Academic literature on the topic 'Atherton Tablelands'

Australia’s two cranes, the brolga (Antigone rubicunda) and Australian sarus crane (Antigone antigone gillae), form dry-season flocks on the Atherton Tablelands in north Queensland, Australia, where they forage almost exclusively amongst planted crops. The long-term relationship between cranes and farmers is therefore critical to their conservation, especially as the cranes can sometimes cause significant economic damage to crops. We interviewed farmers to explore their current attitudes to cranes and their intentions for land use that might affect the birds. We found that most farmers tolerated the cranes, particularly when they feed among stubble. Most, however, are increasing the efficiency of their agronomic practices, harvesting combinable crops such as maize and peanuts in ways that are beginning to reduce post-harvest crop residues. There is also a rapid trend away from field crops to perennial and tree crops that have a higher return per unit area. Both trends may reduce foraging opportunities for the cranes and, unless managed effectively, are likely to increase the potential for damage and conflict with farmers in the field crops that remain.

Lumholtz's Tree-kangaroo Dendrolagus lumholtzi is endemic to the rainforests of north Queensland, Australia. Most records of D. lumholtzi are from upland forests on the Atherton Tablelands, an area extensively cleared for agriculture. In 1997, residents of the Tablelands formed the Tree Kangaroo and Mammal Group Inc. (TKMG) with the aim of promoting the conservation of the species. The first project of TKMG was an intensive community-based survey of the distribution of D. lumholtzi. Residents of all postal districts encompassing areas of upland rainforest within the range of D. lumholtzi were sent a written questionnaire seeking details of tree-kangaroo sightings. The Malanda postal district was surveyed in 1998 while all other postal districts were surveyed in 1999. In total, 10 122 questionairres were distributed in the survey. "Nearly 800 responses were received to the survey, providing 2 368 sighting records of D. lumholtzi. Of these, 367 records were of dead tree-kangaroos, mostly road-kills." The survey has provided a much more comprehensive account of the distribution of the species than was previously available. Most records of D. lumholtzi obtained in the survey were from upland forests between Atherton and Ravenshoe, particularly remnant forests in the central and western Tablelands. Although the survey methodology is biased towards areas frequented by humans, these patterns are consistent with independent surveys. The conservation of D. lumholtzi on the Tablelands would benefit from the protection of remnant forests, the restoration of habitat and a reduction in the incidence of road-kills and dog attacks on tree-kangaroos.

Flocks of brolgas (Antigone rubicunda) and Australian sarus cranes (A. antigone gillae) congregate in cropping areas of the Atherton Tablelands in north Queensland, Australia, during the non-breeding months of May to December each year and sometimes come into conflict with farmers. The central part of the region has been declared a Key Biodiversity Area, largely because it is the only well known non-breeding area for the Australian sarus crane. We investigated spatial and temporal patterns of use of this landscape for foraging by the two species to determine how they might be affected by changes in cropping. Abundances of the species were positively correlated with each other over both time and space. Sarus cranes were nevertheless markedly more abundant on the fertile volcanic soils of the central Tablelands, whilst brolgas were more abundant on a variety of soils in outlying cropping areas close to roost sites, especially in the south-west of the region. Both species used a wide variety of crops and pastures but occurred at highest densities on ploughed land and areas from which crops (especially maize) had been harvested. In addition, brolgas were also strongly associated with early-stage winter cereals with volunteer peanuts from the previous crop. We conclude that maize and peanut crops are important as foraging sites for both species during the non-breeding season, a situation that requires management in the interest of both cranes and farmers, especially as cropping patterns intensify and agricultural technology changes. However, we also note that flocking on the Atherton Tablelands indicates that brolgas and sarus cranes are likely to be adaptable to change and able to take advantage of newly created cropping areas.

AbstractTo investigate the extent of suspected hybridization between the brolga Antigone rubicunda and the Australian sarus crane Antigone antigone gillae, first noted in the 1970s, we analysed the genetic diversity of 389 feathers collected from breeding and flocking areas in north Queensland, Australia. We compared these with 15 samples from birds of known identity, or that were phenotypically typical. Bayesian clustering based on 10 microsatellite loci identified nine admixed birds, confirming that Australian cranes hybridize in the wild. Four of these were backcrosses, also confirming that wild Australian crane hybrids are fertile. Genetic analyses identified 10 times more hybrids than our accompanying visual field observations. Our analyses also provide the first definitive evidence that both brolgas and sarus cranes migrate between the Gulf Plains, the principal breeding area for sarus cranes, and major non-breeding locations on the Atherton Tablelands. We suggest that genetic analysis of shed feathers could potentially offer a cost-effective means to provide ongoing monitoring of this migration. The first observations of hybrids coincided with significantly increased opportunities for interaction between the two species when foraging on agricultural crops, which have developed significantly in the Atherton Tablelands flocking area since the 1960s. As the sarus crane is declining in much of its Asian range, challenges to the genetic integrity of the Australian sarus crane populations have international conservation significance.

Observations of radio-tagged Common Blossom Bats Syconycteris australis on the Atherton Tablelands, Queensland indicate that the time of departure from roost areas is related to the lunar cycle. During the dark phase of the moon, bats leave their roost between 5-20 mins after dark. Departure times are delayed up to 4 hrs between the period of the first quarter and full moon when the moon is bright after dusk. The predatory role of owls at night is suggested as the probable cause of this behavioural change.

Effective conservation of large mammalian species within a human-modified landscape depends on the knowledge of their ability to utilise available suitable habitat within a matrix of unsuitable habitat. We use incidental sightings of Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) in north-eastern Australia that were recorded by community members in a non-standardised way to assess the functional connectivity of the highly fragmented landscape of the Atherton Tablelands for this species. By applying spatial analytical tools to available mapped information on landscape attributes and the reported sightings it was found that the species shows a low matrix resistance. Since most sightings within the matrix were found within 150 m of a patch with suitable habitat and the average distance between these patches was 77 m it can be concluded that Lumholtz’s tree-kangaroos are able to reach most fragmented suitable habitat given certain limitations of the accuracy of the used maps and sighting locations. Based on distances between suitable habitat patches and their predominant size of up to 2 ha we expect that the species can include several fragments into its home range. More sightings of Lumholtz’s tree-kangaroos than expected by chance within the matrix during dry seasons combined with shorter than expected distances into the matrix suggests the existence of seasonal resource-driven movements of this species. Due to the non-standardised nature of the data the derived conclusions need to be tested in rigorous scientific projects before they can be integrated into the development of conservation strategies for Lumholtz’s tree-kangaroos on the Atherton Tablelands.

The effect of windbreaks on the growth and yield of potatoes was measured over a 4-year period. Growth measures included the amount and severity of wind damage to leaves, plant height and number of leaves. Plots were located at various distances from the windbreak in both sheltered and unsheltered positions. The results of this project, while variable both within and between seasons, suggest that windbreaks increase the yield of potatoes between 4.8 and 9.3% for the sheltered portion of the paddock in seasons with higher than average wind speeds. A significant increase in yield has been observed between 3 H and 18 H (where H is the height of the windbreak) in seasons where wind speed was above average, although this result varied within seasons. Increased yield was attributed to a reduction in wind damage to leaves on plants growing in sheltered positions, where it was recorded.

Integrated molecular and morphological studies of newly collected and curated specimens of the genus Caridina from the Atherton Tablelands, Wet Tropics World Heritage Area in north–eastern Queensland, Australia indicated the presence of an undescribed species belonging to the Caridina zebra Short 1993 complex. This species is somewhat intermediate, although distinct on the basis of molecular data and morphology, from two known sympatric species, Caridina zebra and C. confusa Choy & Marshall 1997, and an allopatric species, C. spinula Choy & Marshall 1997, from the Cape York Peninsula, about 500 km north. It is described here as a new species, C. malanda sp. nov., and compared with similar congeners. A key for the identification of the species, as well as notes on its distribution, ecology, and conservation, are provided.

The Atherton Tablelands basalt aquifer is a major source of groundwater supply for irrigation and other agricultural use. The Tertiary to Quaternary age basaltic aquifer can be regarded as a generally unconfined, layered system, comprising numerous basalt flows separated by palaeo-weathering surfaces and minor alluvial gravels of palaeo-drainage channels. Layers of massive basalt and clay-rich weathered zones act as local aquitards, with some local perched aquifers also present. The aquifer is regarded as a system in which several factors interact to produce the overall characteristics of the hydrogeochemistry of the groundwaters. They include the mineralogical composition of both the basalt aquifer and the thick overlying weathered zone, the porosity and permeability of the basalt aquifer, its thickness, bedrock composition, and climate and topography. The hydrogeochemical processes operating in this aquifer system have been investigated though the analysis of 90 groundwater samples collected from October 1998 to October 1999, groundwater chemistry data provided by the Queensland Department of Natural Resources & Mines for more than 800 groundwater samples, rain water samples collected during 1999 by CSIRO, stream chemistry data provided by CSIRO and James Cook University, and mineralogical and whole rock geochemistry data of drill chip samples. The methods used in this research study include the assessment of groundwater major ion chemistry data and field physico-chemical parameters using hydrochemical facies and statistical approaches, investigation of the mineralogical composition of the aquifer, assessment of concentrations and activities of the ions in solution, the degree of saturation with respect to both primary and secondary minerals, and hydrogeochemical modelling to determine the likely controls on the chemical evolution of these groundwaters. The basaltic groundwaters are mostly Mg-Ca-Na, HCO3 type waters, with electrical conductivities generally less than 250 μS/cm and pH values from 6.5 to 8.5. Dissolved silica (H4SiO4) comprises a large proportion of the total dissolved load, with average concentrations of around 140 mg/L. Concentrations of potassium, chloride and sulphate are low, that is, generally less than 3 mg/L, 15 mg/L and 10 mg/L, respectively. Despite the very low salinity of the Atherton Tablelands basalt groundwaters, the relative concentrations of the major ions are comparable to groundwaters from other basaltic regions, and are consistent with expected waterrock interactions. A variety of multivariate statistical techniques may be used to aid in the analysis of hydrochemical data, including for example, principal component analysis, factor analysis and cluster analysis. Principal component factor analyses undertaken using the hydrochemical data for the Atherton groundwaters has enabled the differentiation of groundwaters from various lithological formations, the underlying geochemical processes controlling groundwater composition in the basalt aquifer to be inferred, relative groundwater residence and flow directions to be inferred and mapping of the estimated thickness of the basalt aquifer. The limitations of multivariate statistical methods have been examined, with emphasis on the issues pertinent to hydrochemical data, that is, data that are compositional and typically, non-normally distributed. The need to validate, normalize and standardize hydrochemical data prior to the application of multivariate statistical methods is demonstrated. Assessment of the saturation states of the Atherton basalt groundwaters with respect to some of the primary minerals present indicate that the groundwaters are mostly at equilibrium or saturated with respect to K-feldspar, and approach equilibrium with respect to the plagioclase feldspars (albite and anorthite) with increasing pH. These groundwaters are at equilibrium or saturated with respect to the major secondary minerals, kaolinite, smectite (Ca-montmorillonite) and gibbsite. They also tend to be saturated with respect to the oxidation products, goethite and hematite, common accessory minerals in the Atherton Tablelands basalt sequence. Silicate mineral weathering processes are the predominant influence on the composition of these basalt groundwaters. These weathering processes include the weathering of pyroxenes, feldspars and other primary minerals to clays, aluminium and iron oxides, amorphous or crystalline silica, carbonates and zeolites, releasing ions to solution. The contribution of substantial organic carbon dioxide to the groundwater is an important factor in the extent to which silicate mineral weathering occurs in this aquifer system. Evaporative enrichment of recharging waters, oxidation and ion-exchange reactions and the uptake of ions from, and decomposition of, organic matter, are processes that have a minor influence on the composition of the basalt groundwaters. The relationships observed between mineralogical compositions, basalt character and groundwater occurrence in the Atherton Tablelands region improved the understanding how groundwater is stored and transmitted in this basalt aquifer system. Groundwater is mostly stored in vesicular basalt that may be fresh to highly weathered, and movement of this water is facilitated by pathways through both vesicular and fractured basalt. Related work undertaken as part of this research project showed that the groundwater flow patterns defined by the hydrogeochemical interpretations correspond well with the spatial trends in water level fluctuations, and response to recharge events in particular. Groundwater baseflow to streams and discharge to topographic lows in the Atherton Tablelands region is indicated by the relationships between the major cations and anions in the stream waters. Fracture zones are likely to be preferred pathways of groundwater movement. Recharge estimates, based on a chloride mass balance, range from 310 mm/yr in the north-western part of the study area (north of Atherton) to 600 mm/yr in the wetter southern and eastern parts of the study area. These recharge estimates should be treated with caution however, due to the low groundwater chloride concentrations and the high variability in rainfall chloride concentrations. The findings of this research project have improved the understanding of the hydrogeochemical processes controlling the composition of the low salinity basalt groundwaters in the Atherton Tablelands region, and are applicable to other basalt groundwater systems, particularly those in high rainfall environments.

The Atherton Tablelands basalt aquifer is a major source of groundwater supply for irrigation and other agricultural use. The Tertiary to Quaternary age basaltic aquifer can be regarded as a generally unconfined, layered system, comprising numerous basalt flows separated by palaeo-weathering surfaces and minor alluvial gravels of palaeo-drainage channels. Layers of massive basalt and clay-rich weathered zones act as local aquitards, with some local perched aquifers also present. The aquifer is regarded as a system in which several factors interact to produce the overall characteristics of the hydrogeochemistry of the groundwaters. They include the mineralogical composition of both the basalt aquifer and the thick overlying weathered zone, the porosity and permeability of the basalt aquifer, its thickness, bedrock composition, and climate and topography. The hydrogeochemical processes operating in this aquifer system have been investigated though the analysis of 90 groundwater samples collected from October 1998 to October 1999, groundwater chemistry data provided by the Queensland Department of Natural Resources & Mines for more than 800 groundwater samples, rain water samples collected during 1999 by CSIRO, stream chemistry data provided by CSIRO and James Cook University, and mineralogical and whole rock geochemistry data of drill chip samples. The methods used in this research study include the assessment of groundwater major ion chemistry data and field physico-chemical parameters using hydrochemical facies and statistical approaches, investigation of the mineralogical composition of the aquifer, assessment of concentrations and activities of the ions in solution, the degree of saturation with respect to both primary and secondary minerals, and hydrogeochemical modelling to determine the likely controls on the chemical evolution of these groundwaters. The basaltic groundwaters are mostly Mg-Ca-Na, HCO3 type waters, with electrical conductivities generally less than 250 μS/cm and pH values from 6.5 to 8.5. Dissolved silica (H4SiO4) comprises a large proportion of the total dissolved load, with average concentrations of around 140 mg/L. Concentrations of potassium, chloride and sulphate are low, that is, generally less than 3 mg/L, 15 mg/L and 10 mg/L, respectively. Despite the very low salinity of the Atherton Tablelands basalt groundwaters, the relative concentrations of the major ions are comparable to groundwaters from other basaltic regions, and are consistent with expected waterrock interactions. A variety of multivariate statistical techniques may be used to aid in the analysis of hydrochemical data, including for example, principal component analysis, factor analysis and cluster analysis. Principal component factor analyses undertaken using the hydrochemical data for the Atherton groundwaters has enabled the differentiation of groundwaters from various lithological formations, the underlying geochemical processes controlling groundwater composition in the basalt aquifer to be inferred, relative groundwater residence and flow directions to be inferred and mapping of the estimated thickness of the basalt aquifer. The limitations of multivariate statistical methods have been examined, with emphasis on the issues pertinent to hydrochemical data, that is, data that are compositional and typically, non-normally distributed. The need to validate, normalize and standardize hydrochemical data prior to the application of multivariate statistical methods is demonstrated. Assessment of the saturation states of the Atherton basalt groundwaters with respect to some of the primary minerals present indicate that the groundwaters are mostly at equilibrium or saturated with respect to K-feldspar, and approach equilibrium with respect to the plagioclase feldspars (albite and anorthite) with increasing pH. These groundwaters are at equilibrium or saturated with respect to the major secondary minerals, kaolinite, smectite (Ca-montmorillonite) and gibbsite. They also tend to be saturated with respect to the oxidation products, goethite and hematite, common accessory minerals in the Atherton Tablelands basalt sequence. Silicate mineral weathering processes are the predominant influence on the composition of these basalt groundwaters. These weathering processes include the weathering of pyroxenes, feldspars and other primary minerals to clays, aluminium and iron oxides, amorphous or crystalline silica, carbonates and zeolites, releasing ions to solution. The contribution of substantial organic carbon dioxide to the groundwater is an important factor in the extent to which silicate mineral weathering occurs in this aquifer system. Evaporative enrichment of recharging waters, oxidation and ion-exchange reactions and the uptake of ions from, and decomposition of, organic matter, are processes that have a minor influence on the composition of the basalt groundwaters. The relationships observed between mineralogical compositions, basalt character and groundwater occurrence in the Atherton Tablelands region improved the understanding how groundwater is stored and transmitted in this basalt aquifer system. Groundwater is mostly stored in vesicular basalt that may be fresh to highly weathered, and movement of this water is facilitated by pathways through both vesicular and fractured basalt. Related work undertaken as part of this research project showed that the groundwater flow patterns defined by the hydrogeochemical interpretations correspond well with the spatial trends in water level fluctuations, and response to recharge events in particular. Groundwater baseflow to streams and discharge to topographic lows in the Atherton Tablelands region is indicated by the relationships between the major cations and anions in the stream waters. Fracture zones are likely to be preferred pathways of groundwater movement. Recharge estimates, based on a chloride mass balance, range from 310 mm/yr in the north-western part of the study area (north of Atherton) to 600 mm/yr in the wetter southern and eastern parts of the study area. These recharge estimates should be treated with caution however, due to the low groundwater chloride concentrations and the high variability in rainfall chloride concentrations. The findings of this research project have improved the understanding of the hydrogeochemical processes controlling the composition of the low salinity basalt groundwaters in the Atherton Tablelands region, and are applicable to other basalt groundwater systems, particularly those in high rainfall environments.

This study investigated the utility to vertebrates of upland linear riparian rainforest fragments on the Atherton and Evelyn Tablelands in the Australian Wet Tropics region, north Queensland. Similar linear fragments were selected, that varied in forest age and their connectivity to large areas of continuous forest:- (connected primary (N=6), isolated primary (N=5), connected secondary (N=6) and isolated secondary (N=7)). Primary sites had either never been cleared or only subject to selective logging, while secondary forest had been completely cleared and allowed to regenerate for at least 30 years. These linear fragments were contrasted with riparian sites within continuous forest sites (N=6 to 7), which were situated in State Forest or National Parks, and sites within the cleared matrix (pasture, N=6). Vertebrates surveyed were birds, ground-dwelling mammals and reptiles, particularly leaf-litter skinks. All surveys were conducted between September and December in 2001 and/or 2000. Chapter 2 investigates the effects of forest age, isolation and structural vegetation features on bird assemblages within linear riparian fragments of rainforest. Bird surveys and structural vegetation assessments were conducted within connected and isolated primary and secondary linear fragments, and compared with those of continuous forest habitat (N=6) and pasture. There were strong effects of forest age; all three types of primary rainforest had higher values than secondary rainforest for most measured attributes of vegetation structure (including canopy height and cover; and frequency of large-diameter trees, lianes, epiphytes, strangler figs; and woody debris), but lower frequencies of tree ferns and thorny scramblers. Sites within primary rainforest also had a greater frequency of many bird species across different guilds of habitat, feeding and movement. Assemblages of rainforest-dependent birds showed an effect of isolation, although its strength was less than that of forest age. Isolated fragments of primary rainforest differed significantly from continuous primary rainforest in their rainforest-dependent bird species assemblages (and had lower species richness), and isolated fragments of secondary rainforest differed from those that were connected. There was a significant association between the species composition of rainforest birds and some measured vegetation parameters across all sites, but not within primary or secondary sites. Vegetation differences did not explain the lowered frequency of several species in isolated fragments. Limited dispersal seems unlikely to be a main cause, and causal processes probably vary among species. Specialist rainforest species endemic to the Wet Tropics region showed stronger responses to present-day rainforest age and fragmentation than those not endemic. Variation in nest depredation levels associated with rainforest fragmentation (edge effects) is examined in Chapter 3. Artificial nests were placed in the forest understorey at seven edge sites where continuous forest adjoined pasture, seven interiors (about one kilometre from the edge), and six primary linear riparian forest remnants (50-100 m wide) that were connected to continuous forest. Four nest types were compared, representing different combinations of two factors; height (ground, shrub) and shape (open, domed). At each site, four nests of each type, containing one quail egg and two model plasticine eggs, were interspersed about 15 m apart within a 160 m transect. Predators were identified from marks on the plasticine eggs. The overall depredation rate was 66.5% of 320 nests' contents damaged over a three-day period. Large rodents, especially the rat Uromys caudimaculatus, and birds, especially the spotted catbird Ailuroedus melanotis, were the main predators. Mammals comprised 56.5% and birds 31.0% of identified predators, with 12.5% of unknown identity. The depredation rate did not vary among site-types, or between open and domed nests, and there were no statistically significant interactions. Nest height strongly affected depredation rates by particular types of predator; depredation rates by mammals were highest at ground nests, whereas attacks by birds were most frequent at shrub nests. These effects counterbalanced so that overall there was little net effect of nest height. Mammals accounted for 78.4% of depredated ground nests and birds for at least 47.4% of shrub nests (and possibly up to 70.1%). The main predators were species characteristic of rainforest, rather than habitat generalists, open-country or edge specialists. For birds that nest in the tropical rainforest understorey of the study region, it is unlikely that edges and linear remnants presently function as ecological population sinks due to mortality associated with increased nest depredation. The use of linear riparian remnants by small ground-dwelling mammals and reptiles (mainly leaf litter skinks), is reported in Chapter 4. Site types were continuous rainforest, connected and isolated linear fragments of both uncleared primary rainforest and secondary regrowth rainforest. Mammals were also surveyed in pasture sites. Neither reptile species richness nor abundance varied significantly among site types. Although mammal species richness varied significantly between site types, with isolated primary sites containing highest species richness, overall mammal abundance did not differ significantly among site types. Pasture sites differed significantly from all rainforest sites in their mammal species composition, and were dominated by the introduced house mouse (Mus musculus). This species was absent from all rainforest sites, which were characterised by moderate abundances of bush rat/Cape York rat Rattus fuscipes/leucopus, fawn-footed melomys Melomys cervinipes and giant white-tailed rat Uromys caudimaculatus. None of these species varied significantly in abundance among site types, although the giant white-tailed rat showed a trend (P=0.09) for reduced abundance in isolated secondary sites. A single reptile species, the prickly forest skink Gnypetoscincus queenslandiae, occurred in sufficient numbers for individual analysis, and its abundance varied significantly among the forested site types, being less abundant in all linear fragments than in continuous forest sites. The utility of linear riparian rainforest for vertebrates appears to be species-specific and involves many factors. However, overall, species endemic to the Wet Tropics (which are hence of the highest conservation significance) appear to be the most sensitive to fragmentation. These species were most likely to show altered abundances or frequencies of occurrence due to isolation, forest age, and habitat linearity. The ecology of species within this group warrants further investigation within fragmented and non-fragmented regions of the Tablelands. For many other vertebrates examined in this study, there appears to be sufficient functional connectedness between remnants on the Tablelands to minimise the effects of fragmentation. Nevertheless, the lower density of many of these species in pasture may indicate that their long-term persistence within the fragmented rainforest areas could benefit from the maintenance or establishment of habitat linkages. Certainly, if the current rainforest vegetation cover were further reduced, or if the land use in the matrix became more intensive, the establishment of specific habitat linkages could become more important as existing dispersal routes could be lost. It also appears that nest depredation levels are unlikely to limit the value of linear rainforest remnants and other small rainforest remnants as breeding habitat for birds (at least for understorey-nesting species), relative to more intact rainforest, in the study region.

This study investigated the utility to vertebrates of upland linear riparian rainforest fragments on the Atherton and Evelyn Tablelands in the Australian Wet Tropics region, north Queensland. Similar linear fragments were selected, that varied in forest age and their connectivity to large areas of continuous forest:- (connected primary (N=6), isolated primary (N=5), connected secondary (N=6) and isolated secondary (N=7)). Primary sites had either never been cleared or only subject to selective logging, while secondary forest had been completely cleared and allowed to regenerate for at least 30 years. These linear fragments were contrasted with riparian sites within continuous forest sites (N=6 to 7), which were situated in State Forest or National Parks, and sites within the cleared matrix (pasture, N=6). Vertebrates surveyed were birds, ground-dwelling mammals and reptiles, particularly leaf-litter skinks. All surveys were conducted between September and December in 2001 and/or 2000. Chapter 2 investigates the effects of forest age, isolation and structural vegetation features on bird assemblages within linear riparian fragments of rainforest. Bird surveys and structural vegetation assessments were conducted within connected and isolated primary and secondary linear fragments, and compared with those of continuous forest habitat (N=6) and pasture. There were strong effects of forest age; all three types of primary rainforest had higher values than secondary rainforest for most measured attributes of vegetation structure (including canopy height and cover; and frequency of large-diameter trees, lianes, epiphytes, strangler figs; and woody debris), but lower frequencies of tree ferns and thorny scramblers. Sites within primary rainforest also had a greater frequency of many bird species across different guilds of habitat, feeding and movement. Assemblages of rainforest-dependent birds showed an effect of isolation, although its strength was less than that of forest age. Isolated fragments of primary rainforest differed significantly from continuous primary rainforest in their rainforest-dependent bird species assemblages (and had lower species richness), and isolated fragments of secondary rainforest differed from those that were connected. There was a significant association between the species composition of rainforest birds and some measured vegetation parameters across all sites, but not within primary or secondary sites. Vegetation differences did not explain the lowered frequency of several species in isolated fragments. Limited dispersal seems unlikely to be a main cause, and causal processes probably vary among species. Specialist rainforest species endemic to the Wet Tropics region showed stronger responses to present-day rainforest age and fragmentation than those not endemic. Variation in nest depredation levels associated with rainforest fragmentation (edge effects) is examined in Chapter 3. Artificial nests were placed in the forest understorey at seven edge sites where continuous forest adjoined pasture, seven interiors (about one kilometre from the edge), and six primary linear riparian forest remnants (50-100 m wide) that were connected to continuous forest. Four nest types were compared, representing different combinations of two factors; height (ground, shrub) and shape (open, domed). At each site, four nests of each type, containing one quail egg and two model plasticine eggs, were interspersed about 15 m apart within a 160 m transect. Predators were identified from marks on the plasticine eggs. The overall depredation rate was 66.5% of 320 nests' contents damaged over a three-day period. Large rodents, especially the rat Uromys caudimaculatus, and birds, especially the spotted catbird Ailuroedus melanotis, were the main predators. Mammals comprised 56.5% and birds 31.0% of identified predators, with 12.5% of unknown identity. The depredation rate did not vary among site-types, or between open and domed nests, and there were no statistically significant interactions. Nest height strongly affected depredation rates by particular types of predator; depredation rates by mammals were highest at ground nests, whereas attacks by birds were most frequent at shrub nests. These effects counterbalanced so that overall there was little net effect of nest height. Mammals accounted for 78.4% of depredated ground nests and birds for at least 47.4% of shrub nests (and possibly up to 70.1%). The main predators were species characteristic of rainforest, rather than habitat generalists, open-country or edge specialists. For birds that nest in the tropical rainforest understorey of the study region, it is unlikely that edges and linear remnants presently function as ecological population sinks due to mortality associated with increased nest depredation. The use of linear riparian remnants by small ground-dwelling mammals and reptiles (mainly leaf litter skinks), is reported in Chapter 4. Site types were continuous rainforest, connected and isolated linear fragments of both uncleared primary rainforest and secondary regrowth rainforest. Mammals were also surveyed in pasture sites. Neither reptile species richness nor abundance varied significantly among site types. Although mammal species richness varied significantly between site types, with isolated primary sites containing highest species richness, overall mammal abundance did not differ significantly among site types. Pasture sites differed significantly from all rainforest sites in their mammal species composition, and were dominated by the introduced house mouse (Mus musculus). This species was absent from all rainforest sites, which were characterised by moderate abundances of bush rat/Cape York rat Rattus fuscipes/leucopus, fawn-footed melomys Melomys cervinipes and giant white-tailed rat Uromys caudimaculatus. None of these species varied significantly in abundance among site types, although the giant white-tailed rat showed a trend (P=0.09) for reduced abundance in isolated secondary sites. A single reptile species, the prickly forest skink Gnypetoscincus queenslandiae, occurred in sufficient numbers for individual analysis, and its abundance varied significantly among the forested site types, being less abundant in all linear fragments than in continuous forest sites. The utility of linear riparian rainforest for vertebrates appears to be species-specific and involves many factors. However, overall, species endemic to the Wet Tropics (which are hence of the highest conservation significance) appear to be the most sensitive to fragmentation. These species were most likely to show altered abundances or frequencies of occurrence due to isolation, forest age, and habitat linearity. The ecology of species within this group warrants further investigation within fragmented and non-fragmented regions of the Tablelands. For many other vertebrates examined in this study, there appears to be sufficient functional connectedness between remnants on the Tablelands to minimise the effects of fragmentation. Nevertheless, the lower density of many of these species in pasture may indicate that their long-term persistence within the fragmented rainforest areas could benefit from the maintenance or establishment of habitat linkages. Certainly, if the current rainforest vegetation cover were further reduced, or if the land use in the matrix became more intensive, the establishment of specific habitat linkages could become more important as existing dispersal routes could be lost. It also appears that nest depredation levels are unlikely to limit the value of linear rainforest remnants and other small rainforest remnants as breeding habitat for birds (at least for understorey-nesting species), relative to more intact rainforest, in the study region
Thesis (Masters)
Master of Philosophy (MPhil)
Australian School of Environmental Studies
Full Text

Thesis (M.Phil.) -- Griffith University, 2004.
Facsimile of the author's original dissertation. Pagination of document: x, 121 leaves. Includes bibliographical references. Also available online via the World Wide Web.

Lumholtz’s tree-kangaroo (Dendrolagus Iumholtzi), one of Australia’s largest folivores and one of only two tree-kangaroo species endemic to Australia and far north Queensland’s Wet Tropics. D. Iumholtzi are most commonly found in the fragmented rainforests that remain within an agricultural matrix in a relatively small area on the Atherton Tablelands. Unfortunately the majority of these fragments are on privately owned land and are not totally protected from clearing, therefore their long-term persistence is threatened by land clearing, further habitat fragmentation and mortality from dogs and cars. Although there have been a few studies on the ecology and habitat use of D. Iumholtzi, our current knowledge is limited. A more comprehensive understanding of spatial and floristic habitat use is essential for the conservation and management of D. Iumholtzi. This study examined the spatial organisation and habitat utilisation of Lumholtz’s tree-kangaroos in a Type lb rainforest fragment on the Atherton Tablelands and compared this to earlier studies (Procter-Gray 1985, Newell 1999). The two previous studies were both undertaken on the same spatially restricted rainforest type (Type Sb) only a couple of hundred metres apart, so this study has provided an important expansion of our understanding of D. Iumholtzi ecology across space and rainforest types. There were no significant effects of rainforest type on the home range sizes of D. Iumholtzi (Procter-Gray 1985, Newell 1999, This study). Male D. Iumholtziin this study held home ranges of 2.1 ± 0.7 ha (90% HM) overlapping that of several females but not other males, and females had exclusive home ranges of 2.1 ± 0.8 ha (90% HM) of a similar size to males. However, there was a large amount of variation in female home range sizes (0.1 —4.9 ha). Body weight did not explain this variation in home range sizes. This study also examined structural and floristic characteristics of the habitat and investigated if these could be used to model D. Iumholtzi habitat usage. The structural and floristic characters measured in this study could not be used to determine the focus of habitat usage. This study has shown that there is a more complex association between D. Iumholtzi and its use of habitat other than the structural characters of the habitat. D. Iumholtzi do select specific tree species, but there are strongly expressed individual preferences, similar to other arboreal folivores. The reasons for these specific choices are currently unclear but D. Iumholtzi are likely to choose trees for foliage characters, such as the levels of nutrients or plant defences, rather than for the species at a taxonomic level. This is also consistent with other arboreal folivores such as koalas and leaf-eating monkeys. The determination of which foliar characters are driving tree species or individual tree choice will require further research. This study tested and rejected a number of previous hypotheses regarding the characteristics determining D. Iumholtzi habitat use. They are not edge specialists, do not prefer regrowth or areas with a large variation in canopy height, or areas with high species diversity or density. The gastrointestinal morphology of D. Iumholtzi shares a number of features with other foregut fermenting folivores. Compared to other macropodids, D. Iumholtzi has a large sacciform forestomach and a large overall stomach capacity, and more similar in size and morphology to that of other arboreal foregut fermenting folivores, such as colobine monkeys. It is likely that these characteristics are adaptive for its diet of rainforest leaves. Lumholtz’s tree-kangaroos can be simply aged using a tooth wear index developed during this study. Aging is essential for establishing demographics, such as age specific mortality and fecundity of populations, currently unknown in D. Iumholtzi. Without the ability to age populations we cannot reliably undertake valuable estimations such as population viability analysis, which require these parameters. Additionally, this study has highlighted that not only one rainforest type is important to D. Iumholtzi and that more emphasis should be made on the preservation and restoration of all rainforest types. Furthermore, it is vital that all rainforest fragments including riparian zones, regrowth and corridors and stepping stones, should be conserved, rehabilitated and areas replanted as D. Iumholtzi habitat, as they are crucial to the species long term survival.

Lumholtz’s tree-kangaroo (Dendrolagus Iumholtzi), one of Australia’s largest folivores and one of only two tree-kangaroo species endemic to Australia and far north Queensland’s Wet Tropics. D. Iumholtzi are most commonly found in the fragmented rainforests that remain within an agricultural matrix in a relatively small area on the Atherton Tablelands. Unfortunately the majority of these fragments are on privately owned land and are not totally protected from clearing, therefore their long-term persistence is threatened by land clearing, further habitat fragmentation and mortality from dogs and cars. Although there have been a few studies on the ecology and habitat use of D. Iumholtzi, our current knowledge is limited. A more comprehensive understanding of spatial and floristic habitat use is essential for the conservation and management of D. Iumholtzi. This study examined the spatial organisation and habitat utilisation of Lumholtz’s tree-kangaroos in a Type lb rainforest fragment on the Atherton Tablelands and compared this to earlier studies (Procter-Gray 1985, Newell 1999). The two previous studies were both undertaken on the same spatially restricted rainforest type (Type Sb) only a couple of hundred metres apart, so this study has provided an important expansion of our understanding of D. Iumholtzi ecology across space and rainforest types. There were no significant effects of rainforest type on the home range sizes of D. Iumholtzi (Procter-Gray 1985, Newell 1999, This study). Male D. Iumholtziin this study held home ranges of 2.1 ± 0.7 ha (90% HM) overlapping that of several females but not other males, and females had exclusive home ranges of 2.1 ± 0.8 ha (90% HM) of a similar size to males. However, there was a large amount of variation in female home range sizes (0.1 —4.9 ha). Body weight did not explain this variation in home range sizes. This study also examined structural and floristic characteristics of the habitat and investigated if these could be used to model D. Iumholtzi habitat usage. The structural and floristic characters measured in this study could not be used to determine the focus of habitat usage. This study has shown that there is a more complex association between D. Iumholtzi and its use of habitat other than the structural characters of the habitat. D. Iumholtzi do select specific tree species, but there are strongly expressed individual preferences, similar to other arboreal folivores. The reasons for these specific choices are currently unclear but D. Iumholtzi are likely to choose trees for foliage characters, such as the levels of nutrients or plant defences, rather than for the species at a taxonomic level. This is also consistent with other arboreal folivores such as koalas and leaf-eating monkeys. The determination of which foliar characters are driving tree species or individual tree choice will require further research. This study tested and rejected a number of previous hypotheses regarding the characteristics determining D. Iumholtzi habitat use. They are not edge specialists, do not prefer regrowth or areas with a large variation in canopy height, or areas with high species diversity or density. The gastrointestinal morphology of D. Iumholtzi shares a number of features with other foregut fermenting folivores. Compared to other macropodids, D. Iumholtzi has a large sacciform forestomach and a large overall stomach capacity, and more similar in size and morphology to that of other arboreal foregut fermenting folivores, such as colobine monkeys. It is likely that these characteristics are adaptive for its diet of rainforest leaves. Lumholtz’s tree-kangaroos can be simply aged using a tooth wear index developed during this study. Aging is essential for establishing demographics, such as age specific mortality and fecundity of populations, currently unknown in D. Iumholtzi. Without the ability to age populations we cannot reliably undertake valuable estimations such as population viability analysis, which require these parameters. Additionally, this study has highlighted that not only one rainforest type is important to D. Iumholtzi and that more emphasis should be made on the preservation and restoration of all rainforest types. Furthermore, it is vital that all rainforest fragments including riparian zones, regrowth and corridors and stepping stones, should be conserved, rehabilitated and areas replanted as D. Iumholtzi habitat, as they are crucial to the species long term survival.

Insects are well recognised as being the major contributor to global biodiversity, and for their critical involvement in many biotic interactions. Most of the insect diversity is found in tropical rainforests. However, these forests are threatened by high rates of clearing and the subsequent fragmentation of remaining habitat. The effects on biota, particularly insects, are poorly understood as are the mechanisms mediating faunal changes. Reforestation could potentially alleviate some of the deleterious effects of forest loss and fragmentation. However, because reforestation is a relatively new endeavour, it is little known just how much insect biodiversity can be supported by reforestation and what factors influence insect colonisation. These issues were investigated in the Atherton Tablelands of north-eastern Australia, a landscape whose rainforest has been heavily cleared and fragmented over the last 80 years, but is also the focus of reforestation efforts. To quantify the effects of rainforest loss and fragmentation, pasture sites were compared with small rainforest fragments, and with the edges and interiors of large rainforest fragments (24 sites in total). Sites with replanted rainforest (planted with a high diversity of plants) were also included. These varied in their age (2-17 yrs) and their distance (0-4.5 km) from existing rainforest (24 sites in total). Another set of reforested sites was also studied but these differed in their planting style (number of plant species, spacing etc). This second set of sites was located in two regions: the Atherton Tablelands (50 sites), and in the subtropics of eastern Australia (54 sites). At each site, beetle assemblages were surveyed using methods that sample beetles near the ground (four ground-based flight interception traps in the first set of sites and ten pitfall traps in the second set of sites), and then the assemblages among site-types were compared. Over 32,000 beetles were caught and identified to the level of family, and of these, 15,206 were identified further to the level of species. Very few beetle species were present in pasture, suggesting that converting rainforest into pasture has a very strong negative effect on beetle diversity and species composition. Irrespective of rainforest fragment size, beetle species composition in drier rainforest habitats was different from that of moister rainforest. Beetle species composition also differed between small remnants and interior rainforest: drier-associated species were more abundant in small remnants, whereas wetter-associated species were more abundant in interiors. This pattern can be best attributed to a fragmentation effect mediated by differences in microclimate. With the exception of differences between rainforest and pasture, these results were generally not observed among beetle assemblages identified to coarser taxonomic groups (family, feeding guild, and body size). Among replanted rainforest, older sites and those adjacent to rainforest had a more rainforest-like beetle species composition. However, even the closer and older sites had a substantially lower abundance and richness of rainforest-associated beetles than did rainforest. Age effects were generally stronger than distance effects. Beetle assemblage similarity to rainforest was more strongly correlated with structural similarity to rainforest than with site age or distance from rainforest. Thus the use of revegetation techniques which lead to more rainforest-like structural conditions appears to be of over-riding importance in catalysing the rapid acquisition of rainforest beetle assemblages in the initial stages of restoration. Nevertheless, not all beetle species were equally affected by the factors tested. Large-bodied beetle species (>5 mm) were more strongly influenced by distance than small-bodied species (<5 mm), suggesting that small-bodied species are better dispersers, and thus are amongst the first to colonise new habitats. Spatial ubiquity in rainforest was not a good predictor of a species' dispersal ability. Interestingly, fewer of the broader groups (family, feeding guild, and body size) showed the response to distance evident at the species level although they showed differences between reforested sites differing in age, and between reforested and reference site-types. Therefore, these results and those from the fragmentation study suggest that information at the species level is more sensitive to environmental change than data identified to a coarser level of taxonomy or grouped according to feeding ecology or body size. For the pitfall-trapped beetles in the second reforested site network, beetle assemblages in all styles of reforestation were intermediate in species composition between pasture and rainforest. The similarity of beetle assemblages to intact rainforest increased with the age and structural complexity of reforested sites, although again structural complexity appeared to be of overriding importance. This study has shown that even small patches of rainforest and reforested areas can support diverse rainforest-dependent beetle assemblages. A range of factors influence the development of beetle assemblages in reforested sites although not all species are equally affected. However, even structurally complex reforested sites cannot provide a short- or medium-term substitute for the retention of intact rainforest.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
Faculty of Environmental Studies
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