Academic literature on the topic 'Eucalyptus open woodlands'

Embedded in the extensive Eucalyptus open forests and savanna woodlands that dominate the northern Australian landscape are patches of monsoon rain forest and Acacia thickets and woodlands. In this paper, the vertebrate species composition of patches of lancewood (Acacia shirleyi) thickets and woodlands of the Northern Territory was compared with that of other environments of this region: pindan woodlands (A. eriopoda and A. tumida), gidgee woodlands (A. georginae), patches of monsoon rain forests and the extensive Eucalyptus open forests and woodlands. The vertebrate fauna of lancewood thickets is distinct for that of Eucalyptus open forests, and has fewer species. Differences in species composition and richness are associated with substantial differences in resource availability, with lancewood thickets having far less grass cover (and hence relatively few granivorous birds and rodents, but more ground-feeding insectivorous and omnivorous birds), fewer nectar-bearing flowers (and hence fewer nectarivorous birds) and lower structural and floristic diversity than Eucalyptus forests. There was little difference in species richness or total abundance between the three types of Acacia woodlands sampled. Lancewood thickets had fewer species than monsoon rain forests to coastal dry monsoon rain forests to inland dry monsoon rain forests to lancewood thickets to pindan woodlands to gidgee woodlands, in accord with the pronounced rainfall gradient of this region and with canopy cover and height. Within this broad continuum the three Acacia woodlands were most closely grouped. Species turnover along this gradient consisted of substantial decrease or loss of some foraging groups (e.g. frugivorous birds) or replacement of species within broad foraging groups. The faunal relationship of the monsoon rain forests and Acacia communities provides some support for considering these fire-sensitive environments as fragments of a formerly extensive continuum. Three species (Pomatostomus temporalis, Struthidea cinerea and Melanodryas cucullata), all ground-foraging insectivorous or omnivorous birds, were significantly associated with lancewood in this region, but all three have extensive ranges beyond this area.

Clearing of native vegetation and changes to disturbance regimes have resulted in dense regeneration of native trees and shrubs in parts of Australia. The conversion of open vegetation to dense woodlands may result in changes to the composition of plant communities and ecosystem function if structure, composition and function are tightly linked. Widespread clearing of the floodplain tree Eucalyptus coolabah subsp. coolabah (coolibah), in New South Wales, Australia, has led to state and federal listings of coolibah woodland as an endangered ecological community. Dense regeneration of coolibah in the mid 1970s, however, also resulted in its listing as an ‘invasive native species’ in NSW, meaning it can be legally cleared under certain conditions. Dense regeneration could be a novel state dissimilar to the threatened community or it could represent the next generation of coolibah woodlands and may contribute to passive restoration of heavily cleared landscapes. This study investigated if dense stands are distinct from remnant woodland by comparing floristic composition of the ground-storey community and top-soil properties of four coolibah vegetation states: derived grassland, derived degraded grassland, dense regeneration and remnant woodland. Ground-storey composition was found to overlap broadly among states regardless of tree density. Most species were common to all states, although dense regeneration contained characteristic woodland species that were absent from grasslands. The carbon : nitrogen ratio of the soil was significantly higher in dense regeneration and remnant woodland than in either of the grassland states, indicating that the woody states are broadly similar in terms of nutrient cycling. The study demonstrates that structurally different vegetation states (grasslands, woodlands and dense regeneration) are not associated with distinct plant communities. The results also suggest that grazing management has a more pronounced effect on ground-storey composition of plant communities than tree density and that well managed derived grasslands and dense regeneration are floristically similar to remnant woodlands. Since dense regeneration and remnant woodlands are not floristically distinct from one another, dense regeneration could contribute to the conservation of endangered coolibah woodlands in cleared agricultural landscapes.

Wilson and Bowman (1986) classified and mapped vegetation in a complex mosaic at Howard's Peninsula, Northern Territory. The relationship of bird distribution to this vegetation classification was considered through 10 repeat censuses of 5 replicate quadrats in each of 20 vegetation units. Censusing period was April-May. 118 bird species were recorded. Closed forests (3 units), mangroves (2 units) and swamplands (3 units) all had distinctive bird species compositions, but bird species showed a relatively poor relationship with the classification of woodland and grassland units. Eucalyptus woodlands regrowing after devastation by a cyclone in 1974 had similar bird species diversity and density to undamaged woodlands, though somewhat different bird species composition. Eucalyptus woodlands with a dense shrubby understorey had significantly greater bird density and species diversity than those with open or grassy understories and their bird species composition showed appreciable association with that of closed forests. Closed forest and, less so, mangrove units had highest diversity and density (despite their relatively small proportion in the study area and in the region generally), probably because they offered a wider range of foraging possibilities.

Temperate grassy woodlands were once widespread and dominant in many agricultural regions of south-eastern Australia. Most are now highly degraded and fragmented and exist within a context of broadscale landscape degradation. Greater understanding of natural processes in these woodlands is needed to benchmark management and restoration efforts that are now critical for their ongoing survival. We studied physical and chemical properties of topsoils from rare, little-grazed remnants of grassy Eucalyptus albens Benth. and E. melliodora Cunn. ex Schauer woodlands in central New South Wales and examined natural patterns in topsoil properties and understorey flora in relation to trees and canopy gaps. Topsoils were generally low in available macronutrients (nitrogen, phosphorus and sulfur), but were favourable for plant growth in most other measured characteristics. Topsoils beneath trees were notably more fertile than in open areas, particularly in total carbon, total nitrogen, available phosphorus, available potassium and salinity. Higher nutrient concentrations, particularly of available phosphorus, may have contributed to patterns in understorey dominants, with Themeda australis (R.Br.) Stapf predominating in open areas and Poa sieberiana Spreng. beneath trees. Trees were also associated with a higher native-plant richness, possibly resulting from their influence on the competitive dynamics of the dominant grasses. We discuss the implications of these interactions for the use of burning, grazing and slashing in woodland management and re-establishment of native grasses and trees in restoration efforts.

Russula scarlatina sp. nov. is a common sequestrate fungus found in the dry sclerophyll Eucalyptus woodlands of southeastern Australia. Basidiomata are hypogeous or sometimes emergent; they are scarlet in youth and become dark sordid red or brown with advanced age. Historically, this species would have been placed in the genus Gymnomyces, but in light of recent revisions in the taxonomy of sequestrate Russulaceae, we place it in the genus Russula. It is morphologically distinct from other sequestrate species of Russula because of its scarlet peridium and unusual cystidial turf in youth. It has been collected only in dry grassy woodlands and open forest habitats of southeastern Australia.

Conservation planning and population assessment for widely-distributed, but vulnerable, arboreal folivore species demands cost-effective mapping of habitat suitability over large areas. This study tested whether multispectral data from WorldView-3 could be used to estimate and map foliar digestible nitrogen (DigN), a nutritional measure superior to total nitrogen for tannin-rich foliage for the koala (Phascolarctos cinereus). We acquired two WorldView-3 images (November 2015) and collected leaf samples from Eucalyptus woodlands in semi-arid eastern Australia. Linear regression indicated the normalized difference index using bands “Coastal” and “NIR1” best estimated DigN concentration (% dry matter, R2 = 0.70, RMSE = 0.19%). Foliar DigN concentration was mapped for multi-species Eucalyptus open woodlands across two landscapes using this index. This mapping method was tested on a WorldView-2 image (October 2012) with associated koala tracking data (August 2010 to November 2011) from a different landscape of the study region. Quantile regression showed significant positive relationship between estimated DigN and occurrence of koalas at 0.999 quantile (R2 = 0.63). This study reports the first attempt to use a multispectral satellite-derived spectral index for mapping foliar DigN at a landscape-scale (100s km2). The mapping method can potentially be incorporated in mapping and monitoring koala habitat suitability for conservation management.

The results of a trapping and spotlighting survey in Victoria of the squirrel glider, Petaurus norfolcensis, coupled with examination of historical records showed that the species is restricted to the Riverine Plains, Northern Uplands and northern slopes of the Western Highlands. Within these regions squirrel gliders inhabit remnant woodlands or open-forests which have mature or mixed-age stands of more than one eucalypt species, or riparian open-forests of Eucalyptus camaldulensis. The mixed-species stands which support squirrel gliders invariably include gum-barked and high nectar-producing species including some which flower in winter. The riparian open forests typically contain mature Acacia dealbata which may provide an important winter carbohydrate source. The squirrel glider was often the only arboreal mammal detected at a site; if another species was present it was usually the common brushtail possum, Trichosurus vulpecula. Other petaurids rarely occurred at the same site. We suggest that in Victoria the ecological tolerance of the squirrel glider is narrow 'and that the species should be considered vulnerable because most of its habitat has been cleared for farming. Commercial exploitation of timber and grazing of stock in much of the remaining habitat places further stress upon the small, fragmented populations of this species.

Size/age distribution and vegetative regeneration were examined for 50 Eucalyptus niphophila Maiden & Blakely trees in each of eight subalpine sites in Kosciuszko National Park 1 year after the January–February 2003 bushfires. Trees sampled were generally large and mature, with an average of 2.5 trunks, lignotuber diameter of 54 cm and largest trunk diameter of 18 cm, with a few larger trees at all sites. Converting the girth of largest trunk into rough age estimates by using an existing regression formula gave an approximate minimum (~29 years), maximum (~186 years), median (~58 years) and average age of ~64 years (error of ~15 years). For trees with trunks after fire, 96.5% had lost all existing leaves. Nearly all trees (95%) had shoots from the lignotuber, but only 4.25% of trees had also epicormic shoots on trunks and stems. Size/age were related to some but not all measures of regeneration. In the future, existing trunks could senesce, with nearly all regrowth from the lignotubers. This could result in a change from open woodlands with large/old trees with a few trunks to closed woodlands of lower-growing trees with a mallee form.

Few temporal studies document vegetation change in Australian temperate grassy woodlands. Floristic and structural data were collected from 68 randomly located sites in the Queens Domain, an urban grassy woodland remnant, in 1974, 1984, 1994 and 2000 and a search made for rare species. Species of conservation significance were concentrated at highly disturbed sites, whereas vegetation types of conservation significance decreased in area as a result of increases in the numbers of Allocasuarina verticillata, which caused a change in many unmown areas from Eucalyptus viminalis grassy woodland to E. viminalis–A. verticillata woodland/forest or A. verticillata open/closed forest. Structural changes were associated with changes in species composition and an increase in native-species richness. Increases in tree cover occurred where fires were most frequent, possibly as a result of the lack of mammalian herbivores. The frequencies of herbs and annual grasses were strongly affected by precipitation in the month of sampling. Half of the species that showed a consistent rise or fall through time were woody plants, approximately twice the number expected. In the dataset as a whole, species-richness variables were largely explained by varying combinations of variables related to moisture availability, altitude and the incidence of mowing. The strongest influences on species composition were the same, although slope and time since the last fire also contributed to multiple regression and generalised linear models. Compositional stability was positively related to native-species richness, whereas high levels of exotic-species richness occurred at both low and high levels of native-species richness. The maintenance of native-plant biodiversity on the Domain requires such counterintuitive measures as the maintenance of exotic trees and the control of native trees, demonstrating the contingencies of conservation management in fragmented vegetation that consists of a mixture of native and exotic species.

Temperate grassy woodlands were once the dominant vegetation across many agricultural regions of south-eastern Australia, but most of these are now highly degraded and fragmented. Adequate conservation of these woodlands is dependent on successful ecological restoration; however, ecological barriers often limit ecosystem recovery once degrading processes are removed. To help identify these barriers, we used a state and transition framework to compare topsoils of little-disturbed (reference) and variously degraded remnants of grassy Eucalyptus albens Benth. and E. melliodora Cunn. ex Schauer woodlands. Topsoils of degraded remnants showed a repeated pattern, with the most compacted, most acidic and most depleted topsoils occurring in remnants dominated by Aristida ramosa R.Br. or Austrodanthonia H.P.Linder and Austrostipa scabra (Lindl.) S.W.L.Jacobs & J.Everett; the least compacted and most nutrient rich topsoils in remnants dominated by annual exotics; and generally intermediate topsoils in remnants dominated by Bothriochloa macra (Steud.) S.T.Blake or Austrostipa bigeniculata (Hughes) S.W.L.Jacobs & J.Everett. Surprisingly, topsoils beneath trees in reference sites (supporting Poa sieberiana Spreng.) were similar to topsoils supporting annual exotics for most soil properties. Chemical properties of topsoils from open areas of reference sites [supporting Themeda australis (R.Br.) Stapf] were usually intermediate and similar to Bothriochloa macra and Austrostipa bigeniculata topsoils. The most striking exception to these trends was for soil nitrate, which was extremely low in all reference topsoils and showed a high correlation with annual exotic abundance. We discuss the potential for positive feedbacks between soil nitrogen cycling and understorey composition and the need for intervention to assist possible nitrate-dependent transitions between annual and perennial understorey states. Dominant grasses, trees and annual weed abundance may be useful indicators of soil conditions and could inform selection of target sites, species and techniques for restoration projects.

Clearance of Eucalyptus woodlands has resulted in soil deterioration and lost agricultural production, due to wind erosion, salinity and soil acidity. Despite increasing efforts to reverse these trends through Landcare and other revegetation and agroforestry programs, there is a lack of experimentally-based information about the effects of trees on native pasture performance. The study was carried out in a temperate environment (Southern Tablelands, New South Wales). The altitude at the study sites ranged from 740 to 880m and the aspect at the experimental plots varied from SE to SW. The nearest site was 16 km from Canberra Airport and all sites were situated within similar rainfall isohyets as Canberra Airport. Thus climatic conditions were expected to be similar. Climate records at Canberra Airport indicate that January is the hottest month with mean maximum temperature of 27.7 �C and July is the coldest month with a maximum of 11.1 �C. Rainfall in the area ranges from 37.5 to 66.0 mm monthly average in June and October respectively. The main tree species in the study area were Eucalyptus pauciflora, E. melliodora and E. mannifera. Furthermore, Poa labillardieri, P. sieberiana, Themeda australis, Danthonia penicillata and Microlaena stipoides were the most abundant pasture species on the experimental plots. Species of clover (Trifolium spp.) were also abundant among the herbs. This study used pasture assessment techniques to quantify the effects of remnant patches of Eucalyptus open woodlands on the composition, quality and biomass production of herbaceous understorey vegetation. Microclimate and soil nutrients were also compared under trees and in the open. In addition, consumption by vertebrate grazers under Eucalyptus trees and in the open was compared. Tree density and basal area were compared with herbage standing crop. Remnant patches of Eucalyptus open woodlands modify the microclimate by reducing wind reaching the understorey vegetation. However no significant effects on ambient air temperature and relative humidity were recorded. The effect of trees on soil moisture was contingent to differences between the four sites and soil depth. Despite a 13% higher soil organic matter in the top 15 cm of soil under trees, soil total nitrogen and total phosphorus did not differ from that in the open. Surface soil pH values were lower (by 0.2 units) under the trees. No significant effect of trees on pasture species richness was found. However the classification of quadrats on the basis of species presence showed a distinction between species composition under trees and in the open at one of the four sites. vi The contribution of pasture species to total dry weight on plots under trees and in the open did depend on the particular species involved and was also contingent to differences between sites. However at the sites where Vulpia bromoides and Poa sieberiana were abundant, the two species dominated the biomass under trees. Whereas Microlaena stipoides var. stipoides dominated the biomass under trees at two sites and in the open at only one of the four sites. Pasture total N content differed between sites. Two of the sites had significantly higher (5.9% and 19.7%) N content under trees. On the contrary, pastures at one site contained 18.7% higher N content in the open. The total P content was 18% higher in pastures under trees. Overall, the pasture standing crop under trees was 15% less than in the open during August to May. Vertebrate grazers consumed about the same amount of pasture under the trees and in the open at the four experimental sites.