Forest of gestures : video installation and performance work

Invitation to contribute to Alexander Harrisions' program 'What's Coming' resulted in 'Forest of Gestures' a 3 channel video projection and installation with a live feed component

Antimicrobial activity of Eucalyptus tereticornis and comparison with daily life antibiotics

Eucalyptus is a fast growing tree which has shown to possess high degree of resistance against stressed environmental conditions. Eucalyptus tereticornis is widely cultivated in various parts of the world even in Pakistan. The medicinal properties of this tree reside in its oil. The main aim of our study is to check the antimicrobial activity of this valuable tree and to compare it with commercially available antibiotics. Eucalyptus tereticornis oil was extracted from the fresh leaves and branch tips during flowering season from surrounding areas of Hazara University, Pakistan. Different concentrations of oil were checked against Gram positive bacteria Staphylococcus aureus (ATCC 6538), Enterococcus faecalis (ATCC 49452), Gram negative bacteria including Escherichia coli (ATCC 25922), Salmonella typhimurium (ATCC 14028) and Pseudomonas aeruginosa (ATCC 27853), and also against yeast Candiada albican (ATCC 2091). The oil was significantly active against all the microbes studied. The activity of E. tereticornis oil was compared with standard antibiotics Ciprofloxacin (CIP-5 μg), Chloramphenicol (C-30 μg), Tetracycline (TE-30 μg) and Ampicillin (AMP 25-μg). The comparison gives the significant results and proves the antimicrobial efficiency of this valuable plant.

Effect of Phytophthora cinnamomi on the habitat utilization of Antechinus stuartii in a Victorian forest

Phytophthora cinnamomi (Cinnamon fungus) is a pathogenic soil fungus which infects plant communities along the south-eastern coast of Australia, and the south-western corner of Western Australia. The symptoms of this disease include chlorosis, death of branches (ie. ‘dieback’), retarded growth and the eventual death of infected plants. This leads to devastating effects upon plant communities by altering both the structural and floristic characteristics of these communities. Small mammal species are dependent on specific features of their habitat such as vegetation structure and floristics. This thesis investigated alterations to the habitat of the insectivorous marsupial mouse, Antechinus stuartii, due to the presence of P. cinnamomi. The study was undertaken in an area of an open forest in the Brisbane Ranges, Victoria. Significant changes were found in both the floristic composition and structure of the vegetation at study sites infected with P, cinnamomi, compared to uninfected sites. The habitat utilization by A. stuartii of uninfected and infected vegetation was investigated using live trapping and radio-telemetric techniques. Capture rates were higher at sites uninfected by P. cinnamomi, and both male and females selected areas free from infection. Home range areas of males were significantly larger than those of females as assessed by telemetry. Both sexes spent a high proportion of time in areas dominated by Xanthorrhoea australis (Austral grass tree). There were significant relationships between the abundance of A. stuartii and the denseness of vegetation above 1 metre in height, and in particular, the proportion of cover afforded by X. australis. There were no significant differences in the cover of Eucalyptus spp. between uninfected and infected sites, but there were significantly more nest hollows in infected areas. The abundance of invertebrates was examined using pitfall traps. There were no significant differences in the abundance of the larger invertebrate taxa at infected and uninfected sites, but higher abundances of some micro-invertebrate groups in infected areas were recorded. The most likely factors considered to be influential in the habitat selection of A. stuartii were vegetation structure, and the presence of X. australis. To assess whether these factors were important the leaves of X. australis were removed with a brushcutter, to mimic the early effects of infection with P. cinnamomi. Animals did not respond to the alteration of vegetation structure in the short term (3-4 days). Longer-term experiments are required to assess the habitat utilization of A. stuartii at different periods following habitat manipulation. The implications of the presence of P. cinnamomi on the conservation of fauna are discussed. The destructive nature of the pathogen, and the slow rate of recovery from the disease, means that P. cinnamomi can be considered a threatening process to plant communities and the fauna that reside within that habitat. Future management of this disease within natural areas must therefore be cognisant of the potential of P. cinnamomi to significantly affect faunal as well as vegetative communities.

Diet and habitat of the powerful owl (Ninox strenua) living near Melbourne

The diet of Powerful Owls (Ninox strenua) living at Christmas Hills, 35km north-east of Melbourne was examined by analysis of 686 regurgitated pellets collected over two years. An aid was also developed to help identify potential mammalian prey species based on hair and skeletal characteristics. The following features were found to be most useful in distinguishing between the three species of arboreal marsupials - Common Ringtail Possum (Pseudocheirus peregrinus), Common Brushtail Possum (Trichosurus vulpecula) and Sugar Glider (Petaurus breviceps): - Cross-sectional width of primary guard hairs. - The size and shape of the nasal, frontal, parietal and squamosal bones of the skull. - Dentition. The size and shape of the upper incisor, canine and premolar teeth. The size and shape of the lower incisor and premolar teeth. - The size of the humerus. The Sugar Glider has a much smaller humerus than that of the Common Ringtail Possum and the Common Brushtail Possum. In the Common Brushtail Possum the entepicondyle ends in a very sharp point but the Common Ringtail Possum this point is not as sharp. - The Common Ringtail Possum’s femur has a very prominent trochanter which projects further than that in the Common Brushtail Possum. The femur of the Sugar Glider is distinguished by having a very large depression between the condyle and the trochanter. - The Common Brushtail Possum’s scapula has a narrower lower blade (relative to length) than that in the Common Ringtail Possum. The scapula of the Sugar Glider is smaller in size than that of the other two possums.The pelvic girdle Of the Common Brushtail Possum has a much wider ischium than those of the Common Brushtail Possum and the Sugar Glider. The ilium of the Sugar is much narrower and smaller than that of the other two possums Mammalian prey was found in 89%, insects in 13% and birds in 10% of the pellets. Of the mammals, Common Ringtail Possums occurred most frequently in the pellets over the year. There was no seasonal difference in the frequency of occurrence of Common Ringtail Possums and Sugar Gliders in pellets. However, Common Brushtail Possums were more likely to be taken in spring than in the other seasons. More adult Common Ringtail Possums were taken as prey than were other age classes over the year, except in summer when high numbers of young were consumed by the owls. The habitat of the Powerful Owl was examined by ground surveys and spotlight surveys in sixteen sites within the Warrandyte-Kinglake Nature Conservation Link. Four categories of survey sites were chosen with the following features. Category A - Sites with a dense understorey of shrubs and small trees, as well as many old trees (>10/ha) which might be suitable for nest hollows. Category B - Sites which lacked a dense understorey of shrubs and small trees and containing few or no old trees suitable for nest hollows. Category C - Sites with a dense understorey of shrubs and small trees but containing few or no old trees suitable for nest hollows. Category D - Sites which lacked a dense understorey of shrubs and small trees but having old trees (>10/ha) which might be suitable for nest hollows. High prey densities strongly correlated with the presence of hollows at these sites. In the light of the results, management recommendations were made for the future conservation of the Powerful Owls living at Christmas Hills. The following recommendations were particularly important: 1. Cleared or semi - cleared land within the Warrandyte Kinglake Nature Conservation Link be revegetated using indigenous species of eucalypts and waffles in order to provide a contiguous native forest corridor for the movement of possums and gliders between the Yarra River Valley and the Kinglake Plateau. 2. Continued planting of Eucalyptus spp. and Acacia spp. in the forested areas of the Warrandyte-Kinglake Nature Conservation Link. 3. Continued protection of healthy living trees to provide a continuous supply of hollow trees. 4. No falling of dead standing trees for firewood collecting as these can provide nest hollows for prey species of the Powerful Owl.

Application of SWAT to model the water balance of the Woady Yaloak River catchment, Australia

The widespread land use changes that are expected to occur across the Corangamite region in southwest Victoria, Australia, have the potential to significantly alter the water balance of catchments. Adoption of the Soil and Water Assessment Tool (SWAT), which is a long-term water balance model, as a tool for predicting land use change impacts on catchment water balance for the Corangamite region is currently being considered. This paper describes the initial application of SWAT to the Woady Yaloak River catchment, located within the Corangamite region, to carry out an evaluation of its abilities for simulating the long-term water balance dynamics of the catchment. The performance of the model for predicting runoff at annual and monthly time scales was found to be very good. The excessive recharge of the shallow aquifer that occurred during winter, despite the subsoil being relatively impermeable, ultimately contributed to overestimation of baseflow and underestimation of interflow. The actual evapotranspiration from hydrologic response units (HRU s) containing eucalyptus trees was significantly less than that from HRUs containing pasture, a problem attributed to the incorrect simulation of Leaf Area Index (LAI) and biomass by the model for mature stands of eucalyptus trees and also to assigning inadequate values for two parameters that directly influence evapotranspiration. SWAT has very good potential for being used as tool to study land use change impacts across the Corangamite region provided that several modifications are made to the model to overcome some of the shortcomings and deficiencies that were identified in this initial application.

Failure to respond to food resource decline has catastrophic consequences for koalas in a high-density population in Southern Australia

Understanding the ability of koalas to respond to changes in their environment is critical for conservation of the species and their habitat. We monitored the behavioural response of koalas to declining food resources in manna gum (Eucalyptus viminalis) woodland at Cape Otway, Victoria, Australia, from September 2011 to November 2013. Over this period, koala population density increased from 10.1 to 18.4 koalas.ha-1. As a result of the high browsing pressure of this population, manna gum canopy condition declined with 71.4% manna gum being completely or highly defoliated in September 2013. Despite declining food resources, radio collared koalas (N = 30) exhibited high fidelity to small ranges (0.4-1.2 ha). When trees became severely defoliated in September 2013, koalas moved relatively short distances from their former ranges (mean predicted change in range centroid = 144 m) and remained in areas of 0.9 to 1.0 ha. This was despite the high connectivity of most manna gum woodland, and close proximity of the study site (< 3 km) to the contiguous mixed forest of the Great Otway National Park. Limited movement had catastrophic consequences for koalas with 71% (15/21) of radio collared koalas dying from starvation or being euthanased due to their poor condition between September and November 2013.

Successional changes in feeding activity by threatened cockatoos in revegetated mine sites

Provision of key habitat resources is essential for effectively managing species that have specific ecological requirements and occur in production landscapes. Threatened black cockatoos in the jarrah (Eucalyptus marginata) forest of Western Australia have a wide range, so their conservation requires support from all land tenures, not just reserves. Mining in the jarrah forest temporarily removes cockatoo feeding habitat, so it is important to understand how cockatoos exploit revegetated areas for food resources. Aims We aimed to determine whether there were successional patterns in cockatoo feeding activity in revegetation aged from 4 to 23 years at three mine sites in the jarrah forest in south-Western Australia. Methods We surveyed 232 plots in revegetation to document (1) structural and floristic variation in vegetation across mine sites and revegetation ages, (2) differences in cockatoo feeding activity across mine sites and revegetation ages on the basis of feeding residues and (3) any edge effect reflecting preferential use of vegetation at the interior or exterior of mine pits. We also documented the frequency of occurrence of cockatoo food plants and feeding residues in 480 plots in unmined forest to compare with revegetated areas. Key results Marri (Corymbia calophylla) and jarrah were commonly consumed in unmined forest and Banksia and Hakea species were also fed on to a lesser extent. Revegetated mine pits provided food within 4 years and continued to do so up until the oldest plots studied (23 years). The relative importance of food plants shifted from proteaceous species in young revegetation to myrtaceous species in intermediate to older revegetation. However, extent of feeding on myrtaceous species in older revegetation did not equate to feeding rates in unmined forest, with lower frequencies recorded in revegetation. Conclusions Black cockatoos fed in revegetation at all three mine sites, despite variations in vegetation age, structure and floristics. Feeding on proteaceous and myrtaceous food plants occurred within 4 and 7 years of revegetation being established, respectively, indicating that some food resources are restored quickly after mining disturbance of the jarrah forest. Implications Our results emphasise the importance of monitoring fauna recolonisation over appropriate time scales, to understand how successional processes in revegetation influence fauna population persistence in production landscapes.

Minimum spanning trees for valley and ridge characterization in digital elevation maps

Texture synthesis employs neighbourhood matching to generate appropriate new content. Terrain synthesis has the added constraint that new content must be geographically plausible. The profile recognition and polygon breaking algorithm (PPA) [Chang et al. 1998] provides a robust mechanism for characterizing terrain as systems of valley and ridge lines in digital elevation maps. We exploit this to create a terrain characterization metric that is robust, efficient to compute and is sensitive to terrain properties.

Terrain regions are characterized as a minimum spanning tree derived from a graph created from the sample points of the elevation map which are encoded as weights in the edges of the graph. This formulation allows us to provide a single consistent feature definition that is sensitive to the pattern of ridges and valleys in the terrain Alternative formulations of these weights provide richer characteristicmeasures and we provide examples of alternate definitions based on curvature and contour measures.

We show that the measure is robust, with a significant portion derived directly from information local to the terrain sample. Global terrain characteristics introduce the issue of over- and underconnected valley/ridge lines when working with sub-regions. This is addressed by providing two graph construction strategies, which respectively provide an upper bound on connectivity as a single spanning tree, and a lower bound as a forest of trees.

Efficient minimum spanning tree algorithms are adapted to the context of terrain data and are shown to provide substantially better performance than previous PPA implementations. In particular, these are able to characterize valley and ridge behaviour at every point even in large elevation maps, providing a measure sensitive to terrain features at all scales.

The resulting graph based formulation provides an efficient and elegant algorithm for characterizing terrain features. The measure can be calculated efficiently, is robust under changes of neighbourhood position, size and resolution and the hybrid measure is sensitive to terrain features both locally and globally.

The influence of time since fire and distance from fire boundary on the distribution and abundance of arboreal marsupials in Eucalyptus regnans-dominated forest in the Central Highlands of Victoria

The impact of time since fire after two consecutive wildfires 44 years apart (1939 and 1983) within the same area, and the distance from the fire boundary «100 m or 500-2000 m), were investigated in relation to the distribution and abundance of arboreal marsupials in 1994. Arboreal marsupials were censused by stagwatching and spotlighting in two relatively young age classes of mountain ash (Eucalyptus regnans) dominated forest in the Central Highlands of Victoria. Five species of arboreal marsupial were detected, but only three were detected in sufficient numbers to determine habitat preferences. Petauroides volans (greater glider) was statistically more abundant in 1939 regrowth forests, while Trichosurus caninus (mountain brushtail possum) showed no significant preference for either age class of forest. All but one record of Gymnobelideus leadbeateri (Leadbeater's possum) came from young forest, though the effect of age-class was not statistically significant. Distance from fire boundary explained little or no variation in mammal distribution or abundance. While the actual number of hollow-bearing trees was similar in both age classes of forest, the long-term lifespan of hollow-bearing trees in more recently burnt forest is predicted to be lower than in unburnt or not recently burnt forest. Post-fire salvage logging following the 1983 wildfires appears to have reduced the number of hollow-bearing trees at sites burnt in 1983.

The use of traits to interpret responses to large scale - edge effects: a study of epigaeic beetle assemblages across a Eucalyptus forest and pine plantation edge

Context: Edge effects due to habitat loss and fragmentation have pervasive impacts on many natural ecosystems worldwide. Objective: We aimed to explore whether, in tandem with the resource-based model of edge effects, species feeding-guild and flight-capacity can help explain species responses to an edge. Methods: We used a two-sided edge gradient that extended from 1000 m into native Eucalyptus forest to 316 m into an exotic pine plantation. We used generalised additive models to examine the continuous responses of beetle species, feeding-guild species richness and flight-capable group species richness to the edge gradient and environmental covariates. Results: Phytophagous species richness was directly related to variation in vegetation along the edge gradient. There were more flight-capable species in Eucalyptus forest and more flightless species in exotic pine plantation. Many individual species exhibited multiple-peaked edge-profiles. Conclusions: The resource based model for edge effects can be used in tandem with traits such as feeding-guild and flight-capacity to understand drivers of large scale edge responses. Some trait-groups can show generalisable responses that can be linked with drivers such as vegetation richness and habitat structure. Many trait-group responses, however, are less generalisable and not explained by easily measured habitat variables. Difficulties in linking traits with resources along the edge could be due to unmeasured variation and indirect effects. Some species’ responses reached the limits of the edge gradient demonstrating the need to examine edge effects at large scales, such as kilometres.

Flowering ecology of a Box-Ironbark Eucalyptus community

Box-Ironbark forests occur on the inland hills of the Great Dividing Range in Australia, from western Victoria to southern Queensland. These dry, open forests are characteristically dominated by Eucalyptus species such as Red Ironbark E. tricarpa, Mugga Ironbark E. sideroxylon and Grey Box E. microcarpa. Within these forests, several Eucalyptus species are a major source of nectar for the blossom-feeding birds and marsupials that form a distinctive component of the fauna. In Victoria, approximately 83% of the original pre - European forests of the Box-Ironbark region have been cleared, and the remaining fragmented forests have been heavily exploited for gold and timber. This exploitation has lead to a change in the structure of these forests, from one dominated by large 80-100 cm diameter, widely -spaced trees to mostly small (≥40 cm DBH), more densely - spaced trees. This thesis examines the flowering ecology of seven Eucalyptus species within a Box-Ironbark community. These species are characteristic of Victorian Box-Ironbark forests; River Red Gum E. camaldulensis, Yellow Gum E. leucoxylon, Red Stringybark E. macrorhyncha, Yellow Box E. melliodora, Grey Box E. microcarpa, Red Box E. polyanthemos and Red Ironbark E. tricarpa. Specifically, the topics examined in this thesis are: (1) the floral character traits of species, and the extent to which these traits can be associated with syndromes of bird or insect pollination; (2) the timing, frequency, duration, intensity, and synchrony of flowering of populations and individual trees; (3) the factors that may explain variation in flowering patterns of individual trees through examination of the relationships between flowering and tree-specific factors of individually marked trees; (4) the influence of tree size on the flowering patterns of individually marked trees, and (5) the spatial and temporal distribution of the floral resources of a dominant species, E. tricarpa. The results are discussed in relation to the evolutionary processes that may have lead to the flowering patterns, and the likely effects of these flowering patterns on blossom-feeding fauna of the Box-Ironbark region. Flowering observations were made for approximately 100 individually marked trees for each species (a total of 754 trees). The flower cover of each tree was assessed at a mean interval of 22 (+ 0.6) days for three years; 1997, 1998 and 1999. The seven species of eucalypt each had characteristic flowering seasons, the timing of which was similar each year. In particular, the timing of peak flowering intensity was consistent between years. Other spatial and temporal aspects of flowering patterns for each species, including the percentage of trees that flowered, frequency of flowering, intensity of flowering and duration of flowering, displayed significant variation between years, between forest stands (sites) and between individual trees within sites. All seven species displayed similar trends in flowering phenology over the study, such that 1997 was a relatively 'poor' flowering year, 1998 a 'good' year and 1999 an 'average' year in this study area. The floral character traits and flowering seasons of the seven Eucalyptus species suggest that each species has traits that can be broadly associated with particular pollinator types. Differences between species in floral traits were most apparent between 'summer' and 'winter' flowering species. Winter - flowering species displayed pollination syndromes associated with bird pollination and summer -flowering species displayed syndromes more associated with insect pollination. Winter - flowering E. tricarpa and E. leucoxylon flowers, for example, were significantly larger, and contained significantly greater volumes of nectar, than those of the summer flowering species, such as E. camaldulensis and E. melliodom. An examination of environmental and tree-specific factors was undertaken to investigate relationships between flowering patterns of individually marked trees of E. microcarpa and E. tricarpa and a range of measures that may influence the observed patterns. A positive association with tree-size was the most consistent explanatory variable for variation between trees in the frequency and intensity of flowering. Competition from near-neighbours, tree health and the number of shrubs within the canopy area were also explanatory variables. The relationship between tree size and flowering phenology was further examined by using the marked trees of all seven species, selected to represent five size-classes. Larger trees (≥40 cm DBH) flowered more frequently, more intensely, and for a greater duration than smaller trees. Larger trees provide more abundant floral resources than smaller trees because they have more flowers per unit area of canopy, they have larger canopies in which more flowers can be supported, and they provide a greater abundance of floral resources over the duration of the flowering season. Heterogeneity in the distribution of floral resources was further highlighted by the study of flowering patterns of E. tricarpa at several spatial and temporal scales. A total of approximately 5,500 trees of different size classes were sampled for flower cover along transects in major forest blocks at each of five sample dates. The abundance of flowers varied between forest blocks, between transects and among tree size - classes. Nectar volumes in flowers of E. tricarpa were sampled. The volume of nectar varied significantly among flowers, between trees, and between forest stands. Mean nectar volume per flower was similar on each sample date. The study of large numbers of individual trees for each of seven species was useful in obtaining quantitative data on flowering patterns of species' populations and individual trees. The timing of flowering for a species is likely to be a result of evolutionary selective forces tempered by environmental conditions. The seven species' populations showed a similar pattern in the frequency and intensity of flowering between years (e.g. 1998 was a 'good' year for most species) suggesting that there is some underlying environmental influence acting on these aspects of flowering. For individual trees, the timing of flowering may be influenced by tree-specific factors that affect the ability of each tree to access soil moisture and nutrients. In turn, local weather patterns, edaphic and biotic associations are likely to influence the available soil moisture. The relationships between the timing of flowering and environmental conditions are likely to be complex. There was no evidence that competition for pollinators has a strong selective influence on the timing of flowering. However, as there is year-round flowering in this community, particular types of pollinators may be differentiated along a temporal gradient (e.g. insects in summer, birds in winter). This type of differentiation may have resulted in the co-evolution of floral traits and pollinator types, with flowers displaying adaptations that match the morphologies and energy requirements of the most abundant pollinators in any particular season. Spatial variation in flowering patterns was evident at several levels. This is likely to occur because of variation in climate, weather patterns, soil types, degrees of disturbance and biotic associations, which vary across the Box-Ironbark region. There was no consistency among sites between years in flowering patterns suggesting that factors affecting flowering at this level are complex. Blossom-feeding animals are confronted with a highly spatially and temporally patchy resource. This patchiness has been increased with human exploitation of these forests leading to a much greater abundance of small trees and fewer large trees. Blossom-feeding birds are likely to respond to this variation in different ways, depending upon diet-breadth, mobility and morphological and behavioural characteristics. Future conservation of the blossom-feeding fauna of Box-Ironbark forests would benefit from the retention of a greater number of large trees, the protection and enhancement of existing remnants, and revegetation with key species, such as E. leucoxylon, E. microcarpa and E. tricarpa. The selective clearing of summer flowering species, which occur on the more fertile areas, may have negatively affected the year-round abundance and distribution of floral resources. The unpredictability of the spatial distribution of flowering patches within the region means that all remnants are likely to be important foraging areas in some years.

Ecological value of riparian zones to birds in forest landscapes

Riparian zones are a characteristic component of many landscapes throughout the world and increasingly are valued as key areas for biodiversity conservation. Their importance for bird communities has been well recognised in semi-arid environments and in modified landscapes where there is a marked contrast between riparian and adjacent non-riparian vegetation. The value of riparian zones in largely intact landscapes with continuous vegetation cover is less well understood. This research examined the importance of riparian habitats for avifauna conservation by investigating the ecological interactions contributing to the pattern of bird assemblages in riparian and adjacent non-riparian habitats. Specifically, the focus is on the bird assemblages of riparian zones and those of adjacent non-riparian vegetation types and the influence that associated differences in resource availabilities, habitat structure and conditions have on observed patterns. This study was conducted in the foothill forests of the Victorian Highlands, south-east Australia. Mixed-species eucalypt (genus Eucalyptus) forests dominate the vegetation of this region. Site selection was based on the occurrence of suitable riparian habitat interspersed within extensive, relatively undisturbed (i.e. no recent timber harvesting or fire events) forest mosaics. A series of 30 paired riparian and non-riparian sites were established among six stream systems in three forest areas (Bunyip State Park, Kinglake National Park and Marysville State Forest). Riparian sites were positioned alongside the stream and the non-riparian partner site was positioned on a facing slope at a distance of approximately 750 m. Bird surveys were carried out during 29 visits to each site between July 2001 and December 2002. Riparian sites were floristically distinct from non-riparian sites and had a more complex vegetation structure, including a mid-storey tree layer mostly absent from non-riparian sites, extensive fine litter and coarse woody debris, and dense ground-layer vegetation (e.g. sedges and ground ferns). The characteristic features of non-riparian habitats included a relatively dense canopy cover, a ground layer dominated by grasses and fine litter, and a high density of canopy-forming trees in the smaller size-classes. Riparian zones supported a significantly greater species richness, abundance and diversity of birds when compared to non-riparian habitats. The composition of bird assemblages differed significantly between riparian and non-riparian habitats, with riparian assemblages displaying a higher level of similarity among sites. The strongest contributors to observed dissimilarities between habitat types included species that occurred exclusively in either habitat type or species with large contrasts in abundance between habitat types. Much of the avifauna (36%) of the study area is composed of species that are common and widespread in south-east Australia (i.e. forest generalists). Riparian habitats were characterised by a suite of species more typical of wetter forest types in south-east Australia and many of these species had a restricted distribution in the forest mosaic. Some species (7%) occurred exclusively in riparian habitats (i.e. riparian selective species) while others (43%) were strongly linked to these habitats (i.e. riparian associated species). A smaller proportion of species occurred exclusively (2%) in non-riparian habitats (i.e. non-riparian selective species) or were strongly linked to these habitats (10%; i.e. non-riparian associated species). To examine the seasonal dynamics of assemblages, the variation through time in species richness, abundance and composition was compared between riparian and non-riparian sites. Riparian assemblages supported greater richness and abundance, and displayed less variation in these parameters, than non-riparian assemblages at all times. The species composition of riparian assemblages was distinct from non-riparian assemblages throughout the annual cycle. An influx of seasonal migrants elevated species richness and abundance in the forest landscape during spring and summer. The large-scale movement pattern (e.g. coastal migrant, inland migrant) adopted by migrating species was associated with their preference for riparian or non-riparian habitats in the landscape. Species which migrate north-south along the east coast of mainland Australia (i.e. coastal migrants) used riparian zones disproportionately; eight of eleven species were riparian associated species. Species which migrate north-south through inland Australia (i.e. inland migrants) were mostly associated with non-riparian habitats. The significant differences in the dynamics of community structure between riparian and non-riparian assemblages shows that there is a disproportionate use of riparian zones across the landscape and that they provide higher quality habitat for birds throughout the annual cycle. To examine the ecological mechanisms by which riparian assemblages are richer and support more individual birds, the number of ecological groups (foraging, nest-type and body mass groups) represented, and the species richness of these groups, was compared between riparian and non-riparian assemblages. The structurally complex vegetation and distinctive habitat features (e.g. aquatic environments, damp sheltered litter) provided in the riparian zone, resulted in the consistent addition of ecological groups to riparian assemblages (e.g. sheltered ground – invertebrates foraging group) compared with non-riparian assemblages. Greater species richness was accommodated in most foraging, nest-type and body mass groups in riparian than non-riparian assemblages. Riparian zones facilitated greater richness within ecological groups by providing conditions (i.e. more types of resources and greater abundance of resources) that promoted ecological segregation between ecologically similar species. For a set of commonly observed species, significant differences in their use of structural features, substrates and heights were registered between riparian and non-riparian habitats. The availability and dynamics of resources in riparian and non-riparian habitats were examined to determine if there is differential availability of particular resources, or in their temporal availability, throughout the annual cycle. Riparian zones supported more abundant and temporally reliable eucalypt flowering (i.e. nectar) than non-riparian habitats throughout the annual cycle. Riparian zones also supported an extensive loose bark resource (an important microhabitat for invertebrates) including more peeling bark and hanging bark throughout the year than at non-riparian sites. The productivity of eucalypts differed between habitat types, being higher in riparian zones at most times for all eucalypts combined, and for some species (e.g. Narrow-leaved Peppermint Eucalyptus radiata). Non-riparian habitats provided an abundant nectar resource (i.e. shrub flowering) at particular periods in the annual cycle. Birds showed clear relationships with the availability of specific food (i.e. nectar) and foraging resources (i.e. loose bark). The demonstration of a greater abundance of resources and higher primary productivity in riparian zones is consistent with the hypothesis that these linear strips that occupy only a small proportion of the landscape have a disproportionately high value for birds. Riparian zones in continuous eucalypt forest provide high quality habitats that contribute to the diversity of habitats and resources available to birds in the forest mosaic, with positive benefits for the landscape-level species pool. Despite riparian and non-riparian habitat supporting distinct assemblages of birds, strong linkages are maintained along the riparian-upslope gradient. Clearly, the maintenance of diverse and sustainable assemblages of birds in forest landscapes depends on complementary management of both riparian and non-riparian vegetation.

Other communities : Box mistletoe (Amyema miquelii) parasitism is not detrimental to the health of grey box (Eucalyptus microcarpa) trees at a regional scale

Mistletoes are hemiparasites that occur worldwide in many types of forest, woodland and shrubland ecosystems (Watson 2001). Some species are regarded as pests due to their detrimental effects on host species (Hawksworth 1983; Reid & Yan 2000). Heavy infestations can affect the growth, productivity and form of host trees, and may cause host death (Reid et al. 1994; Shaw et al.2004, 2008). In south-eastern Australia, mistletoes often are visibly obvious in trees along roadsides, in paddocks and on the margins of open forests; and concerns have been expressed about their potentially detrimental effects on host trees.Despite this, little quantitative information is available on the effects of mistletoes on tree health and mortality (Reid et al. 1994). Are detrimental effects widespread or localized? A first step is to assess whether trees parasitized by mistletoe are less healthy than those without such parasites. Here, we investigate the relationship between parasitism by Box Mistletoe (Amyema miquelii (Lehm. ex Miq.) Tiegh.), a common species in south-eastern Australia, and the health of trees of a widespread host species, Grey Box (Eucalyptus microcarpa (Maiden) Maiden), across a large geographic region.