Academic literature on the topic 'Endangered ecological community - NSW, Australia'

Aims: Ecosystems nationally at risk in Australia are listed under the Environmental Protection and Biodiversity Act (EPBC Act), and many cross State jurisdictional boundaries. The determination of these ecosystems across the State boundaries are based on expert knowledge. The International Vegetation Classification has the potential to be useful as a cross-jurisdictional hierarchy which also gives global perspective to ecosystems. Study Area: All bioregions that include Eucalyptus populnea as a dominant or major component of woodlands across the species known distribution. Methods: We use plot-based data (455 plots) from two states (Queensland and New South Wales) in eastern Australia and quantitative classification methods to assess the definition and description for the Poplar Box Woodland ecosystem type (hereafter “ecological community” or “community”) that is listed as endangered under the EPBC Act. Analyses were conducted using kR-CLUSTER methods to generate alliances. Within these alliances, analyses were undertaken to define associations using agglomerative hierarchical clustering and similarity profile testing (SIMPROF). We then explore how assigning this community into the IVC hierarchy may provide a mechanism for linking Australian communities, defined at the association and alliance levels, to international communities at risk. Results: We define three alliances and 23 associations based on the results of floristic analysis. Using the standard rule-set of the IVC system, we found that the IVC hierarchy was a useful instrument in correlating ecological communities across jurisdictional boundaries where different classification systems are used. It is potentially important in giving a broader understanding of communities that may be at risk continentally and globally. Conclusions: We conclude that the IVC hierarchy can incorporate Australian communities at the association level into useful units at higher levels, and provides a useful classification tool for Australian ecosystems. Taxonomic reference: PlantNET (http://plantnet/10rbgsyd.nsw.gov.au/) [accessed June 2019]. Abbreviations: EPBC Act = Environmental Protection and Biodiversity Act; IVC = International Vegetation Classification; NMDS = non-metric multidimensional scaling; NSW = New South Wales; PCT = Plant Community Type; QLD = Queensland; RE = Regional Vegetation Community; SIMPER = similarity percentage analysis; SIMPROF = Similarity profile analysis.

The endangered grassland earless dragon, Tympanocryptis pinguicolla, is present in two geographic locations in Australia: the Australian Capital Territory and adjacent New South Wales (NSW) near Canberra (~580 m above sea level) and Monaro Plains, NSW, near Cooma (~950 m above sea level). The lizards live in native grassland, an endangered ecological community, and although the population ecology of the animal has been examined, the importance of habitat for thermoregulatory patterns is unknown. We studied whether lizards from the two locations differ in their seasonal patterns of thermoregulation by measuring skin and chest temperatures using both radio-telemetry and temperature measurement in the field, as well as thermal preferences in a laboratory thermal gradient. These results are compared with the operative temperatures (Te) in various microhabitats in the two regions to determine to what extent lizards are thermoregulating. We demonstrate that these lizards do not maintain a constant body temperature, but allow Tb to vary between 13 and 39°C when active in the field, although the grand mean for 50% basking temperatures ranged between 32 and 36°C in the laboratory gradient. Temperatures in the various microhabitats can exceed 40°C, but lizards appeared to avoid those temperatures by seeking shelter in either burrows or the base of grass tussocks. Lizards could choose microhabitats that would permit maintenance of body temperatures above 30°C in most seasons, but did not do so. As high body temperature is not selected in field conditions for either population, other processes (e.g. predation) may be more important for determining Tb maintenance.

Habitat complexity plays a critical role in shaping biotic assemblages and ecosystem processes. While the impacts of large differences in habitat complexity are often well understood, we know less about how subtle differences in structure affect key ecosystem functions or properties such as biodiversity and biomass. The late-successional seagrass Posidonia australis creates vital habitat for diverse fauna in temperate Australia. Long-term human impacts have led to the decline of P. australis in some estuaries of eastern Australia, where it is now classified as an endangered ecological community. We examined the influence of P. australis structural complexity at small (seagrass density) and large (meadow fragmentation) spatial scales on fish and epifauna communities, predation and sediment erosion. Fine-scale spatially balanced sampling was evenly distributed across a suite of environmental covariates within six estuaries in eastern Australia using the Generalised Random Tessellation Structures approach. We found reduced erosion in areas with higher P. australis density, greater abundance of fish in more fragmented areas and higher fish richness in vegetated areas further from patch edges. The abundance of epifauna and fish, and fish species richness were higher in areas with lower seagrass density (seagrass density did not correlate with distance to patch edge). These findings can inform seagrass restoration efforts by identifying meadow characteristics that influence ecological functions and processes.

Clearing of native vegetation and changes to disturbance regimes have resulted in dense regeneration of native trees and shrubs in parts of Australia. The conversion of open vegetation to dense woodlands may result in changes to the composition of plant communities and ecosystem function if structure, composition and function are tightly linked. Widespread clearing of the floodplain tree Eucalyptus coolabah subsp. coolabah (coolibah), in New South Wales, Australia, has led to state and federal listings of coolibah woodland as an endangered ecological community. Dense regeneration of coolibah in the mid 1970s, however, also resulted in its listing as an ‘invasive native species’ in NSW, meaning it can be legally cleared under certain conditions. Dense regeneration could be a novel state dissimilar to the threatened community or it could represent the next generation of coolibah woodlands and may contribute to passive restoration of heavily cleared landscapes. This study investigated if dense stands are distinct from remnant woodland by comparing floristic composition of the ground-storey community and top-soil properties of four coolibah vegetation states: derived grassland, derived degraded grassland, dense regeneration and remnant woodland. Ground-storey composition was found to overlap broadly among states regardless of tree density. Most species were common to all states, although dense regeneration contained characteristic woodland species that were absent from grasslands. The carbon : nitrogen ratio of the soil was significantly higher in dense regeneration and remnant woodland than in either of the grassland states, indicating that the woody states are broadly similar in terms of nutrient cycling. The study demonstrates that structurally different vegetation states (grasslands, woodlands and dense regeneration) are not associated with distinct plant communities. The results also suggest that grazing management has a more pronounced effect on ground-storey composition of plant communities than tree density and that well managed derived grasslands and dense regeneration are floristically similar to remnant woodlands. Since dense regeneration and remnant woodlands are not floristically distinct from one another, dense regeneration could contribute to the conservation of endangered coolibah woodlands in cleared agricultural landscapes.

The grassland earless dragon (Tympanocryptis pinguicolla) is a habitat specialist restricted to the highly fragmented native temperate grasslands of the Australian Capital Territory (ACT) and nearby New South Wales (NSW). These grasslands, which are listed as an endangered ecological community, continue to be affected by a range of processes including development and overgrazing. Although changes to its habitat present a significant threat to the grassland earless dragon, little is known about its spatial and habitat requirements. We used radio-tracking to study the home-range areas and habitat requirements of 10 adult lizards in native grassland adjacent to Canberra, ACT. We found that burrows excavated by arthropods are an important resource for grassland earless dragons, with individuals having one or two home burrows around which they maintained home ranges of between 925 m2 and 4768 m2. Fidelity to these burrows increased with the onset of winter, indicating their importance as over-winter refuge sites. Within the native grasslands, grassland earless dragons were found to use a broad range of grassland structure as habitat. This result contrasts with the prevailing view that these dragons are confined to well drained, minimally disturbed areas, which include large patches of short grass dominated by Austrodanthonia. We conclude that habitat management (i.e. grazing, mowing, burning) for this species should aim to retain structural heterogeneity of native grasslands rather than impose a uniform structure.

The taxonomic status of Jalmenus eubulus Miskin stat. rev. is revised and considered to be specifically distinct from J. evagoras (Donovan) based on fundamental differences in morphology, ecology and genetics. Miskin’s holotype is fixed by monotypy and illustrated, with type locality Rockhampton, Queensland. Fixed differences in the mitochondrial genomes of J. eubulus and J. evagoras in which the mean pairwise divergence is only 0.85% indicate absence of matrilineal gene flow, whereas allozyme data show significant structure within and between populations of both species consistent with recent diversification. Underlying causes for the observed genetic patterns are investigated. The two species are parapatric, with a narrow range of overlap along the Great Escarpment in south-eastern Queensland. Jalmenus eubulus is restricted to vegetation communities comprising brigalow-dominated old-growth open-forests and woodlands in the Brigalow Belt (with larvae monophagous on Acacia harpophylla F. Muell. Ex Benth), whereas J. evagoras occurs in a range of disturbed eucalypt woodlands/open-forests predominantly in montane and coastal areas east of this bioregion (with larvae polyphagous on Acacia species other than A. harpophylla). The conservation status of J. eubulus is considered to be vulnerable nationally and critically endangered in New South Wales according to International Union for Conservation of Nature (IUCN) criteria. Nationally, the geographic range has an estimated area of occupancy of less than 2000 km2, is severely fragmented, and the extent or quality of its habitat, which is poorly conserved, continues to decline. It is recommended that the taxon be used as an indicator for identification of remnant old-growth forest for conservation planning, as well as a flagship for the conservation of invertebrate biodiversity associated with this threatened ecological community.

The genus Smeagol consists of five named species of air-breathing marine slugs (restricted to southern Australia and New Zealand) and three undescribed taxa from southern Japan. Only one species, S. hilaris, is known to be from New South Wales (NSW), and it previously had a known distribution limited to one site, Merry Beach on the south coast. This diminutive invertebrate is classified as critically endangered in NSW due to its extremely restricted distribution and concern about its historically declining numbers. Accordingly, the aims of this study were to survey the known population of S. hilaris at Merry Beach and to explore other potentially suitable sites, using a visual census method, to determine if further populations or species exist in NSW. The resulting quantitative surveys of the known population and a new population at Storm Bay, Kiama, NSW, are reported here. DNA barcoding of a ~650 bp segment of the mitochondrial cytochrome c oxidase I (COI) gene for several individuals from each population confirmed the conspecificity among the two populations. The population at Merry Beach was found to remain viable, while the discovery of the new population of S. hilaris represents a doubling of the known global populations of this species. Details of the highly-specialised niche habitat occupied by Smeagol in New South Wales and recommendations for ongoing management are documented.

Groundwater dependent ecosystems (GDEs) require access to groundwater to meet all or some of their water requirements to maintain community structure and function. The increasing demand of surface and groundwater resources has seen the NSW Government put in place management mechanisms to enable the sharing of water between irrigators, the environment, industry, towns and communities via water sharing plans. The groundwater sharing plans aim to provide adaptive management of GDEs by prioritising for protection those that are considered the most ecologically valuable within each plan area. The High Ecological Value Aquatic Ecosystems (HEVAE) framework has already been adopted to prioritise riverine ecosystems for management in surface water sharing plans. Here, we provide a method developed using the HEVAE framework to prioritise vegetation GDEs for management. The GDE HEVAE methods provide a derived ecological value dataset for identified groundwater dependent vegetation that is used to inform the planning and policy decisions in NSW. These decisions are required to manage and mitigate current and future risks caused by groundwater extraction. This is achieved via the identification of ecologically valuable assets to then use as the consequence component in a risk assessment for the groundwater sources, to provide vegetation GDE locations for setback distances for new groundwater production bores, and for the assessment of impacts due to current and potential future groundwater extraction. The GDE HEVAE method uses recorded and predicted spatial data to provide weighted scores for each attribute associated with the four HEVAE criteria (distinctiveness, diversity, vital habitat and naturalness). The combined scores categorise the ecological value of each groundwater dependent vegetation community (depicted as geographic information system (GIS) polygon features) from very high to very low. We apply the GDE HEVAE method to three catchments in order to demonstrate the method’s applicability across the Murray–Darling Basin with varying elevation and climate characteristics. The ecological value outcomes derived from the methods have been used to inform planning and policy decisions by NSW Government processes to allow for protection in not only areas that are currently at risk but to also manage for potential future risks from groundwater extraction.

AbstractConservation management can be aided by knowledge of genetic diversity and evolutionary history, so that ecological and evolutionary processes can be preserved. The Button Wrinklewort daisy (Rutidosis leptorrhynchoides) was a common component of grassy ecosystems in south-eastern Australia. It is now endangered due to extensive habitat loss and the impacts of livestock grazing, and is currently restricted to a few small populations in two regions >500 km apart, one in Victoria, the other in the Australian Capital Territory and nearby New South Wales (ACT/NSW). Using a genome-wide SNP dataset, we assessed patterns of genetic structure and genetic differentiation of 12 natural diploid populations. We estimated intrapopulation genetic diversity to scope sources for genetic management. Bayesian clustering and principal coordinate analyses showed strong population genetic differentiation between the two regions, and substantial substructure within ACT/NSW. A coalescent tree-building approach implemented in SNAPP indicated evolutionary divergence between the two distant regions. Among the populations screened, the last two known remaining Victorian populations had the highest genetic diversity, despite having among the lowest recent census sizes. A maximum likelihood population tree method implemented in TreeMix suggested little or no recent gene flow except potentially between very close neighbours. Populations that were more genetically distinctive had lower genetic diversity, suggesting that drift in isolation is likely driving population differentiation though loss of diversity, hence re-establishing gene flow among them is desirable. These results provide background knowledge for evidence-based conservation and support genetic rescue within and between regions to elevate genetic diversity and alleviate inbreeding.

Knowledge of a target species’ habitat niche and physiological tolerances is important for conservation planning. However, these factors are not well understood for the threatened annual grass Arthraxon hispidus in New South Wales (NSW). Although the species is widespread in modified environments, recent studies have suggested that several threatened wetland types may represent original native habitat for the species, but documented field examples are lacking and the species’ physiological response to soil moisture is not clear. We undertook a detailed survey of an A. hispidus population within a relatively intact native sedgeland community, and carried out a nursery experiment to test the hydrological tolerances of the species. We found that A. hispidus plants grew more vigorously in poorly drained or waterlogged conditions, suggesting that the species is well-adapted to overcome such stressors, possibly through the formation of adventitious roots, a trait shared by many wetland plants globally. Our field survey confirmed that the A. hispidus population within the study site occurred only within species assemblages that were characteristic of a freshwater wetland formation and that matched descriptions of a listed endangered ecological community. These findings provide a deeper insight into the species’ habitat and threats, and offer a valuable management focus for conservation of A. hispidus as a component of threatened wetland communities in north-eastern NSW.

A renewed focus on generalised pollinator systems has inspired a conceptual framework which highlights that spatial and temporal interactions among plants and their assemblage of pollinators can vary across the individual, population, regional and species levels. Pollination is clearly a dynamic interaction, varying in the number and interdependence of participants and the strength of the outcome of the interaction. Therefore, the role of variation in pollination is fundamental for understanding ecological dynamics of plant populations and is a major factor in the evolution and maintenance of generalised and specialised pollination systems. My study centred on these basic concepts by addressing the following questions: (1) How variable are pollinators in a generalised pollination system? To what degree do insect visitation rates and assemblage composition vary spatially among populations and temporally among flowering seasons? (2) How does variation in pollinators affect plant reproductive success? I chose to do this using a model system, Trachymene incisa subsp. incisa (Apiaceae), which is a widespread Australian herbaceous species with simple white flowers grouped into umbels that attract a high diversity of insect visitors. The Apiaceae are considered to be highly generalist in terms of pollination, due to their simple and uniform floral display and easily accessible floral rewards. Three populations of T. incisa located between 70 km and 210 km apart were studied over 2-3 years. The few studies investigating spatial and temporal variation simultaneously over geographic and yearly/seasonal scales indicate that there is a trend for more spatial than temporal variation in pollinators of generalist-pollinated plants. My study showed both spatial and temporal variation in assemblage composition among all populations and variation in insect visitation rates, in the form of a significant population by year interaction. However, removing ants from the analyses to restrict the assemblage to flying insects and the most likely pollinators, resulted in a significant difference in overall visitation rate between years but no difference in assemblage composition between the Myall Lakes and Tomago populations. These results indicate more temporal than spatial variation in the flying insect visitor assemblage of T. incisa. Foraging behaviour provides another source of variation in plant-pollinator interactions. Trachymene incisa exhibits umbels that function as either male or female at any one time and offer different floral rewards in each phase. For successful pollination, pollinators must visit both male and female umbels during a foraging trip. Insects showed both preferences and non-preferences for umbel phases in natural patches where the gender ratio was male biased. In contrast, insects showed no bias in visitation during a foraging trip or in time spent foraging on male and female umbels in experimental arrays where the gender ratio was equal. Pollinator assemblages consisting of a mixture of different pollinator types coupled with temporal variation in the assemblages of populations among years maintains generalisation at the population/local level. In addition, spatial variation in assemblages among populations maintains generalisation at the species level. Fire alters pollination in T. incisa by shifting the flowering season and reducing the abundance of flying insects. Therefore, fire plays an important role in maintaining spatial and temporal variation in this fire-prone system. Although insect pollinators are important in determining the mating opportunities of 90% of flowering plant species worldwide, few studies have looked at the effects of variation in pollinator assemblages on plant reproductive success and mating. In T. incisa, high insect visitation rates do not guarantee high plant reproductive success, indicating that the quality of visit is more important than the rate of visitation. This is shown by comparing the Agnes Banks and Myall Lakes populations in 2003: Agnes Banks received the highest visitation rate from an assemblage dominated by ants but produced the lowest reproductive output, and Myall Lakes received the lowest visitation rate by an assemblage dominated by a native bee and produced the highest seedling emergence. Interestingly, populations with different assemblage composition can produce similar percentage seed set per umbel. However, similar percentage seed set did not result in similar percentage seedling emergence. Differences among years in reproductive output (total seed production) were due to differences in umbel production (reproductive effort) and proportion of umbels with seeds, and not seed set per umbel. Trachymene incisa is self-compatible and suffers weak to intermediate levels of inbreeding depression through early stages of the life cycle when seeds are self-pollinated and biparentally inbred. Floral phenology, in the form of synchronous protandry, plays an important role in avoiding self-pollination within umbels and reducing the chance of geitonogamous pollination between umbels on the same plant. Although pollinators can increase the rate of inbreeding in T. incisa by foraging on both male and female phase umbels on the same plant or closely related plants, most consecutive insect movements were between plants not located adjacent to each other. This indicates that inbreeding is mostly avoided and that T. incisa is a predominantly outcrossing species, although further genetic analyses are required to confirm this hypothesis. A new conceptual understanding has emerged from the key empirical results in the study of this model generalised pollination system. The large differences among populations and between years indicate that populations are not equally serviced by pollinators and are not equally generalist. Insect visitation rates varied significantly throughout the day, highlighting that sampling of pollinators at one time will result in an inaccurate estimate and usually underestimate the degree of generalisation. The visitor assemblage is not equivalent to the pollinator assemblage, although non-pollinating floral visitors are likely to influence the overall effectiveness of the pollinator assemblage. Given the high degree of variation in both the number of pollinator species and number of pollinator types, I have constructed a model which includes the degree of ecological and functional specialisation of a plant species on pollinators and the variation encountered across different levels of plant organisation. This model describes the ecological or current state of plant species and their pollinators, as well as presenting the patterns of generalisation across a range of populations, which is critical for understanding the evolution and maintenance of the system. In-depth examination of pollination systems is required in order to understand the range of strategies utilised by plants and their pollinators, and I advocate a complete floral visitor assemblage approach to future studies in pollination ecology. In particular, future studies should focus on the role of introduced pollinators in altering generalised plant-pollinator systems and the contribution of non-pollinating floral visitors to pollinator assemblage effectiveness. Comparative studies involving plants with highly conserved floral displays, such as those in the genus Trachymene and in the Apiaceae, will be useful for investigating the dynamics of generalised pollination systems across a range of widespread and restricted species.

Doctor of Philosophy (PhD)
A renewed focus on generalised pollinator systems has inspired a conceptual framework which highlights that spatial and temporal interactions among plants and their assemblage of pollinators can vary across the individual, population, regional and species levels. Pollination is clearly a dynamic interaction, varying in the number and interdependence of participants and the strength of the outcome of the interaction. Therefore, the role of variation in pollination is fundamental for understanding ecological dynamics of plant populations and is a major factor in the evolution and maintenance of generalised and specialised pollination systems. My study centred on these basic concepts by addressing the following questions: (1) How variable are pollinators in a generalised pollination system? To what degree do insect visitation rates and assemblage composition vary spatially among populations and temporally among flowering seasons? (2) How does variation in pollinators affect plant reproductive success? I chose to do this using a model system, Trachymene incisa subsp. incisa (Apiaceae), which is a widespread Australian herbaceous species with simple white flowers grouped into umbels that attract a high diversity of insect visitors. The Apiaceae are considered to be highly generalist in terms of pollination, due to their simple and uniform floral display and easily accessible floral rewards. Three populations of T. incisa located between 70 km and 210 km apart were studied over 2-3 years. The few studies investigating spatial and temporal variation simultaneously over geographic and yearly/seasonal scales indicate that there is a trend for more spatial than temporal variation in pollinators of generalist-pollinated plants. My study showed both spatial and temporal variation in assemblage composition among all populations and variation in insect visitation rates, in the form of a significant population by year interaction. However, removing ants from the analyses to restrict the assemblage to flying insects and the most likely pollinators, resulted in a significant difference in overall visitation rate between years but no difference in assemblage composition between the Myall Lakes and Tomago populations. These results indicate more temporal than spatial variation in the flying insect visitor assemblage of T. incisa. Foraging behaviour provides another source of variation in plant-pollinator interactions. Trachymene incisa exhibits umbels that function as either male or female at any one time and offer different floral rewards in each phase. For successful pollination, pollinators must visit both male and female umbels during a foraging trip. Insects showed both preferences and non-preferences for umbel phases in natural patches where the gender ratio was male biased. In contrast, insects showed no bias in visitation during a foraging trip or in time spent foraging on male and female umbels in experimental arrays where the gender ratio was equal. Pollinator assemblages consisting of a mixture of different pollinator types coupled with temporal variation in the assemblages of populations among years maintains generalisation at the population/local level. In addition, spatial variation in assemblages among populations maintains generalisation at the species level. Fire alters pollination in T. incisa by shifting the flowering season and reducing the abundance of flying insects. Therefore, fire plays an important role in maintaining spatial and temporal variation in this fire-prone system. Although insect pollinators are important in determining the mating opportunities of 90% of flowering plant species worldwide, few studies have looked at the effects of variation in pollinator assemblages on plant reproductive success and mating. In T. incisa, high insect visitation rates do not guarantee high plant reproductive success, indicating that the quality of visit is more important than the rate of visitation. This is shown by comparing the Agnes Banks and Myall Lakes populations in 2003: Agnes Banks received the highest visitation rate from an assemblage dominated by ants but produced the lowest reproductive output, and Myall Lakes received the lowest visitation rate by an assemblage dominated by a native bee and produced the highest seedling emergence. Interestingly, populations with different assemblage composition can produce similar percentage seed set per umbel. However, similar percentage seed set did not result in similar percentage seedling emergence. Differences among years in reproductive output (total seed production) were due to differences in umbel production (reproductive effort) and proportion of umbels with seeds, and not seed set per umbel. Trachymene incisa is self-compatible and suffers weak to intermediate levels of inbreeding depression through early stages of the life cycle when seeds are self-pollinated and biparentally inbred. Floral phenology, in the form of synchronous protandry, plays an important role in avoiding self-pollination within umbels and reducing the chance of geitonogamous pollination between umbels on the same plant. Although pollinators can increase the rate of inbreeding in T. incisa by foraging on both male and female phase umbels on the same plant or closely related plants, most consecutive insect movements were between plants not located adjacent to each other. This indicates that inbreeding is mostly avoided and that T. incisa is a predominantly outcrossing species, although further genetic analyses are required to confirm this hypothesis. A new conceptual understanding has emerged from the key empirical results in the study of this model generalised pollination system. The large differences among populations and between years indicate that populations are not equally serviced by pollinators and are not equally generalist. Insect visitation rates varied significantly throughout the day, highlighting that sampling of pollinators at one time will result in an inaccurate estimate and usually underestimate the degree of generalisation. The visitor assemblage is not equivalent to the pollinator assemblage, although non-pollinating floral visitors are likely to influence the overall effectiveness of the pollinator assemblage. Given the high degree of variation in both the number of pollinator species and number of pollinator types, I have constructed a model which includes the degree of ecological and functional specialisation of a plant species on pollinators and the variation encountered across different levels of plant organisation. This model describes the ecological or current state of plant species and their pollinators, as well as presenting the patterns of generalisation across a range of populations, which is critical for understanding the evolution and maintenance of the system. In-depth examination of pollination systems is required in order to understand the range of strategies utilised by plants and their pollinators, and I advocate a complete floral visitor assemblage approach to future studies in pollination ecology. In particular, future studies should focus on the role of introduced pollinators in altering generalised plant-pollinator systems and the contribution of non-pollinating floral visitors to pollinator assemblage effectiveness. Comparative studies involving plants with highly conserved floral displays, such as those in the genus Trachymene and in the Apiaceae, will be useful for investigating the dynamics of generalised pollination systems across a range of widespread and restricted species.

The restoration and management of Cumberland Plain Woodland, an ’Endangered Ecological Community’ found only in western Sydney, has occurred without a sound understanding of soil-vegetation relationships within this community. Since 1992, large tracts of abandoned farmland, which were originally covered with Cumberland Plain Woodland, have been planted with native trees and shrubs to facilitate woodland development. This approach was based on the theory of (small-scale) patch dynamics since it was envisaged that the developing overstorey would facilitate changes to the soil environment, which would advantage native woodland species and disadvantage exotic pasture species. To date, this approach has had limited success and importantly, the restoration of Cumberland Plain Woodland has ignored: (a) characterisation of the soil environment; (b) how different patch types (e.g. tree and shrub) influence the soil; (c) how past land use has affected the soil; and (d) the effects of revegetation on soil properties and processes. These issues are of the utmost importance since soil-related barriers to natural regeneration and restoration may exist as a result of a very long history of agriculture. This thesis addressed these issues by investigating the soils of abandoned farmland, Cumberland Plain Woodland and restored areas of various ages. In addition to this, the impacts of various patch types (woodland tree, shrub and open, as well as improved perennial pasture) on soil properties and processes, as well as the ground flora were examined. Several soil chemical properties and ecological processes were identified as being of particular importance for the ecology of Cumberland Plain Woodland and its restoration on abandoned farmland. The greatest impact on the soil from past agricultural land use was an increase in the concentration of nitrate, ammonium and total nitrogen within the pasture compared to the woodland patch types, although there was an appreciable amount of site-to-site variability. Despite this, data from two different studies, which were carried out over different spatio-temporal scales, suggest that the abandoned pasture and Cumberland Plain Woodland function differently with respect to the cycling of nitrogen and this may hinder restoration efforts.