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Eucalypt Forest (eucalypt + forest)
Selected AbstractsIs the matrix a sea?ECOLOGICAL ENTOMOLOGY, Issue 1 2005Habitat specificity in a naturally fragmented landscape Abstract., 1. Metapopulation and island biogeography theory assume that landscapes consist of habitat patches set in a matrix of non-habitat. If only a small proportion of species conform to the patch,matrix assumptions then metapopulation theory may only describe special cases rather than being of more general ecological importance. 2. As an initial step towards understanding the prevalence of metapopulation dynamics in a naturally fragmented landscape, the distribution of beetle species in three replicates of three habitat types was examined, including rainforest and eucalypt forest (the habitat patches), and buttongrass sedgeland (the matrix), in south-west Tasmania, Australia. 3. Ordination methods indicated that the buttongrass fauna was extremely divergent from the fauna of forested habitats. Permutation tests showed that the abundance of 13 of 17 commonly captured species varied significantly among habitats, with eight species confined to eucalypts or rainforest, and three species found only in buttongrass. Approximately 60% of species were confined to forested habitat implying that metapopulation theory has the potential to be very important in the forest,buttongrass landscape. 4. Although floristically the rainforest and eucalypts were extremely distinct, the beetle faunas from eucalypts and rainforests overlapped substantially. Therefore rainforest patches connected by eucalypt forest represent continuous habitat for most species. 5. Other studies report a wide range of values for the proportion of patch-specific species in fragmented landscapes. Understanding the environmental or historical conditions under which a high proportion of species become patch specialists would help to identify where spatial dynamic theory may be especially applicable, and where habitat loss and fragmentation poses the greatest threat to biodiversity. [source] Runoff generation from logged and burnt convergent hillslopes: rainfall simulation and modellingHYDROLOGICAL PROCESSES, Issue 5 2004Patrick N. J. Lane Abstract This paper reports results from field experiments and hydrological modelling on the dynamics of runoff generation in highly convergent parts of the landscape in a logged and burnt eucalypt forest in south-eastern Victoria, Australia. Large-scale rainfall simulation experiments were conducted to explore runoff generating mechanisms from harvested areas, and to assess the effectiveness of standard water quality protective measures, here a disturbed filter strip, in preventing accession of sediment to near-stream areas. We then examined the likely effects of varying antecedent moisture conditions on surface and subsurface runoff generating mechanisms. Very small volumes of surface runoff were generated only at very high rainfall intensity rates that exceeded a 100 year recurrence interval event during the simulated experiments. There was little or no identifiable impact of either compaction from logging operations or fire-induced hydrophobicity on surface infiltration or generation of surface runoff. Measured soil hydraulic properties and soil depths explained the paucity of surface runoff, and the dominance of subsurface storm flow as the prime runoff generating mechanism. Deep lateral subsurface flow was observed from the cut-face of a fire access track and into a streamhead downslope of the experimental plots. Water balance modelling using Topog_Dynamic indicated the conditions under which saturated overland flow in this environment could be generated are rare, but that care should be taken in siting of roads and tracks in lower parts of convergent landscapes. Copyright © 2004 John Wiley & Sons, Ltd. [source] Decomposition of litter in a dry sclerophyll eucalypt forest and a Pinus radiata plantation in southeastern AustraliaHYDROLOGICAL PROCESSES, Issue 17 2002R. H. Crockford This study of litter decomposition was part of an extensive project examining the partitioning of rainfall, the associated chemistry, and litterfall in a dry sclerophyll eucalypt forest and a Pinus radiata plantation in southeastern Australia. The eucalypt species studied were Eucalyptus rossii, E. mannifera and E. dives. The components tested were Pinus radiata needles, leaves of the three eucalypt species, and the bark of E. rossii and E. mannifera. During the first 16 weeks of the decomposition experiment there was a rapid decrease in the concentrations of potassium, magnesium, sodium and phosphorus; this was attributed to leaching. During this period, concentrations of nitrogen and calcium increased for most components. After this period, decomposition became the dominant process, during which the concentrations of most elements increased. By the end of the experiment there was, compared with the initial values, a marked reduction in concentrations of sodium, magnesium and potassium for all eucalypt and pine litter. Calcium concentrations increased through time, with eucalypt bark showing a mid-period decline. Phosphorus concentrations decreased for the eucalypt leaves but increased substantially for the pine needles and the eucalypt bark. For all components of both the eucalypts and pines, total nitrogen concentrations rose consistently throughout the decomposition period. This was attributed to the formation of nitrogen-substituted lignin, which was more resistant to decomposition than the other nitrogen-containing compounds, as well as some nitrogen being stored in the micro-organisms responsible for decomposition. Because of loss of fragmented litter from the litter bags after 16 weeks, the weight changes could not be confidently measured after this period. Copyright © 2002 John Wiley & Sons, Ltd. [source] Recovery of bird populations after clearfelling of tall open eucalypt forest in Western AustraliaJOURNAL OF APPLIED ECOLOGY, Issue 5 2001M.R. Williams Summary 1Increasing concern over the sustainable management of forested landscapes and the extent of forest clearance world-wide has led to a growing interest in the impacts of logging and associated habitat disturbance on biodiversity. 2We conducted an experimental study of the impact of clearfelling on birds of the karri Eucalyptus diversicolor forest in south-west Western Australia over a 17-year period, and a retrospective study of both clearfelled and naturally regenerated karri stands aged from 0 to 146 years. 3One-third of species still had significantly reduced abundance 14 years after disturbance ceased, although all affected species made limited use of regenerating forest. 4Multivariate analysis of changes in bird community structure showed that the effects of disturbance were still evident 14 years after clearfelling. Clearfelling may also have produced some temporary changes in community structure in adjacent unlogged forest. 5Species richness and total abundance of birds declined by 58% and 96%, respectively, in the first year after clearfelling, and 14 years after logging were still 17% and 55% below levels in adjacent undisturbed forest. During this early successional phase both measures increased as a simple function of stand age. Species richness of regrowth reached that of old-growth at 30,50 years and total abundance of all bird species in regrowth was similar to that of old-growth after approximately 70 years. 6Several bird species offer potential as indicators of the ecological sustainability of karri forest management. These species nest in large hollows in standing live trees (two cockatoo species) or have been slow to recolonize immature regrowth karri forests (six species). 7Post-hoc power analysis showed that even the long-term and intensive sampling employed in this study failed to detect declines in abundance of less than 80,90% for most bird species. For many uncommon species, trying to estimate changes in abundance is problematic and likely to require replication which is difficult to achieve in field situations where logged and unlogged forests are compared. Despite this, the present study identified some key impacts of forest clearfelling on bird communities, with implications both for the consequences of clearfelling of forests and the criteria for sustainable forest management. [source] No detectable impacts of frequent burning on foliar C and N or insect herbivory in an Australian eucalypt forestAPPLIED VEGETATION SCIENCE, Issue 3 2009Fiona J. Christie Abstract Question: What is the effect of frequent low intensity prescribed fire on foliar nutrients and insect herbivory in an Australian eucalypt forest? Location: Lorne State Forest (Bulls Ground Frequent Burning Study), mid-north coast, New South Wales, Australia. Methods: Eighteen independent sites were studied representing three experimental fire regimes: fire exclusion (at least 45 years), frequently burnt (every 3 years for 35 years) and fire exclusion followed by the recent introduction of frequent burning (two fires in 6 years). Mature leaves were collected from the canopy of Eucalyptus pilularis trees at each site and analysed for nutrients and damage by invertebrate herbivores. Results: Almost 75% of all leaves showed some signs of leaf damage. The frequency of past fires had no effect on carbon and nitrogen content of canopy leaves. These results were consistent with assessments of herbivore damage where no significant differences were found in the amount of invertebrate herbivory damage to leaves across fire treatments. Conclusions: This eucalypt forest displayed a high degree of resilience to both frequent burning and fire exclusion as determined by foliar nutrients and damage by insect herbivores. Fire frequency had no detectable ecological impact on this aspect of forest health. [source] Impacts of grazing, selective logging and hyper-aggressors on diurnal bird fauna in intact forest landscapes of the Brigalow Belt, QueenslandAUSTRAL ECOLOGY, Issue 6 2009TERESA J. EYRE Abstract The impact of forest management on diurnal bird assemblages and abundance was investigated in contiguous tracts of eucalypt forest in the Brigalow Belt Bioregion, south central Queensland. Sites were located across three levels of livestock grazing intensity and three levels of selective logging intensity within the most extensive habitat type, Corymbia citriodora -dominant forest. We recorded a high rate of incidence and large numbers of the hyper-aggressive noisy miner Manorina melanocephala (Passeriformes: Meliphagidae) at the majority of our survey sites, a phenomenon rarely reported in non-cleared landscapes. As shown by numerous studies in fragmented landscapes, the distribution of this species in our study had a substantial negative effect upon the distribution of small passerine species. Noisy miners exerted the strongest influence upon small passerine abundance, and masked any forest management effects. However, key habitat features important for small passerines were identified, including a relatively high density of large trees and stems in the midstorey. Selective logging appeared to exert a minimal effect upon noisy miner abundance, whereas grazing intensity had a profound, positive influence. Noisy miners were most abundant in intensively grazed forest with minimal midstorey and a low volume of coarse woody debris. Higher road density in the forest landscape also corresponded with increased numbers of noisy miners. Reduction in grazing pressure in Brigalow Belt forests has the potential to benefit small passerine assemblages across large areas through moderating noisy miner abundance. The strong relationship between noisy miners and small passerines suggests that noisy miner abundance could act as an easily measured indicator of forest condition, potentially contributing to monitoring of forest management outcomes. [source] Vegetation structure and biodiversity along the eucalypt forest to rainforest continuum on the serpentinite soil catena in a subhumid area of Central Queensland, AustraliaAUSTRAL ECOLOGY, Issue 3 2006RAY L. SPECHT Abstract The deep lateritic earths that cap the serpentinite outcrop in the Rockhampton , Marlborough area on the Tropic of Capricorn in Central Queensland have been eroded to expose the underlying ultramafic rock. Water-holding capacity of these nutrient-poor soils increases in a gradient from the skeletal soils to the deep lateritic earths and results in a continuum of structural formations from open-woodland to woodland to open-forest. A couple of closed-forest (rainforest) stands have developed where seepage into Marlborough Creek occurs throughout the year. Aerodynamic fluxes (frictional, thermal and evaporative) in the atmosphere as it flows over and through the vegetation influence the annual foliage growth in all strata in the continuum from skeletal soils to deep lateritic earths. The lateral growth of each plant is abraded so that the sum of the foliage projective covers of overstorey (FPCo) and understorey (FPCu) strata , that is ,(FPCo + FPCu) , remains constant throughout the serpentinite soil catena. As more water becomes available in the soil catena, the mineral nutrient levels in overstorey leaves increase, making developing leaves more vulnerable to insect attack. Although the number of leaves produced annually on each vertical foliage shoot in the overstorey increases along the soil-water gradient, ,(FPCo + FPCu) remains constant in all stands. The carbon isotope ratios (a measure of stomatal resistance) and leaf specific weights (LSWs) (a measure of the proportion of structural to cytoplasmic content in a leaf) of overstorey and understorey strata, however, are constant throughout the continuum. The well-watered rainforest pockets , where seepage occurs , form the end point of this serpentinite continuum. LSWs and carbon isotope ratios of the canopy trees are similar to those in the sheltered understorey in the eucalypt communities. A gradient of foliage attributes is observed from evergreen canopy trees (12 m) to subshrubs (2 m) in the sunlit life forms that compose the complex structure of the rainforest stands in the humid to subhumid climate of Central Queensland. As alpha diversity (number of species per hectare) is correlated with annual shoot growth per hectare, species richness along the serpentinite continuum is almost half that of nearby plant communities on medium-nutrient soils. The one to two eucalypt species per hectare are about a tenth of the number recorded on adjacent medium-nutrient soils. [source] A comparison of litter beetle assemblages (Coleoptera) in mature and recently clearfelled Eucalyptus obliqua forestAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 2 2006Susan C Baker Abstract, This study compares litter-dwelling beetles in mature wet eucalypt forest with those in young forest regenerated following clearfelling. The aims of the study were to determine the extent to which these forest ages support differing litter beetle assemblages, and to identify species characteristic of each age. Beetles were collected with pitfall traps in a spatially replicated study design to avoid confounding forest age and site differences. Three transects of traps were located in each of mature and young forest stands at four study sites. Beetle abundance was greatest in young forest, and young and mature forest supported distinctly different beetle assemblages. Of 37 commonly collected species, an indicator species analysis found 9 species characteristic of young logging regeneration, and 7 species characteristic of mature unlogged forest. These species could be useful in other Tasmanian studies concerning forest management impacts. Only two significant indicator species were carabids, suggesting that focusing only on carabids as indicators of forest management may be undesirable. [source] Habitat islands in fire-prone vegetation: do landscape features influence community composition?JOURNAL OF BIOGEOGRAPHY, Issue 5-6 2002Peter J. Clarke Aim, Location Landscape features, such as rock outcrops and ravines, can act as habitat islands in fire-prone vegetation by influencing the fire regime. In coastal and sub-coastal areas of Australia, rock outcrops and pavements form potential habitat islands in a matrix of fire-prone eucalypt forests. The aim of this study was to compare floristic composition and fire response traits of plants occurring on rocky areas and contrast them with the surrounding matrix. Methods Patterns of plant community composition and fire response were compared between rocky areas and surrounding sclerophyll forests in a range of climate types to test for differences. Classification and ordination were used to compare floristic composition and univariate analyses were used to compare fire response traits. Results The rock outcrops and pavements were dissimilar in species composition from the forest matrix but shared genera and families with the matrix. Outcrops and pavements were dominated by scleromorphic shrubs that were mainly killed by fire and had post-fire seedling recruitment (obligate seeders). In contrast, the most abundant species in the adjacent forest matrix were species that sprout after fire (sprouters). Main conclusions Fire frequency and intensity are likely to be less on outcrops than in the forest matrix because the physical barrier of rock edges disrupts fires. Under the regime of more frequent fires, obligate seeders have been removed or reduced in abundance from the forest matrix. This process may have also operated over evolutionary time-scales and resulted in convergence towards obligate seeding traits on outcrop fire shadows. In contrast, there may have been convergence towards sprouting in the forest matrix as a result of selection for persistence under a regime of frequent fire. [source] | ||||||||||