Description:
Solute import-export dynamics in groundwater (GW) systems interacting with surface-water are complex, particularly under farming systems receiving high fertiliser/pesticide inputs in high rainfall regions. We investigated whether any linkage existed between nitrate-N in: (i) leachate (LC) collected at similar to 1m depth under banana (Musa) and that in GW, and (ii) GW and drain-water (DW). We also assessed the hazard/risk of the concentrations against the trigger values proposed for the sustainable health of different aquatic ecosystems. The LC, GW, and DW samples were collected at short intervals during 3 consecutive rainy seasons (January-July) from a similar to 300-ha banana farm in the wet tropical Tully River Catchment in north-east Queensland, Australia. Water samples were analysed for nitrate-N, dissolved organic carbon, and electrical conductivity. The coefficients of variation, ranging from 13 to 132%, obtained for solute concentrations in LC, GW, and DW indicated large within-and between-season temporal variations. The mean nitrate-N concentrations in LC, GW, and DW were 5320, 4135, and 1976 mu g/L, respectively, and were orders of magnitude higher than the trigger values proposed for the sustainable health of most of the neighbouring aquatic ecosystems. Significant positive associations, with correlation coefficients ranging from 0.56 to 0.96, existed between rainfall received and LC volume collected, and between LC volume and solute concentration, including nitrate-N, in the LC. Similar associations existed between the solutes in (i) LC and GW and (ii) GW and DW. From these associations we conclude the unused/under-utilised nitrate that leached below the root-zone was imported into the GW by the percolating rainwater and was exported into the drain via GW base-flow discharge.
Description:
Solute import-export dynamics in groundwater (GW) systems interacting with surface-water are complex, particularly under farming systems receiving high fertiliser/pesticide inputs in high rainfall regions. We investigated whether any linkage existed between nitrate-N in: (i) leachate (LC) collected at similar to 1m depth under banana (Musa) and that in GW, and (ii) GW and drain-water (DW). We also assessed the hazard/risk of the concentrations against the trigger values proposed for the sustainable health of different aquatic ecosystems. The LC, GW, and DW samples were collected at short intervals during 3 consecutive rainy seasons (January-July) from a similar to 300-ha banana farm in the wet tropical Tully River Catchment in north-east Queensland, Australia. Water samples were analysed for nitrate-N, dissolved organic carbon, and electrical conductivity. The coefficients of variation, ranging from 13 to 132%, obtained for solute concentrations in LC, GW, and DW indicated large within-and between-season temporal variations. The mean nitrate-N concentrations in LC, GW, and DW were 5320, 4135, and 1976 mu g/L, respectively, and were orders of magnitude higher than the trigger values proposed for the sustainable health of most of the neighbouring aquatic ecosystems. Significant positive associations, with correlation coefficients ranging from 0.56 to 0.96, existed between rainfall received and LC volume collected, and between LC volume and solute concentration, including nitrate-N, in the LC. Similar associations existed between the solutes in (i) LC and GW and (ii) GW and DW. From these associations we conclude the unused/under-utilised nitrate that leached below the root-zone was imported into the GW by the percolating rainwater and was exported into the drain via GW base-flow discharge.
Description:
Differences in the assemblages of terrestrial arthropod communities in burnt and adjacent unburnt areas of coastal heathland are reported. The burnt site experienced a wildfire 20 months prior to sampling. Collections of invertebrates from pitfall traps in winter indicated that there was no difference in total species richness or total numbers of individuals trapped between burnt and unburnt plots. However, at species level, 60 percent of the taxa showed a strong preference for either burnt areas or unburnt areas with only a few species trapped in around equal numbers in both areas. Twenty percent of species were only found on the unburnt plots. The implications of these results for fire management are discussed.
Description:
This study suggested that long-term persistence of willow roots can provide a positive effect on aquatic communities until the new native vegetation cover establishes. Leaf type has no significant influence over taxa richness; however their availability and persistence in the system has a significant effect on macroinvertebrate abundance in these streams. A combination of Phragmites reeds with Leptospermum and CalUstemon shrubs in revegetation programs will ensure a persistent supply of leaf litter to macroinvertebrate communities in these streams thus should be retained until native canopy cover eg. Eucalyptus spp. is re-established.
Description:
This study suggested that long-term persistence of willow roots can provide a positive effect on aquatic communities until the new native vegetation cover establishes. Leaf type has no significant influence over taxa richness; however their availability and persistence in the system has a significant effect on macroinvertebrate abundance in these streams. A combination of Phragmites reeds with Leptospermum and CalUstemon shrubs in revegetation programs will ensure a persistent supply of leaf litter to macroinvertebrate communities in these streams thus should be retained until native canopy cover eg. Eucalyptus spp. is re-established.
Description:
Urban expansion is a principal process threatening biodiversity globally. It is predicted that over half of the world's population will reside in urban centres by 2010. If we are to conserve biodiversity, a shift in perspective from traditional ecological studies based in natural environments, to studies based in less natural environments is paramount. To effectively conserve species which occur in urban environments, comprehensive analysis is necessary to determine the processes that are driving this urban usage. Geographical Information Systems (GIS) technology provides a valuable tool for efficient spatial analysis and predictive mapping of species distributions. This study used GIS to analyze current breeding sites for the powerful owl, a vulnerable top order predator in urban Melbourne, Australia. GIS analysis suggests that a number of ecological attributes were influencing powerful owl usage of urban environments. Using these ecological attributes, predictive mapping was undertaken, which identified a number of potential breeding sites for powerful owls within urbanized Melbourne. Urban environments are traditionally perceived as “the wastelands” of natural environments, however, this study demonstrates that they have the potential to support apex predators, an important finding for the management of rare and threatened species.
Description:
Conserving biodiversity is of utmost importance on a global scale. Species conservation, however, is a challenging task, which is often compounded by a lack of knowledge of target species. New advances in information technology and molecular techniques, however, are enabling conservation biologists to obtain large amounts of data quickly, which will certainly aid in assigning conservation priorities. This article reviews the use of genetics in conservation biology and highlights, using the Powerful Owl Ninox strenua as an example, how DNA can be a valuable source of data
Description:
The palaeoecological assessment, and the use of stable isotopes of carbon in subfossils of herbivores and omnivores, represents a novel approach to understand transitions in past food-web structure and the dynamics of lake ecosystems in response to natural perturbations and human impacts. Combined with records of subfossil assemblages of cladocerans and chironomids, it may be possible to decipher whether changes are attributable to external forces or internally derived system shifts. A sediment record taken from the shallow (2.3 m depth) Kings Billabong in the River Murray floodplain (Australia) was analysed to explore changes in trophic dynamics over the past century. The palaeoecological assessment revealed that littoral assemblages of cladocerans and benthic diatoms were gradually replaced by planktonic (planktonic and facultative planktonic) assemblages after river regulation in the 1920s. The stable isotopic composition of carbon (
Description:
The palaeoecological assessment, and the use of stable isotopes of carbon in subfossils of herbivores and omnivores, represents a novel approach to understand transitions in past food-web structure and the dynamics of lake ecosystems in response to natural perturbations and human impacts. Combined with records of subfossil assemblages of cladocerans and chironomids, it may be possible to decipher whether changes are attributable to external forces or internally derived system shifts. A sediment record taken from the shallow (2.3 m depth) Kings Billabong in the River Murray floodplain (Australia) was analysed to explore changes in trophic dynamics over the past century. The palaeoecological assessment revealed that littoral assemblages of cladocerans and benthic diatoms were gradually replaced by planktonic (planktonic and facultative planktonic) assemblages after river regulation in the 1920s. The stable isotopic composition of carbon (
Description:
Masked owls, reputedly all of the Tasmanian race (Tyto novaehollandiae castanops) were introduced onto Lord Howe Island (LHI) in the 1920s in an attempt to control the black rat (Rattus rattus). This attempt, however, has been unsuccessful and a co-eradication of the rats and masked owls has been planned to reduce the threat to endemic species and breeding seabirds on the island. As the Tasmanian masked owl is considered endangered, translocation of LHI masked owls to Tasmania has been suggested. Before translocation is considered the ancestry of the LHI masked owl needs to be confirmed, as LHI masked owls are typically smaller and paler than individuals occurring in Tasmania. Here we sequenced three sections of mitochondrial gene regions: cytochrome b, ATP6 and ND3 to assess the provenance of the LHI masked owl and screened a suite of microsatellite loci isolated from the barn owl (Tyto alba) to assess contemporary divergence. Phylogenetic analysis revealed two clades, one exhibited by individuals from LHI and south-eastern mainland Australia and the second by those from Tasmania. Cross species amplification of microsatellite loci was successful, with 18 loci polymorphic. Genotypic data revealed significant sub-structuring between LHI, south-eastern mainland Australia and Tasmania. Data presented here indicate that the south-eastern mainland masked owl was introduced to LHI and subsequently reproduced. The genetic integrity of the LHI masked owl population is therefore questionable and as such LHI individuals may not be suitable for translocation to Tasmania.
Description:
A brief summary of the genus Temeritas is given with distributions of the four described Australian species and records of other species in the genus. A spelling correction is documented for the Western Australian species and a new name for the Victorian species is formally proposed here as the original name is preoccupied. Characters that distinguish Temeritas from allied genera are noted and the conservation status of the three southern species and Collembola in general are discussed.
Description:
Soil and mine waste around historical gold mining sites may have elevated arsenic concentrations. Recent evidence suggests some systemic arsenic absorption by residents in the goldfields region of Victoria, Australia. Victorian Cancer Registry and geochemical data were accessed for an ecological geographical correlation study, 1984-2003. Spatial empirical Bayes smoothing was applied when estimating standardised incidence ratios (SIRs) for cancers in 61 statistical local areas. The derived soil arsenic exposure metric ranged from 1.4 to 1857 mg/kg. Spatial autoregressive modelling detected increases in smoothed SIRs for all cancers of 0.05 (95% confidence interval (CI), 0.02-0.08) and 0.04 (0.01-0.07) per 2.7-fold increase in the natural log-transformed exposure metric for males and females, respectively, in more socioeconomically disadvantaged areas; for melanoma in males (0.05 (0.01-0.08) adjusted for disadvantage) and females (0.05 (0.02-0.09) in disadvantaged areas). Excess risks were estimated for all cancers (relative risk 1.21 (95% CI, 1.15-1.27) and 1.08 (1.03-1.14)), and melanoma (1.52 (1.25-1.85) and 1.29 (1.08-1.55)), for males and females, respectively, in disadvantaged areas in the highest quintile of the exposure metric relative to the lowest. Our findings suggest small but significant increases in past cancer risk associated with increasing soil arsenic in socioeconomically disadvantaged areas and demonstrate the robustness of this geospatial approach. Journal of Exposure Science and Environmental Epidemiology advance online publication, 21 March 2012.
Description:
Soil and mine waste around historical gold mining sites may have elevated arsenic concentrations. Recent evidence suggests some systemic arsenic absorption by residents in the goldfields region of Victoria, Australia. Victorian Cancer Registry and geochemical data were accessed for an ecological geographical correlation study, 1984-2003. Spatial empirical Bayes smoothing was applied when estimating standardised incidence ratios (SIRs) for cancers in 61 statistical local areas. The derived soil arsenic exposure metric ranged from 1.4 to 1857 mg/kg. Spatial autoregressive modelling detected increases in smoothed SIRs for all cancers of 0.05 (95% confidence interval (CI), 0.02-0.08) and 0.04 (0.01-0.07) per 2.7-fold increase in the natural log-transformed exposure metric for males and females, respectively, in more socioeconomically disadvantaged areas; for melanoma in males (0.05 (0.01-0.08) adjusted for disadvantage) and females (0.05 (0.02-0.09) in disadvantaged areas). Excess risks were estimated for all cancers (relative risk 1.21 (95% CI, 1.15-1.27) and 1.08 (1.03-1.14)), and melanoma (1.52 (1.25-1.85) and 1.29 (1.08-1.55)), for males and females, respectively, in disadvantaged areas in the highest quintile of the exposure metric relative to the lowest. Our findings suggest small but significant increases in past cancer risk associated with increasing soil arsenic in socioeconomically disadvantaged areas and demonstrate the robustness of this geospatial approach. Journal of Exposure Science and Environmental Epidemiology advance online publication, 21 March 2012.
Description:
Exotic willows (Salix spp.) are widespread riparian tree species of rivers in temperate Australia and New Zealand. Despite being a Weed of National Significance, little is known about the novel habitats created by willows and the impact on aquatic biota of vegetation change following willow management programs. Reeds (Phragmites australis) and shrubs (Leptospermum spp. znaCallistemon spp.) are common taxa in the riparian zone of Victorian streams and are considered suitable for planting along channels in revegetation programs following willow removal. Categorisation of macroinvertebrates into 'trophic' groups allows better understanding of the processes of energy flow, material cycle and stream ecosystem function. Macroinvertebrate functional feeding groups associated with willow, Phragmites australis, Leptospermum/CaUistemon and bare bank habitats were examined in three central Victorian streams to gain insights to potential effects of willow removal on functional organisation of macroinvertebrates. There was a significant effect of habitat on macroinvertebrate functional feeding groups except collectors. Notable differences in functional feeding groups included a greater abundance ofpredators and grazers in Phragmites habitats and a greater abundance of snredders in willow habitats; however, these changes were variable during different seasons. It appears riparian vegetation change associated with willow management could bring about change of functional organisation of macroinvertebrates in these streams. This suggests that the vegetation changes can bring about changes in material cycle and energy flow within these streams.
Description:
Green roofs have the potential to address several of the environmental problems associated with urbanisation, and can be used as mitigation for habitats lost at ground level. Brown roofs (a type of green roof) can be used to mitigate for the loss of brownfield habitat, but the best way of designing these habitats remains unclear. This paper reports an experiment to test the effects of different types of recycled aggregate on the development of vegetation assemblages on brown roof mesocosms. Five recycled aggregates were tested: (1) crushed brick, (2) crushed demolition aggregate, (3) solid municipal waste incinerator bottom ash aggregate, (4) a 1:1 mix of 1 and 2, and (5) a 1:1 mix of 3 and 2. Each was seeded with a wildflower mix that also included some Sedum acre and vegetation development was studied over a six-year period. Species richness, assemblage character, number of plants able to seed, and plant biomass were measured. Drought disturbance was the key factor controlling changes in plant assemblage, but effects varied with substrate treatment. All treatments supported a similar plant biomass, but treatments with a high proportion of crushed brick in the growth substrate supported richer assemblages, with more species able to seed, and a smaller amount of Sedum acre. Crushed brick, or recycled aggregates with a high proportion of crushed brick, are recommended as good growth substrate materials for encouraging brown roof plant diversity. This investigation demonstrates the importance of multi-year studies of green roof development for the generation of robust findings.
Description:
This article investigates how cultural landscapes (especially the potentially limiting organically evolved landscape) can be used as a research framework to evaluate historical mining heritage sites in Australia and New Zealand. We argue that when mining heritage sites are read as evolved organic landscapes and linked to the surrounding forested and hedged farmland, the disruptive aspects of mining are masked. Cultural landscape is now a separate listing for World Heritage sites and includes associative and designed landscape as well as those that have evolved organically. These usages have rarely been scrutinized with care. We analyse how mid-nineteenth century goldmining sites can be best thematically interpreted and understood for their heritage, indeed World Heritage, significance and, where appropriate, developed for their sustainable heritage tourism potential. Drawing on a number of research disciplines, a schematic framework is offered for interpreting and classifying these new world cultural landscapes based upon analysis of gold-rush heritage sites throughout the Trans-Tasman world. We evaluate and apply this framework to place-based case studies in Victoria, Australia and Otago, New Zealand