Ecology, Evolution and Landscape Science
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Ecology, Evolution and Landscape Science is concerned with understanding, managing and conserving the natural systems of the Australian continent. Our natural resources are declining due to increasing pressures, including more intensive agriculture, urbanisation, invasive species and climate change. Study within Ecology, Evolution and Landscape Science includes the assessment, monitoring and prediction of the environment and resources and covers marine and coastal systems, natural and constructed wetlands, estuaries, woodlands and the arid zone. Research interests are focussed on marine biology, terrestrial and freshwater ecology, the study of taxonomy and systematics of organisms and their evolution, spatial technology, and natural resource systems.
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Item Metadata only Three new Eocene cycads from eastern Australia(CSIRO Publishing, 1980) Hill, R.S.The descriptions of Pterostoma R.S.Hill, a new cycad genus with two species (P. zamiodes R.S.Hill and P. anastomosans R.S.Hill) and Lepidozamia foveolata R.S.Hill add significantly to our knowledge of the floristic components of the Australian Tertiary. Along with other reports of Tertiary cycads, the discovery of these new species supports the theory that cycads had a greater geographical range and diversity in Australia during the Tertiary than at present. The evolutionary position of Pterostoma in relation to other fossil and extant cycads is considered and it is concluded that Pterostoma represents an extinct line. The possibility that fossil cycads could be of value in biostratigraphy and in estimating palaeoclimate is discussed.Item Metadata only A numerical taxonomic approach to the study of angiosperm leaves(University of Chicago Press, 1980) Hill, R.S.Dolph proposed data banking of angiosperm leaf information. For a data bank to function satisfactorily, the scored character set must be suitable for statistical testing. Such a character set, based on a ratio scale, was compiled from various sources Using 100 leaves from 20 species, the numerical taxonomic methods clearly clustered the leaves into their species. Several factors, such as character number, character correlation, missing data, and sample size, and their effect on the classification were considered. To increase the accuracy of character scoring, a method to determine vein orders was devised. Binary data were also considered, and a strategy to describe fossil floras is presentedItem Metadata only A stopping rule for partitioning dendrograms(University of Chicago Press, 1980) Hill, R.S.The Ratkowsky and Lance criterion for determining the "optimum" number of groups in a dendrogram is applicable to both nominal and numeric data, is easy to calculate, and requires no prior knowledge of the identity of the operational taxonomic units. A modification of that criterion, described in this paper, maintains the advantages of the original criterion and overcomes the problems of the invalid use of phenon lines and lack of objectivity. Preliminary work also suggests that the modification gives improved results for the number of groups.Item Metadata only Resistance to water flow in the sorghum plant(American Society of Plant Biologists, 1980) Meyer, W.S.; Ritchie, J.T.Knowledge of the location and magnitude of the resistance to water flow in a plant is fundamental for describing whole plant response to water stress. The reported magnitudes of these resistances vary widely, principally because of the difficulty of measuring water potential within the plant. A number of interrelated experiments are described in which the water potential of a covered, nontranspiring leaf attached to a transpiring sorghum plant (Sorghum bicolor [L.] Moench) was used as a measure of the potential at the root-shoot junction. This allowed a descriptive evaluation of plant resistance to be made.The water potentials of a covered, nontranspiring leaf and a nonabsorbing root in solution, both attached to an otherwise actively transpiring and absorbing plant, were found to be similar. This supported the hypothesis that covered leaf water potential was equilibrating at a point shared by the vascular connections of both leaves and roots, i.e. the nodal complex of the root-shoot junction or crown. The difference in potential between a covered and exposed leaf together with calculated individual leaf transpiration rates were used to evaluate the resistance between the plant crown and the exposed leaf lamina called the connection resistance. There was an apparent decrease in the connection resistance as the transpiration rate increased; this is qualitatively explained as plant capacitance.Assuming that the covered leaf water potential was equal to that in the root xylem at the point of water absorption in the experimental plants with relatively short root axes, calculated radial root resistances were strongly dependent on the transpiration rate. For plants with moderate to high transpiration rates the roots had a slightly larger resistance than the shoots.Item Metadata only Consequences of long-distance dispersal of plant macrofossils(Royal Society of New Zealand, 1981) Hill, R.S.Long-distance dispersal of plant macrofossils is a commonly recognised phenomenon, but in most fossil assemblages it is difficult to determine its extent. Long-distance dispersal will probably affect any analysis based on foliar physiognomy (leaf size and margin type), particularly if it causes species from more than one vegetation type to be present in the assemblage. Mbre serious objections to the use of foliar physiognomy, particularly for estimating palaeoclimates and vegetation types, arc the frequent over-abundance of streamand lake-side plants in deposits and the current lack of knowledge of the representation of surrounding vegetation in depositional sites.Item Metadata only Rainforest fire in western Tasmania(CSIRO Publishing, 1982) Hill, R.S.Humus/surface litter fires in cool temperate rainforest have received little attention in Tasmania. Past studies suggest that these fires are the result of drought, which dries the humus and surface litter to a flammable level. Such fires are probably extremely variable in effect and extent because of their reliance on weather conditions. A humus/surface litter fire at Zeehan was species-specific, affecting Nothofagus cunninghamii and Eucryphia lucida in particular. The trees which survived were growing on humus that-was too shallow to sustain the fire, and they escaped being burnt. The survival of some trees of all the major species in unburnt areas within the fire boundary will probably be important in regeneration by providing a nearby source of seed. Three months after the fire, seedlings from the fire-stimulated germination of humus-stored Acacia melanoxylon seeds were abundant but the majority died within the following 6 months.Item Metadata only Nothofagus macrofossils from the Tertiary of Tasmania(Taylor & Francis, 1983) Hill, R.S.Leaves assignable to Nothofagus from two fossil deposits in Tasmania represent the first macrofossils of this genus from the Tertiary in southeastern Australia. One fossil species, N. johnstonii, is closely related to the extant Australian species N. cunninghamii while the other fossil species, N. tasmanica, has very close affinites with the extant Australian species N. moorei. All four of these species are closely interrelated. The pollen type produced by the fossil species is unknown, since all three types are present in the microfloras. However, both N. cunninghamii and N. moorei produce N. menziesii-type pollen. The macrofossils confirm the conclusion from pollen studies that evolution in Nothofagus has occurred very slowly.Item Metadata only Rainforest invasion onto Tasmanian old-fields(Blackwell Publishing, 1983) Read, J.; Hill, R.S.The regeneration of rainforest onto land cleared for grazing early this century was studied on several sites in northern Tasmania. Drimys lanceolata, a bird-dispersed species, was the main invader. The climax forest species. Nothofagus cunninghamii and Atherosperma moschatum were invading slowly from the forest edge with occasional trees established in the field. Woody plants in the old-field were clumped around logs. This was related to the role of logs in attracting seed and to possible roles as competition-free sites and sites safe from browsing and climatic stresses. Changes in dominance by particular life forms appeared to be related to dispersal events, environmental modification by the developing vegetation and life history characteristics. The extremely slow invasion by climax species is due to the absence of bare mineral soil as well as to dispersal characteristics, browsing and possibly exposure to climatic stresses.Item Metadata only Evolution of Nothofagus cunninghamii and its relationship to N. moorei as inferred from Tasmanian macrofossils(CSIRO Publishing, 1983) Hill, R.S.Abstract not availableItem Metadata only Reconstruction of the Oligocene vegetation at Pioneer, northeast Tasmania(Taylor & Francis, 1983) Hill, R.S.; Macphail, M.K.The Oligocene vegetation at Pioneer was closed temperate rainforest dominated by Nothofagus johnstonii Hill, which probably produced N. menziesii-type pollen. However, other angiosperms (Quintinia, Cupaniae, Ilex, Cunoniaceae, Myrtaceae, Proteaceae and Winteraceae) were also present, as well as several conifers (Athrotaxis, Phyllocladus, Podocarpus, Dacrydium, Dacrycarpus and Araucariaceae). This rainforest was floristically more complex that the modern Tasmanian Nothofagus cunninghamii rainforests but contained many taxonomically related elements. One major difference was that a fern similar to extant Cyathea filled the riparian niche now largely occupied by the tree-fern Dicksonia antarctica. There is indirect evidence that species producing Nothofagus brassii-type pollen may have occurred upstream of the site of deposition, suggesting that the Nothofagus species were altitudinally zoned or edaphically restricted. The current absence of many of these Nothofagus species in Tasmania may be due to their inability to survive the low temperatures of the Quaternary glaciations. The high degree of similarity of the Pioneer palynoflora to that recorded in Oligocene sediments in onshore (Partridge, 1971) and offshore (Stover & Partridge, 1973; Stover & Evans, 1973) Gippsland Basin strongly suggests that there was little regional differentation in southeastern Australia at that time.Item Metadata only Post-fire regeneration of rainforest and mixed forest in western Tasmania(CSIRO Publishing, 1984) Hill, R.S.; Read, J.Abstract not availableItem Metadata only Lauraceous leaves from the Eocene of Nerriga, New South Wales(Taylor & Francis, 1986) Hill, R.S.A study of extant leaves of the Lauraceae and the results of previous research show that fossil leaves can be placed with confidence in the family, but that leaf morphology within the family is so variable that with few exceptions more detailed affinities are impossible to determine. A review of the taxonomic literature reveals that Laurophyllum Goeppert has priority as the generic name for fossil leaves belonging to the Lauraceae. Twelve species from the Eocene Nerriga locality are assigned to Laurophyllum. This represents 44% of species described from Nerriga, compared with 46% for the Middle Eocene Claiborne Formation in North America. Therefore it is possible that the Lauraceae was a widespread and dominant family in the Eocene. The leaf species from Nerriga represent a wide diversity of leaf morphologies which suggests that they may not be closely related within the family.Item Metadata only Distribution of potential macrofossils in Lake Dobson, Tasmania(British Ecological Society, 1986) Hill, R.S.; Gibson, N.(1) Lake Dobson is a small lake in south-central Tasmania surrounded by tree- and shrub-dominated sub-alpine evergreen vegetation. (2) Most species present in the vegetation surrounding Lake Dobson were recovered as leaves from the lake sediment, but the proportions of species changed rapidly between samples, and an accurate reconstruction of the surrounding vegetation from these samples would be impossible except in terms of species present. (3) Epacris serpyllifolia, a small, lakeside shrub, was overwhelmingly dominant in most sediment samples, and was strongly over-represented in relation to its importance in the surrounding vegetation. Eucalyptus coccifera, the dominant canopy tree species, was common directly below overhanging trees, but as the leaves sank rapidly they were virtually absent from the rest of the lake. E. coccifera was thus strongly under-represented in relation to its importance in the surrounding vegetation. (4) Leaf remains were far more common in Lake Dobson than reproductive structures and could be more reliably identified. (5) The most important features affecting leaf deposition in the lake were the prevailing wind direction, the presence of lakeside or overhanging vegetation, and leaf sinking rates. Decomposition of leaves is relatively slow in the lake.Item Metadata only Selective loss of carbohydrates from plant remains during coalification(Pergamon Press, 1987) Wilson, M.A.; Verheyen, T.V.; Vassallo, A.M.; Hill, R.S.; Perry, G.J.Fossil leaves ofOleinites willsii, Banksieaephyllum angustum, associated organic matter and rhizomes ofGleichenia sp. isolated from Yallourn brown coal deposits, Latrobe Valley, Victoria, Australia and their living relatives have been analysed by high-resolution solid-state13C nuclear magnetic resonance spectroscopy, infrared spectroscopy and pyrolysis—gas chromatography—mass spectrometry. The fossil leaves and rhizomes retain carbohydrates and, on a carbon basis, the amounts of carbohydrates in the fossil rhizomes and their living relatives appear to be similar. On the other hand, the amount of carbohydrates in the fossil leaves is substantially less than in the living relatives. The organic matter found intimately associated with the fossil leaves is quite different in structure from the fossil leaves themselves and bears a closer resemblance to humic acids and the smallest (<75μm) fractions of Yallourn brown coal. Since the fossil leaves are found in stratified beds, interfolded with associated organic matter, it is suggested that during coalification the leaves and associated organic matter undergo independent transformations and are brought together by water transport.Item Metadata only Endemism in Tasmanian cool temperate rainforest: alternative hypotheses(Wiley-Blackwell, 1987) Hill, R.S.; Read, J.Evidence is presented which suggests that hypotheses presented by Kirkpatrick & Brown relating to endemic species in Tasmania are either invalid or of limited importance for woody rainforest species. In their place three hypotheses are presented to account for the presence of endemic species in Tasmanian cool temperate rainforest on the basis of the fossil record and the distribution of species which are closely related to the endemics. The first two hypotheses relate to the presence of the endemic species in the general Tasmanian region. They are: 1 Some species evolved in southeastern Australia during the Tertiary in response to the changing climate. Some of the ancestral species still occur in temperate rainforest at lower latitudes in Australia. 2 Some species have remained essentially unchanged in Tasmania during the Tertiary and Quaternary climatic changes. The third hypothesis relates to the restriction of these cool temperate rainforest species to Tasmania: 1 Post-glacial climatic changes (especially a decrease in rainfall) and the human influence (especially land clearing and fire) may have combined to eliminate some cool temperate rainforest species from mainland Australia.Item Metadata only Discovery of Nothofagus fruits corresponding to an important Tertiary pollen type(Nature Publishing Group, 1987) Hill, R.S.Abstract not availableItem Metadata only Tertiary gymnosperms from Tasmania: Araucariaceae(Taylor & Francis, 1987) Hill, R.S.; Bigwood, A.J.Three new species of the Araucariaceae are described from leaf remains, Araucaria readiae from the Early Eocene Regatta Point flora, A. hastiensis from the Middle-Late Eocene Hasties flora, and Agathis tasmanica from the Early Oligocene-Early Miocene Little Rapid River flora. Additionally, emended diagnoses are presented for Araucarioides linearis and A. annulata. A. readiae is the first organically preserved species in the section Eutacta described from Tasmania, A. hastiensis is the first record of a species not in section Eutacta in Tasmania, and A. tasmanica is the first record of Agathis in Tasmania. These species, along with other records from south-eastern Australia indicate the presence of a high diversity of araucarian species in the region in the Early-Middle Tertiary, although no species survive there today. Climatic change and competition from angiosperms may have led to their demise in that region.Item Metadata only Comparative responses to temperature of the major canopy species of Tasmanian cool temperate rainforest and their ecological significance. I. Foliar frost-resistance(CSIRO Publishing, 1988) Read, J.; Hill, R.S.Foliar frost resistance has been determined using the conductivity method in the rainforest canopy species Nothofagus cunninghamii (Hook.) Oerst., Atherosperma moschatum Labill., Eucryphia lucida (Labill.) Bail]., Phyllocladus aspleniifolius (Labill.) Hook. f. and Athrotaxis selaginoides D. Don in glasshouse experiments and seasonal measurements at Mt Field National Park, Tasmania. Some determinations of frost resistance were also made in Lagarostrobos franklinii (Hook. f.) C. J. Quinn and Nothofagus gunnii (Hook. f.) Oerst. The general trend of foliar frost resistance is in the order A. moschatum < P. aspleniifolius < E. lucida < A. selaginoides < N. cunninghamii. This is consistent with the infrequency of A. moschatum at the higher altitudes, its occupation of the lower canopy in old rainforest and its infrequent establishment on exposed sites. P. aspleniifolius is more common at high altitudes than E. lucida but has a lower foliar frost resistance. A. selaginoides and N. cunninghamii have a high frost resistance consistent with their occurrence at high altitudes and on exposed sites. However, A. selaginoides does not have the superior frost resistance predicted by its occurrence at higher altitudes than N. cunninghamii. The leaves of N. gunnii (winter-deciduous) have a low summer frost resistance relative to the co-occurring evergreen species A. selaginoides and N. cunninghamii. L. franklinii has a higher frost resistance than predicted from its infrequent occurrence at high altitudes.Item Metadata only Australian Tertiary angiosperm and gymnosperm leaf remains - an updated catalogue(Taylor & Francis, 1988) Hill, R.S.A catalogue of Australian Tertiary angiosperm and gymnosperm leaves published to the end of 1986 is presented. Only those taxa which are adequately described and/or illustrated by modern standards are included in the list of 107 taxa in 17 families. Information is also included on taxa which have been critically appraised by other authors. It is concluded that the bulk of published Australian Tertiary leaf fossils are in need of revision, although many of the specimens are inadequate for reliable taxonomic work.Item Metadata only A re-investigation of Nothofagus muelleri (Ett.) Paterson and Cinnamomum nuytsii Ett. from the Late Eocene of Vegetable Creek(Taylor & Francis, 1988) Hill, R.S.Two species described by Ettingshausen (1888) from Vegetable Creek, Nothofagus muelleri and Cinnamomum nuytsii, are re-investigated, including an analysis of the cuticular morphology. It is concluded that four Fagus species proposed by Ettingshausen represent only one valid species. The name selected for this species is Nothofagus muelleri, based on the fact that it is the only species containing specimens with organic preservation. It is recommended that the fossil species Fagus celastrifolia, F. hookeri and F. benthami be regarded as synonyms of N. muelleri. N. muelleri has strong affinities with the extant species N. moorei and N. cunninghamii and the fossil species N. tasmanica and N. johnstonii. Cinnamomum nuytsii clearly belongs to the family Lauraceae, but the affinity with the genus Cinnamomum cannot be substantiated. Therefore it is proposed that this species be transferred to the organ genus Laurophyllum. The confirmation of Nothfagus leaves in the Vegetable Creek flora provides the first macrofossil evidence for cool temperate elements in Eocene vegetation on mainland Australia.