Attiwill, P. M. (1994). "Ecological disturbance and the conservative management of eucalypt forests in Australia." For. Ecol. Manage. 63: 2-3.
There is increasing recognition that natural disturbance is a dominant force in forest development. This paper sets out to review natural disturbances and their effects in forests in Australia, and to determine whether or not the effects of management of forests for all of their benefits can be contained within the known effects of natural disturbance. The history and evolutionary significance of fire in Australia is reviewed, and the differing fire ecologies of two representative species, Eucalyptus regnans in the south-east (which is killed by fire and regenerates prolifically from seed after fire) and Eucalyptus marginata in the south-west (which survives all but the most severe fires and regenerates from both shoots and seeds) are outlined. The development of E. regnans following stand-replacing fire can be defined as highly resilient (returning quickly to the pre-disturbance state) and that of E. marginata as resistant (difficult to move from the pre-disturbance state). There has been speculation that harvesting mountain ash forests by clearfelling and regenerating them following slash-burning will lead to a loss of nutrients and a consequent loss of productivity. Nutrient cycling in mountain ash is shown to be resilient to disturbance. Rapid uptake of nutrients by the regenerating forest, immobilization of nutrients by microorganisms, and increased rates of nitrogen fixation are processes which lead to the conservation of nutrients following stand-replacing fires. There is no evidence of productivity decline following bushfire or timber harvesting. Another concern about forest harvesting is that there will be a reduction in carbon storage. The break-even point for E. regnans plantations yielding short-lived products (e.g. paper) is 37 years and for E. regnans forests grown for sawn timber, 60 years. Harvesting forests on rotations of 80-120 years will therefore result in an increase in carbon storage; however, it would take several rotations to restore carbon storage equivalent to that of old-age forest. This paper presents the view that timber harvesting in Australian forests is ecologically sustainable and that the effects of management can be contained within the framework of those caused by natural disturbance. Given that each plot in the forest differs from all other plots and that none is at steady state, a solution for the management of diversity is to use the whole of the forest estate (parks, stream reserves, catchment reserves, old-age forest, forests of different ages resulting from past fires and logging) so that diversity of the estate, rather than diversity of each plot, is maximized.

Attiwill, P. M. (1994). "The disturbance of forest ecosystems: The ecological basis for conservative management." For. Ecol. Manage. 63: 2-3.
The extensive literature on natural disturbance in forests is reviewed in terms of the hypotheses: (1) that disturbance is a major force moulding the development, structure and function of forests; and (b) that management of forests for all their benefits can be controlled so that the effects can be contained within those which result from natural disturbance. The causal factors of natural disturbance are both endogenous and exogenous; there are major difficulties in the formal characterization of disturbance and of recovery after disturbance. As to the latter, the acceptance of classical generalizations of the nature of succession had led to particular difficulties in the assessment and interpretation of recovery. Tree fall, which creates gaps, is fundamental to the development of many forests, and has been most intensively studied in tropical forests of Central America and the Amazon and in temperate forests of North America. Tree fall is part of autogenic change; mechanisms of gap-filling and subsequent growth and species composition vary widely with forest type and geography. Disturbance by wind is particularly difficult to characterize. Wind varies along a continuum; the blow-down of an individual tree may be mostly due to autogenic processes of ageing and decay, whereas catastrophic hurricanes and cyclones may be defined as wholly exogenous. Nevertheless, the resilience in terms of species diversity of tropical forests following catastrophic disturbance by hurricane is remarkable. A number of studies support the view that the tropical forest in hurricane-prone areas is not a stable steady-state ecosystem but rather that heterogeneity is maintained by catastrophe. The ability to regenerate by suckers and the coincidence of regenerative space and gregarious flowering are important components of the response of rainforest following disturbance. For much of the world, 'fire is the dominant fact of forest history'. As examples, fire and its effects are reviewed for the northern boreal forests, oak-pine forests and north-western sub-alpine forests of North America. The effect of fire on species composition varies with intensity and frequency. That, together with the popular view of fire as unnatural and therefore unacceptable, places great demands on management of forests for all of their benefits, including national parks and reserves. These difficulties also affect management of other ecosystems, such as Mediterranean-type shrublands and heathlands where species diversity, productivity and cycles of regeneration and degradation are governed by fire as a natural disturbance. An extensive literature supports the hypothesis that natural disturbance is fundamentalto the development of structure and function of forest ecosystems. It follows that our management of natural forest should be based on an ecological understanding of the processes of natural disturbance. Whether or not we want to do this, and the extent to which we want to derive all of the benefits from the forest, including timber, depends on social attitudes. Whereas humanism may treat conservation as the wise husbanding of forests in the interests of social traditions and harmony, animism may give nature unalienable rights. The conclusion from this review is that the ecological framework of natural disturbance and the knowledge of its component processes and effects provides the basis on which we can manage our forests as a renewable resource which can be utilized so that the forests 'retain their diversity and richness for mankind's continuing benefit'. Nowhere is this management more desperately needed than for the protection of the world's tropical forests, its peoples and their cultures.

Barker, P., Wardlaw Tj, et al. (1996). "Selection and design of Phytophthora management areas for the conservation of threatened flora in Tasmania." Biological Conservation 76(2): 187-193.
In Tasmania Phytophthora cinnamomi can cause serious disease in heaths, dry sclerophyll forests, moorlands and disturbed rain forests growing below 600 m and receiving more than 600 mm rainfall annually. Before the current research 136 native plant species were known to be hosts for P. cinnamomi. Very few of these plant species are considered threatened by its activities. However, susceptible rare and threatened plants are at the greatest risk. Management areas were selected and designed for the purpose of safeguarding 44 species (many of them woody) that appear on state and national lists of rare and threatened plants and are susceptible to and potentially at risk from P. cinnamomi. The selection process and criteria used for selecting management areas are described. Of the 101 areas surveyed 74 were selected based on their diversity and the aim of selecting 3 management areas, when possible, for each species. The 61 areas finally selected were based on landscape management criteria as well as species criteria; they contained all 44 target species. There were 109 inclusions of target species in the 61 management areas selected out of a possible 136 in the original 101 areas.

Hill, R. and Scriven Lj (1995). "The angiosperm-dominated woody vegetation of Antarctica: a review." Review of Palaeobotany and Palynology 86(3-4): 175-198.
Antarctic vegetation is today mostly restricted to non-vascular plants, with a few small angiosperms clinging to the Antarctic Peninsula. However, probably as recently as the mid-Late Pliocene, woody angiosperms were present in inland Antarctica, suggesting an overall presence of complex and diverse vegetation. Angiosperms were introduced into Antarctica during the Cretaceous from South America and possibly also Southeast Asia via Australia. These angiosperms speciated rapidly at the prevailing high latitudes and were an important source for the developing angiosperm-dominated vegetation of the Southern Hemisphere. The migration and evolution of early angiosperms in Gondwana was probably facilitated by a high level of disturbance caused primarily by the rifting of the supercontinent. This high-latitude region was an important source of evolutionary novelty during the Late Cretaceous-Paleogene. As the climate deteriorated during the Cenozoic, the angiosperm flora was reduced in biomass and diversity, finally being restricted to the current remnants. The timing and nature of this major regional extinction is still poorly understood.

Jarman, S. and G. Kantvilas (1995). "Epiphytes on an old Huon pine tree (Lagarostrobos franklinii) in Tasmanian rainforest." New Zealand Journal of Botany 33(1): 65-78.
The epiphytic flora of an old Huon pine (Lagarostrobos franklinii) in western Tasmania is composed of 76 lichens, 55 bryophytes and 16 vascular plant species. There is a vertical zonation of the cryptogams on the tree, w ith little overlap between basal and canopy floras. Bryophytes are the dominant life form at the base of the tree but there is a marked increase in the diversity of lichens and in the ratio of lichens to bryophytes, with increasing height. The longevity of the tree is manifest in the development of a wide range of microhabitats but it seems unlikely that any of the cryptogams require such longevity per se to become established as rain forest epiphytes. However, several of the vascular species on the tree are normally terrestrial and their occurrence as epiphytes is dependent on the development of sufficient peat to support their root systems. Such a process is likely to be very slow, requiring a long-lived host species. The study illustrates the richness of lichens and bryophytes in the forest ecosystem and the extent to which even a single tree can contribute to the biodiversity of a forest site.

Kantvilas, G. and S. J. Jarman (1993). "The cryptogamic flora of an isolated rainforest fragment in Tasmania." Bot. J. Linn. Soc. 111(2): 211-228.
The cryptogamic flora of a small isolated natural fragment of rainforest in south-eastern Tasmania has retained its rainforest character but has been modified in comparison to the flora of large, well-buffered rainforest stands. There is a high proportion of widespread wet forest species and many typical rainforest lichens and bryophytes are absent or represented only by depauperate and/or sterile individuals. The relative proportions of hepatics to mosses is reversed compared with that normally found in rainforest and there is a much lower diversity in the bryophyte flora. In spite of these modifications, the flora of the rainforest fragment is quite distinct from that of the surrounding sclerophyll vegetation. The community acts as a refuge for many species and contributes significantly to the overall biodiversity of the area. The site is very important for biological conservation but the data suggest that the ecosystem is extremely fragile and must be protected from future disturbance if its rainforest flora is to survive. The new combination, Bacidia vallatula (Jatta) Kantvilas, is proposed, and the lichen Byssoloma subdiscordans (Nyl.) P. James is recorded from Tasmania for the first time.

Kirkpatrick, J. (1990). "A synusia-based mapping system for the conservation management of natural vegetation, with an example from Tasmania, Australia." Biological Conservation 53(2): 93-104.
Much forest and woodland vegetation in national parks worldwide consists of functionally and ecologically different assemblages of species: these synusiae may require different management regimes for their conservation and perpetuation. Vegetation mapping based on height, cover, dominance or floristics may not recognize synusiae with different management requirements. A method for mapping synusiae using colour aerial photographs to discriminate attributes of vegetation cover most relevant to maintaining biotic diversity is presented. The Western Tasmanian World Heritage Area (which varies from high altitude mosaic cushion heath and fjaeldmark communities to sedgeland, scrub, eucalypt and rain forest at lower altitudes) was mapped, and synusiae rated according to criteria of fire response, susceptibility to trampling, community and species rarity, and percentage cover already within secure nature reserves.

Kirkpatrick, J. and Gilfedder L (1995). "Maintaining integrity compared with maintaining rare and threatened taxa in remnant bushland in subhumid Tasmania." Biological Conservation 74(1): 1-8.
The native vegetation (woodland and forest) remnants in the agricultural country of subhumid Tasmania are important strongholds for regionally and globally rare and threatened plant species. A detailed survey of the best 100 of these remnants indicated that there was no relationship between the size, age and juxtaposition of the remnants and an index of rare and threatened species, either in the data set as a whole or in phytosociologically defined subsets. Rare and threatened species were found in remnantsof widely varying integrity, as indicated by native and exotic species richness and cover. Some species were only found in remnants that were of poor integrity. Efforts to preserve vegetation remnants need to be directed towards both those that contain rare and threatened species. No great coincidence can be expected, because the causes of maintenance of good condition are not necessarily the causes of survival of many rare and threatened taxa.

Minchin, P. R. (1989). "Montane vegetation of the Mt. Field massif, Tasmania: A test of some hypotheses about properties of community patterns." Vegetatio 83: 1-2.
Direct gradient analysis was applied to the montane vegetation of the Mt. Field massif, Tasmania. The hypotheses tested were that: (1) the ecological responses of species are generally of Gaussian form; (2) the modes of "minor" species have a uniform random distribution along gradients; (3) the modes of "major" species are evenly distributed; (4) the frequency distribution over species of modal abundance is either lograndom or lognormal; and (5) alpha diversity has a unimodal trend along environmental gradients. Hypothesis (1) was rejected: only 45% of species had response surface which appeared unimodal and symmetric. Hypotheses (2) and (4) were rejected for the full set of species, but each was supported for all but one of the structural groups. Although total alpha diversity had a complex trend surface, the patterns for the alpha diversities of each structural group were unimodal, in accordance with hypothesis (5). The results suggest that an adequate model of community variation along environmental gradients must take into account differences in response patterns between species groups.

Potts, B. M. and L. A. Pederick (1997). Morphology, phylogeny, distribution and genetic diversity of eucalypts. Diseases of Eucalypts and Their Management. P. J. e. a. Keane: in press. Sale, M. M., B. M. Potts, et al. (1996). "Molecular differentiation within and between Eucalyptus risdonii, E. amygdalina and their hybrids using RAPD markers." Aust. J. Bot no. 5: pp.
Random amplified polymorphic DNA (RAPD) studies of a natural hybrid swarm between Eucalyptus amygdalina Labill. and E. risdonii Hook.f. and nearby allopatric stands revealed that, despite clear morphological differences, all bands were shared between species. However, frequency differences revealed genetic divergence between species, populations within species, and individuals within populations. Variation was greatest between individuals within populations and lowest between species. For both species, the direction of variation which distinguished the two populations was in a different direction to that which separated the two species, suggesting population differences were not due to introgression but were the result of genetic isolation and/or strong localised selection. Several morphologically typical individuals with intermediate RAPD profiles were detected in the hybrid swarm and nearby allopatric samples of both species, suggesting that some cryptic introgression may be occurring. Controlled F sub(1) crosses generally had closer genetic affinity to E. risdonii, raising the possibility that some parents used may have been advanced generation hybrids. While natural hybrids selected for their intermediate leaf phenotype were usually also intermediate between the two species using RAPD markers, some deviated markedly toward E. risdonii. The study suggests that morphological appearance does not necessarily reflect genetic (RAPD) status and in some cases detectable RAPD differences between spatially close populations of the same species may be as great or greater than the differences between species.

Tyler, P. A. (1992). "A lakeland from the Dreamtime. The Second Founders' Lecture." Br. Phycol. J no. 4: pp.
The mountainous wilderness of Tasmania's World Heritage Area and contiguous land is a district of lakes and rivers of immense beauty and interest. A congruence of change in climate, relief, geology, soils and vegetation divides the island into western and eastern provinces. A jagged, western land of ancient rocks is mantled by peat-forming rainforest and sedgeland, where creeks run, unenriched with minerals, to topaz, red-window lakes. Eastwards lies a younger, flatter land, covered by sclerophyll forests of Eucalyptus . Minerals from the soluble rocks give the lakes distinctive chemistry compared with the brown dilute sea-water which drains the western quartz. No peat extracts stain these eastern lakes and they lie crystal clear with deep green windows. In this wilderness is a rich diversity of rare microscopic organisms. Some, long forgotten, have been rediscovered there. Others, new and novel, turn up with every cast of the net. Among the richest sites are the coastal, fresh-water lagoons which the Aboriginal inhabitants would have known intimately. Beside the Gordon River are small lakes of very special interest. Periodically, they are topped up with salt water from the estuary, keeping them meromictic, with brackish water below and fresh water above. Such lakes and their unusual features are uncommon in the world. They have social relevance. Because of their meromictic condition, their sediments hold an especially fine-resolution chronology of prehistoric climates and vegetational changes which shaped Aboriginal fortunes to the times of European contact. Tasmania must stand as one of the finest lake districts of the world. Perhaps nowhere else is there such limnological richness and diversity in so small an encompass as this island. Add to this its predominantly pristine nature, its uniqueness and its beauty, and we have in all respects a World Heritage wetland unsurpassed in this degraded world.

Whitham, T. G., P. A. Morrow, et al. (1994). "Plant hybrid zones as centers of biodiversity: The herbivore community of two endemic Tasmanian eucalypts." OECOLOGIA 1994 vol no. 4: pp.
We found the hybrid zone between Eucalyptus amygdalina and Eucalyptus risdonii to be a center of insect and fungal species richness and abundance. Of 40 taxa examined, 73% were significantly more abundant in the hybrid zone than in pure zones, 25% showed no significant differences, and 2% were most abundant on a pure host species. The average hybrid tree supported 53% more insect and fungal species, and relative abundances were, on average, 4 times greater on hybrids than on either eucalypt species growing in pure stands. Hybrids may act as refugia for rare species: 5 of 40 species were largely restricted to the hybrid zone. Also, 50% of the species coexisted only in the hybrid zone, making for unique species assemblages. Although hybrids support more species and greater abundances, all hybrids are not equal: 68% of the 40 taxa examined were significantly more abundant on one hybrid phenotype than another. While herbivore concentrations on F1 type intermediates were rare, concentrations were common on phenotypes resembling backcrosses either to E. amygdalina or E. risdonii. For specialist herbivores, the hybrid phenotype most heavily utilized appears to be determined by its phenotypic affinity to its host species. Generalists exhibit an overall greater abundance on hybrids, but are less likely to utilize one hybrid phenotype over another. Mechanistic explanations for these distributions are numerous and probably species specific, but are likely to include: increased genetic susceptibility of hybrids due to hybrid breakdown; increase in the hybrid zone resulting in greater plant susceptibility; and a greater diversity of resources in the hybrid zone which could support more species. Seed capsule production by hybrids and their parental species is negatively correlated with herbivory. However, it is difficult to determine whether herbivores cause this pattern as hybrids may have inherently lower sexual reproduction. Laws enacted to protect rare and endangered species do not include hybrids. We argue that a re-examination of our current "hybrid policy" is warranted. Plant hybrid zones are centers of plant evolution and speciation, sources of economically important plants and potential biocontrol agents, and, as our study suggests, also provide essential habitats for phytophagous communities.