ABSTRACT The morpho-ecological adaptations of Eleocharis sphacelata in response to water depth an... more ABSTRACT The morpho-ecological adaptations of Eleocharis sphacelata in response to water depth and the sequential effects of resultant differences in deep water conditions on the long term population dynamics were investigated based on the observations carried out in three stable homogeneous populations in Goulburn and Ourimbah, New South Wales, Australia from August 2003 to May 2005. The deep water populations attained a higher harvestable shoot biomass and a lower rhizome biomass with increased growth in root structure thus significantly enhancing the nutrient uptake rates leading to a higher accumulation of shoot bound macronutrients. However, the accretion of excessive amounts of autogenous shoot litter coupled with slower decomposition rates under anaerobic conditions in the two deep water populations led to higher nutrient enrichment in sediments and overlying water column causing subsequent eutrophication with signs of growth inhibition including typical stress symptoms like stunted growth and chlorotic shoots. The shallow water population that intermittently experienced alternative inundation-drawdown pattern depicted an unaffected continuation of seasonal growth affirming that strict water regime management practices coupled with timely mowing or the removal of accumulating litter are necessary to ensure long-term survival of healthy E. sphacelata stands when it is used in applications where deep water conditions prevail.
Abstract Regeneration patterns of Eucalyptus coolabah Blakely & Jacobs subsp. arida (Blakely)... more Abstract Regeneration patterns of Eucalyptus coolabah Blakely & Jacobs subsp. arida (Blakely) L. Johnson & K. Hill (coolibah), a riparian tree of inland Australia, were inferred from size classes at two locations in South Australia; part of the floodplain of Cooper Creek ...
Executive Summary The expansion of water markets and resultant inter-valley trade has the potenti... more Executive Summary The expansion of water markets and resultant inter-valley trade has the potential to increase water demand in areas such as the Sunraysia district in north-west Victoria. The Goulburn-Broken system is pivotal in meeting any increase in demand in this ...
ABSTRACT Riparian ecosystems in the 21st century are likely to play a critical role in determinin... more ABSTRACT Riparian ecosystems in the 21st century are likely to play a critical role in determining the vulnerability of natural and human systems to climate change, and in influencing the capacity of these systems to adapt. Some authors have suggested that riparian ecosystems are particularly vulnerable to climate change impacts due to their high levels of exposure and sensitivity to climatic stimuli, and their history of degradation. Others have highlighted the probable resilience of riparian ecosystems to climate change as a result of their evolution under high levels of climatic and environmental variability. We synthesize current knowledge of the vulnerability of riparian ecosystems to climate change by assessing the potential exposure, sensitivity, and adaptive capacity of their key components and processes, as well as ecosystem functions, goods and services, to projected global climatic changes. We review key pathways for ecological and human adaptation for the maintenance, restoration and enhancement of riparian ecosystem functions, goods and services and present emerging principles for planned adaptation. Our synthesis suggests that, in the absence of adaptation, riparian ecosystems are likely to be highly vulnerable to climate change impacts. However, given the critical role of riparian ecosystem functions in landscapes, as well as the strong links between riparian ecosystems and human well-being, considerable means, motives and opportunities for strategically planned adaptation to climate change also exist. The need for planned adaptation of and for riparian ecosystems is likely to be strengthened as the importance of many riparian ecosystem functions, goods and services will grow under a changing climate. Consequently, riparian ecosystems are likely to become adaptation ‘hotspots’ as the century unfolds.
Common Reed Phragmites australis, a competitive species, is perceived as a threat to the conserva... more Common Reed Phragmites australis, a competitive species, is perceived as a threat to the conservation value of spring wetlands in the South Australian part of the Great Artesian Basin, Australia. The evidence for its presence, and the likelihood of it dispersing into and establishing in these spring wetlands in the hot arid centre of Australia is considered.
Section 1: Introduction This review is concerned with deliberate or planned change of vegetation ... more Section 1: Introduction This review is concerned with deliberate or planned change of vegetation from one state to another, a process that is here called recovery but which refers to activities such as restoration, rehabilitation and repair. The aim is to present a useful and accessible summary of ecological understanding about wetland vegetation recovery, as it relates to Australia. This is an essential step in the development of scientifically sound tools that will assist wetland practitioners to be more effective in restoring wetland vegetation. Such a review is timely. Knowledge about the distribution and general ecology of wetland plant communities in inland Australia has advanced considerably over the last 35 years. However, wetlands are under threat: a compilation of findings from around Australia shows a nation-wide pattern of loss and degradation, with very few instances of wetlands being in good condition. The challenge for the future is how to protect the remaining wetlands, and how to restore and rehabilitate wetland plant communities. Scientific input is needed if restoration and rehabilitation are to be done effectively. Despite huge community efforts in onground works, there is very little documentation, and hence only localised transfer of experience. This review aims to compensate for this by making existing scientific knowledge more available to users. The review is limited to the vegetation of natural inland wetlands, including woody and non-woody vegetation, but with an emphasis on non-woody vegetation. Four topics relevant to vegetation recovery are covered: success and recovery, theoretical under-pinning, the significance of current vegetation, and climate change. Section 2: Success and recovery If recovery is to be successful, there must be an understanding and an appreciation of what success means, and that past activities are opportunities for learning and improving practice. In Australia there has been little focus on measuring success in terms of outputs, but a lot of attention on measuring success in terms of inputs, reported as statistics of activities, effort and materials. Despite the very large number of projects, documentation has been minimal and few appraisals have been done. However, this is beginning to change. The concept of success, once considered nebulous, is being teased out: different types of success are now recognised, such as compliance (meeting contractual targets), functional (providing ecosystem functions and processes), and landscape (contributing to regional-scale ecology). Options for increasing success by learning from scientific knowledge are distilling scientific knowledge into practical tools, detailed reviews of case studies, examination of failures, adaptive management, and targeted research. Selected options are described, using Australian examples where possible: the review covers just four topics (passive restoration, types of intervention, wetland characteristics, recovery rates). Section 3: Theoretical underpinning A conceptual framework is provided as a diagram that integrates current knowledge about factors that influence change in wetland vegetation, and hence that shape vegetation recovery. The framework is in the form of a coherent diagram of the factors and processes shaping vegetation recovery in inland wetlands. This framework differs from conventional representations of ecosystem influences on wetland vegetation in explicitly recognising: • two spatial scales (wetland and landscape) • three types of connections between these (movement pathways) • a temporal shift from current to future vegetation • the vegetation that is currently present (noting that both landscape and site characteristics influence how vegetation develops). The structure of the conceptual framework is described, with examples. Development or progress towards an expected end-point is known as a recovery trajectory. It is sometimes assumed by restoration practitioners that arrival at the expected end-point is an inevitable consequence of management activities, but this is not always the case. Five possible recovery trajectories are recognised, and shown diagrammatically: rapid recovery, delayed recovery, stalled, cyclical, and rapid decline. The first two reach the endpoint, so they can be counted as successful: these are fairly stable, single equilibrium Summary
Vegetation recovery in inland wetlands: an Australian perspective 5 endpoints. Stalled and cyclical trajectories are when the trajectory does not reach the expected endpoint, instead resulting in persistent non-equilibrium states. Rapid decline is another case of not reaching the expected endpoint, and instead moves away from it: this can have multiple equilibrium endpoints. Section 4: The significance of current vegetation Current vegetation, meaning the existing plants as well as the sediment and canopy seed banks, contributes to vegetation recovery by providing propagules as well as favourable micro-sites where plants can establish. However, the capacity to do this depends on these elements remaining healthy and vigorous, and can be compromised if the plants become stressed. Current vegetation can also hinder recovery by seedling establishment by space pre-emption. Perennial plants that form dense tussocks or that grow laterally by rhizomatous clonal growth are highly effective at excluding other species. If these plants are not part of the long-term vegetation objective, then they need to be controlled, stressed or eradicated. Seed banks give a wetland resilience, allow plants to establish even if no living plants are present, and are recognised as an important part of vegetation recovery for their role in passive regeneration. The seed bank is not a static entity. Seed abundance increases as seeds are deposited, and decreases as seeds germinate, lose viability, are predated or decay. Seed diversity also changes through time. Because of natural biases concerning which species become part of the seed bank, there may be very little similarity between the species composition of the seed bank and the species present in the wetland. Section 5: Climate change and vegetation recovery Climate projections for Australia, based on down-scaled projections of the 5th Intergovernmental Panel on Climate Change (IPCC), are that nearly everywhere will be warmer with more extreme conditions (heat, rainfall, drought) and that the southern regions will be drier because of altered rainfall patterns and higher evapotranspiration. Existing knowledge of wetland plants and wetland plant communities suggests that the effects could be profound, though it is not clear over what time-scale this could occur: species growth, species interactions, and life-cycles could all be affected, as well as processes that help to maintain populations such as dispersal, colonisation and recruitment; and there could be more opportunities for invasive species to grow. Many studies comment on the individualistic nature of species response. Plant assemblages of the future will be novel assemblages, being a mix of resistant and resilient species and invading species, with some species losses. The challenges for vegetation recovery are how to set objectives and while working with different contexts simultaneously. Section 6: Concluding remarks As envisaged, the literature review has facilitated the development of a set of guiding principles and a decision support tool (DST) that will assist wetland practitioners when planning a vegetation recovery project. The four principles are expanded on, and future needs noted. A first version of the DST has been drafted, and a User Guide is in preparation that will be available as a downloadable application for a portable device. Also described here are two options that will be useful when planning whether to rely on passive or active restoration, and a recent advisory guide to restoration in a changing climate.
ABSTRACT The morpho-ecological adaptations of Eleocharis sphacelata in response to water depth an... more ABSTRACT The morpho-ecological adaptations of Eleocharis sphacelata in response to water depth and the sequential effects of resultant differences in deep water conditions on the long term population dynamics were investigated based on the observations carried out in three stable homogeneous populations in Goulburn and Ourimbah, New South Wales, Australia from August 2003 to May 2005. The deep water populations attained a higher harvestable shoot biomass and a lower rhizome biomass with increased growth in root structure thus significantly enhancing the nutrient uptake rates leading to a higher accumulation of shoot bound macronutrients. However, the accretion of excessive amounts of autogenous shoot litter coupled with slower decomposition rates under anaerobic conditions in the two deep water populations led to higher nutrient enrichment in sediments and overlying water column causing subsequent eutrophication with signs of growth inhibition including typical stress symptoms like stunted growth and chlorotic shoots. The shallow water population that intermittently experienced alternative inundation-drawdown pattern depicted an unaffected continuation of seasonal growth affirming that strict water regime management practices coupled with timely mowing or the removal of accumulating litter are necessary to ensure long-term survival of healthy E. sphacelata stands when it is used in applications where deep water conditions prevail.
Abstract Regeneration patterns of Eucalyptus coolabah Blakely & Jacobs subsp. arida (Blakely)... more Abstract Regeneration patterns of Eucalyptus coolabah Blakely & Jacobs subsp. arida (Blakely) L. Johnson & K. Hill (coolibah), a riparian tree of inland Australia, were inferred from size classes at two locations in South Australia; part of the floodplain of Cooper Creek ...
Executive Summary The expansion of water markets and resultant inter-valley trade has the potenti... more Executive Summary The expansion of water markets and resultant inter-valley trade has the potential to increase water demand in areas such as the Sunraysia district in north-west Victoria. The Goulburn-Broken system is pivotal in meeting any increase in demand in this ...
ABSTRACT Riparian ecosystems in the 21st century are likely to play a critical role in determinin... more ABSTRACT Riparian ecosystems in the 21st century are likely to play a critical role in determining the vulnerability of natural and human systems to climate change, and in influencing the capacity of these systems to adapt. Some authors have suggested that riparian ecosystems are particularly vulnerable to climate change impacts due to their high levels of exposure and sensitivity to climatic stimuli, and their history of degradation. Others have highlighted the probable resilience of riparian ecosystems to climate change as a result of their evolution under high levels of climatic and environmental variability. We synthesize current knowledge of the vulnerability of riparian ecosystems to climate change by assessing the potential exposure, sensitivity, and adaptive capacity of their key components and processes, as well as ecosystem functions, goods and services, to projected global climatic changes. We review key pathways for ecological and human adaptation for the maintenance, restoration and enhancement of riparian ecosystem functions, goods and services and present emerging principles for planned adaptation. Our synthesis suggests that, in the absence of adaptation, riparian ecosystems are likely to be highly vulnerable to climate change impacts. However, given the critical role of riparian ecosystem functions in landscapes, as well as the strong links between riparian ecosystems and human well-being, considerable means, motives and opportunities for strategically planned adaptation to climate change also exist. The need for planned adaptation of and for riparian ecosystems is likely to be strengthened as the importance of many riparian ecosystem functions, goods and services will grow under a changing climate. Consequently, riparian ecosystems are likely to become adaptation ‘hotspots’ as the century unfolds.
Common Reed Phragmites australis, a competitive species, is perceived as a threat to the conserva... more Common Reed Phragmites australis, a competitive species, is perceived as a threat to the conservation value of spring wetlands in the South Australian part of the Great Artesian Basin, Australia. The evidence for its presence, and the likelihood of it dispersing into and establishing in these spring wetlands in the hot arid centre of Australia is considered.
Section 1: Introduction This review is concerned with deliberate or planned change of vegetation ... more Section 1: Introduction This review is concerned with deliberate or planned change of vegetation from one state to another, a process that is here called recovery but which refers to activities such as restoration, rehabilitation and repair. The aim is to present a useful and accessible summary of ecological understanding about wetland vegetation recovery, as it relates to Australia. This is an essential step in the development of scientifically sound tools that will assist wetland practitioners to be more effective in restoring wetland vegetation. Such a review is timely. Knowledge about the distribution and general ecology of wetland plant communities in inland Australia has advanced considerably over the last 35 years. However, wetlands are under threat: a compilation of findings from around Australia shows a nation-wide pattern of loss and degradation, with very few instances of wetlands being in good condition. The challenge for the future is how to protect the remaining wetlands, and how to restore and rehabilitate wetland plant communities. Scientific input is needed if restoration and rehabilitation are to be done effectively. Despite huge community efforts in onground works, there is very little documentation, and hence only localised transfer of experience. This review aims to compensate for this by making existing scientific knowledge more available to users. The review is limited to the vegetation of natural inland wetlands, including woody and non-woody vegetation, but with an emphasis on non-woody vegetation. Four topics relevant to vegetation recovery are covered: success and recovery, theoretical under-pinning, the significance of current vegetation, and climate change. Section 2: Success and recovery If recovery is to be successful, there must be an understanding and an appreciation of what success means, and that past activities are opportunities for learning and improving practice. In Australia there has been little focus on measuring success in terms of outputs, but a lot of attention on measuring success in terms of inputs, reported as statistics of activities, effort and materials. Despite the very large number of projects, documentation has been minimal and few appraisals have been done. However, this is beginning to change. The concept of success, once considered nebulous, is being teased out: different types of success are now recognised, such as compliance (meeting contractual targets), functional (providing ecosystem functions and processes), and landscape (contributing to regional-scale ecology). Options for increasing success by learning from scientific knowledge are distilling scientific knowledge into practical tools, detailed reviews of case studies, examination of failures, adaptive management, and targeted research. Selected options are described, using Australian examples where possible: the review covers just four topics (passive restoration, types of intervention, wetland characteristics, recovery rates). Section 3: Theoretical underpinning A conceptual framework is provided as a diagram that integrates current knowledge about factors that influence change in wetland vegetation, and hence that shape vegetation recovery. The framework is in the form of a coherent diagram of the factors and processes shaping vegetation recovery in inland wetlands. This framework differs from conventional representations of ecosystem influences on wetland vegetation in explicitly recognising: • two spatial scales (wetland and landscape) • three types of connections between these (movement pathways) • a temporal shift from current to future vegetation • the vegetation that is currently present (noting that both landscape and site characteristics influence how vegetation develops). The structure of the conceptual framework is described, with examples. Development or progress towards an expected end-point is known as a recovery trajectory. It is sometimes assumed by restoration practitioners that arrival at the expected end-point is an inevitable consequence of management activities, but this is not always the case. Five possible recovery trajectories are recognised, and shown diagrammatically: rapid recovery, delayed recovery, stalled, cyclical, and rapid decline. The first two reach the endpoint, so they can be counted as successful: these are fairly stable, single equilibrium Summary
Vegetation recovery in inland wetlands: an Australian perspective 5 endpoints. Stalled and cyclical trajectories are when the trajectory does not reach the expected endpoint, instead resulting in persistent non-equilibrium states. Rapid decline is another case of not reaching the expected endpoint, and instead moves away from it: this can have multiple equilibrium endpoints. Section 4: The significance of current vegetation Current vegetation, meaning the existing plants as well as the sediment and canopy seed banks, contributes to vegetation recovery by providing propagules as well as favourable micro-sites where plants can establish. However, the capacity to do this depends on these elements remaining healthy and vigorous, and can be compromised if the plants become stressed. Current vegetation can also hinder recovery by seedling establishment by space pre-emption. Perennial plants that form dense tussocks or that grow laterally by rhizomatous clonal growth are highly effective at excluding other species. If these plants are not part of the long-term vegetation objective, then they need to be controlled, stressed or eradicated. Seed banks give a wetland resilience, allow plants to establish even if no living plants are present, and are recognised as an important part of vegetation recovery for their role in passive regeneration. The seed bank is not a static entity. Seed abundance increases as seeds are deposited, and decreases as seeds germinate, lose viability, are predated or decay. Seed diversity also changes through time. Because of natural biases concerning which species become part of the seed bank, there may be very little similarity between the species composition of the seed bank and the species present in the wetland. Section 5: Climate change and vegetation recovery Climate projections for Australia, based on down-scaled projections of the 5th Intergovernmental Panel on Climate Change (IPCC), are that nearly everywhere will be warmer with more extreme conditions (heat, rainfall, drought) and that the southern regions will be drier because of altered rainfall patterns and higher evapotranspiration. Existing knowledge of wetland plants and wetland plant communities suggests that the effects could be profound, though it is not clear over what time-scale this could occur: species growth, species interactions, and life-cycles could all be affected, as well as processes that help to maintain populations such as dispersal, colonisation and recruitment; and there could be more opportunities for invasive species to grow. Many studies comment on the individualistic nature of species response. Plant assemblages of the future will be novel assemblages, being a mix of resistant and resilient species and invading species, with some species losses. The challenges for vegetation recovery are how to set objectives and while working with different contexts simultaneously. Section 6: Concluding remarks As envisaged, the literature review has facilitated the development of a set of guiding principles and a decision support tool (DST) that will assist wetland practitioners when planning a vegetation recovery project. The four principles are expanded on, and future needs noted. A first version of the DST has been drafted, and a User Guide is in preparation that will be available as a downloadable application for a portable device. Also described here are two options that will be useful when planning whether to rely on passive or active restoration, and a recent advisory guide to restoration in a changing climate.
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Summary
Vegetation recovery in inland wetlands: an Australian perspective 5
endpoints. Stalled and cyclical trajectories are when the trajectory does not reach the expected endpoint, instead resulting in persistent non-equilibrium states. Rapid decline is another case of not reaching the expected endpoint, and instead moves away from it: this can have multiple equilibrium endpoints. Section 4: The significance of current vegetation Current vegetation, meaning the existing plants as well as the sediment and canopy seed banks, contributes to vegetation recovery by providing propagules as well as favourable micro-sites where plants can establish. However, the capacity to do this depends on these elements remaining healthy and vigorous, and can be compromised if the plants become stressed. Current vegetation can also hinder recovery by seedling establishment by space pre-emption. Perennial plants that form dense tussocks or that grow laterally by rhizomatous clonal growth are highly effective at excluding other species. If these plants are not part of the long-term vegetation objective, then they need to be controlled, stressed or eradicated. Seed banks give a wetland resilience, allow plants to establish even if no living plants are present, and are recognised as an important part of vegetation recovery for their role in passive regeneration. The seed bank is not a static entity. Seed abundance increases as seeds are deposited, and decreases as seeds germinate, lose viability, are predated or decay. Seed diversity also changes through time. Because of natural biases concerning which species become part of the seed bank, there may be very little similarity between the species composition of the seed bank and the species present in the wetland. Section 5: Climate change and vegetation recovery Climate projections for Australia, based on down-scaled projections of the 5th Intergovernmental Panel on Climate Change (IPCC), are that nearly everywhere will be warmer with more extreme conditions (heat, rainfall, drought) and that the southern regions will be drier because of altered rainfall patterns and higher evapotranspiration. Existing knowledge of wetland plants and wetland plant communities suggests that the effects could be profound, though it is not clear over what time-scale this could occur: species growth, species interactions, and life-cycles could all be affected, as well as processes that help to maintain populations such as dispersal, colonisation and recruitment; and there could be more opportunities for invasive species to grow. Many studies comment on the individualistic nature of species response. Plant assemblages of the future will be novel assemblages, being a mix of resistant and resilient species and invading species, with some species losses. The challenges for vegetation recovery are how to set objectives and while working with different contexts simultaneously. Section 6: Concluding remarks As envisaged, the literature review has facilitated the development of a set of guiding principles and a decision support tool (DST) that will assist wetland practitioners when planning a vegetation recovery project. The four principles are expanded on, and future needs noted. A first version of the DST has been drafted, and a User Guide is in preparation that will be available as a downloadable application for a portable device. Also described here are two options that will be useful when planning whether to rely on passive or active restoration, and a recent advisory guide to restoration in a changing climate.
Summary
Vegetation recovery in inland wetlands: an Australian perspective 5
endpoints. Stalled and cyclical trajectories are when the trajectory does not reach the expected endpoint, instead resulting in persistent non-equilibrium states. Rapid decline is another case of not reaching the expected endpoint, and instead moves away from it: this can have multiple equilibrium endpoints. Section 4: The significance of current vegetation Current vegetation, meaning the existing plants as well as the sediment and canopy seed banks, contributes to vegetation recovery by providing propagules as well as favourable micro-sites where plants can establish. However, the capacity to do this depends on these elements remaining healthy and vigorous, and can be compromised if the plants become stressed. Current vegetation can also hinder recovery by seedling establishment by space pre-emption. Perennial plants that form dense tussocks or that grow laterally by rhizomatous clonal growth are highly effective at excluding other species. If these plants are not part of the long-term vegetation objective, then they need to be controlled, stressed or eradicated. Seed banks give a wetland resilience, allow plants to establish even if no living plants are present, and are recognised as an important part of vegetation recovery for their role in passive regeneration. The seed bank is not a static entity. Seed abundance increases as seeds are deposited, and decreases as seeds germinate, lose viability, are predated or decay. Seed diversity also changes through time. Because of natural biases concerning which species become part of the seed bank, there may be very little similarity between the species composition of the seed bank and the species present in the wetland. Section 5: Climate change and vegetation recovery Climate projections for Australia, based on down-scaled projections of the 5th Intergovernmental Panel on Climate Change (IPCC), are that nearly everywhere will be warmer with more extreme conditions (heat, rainfall, drought) and that the southern regions will be drier because of altered rainfall patterns and higher evapotranspiration. Existing knowledge of wetland plants and wetland plant communities suggests that the effects could be profound, though it is not clear over what time-scale this could occur: species growth, species interactions, and life-cycles could all be affected, as well as processes that help to maintain populations such as dispersal, colonisation and recruitment; and there could be more opportunities for invasive species to grow. Many studies comment on the individualistic nature of species response. Plant assemblages of the future will be novel assemblages, being a mix of resistant and resilient species and invading species, with some species losses. The challenges for vegetation recovery are how to set objectives and while working with different contexts simultaneously. Section 6: Concluding remarks As envisaged, the literature review has facilitated the development of a set of guiding principles and a decision support tool (DST) that will assist wetland practitioners when planning a vegetation recovery project. The four principles are expanded on, and future needs noted. A first version of the DST has been drafted, and a User Guide is in preparation that will be available as a downloadable application for a portable device. Also described here are two options that will be useful when planning whether to rely on passive or active restoration, and a recent advisory guide to restoration in a changing climate.