Tasmanian Highlands Research Articles

Channel to the Strait : the geological history of the Tamar Valley–Launceston area

The Tamar Valley occupies the Tamar Graben, a geological structure defined by a series of parallel NW-trending faults which have lowered the dolerite basement to below sea level. The resulting narrow trough, some 50 km long and 5 km wide, has been partially infilled with soft sands, clays and gravels, with intercalated basalt flows in places, of mainly Paleogene (lower Tertiary) age. Low hills of hard Jurassic dolerite define the structure on either side. The graben was formed during the break-up of Gondwana, the separation of Australia from Antarctica, and the making of Tasmania, in the Cretaceous-early Cenozoic period, some 70–140 million years ago (Ma). A spreading ridge had propagated eastwards through the Great Australian Bight but was unable to break through the Bass Strait area, and instead a large wedge of crust containing the future Tasmania was pulled away from the corner of Antarctica on a series of transcurrent faults. The associated crustal stretching in the Bass Strait area resulted in the formation of the deep ‘hole’ of Bass Basin, which had offshoots onto what became Tasmania, including the Tamar Graben. For much of its life, the Tamar River was a major feeder stream into the Bass Basin, carrying large volumes of sediment eroded from the Tasmanian highlands. The course of its major tributary, the South Esk River, within the southern part of the graben was completely blocked by basalt flows near the present Evandale about 35 Ma, forcing it into a new course to the west through the dolerite, to form the Cataract Gorge.

An Alpine Malaise trap

The Southernmost region of Australia, the island of Tasmania, is also the most mountainous, with large areas of rugged alpine environments. This entomological frontier offers a distinct suite of insects for study including many endemic taxa. However, harsh weather, remote locations and rough terrain represent an environment too extreme for many existing insect trap designs. We report here on the design and efficacy of a new Alpine Malaise Trap (AMT), which can be readily hybridised with several other common insect trapping techniques. Advantages of the design include its light weight and portability, low cost, robustness, rapid deployment and long autonomous sampling period. The AMT was field tested in the Tasmanian highlands (AUST) in 2017. A total of 16 orders were collected. As expected, samples are dominated by Diptera. However, the trap also collected a range of flightless taxa including endemic and apterous species, Apteropanorpatasmanica – closest relative of the boreal, snow scorpionflies (Boreidae). Combined and compared with other trap types the Alpine Malaise Traps captured less specimens but of a greater diversity than passive sticky traps, while drop traps captured less specimens but a greater diversity than AMT. The statistical potential of the catch is discussed.

Disturbance ecology of Tasmanian highland grassland — an overview and implications for conservation management

Active manipulation of disturbances such as fire and grazing is often necessary to maintain or enhance biodiversity values in grasslands. However in many instances information is lacking on the disturbance regimes most likely to achieve conservation aims. This paper provides an overview of the effects of fire and grazing in Tasmanian highland grasslands, and the implications of these for conservation management of this vegetation. In Tasmania, highland grassland is defined as occurring above 600 m above sea level. The vegetation is typically dominated by species of Poa. Highland grassland is grazed by a suite of native herbivores and has a history of stock grazing, which continues at some sites of high biodiversity value. There is evidence that Indigenous Tasmanians regularly burnt highland grasslands and that Indigenous burning was instrumental in maintaining grassland at sites that otherwise would be forest. For highland grasslands below 1000 m asl, a reduction in the biomass of dominant grasses through disturbance is necessary in order to maintain plant species diversity. The use of periodic fire, together with native grazing, is likely to be beneficial in this regard. The combination of fire and grazing is also likely to prevent woody plant invasion and maintain vegetation structural heterogeneity. The near ubiquity of native grazing species means there is no ecological imperative for stock grazing. Low productivity of grasslands occurring above 1000 m means that competitive exclusion of interstitial species by grasses is unlikely and therefore active application of disturbance as a management tool will rarely, if ever be necessary. Disturbance management should be accompanied by a well-designed monitoring program and regular review of the management strategy

Additions to the genus Trapelia (Trapeliaceae: lichenised Ascomycetes)

Two new species in the genus Trapelia, namely, T. calvariana Kantvilas & Lumbsch from the Tasmanian highlands and T. thieleana Kantvilas & Lumbsch from south-western Western Australia, are described. Examination of ascus types and analyses of DNA-sequence data confirmed the inclusion of these taxa in Trapelia sensu lato, but raised questions concerning the homogeneity of the genus as currently circumscribed and, in particular, the generic classification of T. lilacea Kantvilas & Elix.

Lagoons with Islands, Tasmanian Highlands

Lagoons with Islands, Tasmanian Highlands

Monts d’Australie, espaces des mythes, des quêtes, des déchirements

From Ayers Rock (Uluru) to Tasmanian mountains, this article focuses on real and symbolic spaces. It aims at underlining the existential, spiritual dimension of the perception and representation of the Australian landscape traditionally associated with Aboriginal people, and which stands in stark contrast with the colonial enterprise characterized by violation and exploitation. However, a more harmonious future is suggested with visions of rebirth, regeneration and plenitude in the Tasmanian highlands

Box Gully: new evidence for Aboriginal occupation of Australia south of the Murray River prior to the last glacial maximum

ABSTRACT Recent archaeological investigation at Box Gully, located on the north western tip of the Lake Tyrrell lunette, has resulted in the first documentation of pre‐30,000 calBP Aboriginal occupation of the extensive area between the Murray River and the Tasmanian highlands. The remains of repeated small scale camping episodes were uncovered in a palaeosol capping a buried pelletal clay lunette. Five new radiocarbon determinations on charcoal associated with cultural material in the palaeosol range from ca. 32,000 calBP near the bottom to ca. 26,600 calBP near the top, and are supported by both conventional radiocarbon and Optically Stimulated Luminescence dates obtained independently during geomorphic investigations of Box Gully. Hearth features, stone artefacts and the remains of bettong, hare‐wallaby, shingle‐backed lizard, emu and fresh water mussel were present within the palaeosol. Review of the late Pleistocene archaeological record of the western Murray Basin allows the finds at Box Gully to be placed in a human occupation context of adaptation to severe climatic stress leading to the Last Glacial Maximum. As conditions deteriorated further after ca. 27,000 calBP, lacustrine localities including the Willandra Lakes, Lake Tandou and the Lower Darling were much less heavily frequented than previously, or like Lake Tyrrell, abandoned. At the same time sustained occupation of the Murray River valley occurred, as did the initial occupation of rockshelters in the highlands of southern Victoria.

Catchment characteristics and chemical limnology of small lakes, tarns and mire pools in New Zealand (South Island) and Tasmania

Small alpine water bodies can play a large role in defining patterns of biological and landscape diversity, and may be particularly sensitive to climate change. A large limnological dataset, consisting of 65 and 6 water bodies, respectively, on South Island and Stewart Island (New Zealand) and 76 and 12 water bodies, respectively, in the Tasmanian highlands and coastal areas (Australia), was constructed to assess patterns of variation in alpine and subalpine lakes in the Australasian region. With the exception of the coastal systems, most lakes were very dilute. In general, lake water chemistry resembled world average seawater cationic ratios (WASW). In addition, some New Zealand lakes fell close to the world average freshwater cationic ratios (WAFW), due to relatively high calcium concentrations, and some were dominated by magnesium due to the presence of serpentine bedrock in the catchment area. Multivariate analyses of the joint dataset revealed that the variation in chemical limnological variables was dominated by gradients in conductivity, pH and gilvin. The concurrent relationships between pH, calcium and gilvin, which enabled the differentiation of Tasmanian water bodies into limnological provinces, were absent in New Zealand. In the latter, pH and gilvin contents were not coincident, as clear-water acidic systems occurred in New Zealand. The higher diversity of freshwater bodies in New Zealand will enable independent assessment of the effects of pH and gilvin on the distribution and diversity of biota.

The timing of the Last Glacial Maximum in Australia

Late Pleistocene glaciation of Australia was restricted to the Snowy Mountains and the Tasmanian highlands. Glaciers were most extensive in Tasmania where ice caps formed on the Central Plateau and West Coast Ranges, and systems of valley and cirque glaciers formed on surrounding mountains. To investigate the timing of maximum glacier advance during the Last Glacial Maximum (LGM), we dated boulders on 18 moraines in 8 glaciated areas using cosmogenic 36Cl and 10Be. We sampled moraines deposited by cirque and valley glaciers, in a range of climate types and lithologies over a 7° latitudinal and a 1430 m altitudinal transect. Exposure ages for LGM moraine boulders group tightly in the range 17–20 ka. Boulders from the Hamilton moraine, often treated as the LGM type moraine, range in age from ∼190–350 ka, indicating that it was deposited well before the last glaciation. Collectively, the exposure ages show that southeastern Australia was glaciated briefly during and after the LGM, and deglaciated well before the Holocene. Ice retreated from the terminal moraines after the period of coldest sea-surface temperatures in the southwest Pacific Ocean. No evidence was found for readvance of glaciers during the Antarctic Cold Reversal or the Younger Dryas period.

From rainforest to wasteland in 100 years: The limnological legacy of the Queenstown mines, Western Tasmania

Areas within the rainforests of south-west Tasmania, home to Aboriginal tribes for more than 36,000 years, were dramatically changed in the late 1800s with the arrival of European prospectors. Subsequent large-scale mining and smelting operations resulted in acid rain, local deforestation and extensive soil erosion. Much of the area is now bare rock. The aims of this study were to examine the terrestrial and lacustrine responses to industrial acidification and deforestation as revealed by a sediment core from 'Owen Tarn', a small cirque lake down-wind of the mining town of Queenstown, and adjacent to a World Heritage Area. Terrestrial responses were investigated using pollen analysis to document both the state of the rainforest before and after the arrival of the Europeans. Limnological responses were documented by examining changes in diatom communities in the core. Results show both the terrestrial vegetation and the aquatic microscopic vegetation have been considerably modified by mining activities in the last 100 years. Pollen analysis provides a chronology of industrial deforestation and diatom analysis shows changes in species composition and a decline in species richness. Indirect ordination (PCA) of sediment diatom assemblages in the core with autecological data from 76 Tasmanian highland lakes (TASDIAT) reveals that diatom assemblages in the bottom parts of the core are analogous to those of Tasmanian oligotrophic corridor lakes' while recent species assemblages are similar to those of acidic Tasmanian 'western lakes'. Although a number of cosmopolitan' species indicative of lake acidification in the northern hemisphere are present in Owen Tarn, acidification has resulted in a different species response.

Distribution of benthic diatom assemblages in Tasmanian highland lakes and their possible use as indicators of environmental changes

Classification and gradient analyses of littoral diatom assemblages and 37 chemical and physical variables in littoral sediments of 76 Tasmanian dystrophic and (ultra-)oligotrophic highland lakes indicate strong west-east gradients in pH, calcium concentration, sodium concentration, alkalinity, and gilvin, which are underlain by an oceanic-inland gradient and geological discontinuities. Two major clusters of lakes are recognised, concordant with the recognition on chemical and optical criteria of western and eastern limnological provinces and coinciding with a steep gradient in mean annual rainfall and major geological changes. Changes in species composition occur gradually across the corridor separating the two provinces. Highly significant inference models can be constructed for pH and calcium concentration and related variables, which can be used in palaeolimnological reconstructions in Tasmanian highland lakes. Resume : D'apres une classification et des analyses de gradient des assemblages de diatomees du littoral et de 37 variables chimiques et physiques observees dans des sediments littoraux de 76 lacs des hautes terres de Tasmanie, de type dystrophique et (ultra-)oligotrophe, il existe de forts gradients ouest-est de pH, de calcium, d'alcalinite et d'absorbance optique (gilvin), qui sont sous-tendus par un gradient des caracteristiques oceaniques et interieures et des discontinuites geologiques. On distingue deux grappes principales de lacs, qui correspondent a la presence, d'apres des criteres chimiques et optiques des provinces limnologiques de l'ouest et de l'est, et qui coincident avec un gradient prononce des precipitations annuelles moyennes et des grands changements geologiques. On note generalement des changements graduels dans la composition specifique en travers du corridor separant les deux provinces. On peut construire des modeles d'inference tres significatifs a partir du pH, du calcium et de variables connexes, et ceux-ci peuvent servir a reconstructions paleolimnologiques sur les lacs des hautes terres de Tasmanie. (Traduit par la Redaction)

The Tasmanian geometrid moths associated with the genus Amelora auctorum (Lepidoptera : Geometridae : Ennomina)

The Tasmanian species associated by previous authors with the geometrid moth genus Amelora Guest are reviewed. Nine, including two new species, are assigned to Amelora sensu stricto on the basis of new morphological evidence: A. sparsularia (Guenee) with synonyms A. cyclocentra Turner, syn. nov., and A. oxytona Turner, syn. nov., A. arotraea Meyrick, A. adusta Turner, A. zophopasta Turner, A. nebulosa, sp. nov., A. oritropha Turner, A. leucaniata (Guenée), A. acontistica (Turner), comb. nov., and A. acromegala, sp. nov. Xantholepidote Gumppenberg, syn. nov., and Stinoptila Turner, syn. nov., are considered new generic synonyms of Amelora. All other Tasmanian species associated with Amelora in original combination are reassigned to new genera: Dolabrossa, gen. nov., includes the type species D. suffusa (Turner), comb. nov., and D. amblopa (Guest), comb. nov.; Furcatrox, gen, nov., is erected for a complex of superficially similar species including F. australis (Rosenstock), comb. nov., as type species, F. serrula, sp. nov., F. pervaga, sp. nov., F. furneauxi, sp. nov., F. paracus, sp. nov., F. procera, sp. nov., and F. crenulata (Turner), comb. nov.; Lackrana, gen. nov., includes the type species L. carbo, sp. nov., and L. durafrons, sp. nov.; Cassythaphaga, gen. nov., is a Cassytha (Lauraceae)-feeding genus with C. macarta (Turner), comb. nov., as type species and Androchela, gen. nov., includes A. newmannaria (Guenée), comb. nov., newly confirmed from Australia after 130 years, the polyphagous genotype A. milvaria (Guenée), comb. nov., and a new species, A. smithi, sp. nov., from the Tasmanian highlands. Biological and ecological notes are given where known.

Distribution of benthic diatom assemblages in Tasmanian highland lakes and their possible use as indicators of environmental changes

Classification and gradient analyses of littoral diatom assemblages and 37 chemical and physical variables in littoral sediments of 76 Tasmanian dystrophic and (ultra-)oligotrophic highland lakes indicate strong west-east gradients in pH, calcium concentration, sodium concentration, alkalinity, and gilvin, which are underlain by an oceanic-inland gradient and geological discontinuities. Two major clusters of lakes are recognised, concordant with the recognition on chemical and optical criteria of western and eastern limnological provinces and coinciding with a steep gradient in mean annual rainfall and major geological changes. Changes in species composition occur gradually across the corridor separating the two provinces. Highly significant inference models can be constructed for pH and calcium concentration and related variables, which can be used in palaeolimnological reconstructions in Tasmanian highland lakes. Resume : D'apres une classification et des analyses de gradient des assemblages de diatomees du littoral et de 37 variables chimiques et physiques observees dans des sediments littoraux de 76 lacs des hautes terres de Tasmanie, de type dystrophique et (ultra-)oligotrophe, il existe de forts gradients ouest-est de pH, de calcium, d'alcalinite et d'absorbance optique (gilvin), qui sont sous-tendus par un gradient des caracteristiques oceaniques et interieures et des discontinuites geologiques. On distingue deux grappes principales de lacs, qui correspondent a la presence, d'apres des criteres chimiques et optiques des provinces limnologiques de l'ouest et de l'est, et qui coincident avec un gradient prononce des precipitations annuelles moyennes et des grands changements geologiques. On note generalement des changements graduels dans la composition specifique en travers du corridor separant les deux provinces. On peut construire des modeles d'inference tres significatifs a partir du pH, du calcium et de variables connexes, et ceux-ci peuvent servir a reconstructions paleolimnologiques sur les lacs des hautes terres de Tasmanie. (Traduit par la Redaction)

Mitochondrial and allozyme genetics of two Tasmanian galaxiids (Galaxias auratus and G. tanycephalus, Pisces: Galaxiidae) with restricted lacustrine distributions

Galaxias auratus and G. tanycephalus have a restricted distribution in Tasmanian highland lakes and were probably derived from a landlocked population of the diadromous G. truttaceus during the last 100,000 years. We have analysed the mitochondrial DNA and the allozyme products of 22 nuclear loci for each lake species. Four mitochondrial DNA haplotypes, defined by 40-42 six-base restriction sites, were identified amongst 26 G. auratus and three haplotypes, defined by 38-39 restriction sites, were found in six G tanycephalus. The evolutionary genetics of reproductive isolation appears to have inflated mitochondrial but not nuclear DNA diversity between the lake species and their hypothesized progenitor, G. truttaceus. The amount of intraspecific mitochondrial and nuclear DNA diversity for G. auratus and G. tanycephalus is consistent with their having an extended and independent evolutionary history in reproductive isolation.

Thirty Thousand Years of Human Colonization in Tasmania: New Pleistocene Dates

Basal dates of 30,420 years before present (BP) from a limestone cave in the Florentine River valley and 30,840 BP from a sandstone rockshelter in the Shannon River valley on the edge of the central Tasmanian highlands indicate colonization of Tasmania 8,000 years earlier than previously thought. These data indicate that people arrived before the Bassian Bridge was exposed about 23,000 years ago and support evidence that Tasmania and Australia may have been connected intermittently during the past 50,000 years. The dates support earlier suggestions that the Tasmanian inland was an important focus for systematic occupation and exploitation by human groups and dispel a belief that the Aboriginal economy 30,000 years ago was based on littoral, lacustral, and riverine resources. The absence of megafauna at both sites points to their extinction by 30,000 years ago in Tasmania. The people inhabiting Tasmania at this time, together with those at Monte Verde in Chile, were the most southerly humans on Earth.

10,000 Years in the Tasmanian Highlands

Archaeological evidence from the Warragarra rockshelter in the Upper Mersey River, Tasmania, has shown that Aboriginal occupation took place in this central highland region around 10,000 BP, i.e. following immediately upon its deglaciation. This archaeological evidence therefore helps to define more closely the Pleistocene/Holocene boundary which has until now depended upon environmental (e.g. palynological) analyses.

A Preliminary Observation on the Littoral Rock Fauna of Hartz Lake and Hartz Creek, Southern Tasmania, with Notes on the Water Chemistry of some Neighbouring Lakes

The temperature of the surface waters of Hartz Lake varied between 2.6 and 25� C during the 12-month period of the study. The waters of the Hartz lakes are oligotrophic but due to their enrichment with Na+ they are not typical of water from other areas of dolerite in their cationic proportions. The rock fauna of the lake and creek were sampled four times in 1974. The rock fauna is dominated by crustaceans if the actively swimming Anaspides tasmaniae is included. The fauna of the creek is richer in number of animals and species than that of the lake. It is dominated by insects. The dominance by crustaceans of the rock fauna of this lake contrasts with the insect-dominated rock faunas reported in other Tasmanian and European lakes, and may represent the situation in Tasmanian highland lakes where trout have not been introduced.

The Effects of Artifical Enrichment of a Lake

A Tasmanian highland lake of low natural productivity was enriched by the addition of a mixture of chemicals. The first application, to the mud, stimulated the existing stunted aquatic vegetation to produce a prolific growth; a later application, broadcast over a portion of the lake, had the additional effect of increasing phytoplankton and zooplankton. Concurrent with the growth of plants there was a marked increase in the total numbers of epiphytic fauna. Fish living in the lake at the time of enrichment showed a marked increase in growth rate, and others released later showed a similar response. It is tentatively concluded that phosphorus was the element responsible for the stimulus to the growth of plants and plankton. It is shown that an unproductive lake of this type can, by suitable enrichment, be rendered capable of carrying a stock of fish.