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Abstract This paper explores the potential of a new method of reconstructing historical vegetation change in the Australian rangelands. Historical monitoring of rangeland vegetation has been so deficient that it is not possible to determine whether a long-term trend toward degradation has occurred (as is often assumed) or, indeed, if it is continuing to occur. Because long-term records are unavailable any attempt to monitor vegetation retrospectively must be based on proxy measures rather than direct observation. Where historical data are lacking an integration of palaeoecological, archaeological and ecological methods is required to reconstruct the past. Our research is based on a detailed analysis of sheep faeces deposited near a shearing shed in the semiarid rangelands of south-west Queensland between the late 1930s and the mid-1990s. The faeces in these deposits represent the diet of sheep in the days leading up to the property’s annual shearing and as such are a potentially useful index to changes in vegetation. Results indicate significant changes in the diet of sheep since the late 1940s. The potential of this method, and its limitations, are discussed. Long-term records are critical in understanding issues of sustainability in land management and it is intended that this paper will stimulate further research into historical vegetation change in rangelands. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the interactions of natural and anthropogenic variables at different spatial scales related to changes in mangrove distribution during a relatively wet period (1972-1990) and a dry period (1991-2004) in subtropical eastern Australia. Previous research has demonstrated that mangroves are encroaching into salt marsh. Mangrove spatial change in southeast Queensland is related generally to landscape variables especially during the relatively wet period. What has not been explored is the spatial scale of the influence under the two rainfall regimes (wet and dry) and that is the aim of this paper. Ten sites were examined at different levels of resolution including catchment, sub-catchment and two buffer zones (1000 and 500 m), under the period of relatively higher and lower rainfall. Land use was ascertained from Landsat satellite imagery using Maximum Likelihood Classification techniques. Partial least squares regression analysis was used to study the relationships between the predictor variables and the rate of change in the mangrove distribution. The research has found that the impact of land use/cover on the encroachment of mangrove into saltmarsh can vary and appears to be related to rainfall patterns, which in turn affect hydrological connectivity. A major finding of this research was that the changing spatial patterns of mangroves during the wet period was more a function of land use/cover pattern and population density at the sub-catchment level, whereas during drier periods it was more affected by the local effects of nearby land use/cover in buffer zones. [ABSTRACT FROM AUTHOR]

This paper examines invasion of grasslands on Cape York Peninsula, Australia, by Melaleuca viridiflora and other woody species, and the role of storm-burning (lighting fires after the first wet season rains) in their maintenance. Trends in disturbance features, fuel characteristics, ground layer composition, and woody plants dynamics under combinations of withholding fire and storm-burning over a 3-year period were measured on 19 plots in three landscape settings. Population dynamics of M. viridiflora are described in detail and 20-year population projections based on transition matrices under different fire regimes generated. Numerous M. viridiflora suckers occurred within the grass layer, increasing each year regardless of fire regime, and were rapidly recruited to the canopy in the absence of fire. Storm-burning had little impact on fuel, ground layer or woody plant composition, but maintained open vegetation structure by substantially reducing recruitment of M. viridiflora suckers to the sapling layer, and by reducing the above-grass-layer abundance of several other invasive woody species. Population projections indicated that withholding fire for 20 years could cause a sevenfold increase of M. viridiflora density on Ti-tree flats, and that annual to triennial storm-burning should be effective at maintaining a stable open vegetation structure. These findings argue against vegetation thickening being an inevitable consequence of climate change. We conclude that a fire regime that includes regular storm-burning can be effective for maintaining grasslands and grassy woodlands being invaded by M. viridiflora. [ABSTRACT FROM AUTHOR]

The detection and mapping of canopy disturbance caused by natural events such as cyclones in tropical rainforests is important for monitoring and understanding rainforest dynamics and recovery. In February 1999 tropical cyclone Rona crossed the coastline of Far North Queensland, Australia, causing significant damage to the rainforest canopy in some areas. This paper examines the application of multitemporal canopy digital elevation models (DEMs) generated by a NASA-operated airborne radar mapping system called TOPSAR in 1996 and 2000, for detection of canopy disturbance caused by cyclone damage. Canopy damage was mapped here by identifying areas with a significant decrease in canopy height estimated from the difference of the 1996 and 2000 TOPSAR DEMs. Conventional aerial photographs, flown shortly after the cyclone (March 1999), were used to validate the resulting map of cyclone damaged rainforest canopy. The results showed that the DEM-derived canopy damage map performed reasonably well when comparing the spatial distribution and size of damaged areas, while taking into account the time difference between cyclone damage and the second radar acquisition. Some errors were encountered on the steeper slopes which were related to terrain distortions inherent in radar images of steep terrain. The height accuracy of the DEM was close to the depth of some of the gaps being mapped, which also contributed to errors. Even so, the results demonstrate there may be potential for weather-independent, regional-scale mapping of forest canopy change from imaging radar that is not always possible from traditional optical means of measuring canopy elevation, for example, airborne laser data and stereo aerial photography. This may be possible in relatively flat areas, provided the second radar acquisition occurs within months of the damaging event. Further algorithm refinement is required to improve its robustness and the range of topographies where this approach can provide reliable estimates of the extent of canopy disturbance. [ABSTRACT FROM AUTHOR]

The Mahogany Glider (Petaurus gracilis) is one of the most endangered marsupials in Australia. Its known distribution is an approximately 120 km strip of fragmented coastal woodland in north‐east Queensland, from north of Townsville to the Tully area. Records are clustered in a number of well‐surveyed areas, with significant areas of lowland habitat unsurveyed. Around 30% of historic records fall in areas that were subsequently cleared for farmland, and ongoing clearing and fragmentation of lowland sclerophyll forest continues within the potential distribution. Resolving the distribution is an urgent requirement to guide conservation but Mahogany Gliders are difficult to detect in the field. Species distribution modelling offers a technique for estimating the fine‐scale distribution and for targeting further field survey and conservation efforts. We used known occurrence records (N = 481) to predict the distribution of Mahogany Gliders across the Wet Tropics bioregion. We used climatic, topographic and other environmental predictors to generate distribution models using Maxent and Random Forest algorithms, each with two bias correction methods. The predictions revealed that many unknown populations may exist within the currently defined distribution and in important areas beyond this (e.g. Hinchinbrook Island). There was reasonable congruence between models, and we include syntheses of the models to present the most likely current distribution. The most important predictor variables across the models were precipitation seasonality (high seasonality), elevation (generally <100 m), soil type (hydrosols) and vegetation type (including Eucalyptus and Melaleuca woodlands). Our results identify core habitat and reveal key areas that require targeted field surveys. Importantly, the predicted suitable habitat is highly fragmented and ongoing conservation efforts need to improve habitat connectivity and limit further fragmentation. [ABSTRACT FROM AUTHOR]

The Carpentarian Pseudantechinus (Pseudantechinus mimulus) is a poorly studied dasyurid marsupial that inhabits rocky outcrops in the Mount Isa Inlier bioregion in Queensland and the Gulf Coastal and Gulf Fall and Uplands bioregions in the Northern Territory. It is readily detected by passive infrared triggered camera traps ('camera traps'). Camera trap data can be used to develop detection probability estimates from which activity patterns can be inferred, but no effort has previously been made to determine changes in the detectability of P. mimulus throughout the year. We undertook a 13‐month baited camera trap survey across nine sampling periods at 60 locations of known historic presence or nearby suitable habitat to assess the change in detection rates and detection probabilities of P. mimulus across a year. Detection probabilities were calculated from camera trap data within a single‐species, multi‐season occupancy framework to determine optimal survey timing. Detection probability data were used to calculate the likelihood of false absences to determine optimal survey duration. We recorded 2493 detections of P. mimulus over 10 966 camera days. Detection probability ranged from 0.009 to 0.179 and was significantly higher from April to October than from November to March. The likelihood of false absences varied by sampling period and desired level of confidence. We find that camera trap surveys for P. mimulus are best conducted from April to October, but optimal survey duration is dependent upon the time of year and desired level of confidence that an observed absence from a given site reflects a true absence at that site. Attaining a minimum of 80% confidence of absence requires as few as 9 days of survey effort in May to 16 days of survey effort in October. [ABSTRACT FROM AUTHOR]

Wind dispersal is considered to be a potentially important mode of spread for parthenium weed (Parthenium hysterophorus L.), an invasive Asteraceae herb of worldwide significance. However, empirical evidence of the role of wind dispersal on the seeds (achenes) of parthenium weed in natural landscapes is lacking. The results of a simulation study undertaken at a wind tunnel facility, Australia, indicated that the dispersal distance of parthenium weed achenes is largely determined by wind velocity (109–131% increase in distance where wind velocity is doubled) and plant release height (75–80% increase when release height is doubled). Glasshouse harvested achenes released from 1 m in height could travel up to 2 m under a 2 m s−1 wind velocity, with the majority of achenes reaching more than 1 m. Smaller‐sized achenes travelled 5% further than larger‐sized achenes. The terminal velocity was calculated to be 1.256 ± 0.006 m s−1, indicating a moderate wind dispersal ability for the weed. A complementary field study in Southeast Queensland, Australia, indicated that the cumulative wind velocity and wind direction, instead of the mean wind velocity, determined the direction of dispersal of the achenes. Further post‐dispersal surveys suggested the number of achenes outside of a standing population declined rapidly as distance from the population increased. Most achenes were dispersed less than 2 m from their parent plant, while the maximum distance achieved was less than 5 m under natural conditions in North Queensland. In conclusion, the natural wind dispersal of parthenium weed consists of small, but measurable increments each year, thus contributing to the weed proliferation and spread at the landscape scale level. [ABSTRACT FROM AUTHOR]

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Vehicles play a significant role in spreading plants, both in terms of quantity and quality (species). This study was conducted in Southeast Queensland to determine the role of utility vehicles in spreading seeds. These vehicles were found to carry up to 397 seeds per vehicle and in all four seasons of the year, with the majority of these species being alien to Australia and/or Queensland. The largest seed loads were found in autumn in this summer rainfall environment. Seeds were shown to attach to all parts of the vehicle, often in mud picked up from the ground, affixed directly to the engine or radiator, or carried into the cabin by the driver. Therefore, much of the seed load is to be found on the underside, on the back and front mudguards while smaller collections were found in the cabin, on the radiator and engine, and on the tyres. Fewer viable seeds were found on the engine, presumably as desiccation and heat contributed more to their death on this part of the vehicle. One method used to reduce weed seed spread by vehicles in Queensland is washing and vacuuming of vehicles. From the present study, these procedures would need to be applied to all parts of the vehicle and in all seasons of the year. [ABSTRACT FROM AUTHOR]

Cyclones cause profound immediate impacts on tropical rainforest trees, including defoliation, limb loss, snapping of stems and uprooting. Some studies have shown that plant functional traits such as tree size, buttress roots and wood density are correlated with these forms of cyclone damage. On 20 March 2006, Severe Tropical Cyclone Larry crossed the north Queensland coast and proceeded inland across the Atherton Tablelands, impacting the critically endangered Mabi Type 5b rainforest. We investigated the effects of Cyclone Larry on common tree species by categorizing damage to trees as uprooted, snapped, limbs damaged (light, moderate, severe) or upright and estimating levels of defoliation. Damage was then related to functional traits including tree size, presence of buttress roots, wood density, and leaf size and strength. Levels of damage differed between species. Tree size (diameter at breast height) and the presence of buttress roots were not related to damage levels. Wood density was significantly negatively correlated to proportion of trees with snapped stems and significantly positively correlated with the proportion of trees upright with no or light limb damage. Levels of defoliation were significantly related to leaf strength (specific leaf area – SLA) and to leaf width, but not other components of leaf size (area or length) or petiole length. Species with high wood density and low SLA (e.g. Argyrodendron spp.) were found to have high cyclone resistance, the ability to resist damage, while species with low wood density and high SLA (e.g. Dendrocnide photinophylla) exhibited low resistance. However, traits related to low resistance are also those linked to rapid growth and high cyclone resilience, the ability to recover from damage, so it is unlikely that the Mabi forest will experience long-term changes in floristic composition following Cyclone Larry. [ABSTRACT FROM AUTHOR]

Riparian habitats are highly important ecosystems for tropical biodiversity, and highly threatened ecosystems through changing disturbance regimes and weed invasion. An experimental study was conducted to assess the ecosystem impacts of fire regimes introduced for the removal of the exotic woody vine, Cryptostegia grandiflora, in tropical north-eastern Australian woodlands. Experimental sites in subcatchments of the Burdekin River, northern Queensland, Australia, were subjected to combinations of early wet-season and dry-season fires, and single and repeated fires, with an unburnt control. Woody vegetation was sampled using permanent quadrats to record and monitor plants species, number and size-class. Sampling was conducted pre-fire in 1999 and post-fire in 2002. All fire regimes were effective in reducing the number and biomass of C. grandiflora shrubs and vines. Few woodland or riparian species were found to be fire-sensitive and community composition did not change markedly under any fire regime. The more intense dry-season fires impacted the structure of non-target vegetation, with large reductions in the number of sapling trees (<5 cm d.b.h.) and reductions in the largest tree size-class and total tree basal area. Unexpectedly, medium-sized canopy trees (10–30 cm d.b.h.) appear to have been significantly benefited by fires, with decreases in number of trees of this size-class in the absence of fire. Although the presence of C. grandiflora as a vine in riparian forest canopies changed the nature and intensity of crown combustion patterns, this did not lead to the initiation of a self-perpetuating weed–fire cycle, as invaders were unable to take advantage of gaps caused by fire. Low intensity, early wet-season burning, or early dry-season burning, is recommended for control of C. grandiflora in order to minimize the fire intensity and risk of the loss of large habitat trees in riparian habitats. [ABSTRACT FROM AUTHOR]

The vertical stratification of insect species assemblages inhabiting tropical rainforests is well established but few have examined whether these patterns are reflected in vertical stratification of body size or feeding guilds. We used Malaise and Flight Interception Traps to sample beetle assemblages from five locations, at both canopy and ground zones of a tropical lowland rainforest site near Cape Tribulation, Australia. Beetles from 4 years of sampling were sorted to Family and morphospecies, and allocated to one of five feeding guilds. Within feeding guilds the number of species and individuals, from canopy- and ground-caught traps were compared. The body lengths of species were measure and compared within feeding guilds and families. Herbivores was the dominant guild but was not the majority of all species or individuals. Most beetle species (69%) were less than 5 mm in length and the mean size of canopy-caught species was greater than that for ground-caught species. This was probably due to slightly more species of plant feeders (herbivores and xylophages) present in the canopy, which were significantly larger than saprophages, fungivores and predators. Among feeding guilds, there were few overall canopy–ground differences. These results contrast with species composition results presented elsewhere where strong differences between the canopy and the ground were evident. We suggest that our guild groupings may have been too coarse to detect fine-scale differences and that resource partitioning may have also masked faunal stratification. We propose that fine-scale differences in resources between the canopy and the ground, together with strong microclimate gradients, are likely to be important in structuring the vertical stratification of insect assemblages at the level of species, but not with respect to functional groups. [ABSTRACT FROM AUTHOR]

Current estimates of the total biomass in tropical rainforests vary considerably; this is due in large part to the different approaches that are used to calculate biomass. In this study we have used a canopy crane to measure the tree architectures in a 1 ha plot of complex mesophyll vine forest at Cape Tribulation, Australia. Methods were developed to measure and calculate the crown and stem biomass of six major species of tree and palm ( Alstonia scholaris (Apocynaceae) , Cleistanthus myrianthus (Euphorbiaceae) , Endiandra microneura (Lauraceae) , Myristica insipida (Myristicaceae) , Acmena graveolens (Myrtaceae), Normanbya normanbyi (Arecaceae)) using the unique access provided by the crane. This has allowed the first non-destructive biomass estimate to be carried out for a forest of this type. Allometric equations which relate tree biomass to the measured variable ‘diameter at breast height’ were developed for the six species, and a general equation was also developed for trees on the plot. The general equation was similar in form to equations developed for tropical rainforests in Brazil and New Guinea. The species equations were applied at the level of families, the generalized equation was applied to the remaining species which allowed the biomass of a total of 680 trees to be calculated. This has provided a current estimate of 270 t ha−1 above-ground biomass at the Australian Canopy Crane site; a value comparable to lowland rainforests in Panama and French Guiana. Using the same tree database seven alternative allometric equations (literature equations for tropical rainforests) were used to calculate the site biomass, the range was large (252–446 t ha−1) with only three equations providing estimates within 34 t ha−1 (12.5%) of the site value. Our use of multiple species-specific allometric equations has provided a site estimate only slightly larger (1%) than that obtained using allometric equations developed specifically for tropical wet rainforests. We have demonstrated that it is possible to non-destructively measure the biomass in a complex forest using an on-site canopy crane. In conjunction the development of crown maps and a detailed tree architecture database allows changes in forest structure to be followed quantitatively. [ABSTRACT FROM AUTHOR]

The concept of ‘ant mosaics’ has been established to describe the structure of arboreal ant communities in plantations and other relatively simple forest systems. It is essentially built upon the existence of negative and positive associations between ant species plus the concept of dominance hierarchies. Whether this concept can be applied to ant communities in more complex mature tropical rain forests has been questioned by some authors. Here we demonstrate that some previous attempts to prove or disprove the existence of such ant mosaics sampled by knockdown insecticide canopy fogging in near pristine tropical forests may have been thwarted by poor statistical power and too coarse spatial resolution, and the conclusions may be highly dependent on ant species and forest stratum selected for the study. Moreover, the presence or absence of ant mosaics may be driven by the density of suitable resources. We use an intensively studied ant community in the lowland rainforests of North-East Queensland, Australia to outline processes that may lead to ant mosaic patterns, reasoning that competition for highly predictable resources in space and time such as honeydew and nectar is a fundamental process to maintain the mosaic structure. Honeydew and nectar sources, particularly their amino acids, are of crucial importance for nourishment of arboreal ant species. We use canopy fogging data from the same site in Australia and from two mature rainforests in South-East Asia to compare spatial avoidance and co-occurrence patterns implied by ant mosaics. Significant negative and positive associations were found among the three most abundant ant species in each dataset. Several problems with such spatial analyses are discussed, and we suggest that studies of ant mosaics in complex rainforest communities would benefit from a more focused approach on patterns of resource distribution and their differential utilisation by ants. [ABSTRACT FROM AUTHOR]

This study describes the floristics and structure of a 0.95-ha lowland tropical rainforest plot at the Australian Canopy Crane Research Facility at Cape Tribulation, Queensland. Five years of post-cyclonic change in forest floristics and structure following the passage of Tropical Cyclone ‘Rona’ in February 1999 are examined. Local and regional variation in tropical rainforest is examined in comparison with other lowland plots established nearby and mid-elevation plots located elsewhere in north Queensland at Eungella, Paluma and the Atherton Tablelands. These plots are placed in a broader Australasian context along with lowland rainforest plots at Baitabag and Oomsis, Papua New Guinea. The 2005 survey found 680 stems of 82 species ≥10 cm d.b.h. on the crane plot, an increase of 30.3% in stems and 16.4% of species in the 5 years since the previous survey. The most abundant families were Meliaceae, Euphorbiaceae, Lauraceae, Myrtaceae and Apocynaceae and the most abundant species were Cleistanthus myrianthus, Alstonia scholaris, Myristica insipida, Normanbya normanbyi and Rockinghamia angustifolia. Temporal floristic and structural variation suggests that the crane site remains in an active stage of post-cyclonic recovery. Local spatial variability in floristics and structure at Cape Tribulation exceeded the variation exhibited by a single plot over a period of 5 years, despite the impact of Cyclone Rona. This finding suggests a high degree of temporal stability within this stand of rainforest despite frequent catastrophic disturbances. The rainforests of Cape Tribulation constitute a relatively unique floristic community when observed in an Australasian context. Variation in rainforest community composition across the region shows the importance of biogeographical connections, the impacts of local topography, environmental conditions and disturbance history. [ABSTRACT FROM AUTHOR]

We examined factors affecting roost tree selection by the white-striped freetail bat Tadarida australis (Chiroptera: Molossidae), a large insectivorous bat in suburban Brisbane, Australia. We compared biophysical characteristics associated with 34 roost trees and 170 control trees of similar diameter, height and tree senescence characters. Roost trees used by the white-striped freetail bat had significantly higher numbers of hollows in the trunk and branches ( P < 0.003) and were more likely to contain a large trunk cavity with an internal diameter of >30 cm ( P < 0.001) than control trees. These trees also accommodated more species of hollow-using fauna ( P = 0.005). When comparing roost trees with control trees of similar diameters and heights, roost trees were on average at a later stage of tree senescence ( P < 0.001). None of the roost trees were found in the large forest reserves fringing the Brisbane metropolitan area despite these areas being used for foraging by the white-striped freetail bat. Although all tree locations in this study were in modified landscapes, roost trees tended to be surrounded by groups of trees and undergrowth. Roost trees provide important habitat requirements for hollow-using fauna in suburban, rural and forested environments. [ABSTRACT FROM AUTHOR]

Cover provides shelter, food, nesting opportunities and protection from predators. The behavioural response of small mammals to reduced cover has been well documented. However, very little is known about the effect of cover on community and population dynamics. Australian small mammals generally inhabit extremely dynamic ecosystems, where cover and food supplies are greatly affected by fire. Species are described as early or late seral specialists, generally returning to a disturbed area once their habitat requirements are met. Habitat requirements have loosely been interpreted as cover and food supply, however, these factors are not mutually exclusive and few studies have attempted to determine the driving factors behind small mammal succession. In this study, we manipulated specific aspects of cover in the eucalypt forests of Fraser Island and show that the behaviour and population dynamics of small mammals were greatly affected. A reduction of cover from grass-trees ( Xanthorrhoea johnsonii) did not affect small mammal species composition, however, the abundance and size structure distribution of the dominant species ( Rattus fuscipes) decreased. Patch use by rodents also decreased after cover was reduced. Rattus fuscipes must trade-off remaining in an environment with increased risk of predation, or disperse to an area with greater cover but increased competition. Juveniles dominated (>60%) populations of R. fuscipes after cover was reduced, however, size distributions of control sites were relatively more even (<25% juvenile). While adult R. fuscipes are either killed by predators or disperse to other areas, juveniles that remained or immigrated to an area of reduced cover gained a selective advantage over those in control sites, because reduced competition with adults increased body condition of juvenile R. fuscipes. [ABSTRACT FROM AUTHOR]

Patch formation is common in grazed grasslands but the mechanisms involved in the formation and maintenance of patches are not clear. To increase our knowledge on this subject we examined possible reasons for patch formation and the influence of management on changes between patch states in three experiments in native pasture communities in the Crows Nest district, south-east Queensland. In these communities, small-scale patches (tall grassland (dominated by large and medium tussock grasses), short swards (dominated by short tussock grasses and sedges), and lawns (dominated by stoloniferous and/or rhizomatous grasses)) are readily apparent. We hypothesized that the formation of short sward and lawn patches in areas of tall grassland was due to combinations of grazing and soil fertility effects. This was tested in by applying a factorial combination of defoliation, nutrient application and transplants of short tussock and stoloniferous species to a uniform area of tall grassland. Total species density declined during the experiment, was lower with high nutrient applications, but was not affected by defoliation. There were significant changes in abundance of species that provided support for our hypotheses. With light defoliation and low nutrients, the tall grassland remained dominated by large tussock grasses and contained considerable amounts of forbs. With heavy defoliation, the pastures were dominated by medium tussock grasses and there were significant decreases in forbs and increases in sedges (mainly with low nutrients) and stoloniferous grasses (mainly with high nutrients). Total germinable seed densities and those of most species groups were significantly lower in the heavy defoliation than the light defoliation plots. Total soil seed numbers were not affected by nutrient application but there were fewer seeds of the erect forbs and more sedge seeds in plots with high nutrients. The use of resting from grazing and fire to manage transitions between patches was tested. In, changes in species density and abundance were measured for 5 years in the three patch types with and without grazing. examined the effects of fire, grazing and resting on short sward patches over 4 years. In, total species density was lower in lawn than short sward or tall grassland patches, and there were more species of erect forbs than other plant groups in all patch types. The lawn patches were originally dominated by Cynodon spp. This dominance continued with grazing but in ungrazed patches the abundance of Cynodon spp. declined and that of forbs increased. In the short sward patches, dominance of short tussock grasses continued with grazing but in ungrazed plots their abundance declined while that of large tussock grasses increased. The tall grassland patches remained dominated by large and medium tussock species. In, fire had no effect on species abundance. On the grazed plots the short tussock grasses remained dominant but where the plots were rested from grazing the small tussock grasses declined and the large tussock grasses increased in abundance. The slow and relatively small changes in these experiments over 4 or 5 years showed how stable the composition of these pastures is, and that rapid changes between patch types are unlikely. [ABSTRACT FROM AUTHOR]

The effects of recent fire frequency and time-since-fire on plant community composition and species abundance in open-forest and woodland vegetation in Girraween National Park, south-east Queensland, Australia, were examined. Cover-abundance data were collected for shrub and vine species in at least 10 400-m2 plots in each of four study areas. Study areas were within one community type and had burnt most recently either 4 or 9 years previously. Variations in fire frequency allowed us to compare areas that had burnt at least three times in the previous 25 years with less frequently burnt areas, and also woodlands that had experienced a 28-year interfire interval with more frequently burnt areas. Although species richness did not differ significantly with either time-since-fire or fire frequency, both these factors affected community composition, fire frequency being the more powerful. Moisture availability also influenced floristics. Of the 67 species found in five or more plots, six were significantly associated with time-since-fire, whereas 11 showed a significant difference between more and less frequently burnt plots in each of the two fire-frequency variables. Most species, however, did not vary in cover-abundance with the fire regime parameters examined. Even those species that showed a marked drop in cover-abundance when exposed to a particular fire regime generally maintained some presence in the community. Five species with the capacity to resprout after fire were considered potentially at risk of local extinction under regimes of frequent fire, whereas two species were relatively uncommon in long-unburnt areas. Variable fire regimes, which include interfire intervals of at least 15 years, could be necessary for the continuity of all species in the community. [ABSTRACT FROM AUTHOR]

Abstract The possibility that plants could serve as indicators of underlying soil salinity in northern Queensland, Australia, was investigated using 2197 site observations recorded during a land resources inventory of the Dalrymple Shire. The area surveyed intersects three biogeographical regions: the desert uplands, the Einasleigh uplands and the northern brigalow belt. The three dominant plant species in the lower, middle, and upper vegetation strata were recorded, along with laboratory measurements of electrical conductivity down each soil profile. Correspondence analysis, generalized additive models and clustering were used to investigate the relationship between plant occurrence, climatic and edaphic factors. The results of these statistical analyses strongly suggest a relationship between salinity and brigalow plant communities. A generalized additive model to predict soil salinity from environmental variables including vegetation data is presented. [ABSTRACT FROM AUTHOR]

Abstract This study aims primarily to assess the response of two invertebrate groups to the effects of pastoralism and military training, at one site in the tropical savanna of north-eastern Queensland. The richness and species composition of ants and terrestrial spiders were examined at two contrasting times of year across three land use treatments (pastoralism, military training and undisturbed) and four landscape positions (upper slope to riparian). Ant species richness was least in the grazed sites, and a high proportion of the ant species recorded varied significantly in frequency between the grazed and the two ungrazed land uses. This variation was generally greater than that associated with landscape position. Although variation in the richness of spiders was significantly related to land-use type, this effect was less pronounced than for ants, was less marked than variation associated with landscape position and was confounded by a strong interaction between land use and landscape position. Quadrat-scale variation in the composition of spider assemblages was influenced most by season of sampling. For both spiders and ants, there were few differences in richness or species composition between undisturbed land and that managed for military use. [ABSTRACT FROM AUTHOR]

AbstractAn analysis using an artificial neural network model suggests that the tropical forests of north Queensland are highly sensitive to climate change within the range that is likely to occur in the next 50–100 years. The distribution and extent of environments suitable for 15 structural forest types were estimated, using the model, in 10 climate scenarios that include warming up to 1°C and altered precipitation from –10% to +20%. Large changes in the distribution of forest environments are predicted with even minor climate change. Increased precipitation favours some rainforest types, whereas decreased rainfall increases the area suitable for forests dominated by sclerophyllous genera such as Eucalyptus and Allocasuarina. Rainforest environments respond differentially to increased temperature. The area of lowland mesophyll vine forest environments increases with warming, whereas upland complex notophyll vine forest environments respond either positively or negatively to temperature, depending on precipitation. Highland rainforest environments (simple notophyll and simple microphyll vine fern forests and thickets), the habitat for many of the region’s endemic vertebrates, decrease by 50% with only a 1°C warming. Estimates of the stress to present forests resulting from spatial shifts of forest environments (assuming no change in the present forest distributions) indicate that several forest types would be highly stressed by a 1°C warming and most are sensitive to any change in rainfall. Most forests will experience climates in the near future that are more appropriate to some other structural forest type. Thus, the propensity for ecological change in the region is high and, in the long term, significant shifts in the extent and spatial distribution of forests are likely. A detailed spatial analysis of the sensitivity to climate change indicates that the strongest effects of climate change will be experienced at boundaries between forest classes and in ecotonal communities between rainforest and open woodland. [ABSTRACT FROM AUTHOR]

The author looks at the scientific interest for researchers to study the above-ground layers of forest at the Australian Canopy Crane in the Downtree lowland rainforest of Queensland. He states that the area has a highly diverse and unique flora that makes in a heaven for scientific exploration and survey to its biological diversity. He also focuses on the environmental and climatic change in a tropical rain forest and what are the effects to its ecology.