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Aim: There is widespread support that species richness increases with the available energy of an ecosystem, but the mechanisms underlying this driver of biodiversity patterns remain elusive. We evaluated gradients of functional diversity to test whether the higher species richness of productive, structurally diverse environments is due to a greater range of niches being supported by the abiotic conditions present (environmental filtering), greater availability of biotic resource and habitat niches (more niches) or increasing functional similarity of species (niche packing). Location: Australia. Taxon: Birds and mammals. Methods: We used structural equation modelling to evaluate the relative contributions of climatic harshness (actual evapotranspiration, AET) and the availability of resource (gross primary productivity, GPP) and habitat (tree height) niches on taxonomic richness and functional richness, dispersion and evenness. We performed parallel analyses within 15 bioclimatic zones and continentally to evaluate the scaling of biodiversity gradients and the shifting balance between niche‐based mechanisms along environmental gradients. Results: All continental diversity gradients were primarily associated with energy variables, but while species richness of both taxa and all functional diversity measures of bird assemblages increased with AET, mammal functional diversity was more strongly associated with GPP gradients. Results were more variable at the regional scale, but species richness gradients along tree height (birds and mammals) and GPP (mammals) within bioclimatic zones tended not to be paralleled by increases in functional richness or dispersion. Main Conclusions: The niche‐based explanations of biodiversity gradients varied in importance with scale, position on environmental gradients and taxonomic group. At the continental extent, bird biodiversity gradients were structured by environmental filtering by climatic harshness, while mammal biodiversity was related to the increasing availability of resource niches with increasing productivity. Niche packing was more prominent at the regional scale, especially in bioclimatic zones where productivity and vegetation height were less limiting, and in mammal assemblages, suggesting that biodiversity patterns scale differently for birds and mammals. [ABSTRACT FROM AUTHOR]

In wild bird populations, the structure of vegetation around nest‐sites can influence the risk of predation of dependent offspring, generating selection for nest‐sites with vegetation characteristics associated with lower predation rates. However, vegetation structure can be difficult to quantify objectively in the field, which might explain why there remains a general lack of understanding of which characteristics are most important in determining predation rates. Airborne laser scanning (ALS) offers a powerful means of measuring vegetation structure at unprecedented resolution. Here, we combined ALS with 11 years of breeding data from a wild population of superb fairy‐wrens Malurus cyaneus in southeastern Australia, a species which nests relatively close to the ground and has high rates of nest and fledgling predation. We derived structural measurements of understorey (0–8 m) vegetation from a contiguous grid of 30 × 30 m resolution cells across our c. 65 hectares study area. We found that cells with nests (nest‐cells) differed in their understorey vegetation structure characteristics compared to unused cells, primarily in having denser vegetation in the lowest layer of the understorey (0–2 m; the 'groundstorey' layer). The average height of understorey vegetation was also lower in cells with nests than in those without nests. However, relationships between understorey vegetation structure characteristics and breeding performance were mixed. Nest success rates decreased with higher volumes of groundstorey vegetation, as did fledgling survival rates, though only in nest‐cells with lower height vegetation. Our results indicate that ALS can identify vegetation characteristics relevant for superb fairy‐wren nest‐site selection, but that nesting preferences are not beneficial under current predation pressures. The study illustrates the potential for using ALS to investigate how ecological conditions affect behaviour and life‐histories in wild animal populations. [ABSTRACT FROM AUTHOR]

Aims: The effect of spatial scale on the location and abundance of species has long been a major topic of interest in ecology. Accounting for key drivers at multiple scales is critical for rigorous description of patterns of species distribution and biodiversity change. We quantified the effects of potential drivers of bird occupancy across a geographically dispersed, but heavily disturbed and fragmented ecosystem. Location: Threatened Box‐Gum Grassy Woodlands in south‐eastern Australia, which stretch across 9° of latitude (~900 km). Taxon: Birds (Class Aves). Methods: We grouped data from four monitoring studies of birds that spanned 10–22 years in Box‐Gum Grassy Woodlands. We then employed joint species distribution modelling to investigate multi‐species responses to environmental drivers measured at patch, landscape and regional scales, and selected combinations of all three. Results: We show that in Box‐Gum Grassy Woodlands: vegetation structure influences bird occupancy beyond the presence of the despotic Noisy Miner (Manorina melanocephala); woodland cover is more important than vegetation productivity and topographic position; bird occupancy is sensitive to a combination of average climate, seasonality, and summer and winter extremes; and there is limited redundancy between drivers of bird occupancy at different scales. Species differ most in their response to presence of the Noisy Miner, high summer temperatures and nearby woodland cover. Main Conclusions: Quantifying the influence of environmental drivers that act at different spatial scales is valuable for understanding patterns of bird species occurrence. Fine‐scale studies can benefit from considering the climate and biogeographical context in which the research occurs. Conversely, large‐scale studies should recognise that downscaling species occupancy projections from continental to patch scales requires careful consideration of the role of patch‐scale vegetation. [ABSTRACT FROM AUTHOR]

Summary: Native herbivores can affect the structure and function of plant communities. Most studies of overabundant native herbivore effects on native plant communities in south‐eastern Australia are observational or compare, at most, two levels of herbivory (ambient vs. none), and typically do not separate out the impacts of multiple herbivores. Several studies show that high densities of herbivores had mostly negative effects on plant regeneration and growth. These effects were usually attributed to palatability differences amongst plant species. Surprisingly, few studies have quantified vegetation responses across a gradient of herbivore density, and impacts on plant communities (i.e. species richness, composition, beta diversity) have not been well studied. Hence, there remains a need to better understand how native herbivores impact plant communities at different densities. [ABSTRACT FROM AUTHOR]

Fire regimes have a major influence on biodiversity in many ecosystems around the globe, yet our understanding of the longer‐term response of fauna is typically poor. We sampled bats with ultrasonic detectors in three different years in dry sclerophyll forests of south‐eastern Australia in a long‐term, management‐scale experiment. Frequent low‐intensity burning (every 2 or 4 years plus unburnt) and logging (with 33% retention of the original unlogged tree basal area) were manipulated to assess their effects on bats. We found that both the fire regime and regrowth after logging influenced the local bat community. The routine burning treatment (burnt every 4 years) in unlogged forest was consistently related to higher total bat activity (2–3 times) and species richness when compared to unburnt controls and logging treatments. Foraging activity was more variable, but it was typically lowest in Unlogged Unburnt Controls. These patterns were evident at both the detector site scale and the block scale and were probably due to a reduction in understorey stem density with burning, especially in unlogged forest. Bat activity was significantly lower across the entire study area (including controls) in 1 year, when sampling occurred within 6 months of burning. When pooled across burning treatments, unlogged forest supported higher bat activity (1.5 times) and species richness than logged forest (12‐ to 17‐year‐old regrowth), again most likely because of a negative association with high stem density in regrowth after logging. We conclude that low‐intensity burning had positive benefits for echolocating bats, most notably in unlogged forest. However, careful planning is required to generate heterogeneous vegetation patterns that are likely to be most suitable for a range of taxa. [ABSTRACT FROM AUTHOR]

Operational forest fire simulation models typically incorporate reduction factors to modify winds forecast to meteorological standards for open environments so that they characterise the sub-canopy winds that drive fire spread. While these reduction factors may vary between forest types, they are typically static; wind reduction is constant regardless of height within the sub-canopy space and forecast wind speed. The validity of using static wind reduction factors was investigated by measuring sub-canopy horizontal wind speeds at different heights in seven vegetation types across Victoria, Australia. We found that the vertical wind profiles were highly variable, with substantial variation in response to height above ground and the prevailing (open environment) wind speed. The combined effect of these influences meant that within each forest type, wind reductions can vary by factors of greater than four. As wind is proportional to fire spread in most simulation models, this high level of variation will be carried through to wildfire predictions and may have consequences for decision making. We believe further investigation into the use of wind reduction factors is warranted, in particular the potential to recognise dynamic wind profiles. • Forest fire simulation models use wind reduction factors to reduce open area winds. • Forest wind profiles can be complex due to vegetation structure. • The relationship between sub-canopy vegetation structure and wind was investigated. • Forest wind speeds varied with height, vegetation structure and open wind speeds. • Fire predictions could be improved by considering dynamic forest winds. [ABSTRACT FROM AUTHOR]

It is well known that the recovery of abandoned tropical pastures to secondary rainforest benefits from the arrival of seeds from adjacent rainforest patches. Less is known, however, about how the structural attributes of adjacent rainforest (e.g. tree density, canopy cover and tree height) impact seed rain patterns into abandoned pastures. Between 2011 and 2013, we used seed traps and ground seed surveys to track the richness and abundance of rainforest seeds entering abandoned pastures in Australia's wet tropics. We also tested how seed rain diversity is related to the distance from forest, the proportion of forest cover in the landscape and several structural attributes of adjacent forest patches, specifically average tree height, canopy cover, tree species richness and density. Almost no seeds were captured in elevated pasture seed traps, even near forest remnants. Abundant forest seeds were found in ground surveys but only within 10 m of forest edges. In ground surveys, seeds from wind-dispersed species were more abundant, but less species rich, than animal-dispersed species. A survey of pasture seedling recruits suggested that some forest seeds must be dispersing more than 10 m into pasture at very low frequencies, but only a few species are establishing there. Recruits were predominantly animal-dispersed not wind-dispersed species. In addition to distance from forest and the proportion of forest within a 100- to 200-m radius of sampling sites, the richness and density of adjacent forest trees were the most important factors for explaining the probability of seed occurrence in abandoned pastures. Results suggest that without some restoration assistance, the recovery of abandoned pastures into secondary rainforest in Australia's tropical rainforests will likely be limited, at least in part, by a very low rate of seed dispersal away from forest edges and by the diversity and density of trees in adjacent remnant forests. [ABSTRACT FROM AUTHOR]

Vegetation structure influences landscape use and habitat quality for many bird species. Owing to the difficulties associated with collecting structural data from traditional field measurements, numerous studies have investigated the utility of Light detection and ranging (LiDAR) for providing landscape-scale structural information that may be useful for exploring animal-habitat associations. Notably, almost all of these studies have involved the use of LiDAR from airborne rather than terrestrial platforms. However, vegetation metrics that might be important for explaining bird species occurrence and diversity, such as understory vegetation complexity and overall vegetation volume, may be partially obscured from airborne sensors by tree canopy cover. These challenges might be overcome by terrestrial and UAV LiDAR sensors that can provide detailed information of understory forest strata. For the first time, we collected terrestrial LiDAR (TLS) and unoccupied aerial vehicle LiDAR (ULS) data in a woodland landscape to compare the ability of both sensors to identify relationships among vegetation structural metrics and bird species richness and abundance. Overall, TLS and ULS models provided similar results based on the sampling methodology we used for LiDAR data collection in an open woodland landscape. Canopy roughness, ground vegetation vertical complexity, total vegetation volume and canopy height derived from these sensors were among the most common significant variables in explaining avian diversity and individual species abundance. Individual species abundance models provided better prediction power (up to R2 = 0.82 (TLS) and R2 = 0.83 (ULS)) than bird community abundance by functional guilds (up to R2 = 0.40 (TLS), R2 = 0.41 (ULS)) and overall bird abundance (R2 = 0.10 (TLS), R2 = 0.16 (ULS)), species richness (R2 = 0.14 (TLS), R2 = 0.14 (ULS)) and diversity (R2 = 0.17 (TLS), R2 = 0.16 (ULS)). Additionally, we found that several vulnerable bird species are strongly associated with LiDAR structural variables, which may assist with habitat assessment and conservation management. • Woodland vegetation structural metrics werederived from terrestrial and UAV LiDAR. • We assessed the ability of this datato model bird-habitat associations. • TLS and ULS models provided similar results based on this study's methodologies. • Individual species and guilds were modelled betterthanspecies richness/abundance. • We discuss effectsof incident angle,returns, coverage, scale, and landscape-type. [ABSTRACT FROM AUTHOR]

Owers, C.J.; Rogers, K.; Mazumder, D., and Woodroffe, C.D., 2016. Spatial Variation in Carbon Storage: A Case Study for Currambene Creek, NSW, Australia. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1297 - 1301. Coconut Creek (Florida), ISSN 0749-0208. Quantifying carbon storage in coastal wetland environments is important for identifying areas of high carbon sequestration value that could be targeted for conservation. This study combines remote sensing and sediment analysis to identify spatial variation in soil carbon storage for Currambene Creek, New South Wales, Australia to establish whether vegetation structure influences soil carbon storage in the upper 30 cm. Wetland vegetation was delineated to capture structural complexity within vegetation communities using Light detection and ranging (Lidar) point cloud data and aerial imagery with an object-based image analysis approach. Sediment cores were collected and analysed for soil carbon content to quantify below-ground carbon storage across the site. The total soil carbon storage in the upper 30 cm for the wetland (59.6 ha) was estimated to be 3933 ± 444 Mg C. Tall mangrove were found to have the highest total carbon storage (1420 ± 198 Mg C), however are particularly sensitive to changes in sea-level as they are positioned lowest in the intertidal frame. Conservation efforts targeted at protecting areas of high carbon sequestration, such as the tall mangrove, will lead to a greater contribution to carbon mitigation efforts. [ABSTRACT FROM AUTHOR]

LiDAR remote sensing can be considered a key instrument for studies related to quantifying the vegetation structure. We utilised LiDAR metrics to estimate plot-scale structural parameters of subtropical rainforest and eucalypt-dominated open forest in topographically dissected landscape in north-eastern Australia. This study is considered an extreme application of LiDAR technology for structurally complex subtropical forests in complex terrain. A total of 31 LiDAR metrics of vegetation functional parameters were examined. Multiple linear regression models were able to explain 62% of the variability associated with basal area, 66% for mean diameter at breast height, 61% for dominant height and 60% for foliage projective cover in subtropical rainforest. In contrast, mean height (adjusted r² = 0.90) and dominant height (adjusted r² = 0.81) were predicted with highest accuracy in the eucalypt-dominated open canopy forest. Nevertheless, the magnitude of error for predicting structural parameters of vegetation was much higher in subtropical rainforest than those documented in the literature. Our findings reinforce that obtaining accurate LiDAR estimates of vegetation structure is a function of the complexity of horizontal and vertical structural diversity of vegetation. [ABSTRACT FROM AUTHOR]

Understanding fire behaviour and vegetation flammability is important for predicting the consequences of fires. Visual assessments of fuel, such as those developed in Project Vesta, have been widely applied to facilitate rapid data acquisition to support fire behaviour models. However, the accuracy and potential wider application to other plant communities of Vesta visual fuel assessments has received limited attention. We conducted visual fuel assessments and detailed quantitative structural measurements in Eucalyptus salubris (gimlet) woodlands in the world's largest extant Mediterranean-climate woodland. With one exception, there was moderate to strong correlation between visual assessments of cover in vegetation layers and quantitative measurements, indicating that visual assessments adequately capture changes in fuels. This suggests that the Vesta visual fuel assessment methodology may have wide application in Australian eucalypt forests and woodlands and perhaps in similar communities around the world. However, several issues limiting the wider application of Vesta visual fuel assessments were identified, mainly associated with differences in community ecology between non-resprouter dominated E. salubris woodlands and the epicormic resprouter-dominated dry forests where the method was developed. Patterns of change in fuels suggest that flammability in E. salubris woodlands peaks at intermediate times since fire, potentially providing opportunities for fire management interventions. [ABSTRACT FROM AUTHOR]

National and global scale initiatives to reduce loss and promote restoration of coastal ecosystems have leveraged the capacity of mangrove and saltmarsh to contribute to climate change mitigation through carbon sequestration. The success of these programs is predicated on reliable estimates of carbon storage and how this changes over time. Efforts to describe spatial variation in below-ground carbon storage have largely focussed on surface sediments, with few studies able to characterise carbon at greater soil depths. This study demonstrates that landscape position occupied by wetland vegetation influences both carbon storage and sources, and that understanding evolutionary infill of estuaries is crucial for characterising spatial variation in carbon storage. We focussed on coastal wetlands in southeast Australia where sea level has a long history of relative stability over the past few millennia. Under these conditions, we show that carbon storage varies across three depth zones in substrate: the active root zone (associated with distribution of contemporary vegetation), inactive root zone (associated with past environmental conditions) and subtidal zone (beyond the contemporary intertidal zone). This conceptual approach relates spatial variation in carbon storage to key processes influencing carbon addition and decomposition, and can be applied elsewhere depending on the sea-level history at the specific site. We demonstrate that models that define carbon storage in the context of variation in landscape position of vegetation in the tidal frame provide improved confidence required for blue carbon assessments. [Display omitted] • Wetland vegetation position in the landscape influences carbon storage. • Carbon in sediments varies with depth of substrate. • Spatial models conceptualising variation with depth will improve carbon storage estimates. [ABSTRACT FROM AUTHOR]

The Great Western Woodlands in S.W. Australia is the largest remaining expanse of temperate woodland on the continent and globally, providing habitat for a significance number of bird species. Conservation planning needs information about bird distributions and habitat resource requirements. Using published information, bird habitat functional groups were identified based upon species that use similar vegetation-based resources. Data from four satellite-borne sensors were analysed to model the distribution of a subset of the key vegetation variables. These results were then used to predict the potential distribution of the functional groups. Field validation suggests ongoing advances in satellite data will enhance the model's accuracy. [ABSTRACT FROM PUBLISHER]

Understanding mechanisms underlying fire regime effects on savanna fauna is difficult because of a wide range of possible trophic interactions and feedbacks. Yet, understanding mechanisms underlying fauna dynamics is crucial for conservation management of threatened species. Small savanna mammals in northern Australia are currently undergoing widespread declines and regional extinctions partly attributable to fire regimes. This study investigates mammal trophic and ecosystem responses to fire in order to identify possible mechanisms underlying these declines. Mammal trophic responses to fire were investigated by surveying mammal abundance, mammal diet, vegetation structure and non-mammal fauna dynamics in savannas six times at eight sites over a period of 3 years. Known site-specific fire history was used to test for trophic responses to post-fire interval and fire frequency. Mammal and non-mammal fauna showed only minor responses of post-fire interval and no effect of fire frequency. Lack of fauna responses differed from large post-fire vegetation responses. Dietary analysis showed that two mammal species, Dasyurus hallucatus and Isoodon auratus, increased their intake of large prey groups in recently burnt, compared to longer unburnt vegetation. This suggests a fire-related change in trophic interactions among predators and their prey, after removal of ground-layer vegetation. No evidence was found for other changes in food resource uptake by mammals after fire. These data provide support for a fire-related top-down ecosystem response among savanna mammals, rather than a bottom-up resource limitation response. Future studies need to investigate fire responses among other predators, including introduced cats and dingoes, to determine their roles in fire-related mammal declines in savannas of northern Australia. [ABSTRACT FROM AUTHOR]

In this study, we explored the capacity of vegetation indices derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance products to characterize global savannas in Australia, Africa and South America. The savannas were spatially defined and subdivided using the World Wildlife Fund (WWF) global ecoregions and MODIS land cover classes. Average annual profiles of Normalized Difference Vegetation Index, shortwave infrared ratio (SWIR32), White Sky Albedo (WSA) and the Structural Scattering Index (SSI) were created. Metrics derived from average annual profiles of vegetation indices were used to classify savanna ecoregions. The response spaces between vegetation indices were used to examine the potential to derive structural and fractional cover measures. The ecoregions showed distinct temporal profiles and formed groups with similar structural properties, including higher levels of woody vegetation, similar forest–savanna mixtures and similar grassland predominance. The potential benefits from the use of combinations of indices to characterize savannas are discussed. [ABSTRACT FROM PUBLISHER]

Prescribed burning of regrowth jarrah stands established after bauxite mining is key to their integration into standard jarrah forest management, but fire management in thinned regrowth stands has not been studied. Fuel loads in 10- to 13-year-old thinned regrowth increased exponentially with thinning intensity, doubling from 18 t ha-1 in untreated stands (1500-2500 stems ha-1) to 37.4 t ha-1 in the heaviest treatment (400 stems ha-1 retained); however, litter and standing dead vegetation were concentrated within 60 cm of the ground. Intensities of subsequent autumn prescribe-burns increased with increasing fuel loads, but all burns were typically of low to moderate intensity <1800kWm-1. Three months post-burn, total fuel loads averaged 5 t ha-1, recovering after 4.5 years to 75% of pre-burn levels across all thinning treatments owing mostly to dense understorey regeneration. Where no burning occurred after thinning, total fuel loads declined to be comparable to the unthinned control after 4.5 years, averaging 20 t ha-1. Prescribed burns in autumn following thinning are not recommended because a dense well-aerated and elevated fuel layer is reinstated, posing a future fire risk. Burning 1-2 years before thinning may be an appropriate alternative strategy. [ABSTRACT FROM AUTHOR]

Prescribed burning of regrowth jarrah stands established after bauxite mining is key to their integration into standard jarrah forest management, but fire management in thinned regrowth stands has not been studied. Fuel loads in 10- to 13-year-old thinned regrowth increased exponentially with thinning intensity, doubling from 18 t ha-1 in untreated stands (1500-2500 stems ha-1) to 37.4 t ha-1 in the heaviest treatment (400 stems ha-1 retained); however, litter and standing dead vegetation were concentrated within 60 cm of the ground. Intensities of subsequent autumn prescribe-burns increased with increasing fuel loads, but all burns were typically of low to moderate intensity o1800kWm-1. Three months post-burn, total fuel loads averaged 5 t ha-1, recovering after 4.5 years to 75% of pre-burn levels across all thinning treatments owing mostly to dense understorey regeneration. Where no burning occurred after thinning, total fuel loads declined to be comparable to the unthinned control after 4.5 years, averaging 20 t ha-1. Prescribed burns in autumn following thinning are not recommended because a dense well-aerated and elevated fuel layer is reinstated, posing a future fire risk. Burning 1-2 years before thinning may be an appropriate alternative strategy. [ABSTRACT FROM AUTHOR]

The structural and floristic changes occurring with time since fire in Taxandria linearifolia swamps were investigated using chronosequence analysis. Sixty-six swamps in the northern jarrah forest of south-western Australia were investigated and the effect of fire on them was quantified. Habitat units were mapped from aerial photographs that were imported into a geographic information system. Field surveys were then conducted at each site to ground-truth mapped habitat units. Habitat units were differentiated using factor analysis. The vegetation within the swamps remained relatively open for the first five years following a fire while being largely dominated by three or four species. Thereafter, vegetation density increased to a peak between 20 and 24 years (>90%) and species richness from 10 to 14 (mean = 5.7 ± 0.4). Long unburnt Taxandria swamp shrubland habitat returned to intermediate vegetation density levels, although becoming increasingly woody, as relatively few species dominated. Such a response to fire probably reflects adaptations to the frequent, low intensity fire regimes utilised by Aborigines prior to European colonisation. [ABSTRACT FROM AUTHOR]

The binary classification of landscapes into suitable vs. unsuitable areas underlies several prominent theories in conservation biogeography. However, a binary classification is not always appropriate. The textural discontinuity hypothesis provides an alternative theoretical framework to examine the geographical distribution of species, and does not rely on a binary classification scheme. The texture of a given landscape is the combination of its vertical structural complexity and horizontal spatial grain. The textural discontinuity hypothesis states that biophysical features in the environment are scaled in a discontinuous way, and that discontinuities in the body size distribution of animals mirror these biophysical discontinuities. As a result of this relationship, a complex landscape texture should be associated with small-bodied animals, whereas a simple landscape texture should be associated with larger-bodied animals. We examined this hypothesis for birds in five landscapes in south-eastern Australia that represented a gradient from simple to complex landscape texture. In landscapes with a complex texture, the number of detections of small birds was higher than expected, and the number of detections of larger-bodied birds was lower than expected. The opposite pattern was found in landscapes with a simple texture. The pattern remained significant when only bird species found in each of the five landscapes were considered, which demonstrated that the association of landscape texture with body size was not an artefact of landscapes differing in their species pools. Understanding the effects of landscape texture on species distribution patterns may be a promising research frontier for conservation biogeography. We hypothesize that the active management of landscape texture may be used to attract or deter animals of certain body sizes. Consistent with other theories, the textural discontinuity hypothesis therefore suggests that managing entire landscapes, rather than only predefined patches, is an important conservation strategy. [ABSTRACT FROM AUTHOR]

We present the results of a study that is the first to investigate the landscape-scale distribution of small mammals in direct relation to the spatial and temporal variation of snow cover. We investigated the distribution of the dusky antechinus Antechinus swainsonii and bush rat Rattus fuscipes in the subalpine zone of Kosciuszko National Park in the Snowy Mountains of south-eastern Australia. A new hair tube technique was used to detect the presence of small mammals active in the subnivean space. In 2002, we sampled 72 sites stratified by elevation (1501–1600, 1601–1700, 1701–1800 m), aspect (accumulating, ablating) and habitat type (woodland, wet heath, dry heath, grassland). These factors were considered important in influencing snow accumulation and generally reflected the types of habitats available to small mammals. In 2003, the presence of small mammals was investigated at 30 high-elevation sites including six boulderfields. The development of the subnivean space in the Snowy Mountains is dependent on the presence of structures such as shrubs, boulders and microtopographic features that are capable of supporting a snow layer above ground level. When snow was present, small mammal detections were negatively correlated with snow depth and duration, and positively correlated with the complexity of structures and microtopography. At high elevations detections were largely confined to boulderfields, and at mid and low elevations small mammals were detected primarily in habitats where the subnivean space was most extensive. Antechinus swainsonii and R. fuscipes responded differently to snow cover, with the latter seeming better able to overwinter where snow cover was shallow and patchy, in contrast to A. swainsonii whose occurrence was correlated to the size of the subnivean space. [ABSTRACT FROM AUTHOR]

Vegetation structure and composition during the pre- and early-European period in Australia is often proposed as a benchmark against which to measure the effects of modern landscape management practices. However, little quantifiable information exists for that historical period. One potential source of information is the land survey record, used in this study to provide estimates of tree densities that existed during the period 1870 to 1900 in part of central New South Wales. Estimates were obtained for 23 parishes in the north Lachlan River valley, between the towns of Condobolin and Tottenham. Densities were calculated from portion corner to nearest tree data obtained from historical survey plans, using the plotless, closest individual method. Densities ranged from 6.0 to 31.4 trees per hectare for parishes with enough data points for reliable calculation. These figures would account for trees of a diameter large enough to be blazed with a survey mark. Any smaller trees would be additional and, although no quantitative data existed for this, qualitative evidence suggested that the figures obtained were more likely to be underestimates due to the presence of such small trees. The study area was predominantly covered by woodlands which varied in density across the landscape, in comparison to the modern landscape where much of the native vegetation has been cleared for agriculture. Although the tree density figures should be considered to be indicative rather than precise, they provide quantifiable historical figures for past conditions in an area where the historical record is otherwise sparse. Such information is valuable for interpreting ecological changes brought about by modern land management. [ABSTRACT FROM AUTHOR]

Bauxite mines being restored to native jarrah (Eucalyptus marginata)-dominated forest in Western Australia have accumulated substantial fuel loads. Assessment of fire management aspects is necessary for the effective integration of restored areas into forest-wide management. Fuel characteristics, vegetation structure and fire behaviour of young (5- and 8-year-old) restored bauxite mines in Western Australia were examined. Pre-burn fuel loads were moderate in 5-year-old restoration (15.0 t ha−1) and high in 8-year-old restoration (29.8 t ha−1). Large ranges in available fuel load estimates of sample sites (2.2–60.8 t ha−1) indicated the heterogeneous nature of fuel distribution leading to variable fire behaviour. The vegetation structure of restored areas differed from that of the unmined jarrah forest due to the presence of a prominent mid-storey layer composed of number of acacias (Acacia pulchella, A. celastrifolia, A. extensa, A. drummondii and A. lateriticola). This mid-storey layer contributed 49% of the total fuel load in 5-year-old restoration, although the high proportion of live material (73.6%) inhibited fire development. In 8-year-old restoration the mid-storey layer contributed 46% of the total fuel load. The lower proportion of live material in these sites (27.9%), due to the senescence and death of the relatively short-lived acacias, led to increased fire intensities, flame heights and higher levels of crown scorch and defoliation. Prescribed burns were conducted in early summer 1997. Burns in 5-year-old restoration were of low intensity (<250 kW m−1) while burns in 8-year-old restoration were of very high intensity (>7000 kW m−1). Fuel re-accumulation was rapid in the first 2 weeks post-burn, with litter-fall rates 2–3.5 times that of unburnt control sites. Thereafter, litter-fall and fuel accumulation in burnt restored and unmined sites was comparable to that of unburnt control sites. Analysis of 1 and 2 years post-burn 5-year-old restoration indicated that the prescribed burns had failed to remove the mid-storey acacia layer and actually increased the proportion of dead standing material, whereas in the 8-year-old restoration, the prescribed burns removed the mid-storey layer of acacia shrubs and stimulated an increase in the proportion of live plant material, particularly near ground level. Maximum soil temperatures recorded by heat sensitive crayons exceeded 300 °C in 8-year-old restoration burns but were less than 100 °C in 5-year-old restoration burns. Hard-seeded species were stimulated to germinate in the top 2–3 cm of the soil following burns in 8-year-old restoration and only in the top 0.5 cm of the soil following burns in 5-year-old restoration. Some seeds in the top 1 cm of the soil may also have been killed by the high temperatures generated in burns in the 8-year-old sites. Fire management of jarrah forest restoration will have to be different to that employed in unmined jarrah forest due to differences in fuel characteristics, vegetation structure and fire behaviour. [Copyright &y& Elsevier]

Abstract Aim Recent research has shown that much of the variability in leaf gas exchange and leaf longevity can be related to variations in the surface : volume ratio of leaves. The aim of this paper was to develop a theoretical framework and a practical method to extend that result to the vegetation at the continental scale. Location The study was conducted in Australia. Methods We propose that vegetation is composed of a mixture of three basic leaf types, ‘turgor’ (T), ‘mesic’ (M) and ‘sclerophyll’ (S) leaves. Changes in the relative proportions of T, M and S leaves within a vegetation type are visualized using a ternary diagram and differences in vegetation structure are shown to be easily mapped onto the ternary diagram. We estimate the proportions of T, M and S leaves using readily available data. The total amount of PAR absorbed by the vegetation (fPAR) is estimated using continental-scale satellite observations. The total fPAR is then decomposed into that absorbed by T, M and S leaves. The relative absorption of PAR by T leaves is estimated from the temporal dynamics in the satellite signal, while the relative proportions of M and S leaves are estimated using climatic (solar radiation, rainfall) data. Results When the availability of light, nutrients and water were near-optimal, the vegetation was composed of predominantly M leaves. In low nutrient environments S leaves predominated. T leaves were dominant in disturbed environments. Conclusions The theoretical framework is used to predict that elevated atmospheric CO2 would tend to increase the proportion of M and S leaves in an ecosystem and the resulting change means that the proportion of T leaves would decrease. In terms of the TMS scheme, this implies that elevated CO2 has the same net effect on the vegetation as a decrease in disturbance. [ABSTRACT FROM AUTHOR]

We compared selectively harvested and unharvested areas located among treatments of annual burning since 1952, triennial burning since 1973 and an area that had received no prescribed burning, but with a single wildfire in 2006 (one fire in 72 years), in a dry sclerophyll eucalypt forest, south-eastern Queensland, Australia. Historic fire regime, rather than low-intensity, selective timber harvesting (17% to 37% live tree basal area removed) had a greater impact on a range of vegetation and soil attributes. Plant taxa composition was influenced more by historic fire regime than recent harvesting; of the 25.5% of the variation in taxa composition explained, fire treatments alone accounted for 96.4% of the explained variation and harvesting alone accounted for just 4.8%. Selective harvesting of timber had a predictable influence associated with removal of tree cover and physical impacts associated with extraction of logs. In harvested areas there were increases (p < 0.05) in bare-ground cover and in coarse woody debris volumes and decreases in understorey vegetation height, particularly where woody understorey was present. However, overall, the combined effects of timber harvesting and fire regime were relatively minor. These sub-tropical dry eucalypt forests appear to be resilient to the impacts of combined, but low-intensity disturbances. [ABSTRACT FROM AUTHOR]

• Frequent prescribed burning was applied over 45 years at a long running experiment. • Annual burning encouraged tree diameter growth rates. • Stand basal area had a negative influence on tree growth rates. • Triennial burning enhanced tree recruitment, resulting in higher tree densities. Frequent fire often has a negative impact of tree recruitment and growth. Tree growth rates, density and recruitment were compared among treatments of annual burning since 1952, triennial burning since 1973 and no burning (1946 to 1996) or single wildfire (1996 to 2018), in a dry sclerophyll eucalypt forest, south-eastern Queensland, Australia. Tree diameter (at breast height, DBH) growth rates were greater in the annually burnt treatment than in the triennially burn and single wildfire treatments over the period from 1974 to 2018, and these differences were also apparent pre-wildfire (period from 1974 to 1996). In the period from 1996 to 2018, the annually burnt treatment had greater DBH growth relative to the single wildfire treatment, but the triennial treatment had intermediate growth rates. Competitive interactions between trees (assessed using plot basal area) also had a negative impact on individual tree growth rates. The impacts of different fire regimes at this site on tree crown health were not apparent (P > 0.05) and there was only limited evidence that differences in growth rates were due to differences in soil nutrients (marginally higher topsoil phosphorus in the frequently burnt treatments, P = 0.075). Greater tree growth rates in the annually burnt treatment may be related to the lower density of understorey woody plants in this treatment and potentially reduced competition for soil moisture. The density of trees (DBH ≥ 10 cm) in 2018 was surprisingly higher in the triennially burnt treatment (381 stems/ha) relative to both the annually burnt (192 stems/ha) and single wildfire (234 stems/ha) treatments. This was largely due a higher level of recruitment over time and a higher density of stems 10–20 cm DBH in triennially burnt plots. Concerns regarding the impacts of frequent prescribed fire on tree recruitment and growth may be unwarranted in these remarkably resilient dry eucalypt forests. [ABSTRACT FROM AUTHOR]

Tree canopy density metrics (TCDM) derived from airborne lidar data are used in a range of crucial environmental monitoring, forestry and natural resource management applications. The derivation of spatially and temporally consistent TCDM, however, typically requires field calibration to account for differences in instrument/survey parameters. Lidar surveys with no coincident field measurements consequently will have an unknown error associated with TCDM limiting their application. In this study, we analysed an extensive set of lidar captures with coincident field data to determine the lidar TCDM that best match the canopy gap probability (P gap), foliage projective cover (FPC) and crown projective cover (CPC). Furthermore, we developed and evaluated models designed to reduce the bias introduced by variations in lidar instrument and survey acquisition parameters. The dataset incorporated 148 field sites (100 m diameter circular plots) coincident with 13 different lidar surveys between 2008 and 2015, distributed across a range of Australian forests and woodlands. The best lidar metric for 1 − P gap , achieving a root mean square error (RMSE) of 6.7% with 95% confidence intervals (CI) of 6.1–7.3%, was the proportion of all returns greater than a canopy height threshold (t canopy) of 1.5 m above ground (d all). The best metric for FPC (RMSE = 6.0%, CI = 5.3–6.7%) used the proportion of returns, weighted as the fraction of the number of returns recorded from each pulse (d weighted), with t canopy of 1.7 m. The best metric for CPC (RMSE = 7.0%, CI = 6.4–7.7%) was the proportion of 0.5 m pixels greater than 0.8 m above the ground, for an interpolated canopy height model (d interp). Overall bias for these metrics was low (~1%), however, the bias for individual surveys varied significantly. For example, for one survey d all consistently underestimated 1 − P gap with a bias of −8.3%, while a different survey consistently overestimated 1 − P gap with a bias of 3.8%. Elastic net regression models, using instrument, survey and plot parameters as predictor variables, were unable to consistently remove the bias. No relationships could be discerned between lidar parameters and the bias between lidar metrics and field measurements, potentially due to complex interactions between parameters, the spatial scale of the field plots, and uncertainties in field measurements and lidar attributes. Although the bias could not be modelled, the results provide metrics to derive P gap , FPC and CPC with less than 10% error from lidar surveys captured with similar parameters across Australia (>600,000 km2). • An extensive dataset of field plots and airborne lidar data was collated. • The effect of lidar parameters on canopy density metrics could not be modelled. • Standard canopy density metrics matched field measurements with low RMSE (~7%). [ABSTRACT FROM AUTHOR]

The critically endangered Cumberland Plain woodland within the greater Sydney metropolitan area hosts a dwindling refuge for melaleuca trees, an integral part of Australia's native vegetation. Despite their high carbon stocks, melaleucas have not explicitly been targeted for studies assessing their carbon sequestration potential, and especially little is known about their energy cycling or their response to increasing climate stress, precluding a holistic assessment of the resilience of Australia's forests to climate change. To improve our understanding of the role of melaleuca forest responses to climate stress, we combined forest inventory and airborne LiDAR data to identify species distribution and associated variations in forest structure, and deployed flux towers in a melaleuca-dominated (AU-Mel) and in a eucalypt-dominated (AU-Cum) stand to simultaneously monitor carbon and energy fluxes under typical growing conditions, as well as during periods with high atmospheric demand and low soil water content. We discovered that the species distribution at our study site affected the vertical vegetation structure, leading to differences in canopy coverage (75% at AU-Cum vs. 84% at AU-Mel) and plant area index (2.1 m 2  m -2 at AU-Cum vs. 2.6 m 2  m -2 at AU-Mel) that resulted in a heterogeneous forest landscape. Furthermore, we identified that both stands had comparable net daytime carbon exchange and sensible heat flux, whereas daytime latent heat flux (115.8 W m -2 at AU-Cum vs 119.4 W m -2 at AU-Mel, respectively) was higher at the melaleuca stand, contributing to a 0.3 °C decrease in air temperature and reduced vapor pressure deficit above the melaleuca canopy. However, increased canopy conductance and higher latent heat flux during moderate VPD or when soil moisture was low indicated a lack of water preservation at the melaleuca stand, highlighting the potential for increased vulnerability of melaleucas to projected hotter and drier future climates., (Copyright © 2019 Elsevier B.V. All rights reserved.)

1. There is increasing evidence that passive faunal recolonisation of restored areas can take decades or even centuries, reducing benefits to biodiversity from restoration. Thus, there is a need to develop restoration and management strategies that facilitate and accelerate faunal recolonisation. This requires identification of habitat features that act as filters to slow or prevent recolonisation and whether those filters are temporally unidirectional or dynamic. 2. We investigated successional patterns of reptiles and mammals in restored mine-pits in south-western Australia to identify potential filters to faunal recolonisation. We sampled reptiles and small mammals using 30 trapping grids across each of four restoration ages (4, 8, 12 and 17-years old) and unmined forest and assessed vegetation structure to identify animal-habitat relationships. 3. Mammal communities in restored areas converged on unmined forest communities as restoration matured, and all species recolonised rapidly, indicating there were no filters to mammal recolonisation. In contrast, reptile communities did not converge in the same way, indicating there were filters that slowed or prevented reptile recolonisation. We identified three reptile species that were slow, or failed, to recolonise restored areas and a fourth species that rapidly recolonised but disappeared as restoration matured. We identified low coarse woody debris (CWD) volumes and high overstorey stem densities as likely filters; the former is a unidirectional filter that will decrease gradually over long time frames, possibly centuries, while the latter is a dynamic filter that fluctuates in its intensity over short time frames of years. 4. Synthesis and applications. Our study adds to growing evidence that filters to faunal recolonisation may be widespread in restored areas, with important implications for restoration practices. Firstly, examining individual species may more effectively identify filters than examining community successional patterns. Secondly, filters can persist over long time frames, possibly centuries, so management, such as the provision and accelerated development of CWD, may need to occur over similar time frames. Lastly, filters can be dynamic and repeated management interventions, such as thinning, may be required to overcome these filters. The growing evidence for filters suggests that facilitating faunal recolonisation is more complex than simply returning vegetation to restoration sites. [ABSTRACT FROM AUTHOR]