylidae), with notes on the identity use for twenty years before its deleterious of Krefft's frog (Litoria krefftii). Aust. Zool. 20(3): 375-90. effects on birds of prey were detected (Ratcliffe WHITE, A. W., WHITFORD, D. AND MAHONY, M. J., in press. 1980). Thus it is necessary to adopt a pro-active A new species of tree frog (Anura: Hylidae) from eastern approach and establish research programmes Australia. Proc. Linn. Soc. NSW.

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