Spelling suggestions: "subject:"resourcemanagement"" "subject:"resourcesmanagement""
281 |
Physical Resource Management and Access Mediation Within the Cloud Computing ParadigmBetts, Hutson 2012 August 1900 (has links)
Cloud computing has seen a surge over the past decade as corporations and institutions have sought to leverage the economies-of-scale achievable through this new computing paradigm. However, the rapid adoptions of cloud computing technologies that implement the existing cloud computing paradigm threaten to undermine the long-term utility of the cloud model of computing. In this thesis we address how to accommodate the variety of access requirements and diverse hardware platforms of cloud computing users by developing extensions to the existing cloud computing paradigm that afford consumer-driven access requirements and integration of new physical hardware platforms.
|
282 |
Carbon sequestration in native rainforest tree plantationsRichards, A. Unknown Date (has links)
The recent rapid decline in tropical and subtropical forests and subsequent loss of biodiversity, coupled to the threat posed by climate change, has led to a requirement for sustainable forest systems. Large-scale monocultures supply timber that can no longer be harvested in sufficient quantity from natural forests in subtropical and tropical regions. However, there is a general perception that forest systems need to be managed to provide multiple production and environmental services, including carbon (C) sequestration, restoration of soil fertility, and biodiversity. Overall, traditional plantation monocultures cannot meet all of these new objectives, and native and mixed-species plantations may provide an alternative, when provision of ecosystem services, besides timber, becomes a priority. The objective of this thesis was twofold. Firstly to assess C storage in native rainforest tree (hoop pine, Araucaria cunninghamii) plantations, planted as monocultures in subtropical Australia. Plantations were examined to evaluate their potential as a sustainable forest system for provision of high-value timber products and C sinks. The second objective was to contrast the traditional monoculture system with a multi-species system, and a mixed-species rainforest tree plantation was studied. These systems are receiving substantial attention from private forest growers as they could provide economic benefits, including greater productivity, coupled to biologically desirable outcomes, such as higher biodiversity. The focus of the second objective was to improve the design of mixtures for maximum wood production and C sequestration, so that other ecological benefits could be realised. Subtropical native hoop pine monocultures did not store soil C into long-term storage pools as rapidly as adjacent native rainforest or pastures. In addition, substantial amounts of soil nitrogen were lost from tree plantations, indicating that with current management, these systems may not be sustainable in the long-term. Overall, total C storage, including soil and aboveground biomass C, was higher in tree plantations than pastures highlighting the potential of native tree plantations for C sequestration. The mechanisms behind lower soil C storage of native hoop pine plantations, compared with rainforest and pasture, may be related to differences in soil C stabilization. While native forest and pasture systems stored C within soil aggregates and through organo-mineral interactions, tree plantations did not show a strong aggregate hierarchy and most soil C was associated with mineral-sized particles. Because soil minerals have a limited capacity to adsorb soil organic C, they may limit the C storage capacity of the studied tree plantations. We conclude that changes to management of hoop pine monocultures, such as increasing plant diversity in tree plantations, may create conditions similar to the native forest and promote greater C sequestration in plantation soils by stabilization through both soil aggregation and organomineral interactions. Since traditional monoculture forest production systems may not provide the multiple benefits needed for sustainable forestry, an alternative mixed-species tree plantation was investigated. We examined the dominant paradigm that mixtures of two fast growing species (Grevillea robusta and Elaeocarpus angustifolius) compete for site resources, while mixtures of shade tolerant (Castanospermum australe) and shade intolerant (G. robusta or E. angustifolius) species are complementary. Contrary to predictions, there was evidence for complementary interactions between the fast-growing species in terms of nutrient uptake, nutrient use efficiency and nutrient cycling. Preliminary model simulations of interactions between species for light indicated that G. robusta maintained the highest rates of photosynthesis under different light conditions and may be combined with C. australe and the more light demanding E. angustifolius in mixtures. Overall there was evidence for tree species combinations which could potentially sequester more C, in addition to other benefits including higher biodiversity and improved use of soil resources, in mixed-species plantations. Such knowledge is useful to encourage implementation of these new timber production systems.
|
283 |
Repositioning human resource management in a global airline : the struggle for legitimacy.Wilcox, Tracy Patricia, Organisation & Management, Australian School of Business, UNSW January 2009 (has links)
This thesis presents a study of intra-organisational legitimation of the Human Resource function in a large Australian airline. Major changes in senior management and strategy, under tumultuous circumstances for the industry and the firm, saw a repositioning of human resources in the organisation. The study draws on empirical ethnographic research conducted within a large global airline over approximately fourteen months, focusing on 2001. Using a longitudinal and processual research strategy, the study adopted enabled the close examination of the interrelationships between institutional structures and organisational action, embedded in an organisational setting. In particular, it considers the loss of legitimacy and agency of managers in a corporate human resources department and their response in re-establishing legitimacy in a new institutional context. Legitimacy implies the actions and existence of these actors and their sub-unit are both valued and considered valid by their constituencies. In the analysis of the unfolding multi-layered processes of legitimation, I employed elements of neo-institutional theory and critical realist ontology and applied this analysis to a modified conception of structuration, mapping out the HR managers' experience of the inner context and how it came to position their practices and constrain their agency. The study found that the human resource actors in the airline were able to re-form and regain the legitimacy of their sub-unit and of their major strategic initiative, by drawing on their stock of political relationships and on the plurality of logics, values and norms available within the large, diverse firm" Their reflexive awareness of their contextual positioning enabled them to alter their legitimation strategies and regain legitimacy" This thesis makes a contribution to our understanding of processes of deinstitutionalisation and legitimation and ongoing structuration in organisational settings. It also expands our conceptualisation of legitimacy, by focusing on legitimation as an act of becoming, and developing the notion of legitimacy struggles as institutional politics. Finally, the thesis contributes to critical human resource management research and our understanding of human resource managers' capacity for agency within broader institutional contexts.
|
284 |
Models and frameworks that enhance systematic planning for coral reef biodiversity conservationBeger, Maria Unknown Date (has links)
The global decline of coral reef biodiversity requires rapid, efficient and practical solutions. No-take marine reserves and reserve systems and other managed marine conservation areas are currently considered one of the most effective management methods to deal with this ongoing decline. Although the effects, design, and establishment of coral reef reserves have been widely debated in the literature, few examples of systematic approaches to the design of reserve systems exist. Systematic conservation planning is a procedure to prioritise sites for their inclusion in reserve systems based on data and a set of conservation principles. For coral reefs the systematic design of reserve systems has been hampered by the lack of spatially explicit data, and the lack of practical recommendations to resource managers of how to apply new scientific findings. This thesis fills critical gaps at the interface between theory, planning, and implementation of coral reef reserve systems, and provides practical guidance to reef managers. In the first chapter, literature on marine reserves is discussed and the implications for coral reef reserves are considered. Chapter 2 discusses the lessons learned in the design and implementation of a community-based marine reserve in the Philippines. Reviewing relevant literature, a framework of ‘lessons learnt’ during the establishment of local protected areas is presented, highlighting the importance of a number of factors that are vital to the success of these reserves: (a) an island location; (b) small community population size; (c) minimal effect of land-based development; (d) application of a bottom-up approach; (e) an external facilitating institution; (f) acquisition of title; (g) use of a scientific information database; (h) stakeholder involvement; (i) the establishment of legislation; (j) community empowerment; (k) alternative livelihood schemes; (l) surveillance; (m) tangible management results; (n) continued involvement of external groups after reserve establishment, and (o) small-scale project expansion. To manage coral reef species it is important to understand the processes that influence their distribution. Chapter 3 identifies the environmental factors most influential in determining coral reef fish species distributions on a regional scale. Logistic regression models for 227 fish species related presence-absence data to four remotely determined environmental predictor variables: depth 500 m away from a reef, presence of a land-sea interface, exposure, and the distance to the nearest estuary. A novel method of evaluating model significance identified suitable models for 134 species. All four predictor variables were important for the distributions of the chosen suite of fishes. Depth was the most frequently significant variable in single variable models, and the proximity of a reef to an island was the least frequently important variable. For combinations of two predictor variables, depth and exposure as well as depth and distance from the nearest estuary were the prevalent predictors of fish distributions. Several fish species responded to the combination of the distance from an estuary and the presence of the terrestrial-marine interface, indicating that these species depend on intact coastal reef habitat, which is in decline near the main sediment-laden rivers. Significant models were predominantly developed for habitat specific species. These habitat specific species are of greater conservation concern than widespread species because of their restricted range, or because threats affect them more severely if they are selectively affecting their habitat. For this reason, species distribution modelling may be an efficient method to inform reserve design. The relevance of cross-taxon congruence to the suitability of taxa as conservation representation surrogates of coral reef biodiversity across the Indo-Pacific is tested in Chapter 4, using species lists of fishes, corals, and molluscs. Congruence is identified with a linear regression analysis of dissimilarity values. The utility of a surrogate was determined by the degree to which each taxon can represent the others in a marine reserve network using a greedy reserve selection algorithm. None of the taxonomic groups examined was capable of acting as a general conservation representation surrogate. Even a data-rich taxon like fishes could be severely under-represented in reserve systems designed based on a surrogate taxon such as corals, implying that data-deficient taxa are unlikely to be represented adequately where surrogate taxa are used for planning. Despite the high cross-taxon congruence between fishes and corals, and between corals and molluscs for some regions, cross-taxon congruence was not always a reliable indicator of conservation representation surrogacy. Consequently, in Indo-Pacific coral reef ecosystems one can only be sure that a target taxon is represented fully in a marine reserve network when data on this taxon are used to select reserve sites. The fifth chapter provides a theoretical and practical framework for incorporating ecological processes that span terrestrial, marine, and freshwater environmental realms into systematic conservation planning. Firstly the types of processes are classified as interactions that exist: a) on narrow interfaces such as inter-tidal zones; b) on broad interfaces such as mangrove swamps; c) along constrained connections such as corridors used by amphibian movements between natal ponds and adult habitat; and d) through diffuse connections like bird migrations. A framework of conservation planning approaches to promote the persistence of these types of processes and examples of how they might be implemented is developed. The framework focuses both on problem formulations consistent with existing decision support tools, such as the conservation planning software MARXAN, and on new methods. The review is aimed at a broad audience of scientists, planners, and managers and takes a practical and illustrative approach, providing examples of existing work and pointing readers to tools that are available to enhance conservation planning across realms. In the concluding chapter ideas from all chapters are synthesised. This chapter discusses how the approaches and frameworks presented here could be extended, and profitable areas for future research are suggested. Overall this thesis provides new insights, concepts, and tools that can assist reef managers and scientists struggling to minimise the loss of coral reefs.
|
285 |
Models and frameworks that enhance systematic planning for coral reef biodiversity conservationBeger, Maria Unknown Date (has links)
The global decline of coral reef biodiversity requires rapid, efficient and practical solutions. No-take marine reserves and reserve systems and other managed marine conservation areas are currently considered one of the most effective management methods to deal with this ongoing decline. Although the effects, design, and establishment of coral reef reserves have been widely debated in the literature, few examples of systematic approaches to the design of reserve systems exist. Systematic conservation planning is a procedure to prioritise sites for their inclusion in reserve systems based on data and a set of conservation principles. For coral reefs the systematic design of reserve systems has been hampered by the lack of spatially explicit data, and the lack of practical recommendations to resource managers of how to apply new scientific findings. This thesis fills critical gaps at the interface between theory, planning, and implementation of coral reef reserve systems, and provides practical guidance to reef managers. In the first chapter, literature on marine reserves is discussed and the implications for coral reef reserves are considered. Chapter 2 discusses the lessons learned in the design and implementation of a community-based marine reserve in the Philippines. Reviewing relevant literature, a framework of ‘lessons learnt’ during the establishment of local protected areas is presented, highlighting the importance of a number of factors that are vital to the success of these reserves: (a) an island location; (b) small community population size; (c) minimal effect of land-based development; (d) application of a bottom-up approach; (e) an external facilitating institution; (f) acquisition of title; (g) use of a scientific information database; (h) stakeholder involvement; (i) the establishment of legislation; (j) community empowerment; (k) alternative livelihood schemes; (l) surveillance; (m) tangible management results; (n) continued involvement of external groups after reserve establishment, and (o) small-scale project expansion. To manage coral reef species it is important to understand the processes that influence their distribution. Chapter 3 identifies the environmental factors most influential in determining coral reef fish species distributions on a regional scale. Logistic regression models for 227 fish species related presence-absence data to four remotely determined environmental predictor variables: depth 500 m away from a reef, presence of a land-sea interface, exposure, and the distance to the nearest estuary. A novel method of evaluating model significance identified suitable models for 134 species. All four predictor variables were important for the distributions of the chosen suite of fishes. Depth was the most frequently significant variable in single variable models, and the proximity of a reef to an island was the least frequently important variable. For combinations of two predictor variables, depth and exposure as well as depth and distance from the nearest estuary were the prevalent predictors of fish distributions. Several fish species responded to the combination of the distance from an estuary and the presence of the terrestrial-marine interface, indicating that these species depend on intact coastal reef habitat, which is in decline near the main sediment-laden rivers. Significant models were predominantly developed for habitat specific species. These habitat specific species are of greater conservation concern than widespread species because of their restricted range, or because threats affect them more severely if they are selectively affecting their habitat. For this reason, species distribution modelling may be an efficient method to inform reserve design. The relevance of cross-taxon congruence to the suitability of taxa as conservation representation surrogates of coral reef biodiversity across the Indo-Pacific is tested in Chapter 4, using species lists of fishes, corals, and molluscs. Congruence is identified with a linear regression analysis of dissimilarity values. The utility of a surrogate was determined by the degree to which each taxon can represent the others in a marine reserve network using a greedy reserve selection algorithm. None of the taxonomic groups examined was capable of acting as a general conservation representation surrogate. Even a data-rich taxon like fishes could be severely under-represented in reserve systems designed based on a surrogate taxon such as corals, implying that data-deficient taxa are unlikely to be represented adequately where surrogate taxa are used for planning. Despite the high cross-taxon congruence between fishes and corals, and between corals and molluscs for some regions, cross-taxon congruence was not always a reliable indicator of conservation representation surrogacy. Consequently, in Indo-Pacific coral reef ecosystems one can only be sure that a target taxon is represented fully in a marine reserve network when data on this taxon are used to select reserve sites. The fifth chapter provides a theoretical and practical framework for incorporating ecological processes that span terrestrial, marine, and freshwater environmental realms into systematic conservation planning. Firstly the types of processes are classified as interactions that exist: a) on narrow interfaces such as inter-tidal zones; b) on broad interfaces such as mangrove swamps; c) along constrained connections such as corridors used by amphibian movements between natal ponds and adult habitat; and d) through diffuse connections like bird migrations. A framework of conservation planning approaches to promote the persistence of these types of processes and examples of how they might be implemented is developed. The framework focuses both on problem formulations consistent with existing decision support tools, such as the conservation planning software MARXAN, and on new methods. The review is aimed at a broad audience of scientists, planners, and managers and takes a practical and illustrative approach, providing examples of existing work and pointing readers to tools that are available to enhance conservation planning across realms. In the concluding chapter ideas from all chapters are synthesised. This chapter discusses how the approaches and frameworks presented here could be extended, and profitable areas for future research are suggested. Overall this thesis provides new insights, concepts, and tools that can assist reef managers and scientists struggling to minimise the loss of coral reefs.
|
286 |
Carbon sequestration in native rainforest tree plantationsRichards, Anna Elizabeth Unknown Date (has links)
The recent rapid decline in tropical and subtropical forests and subsequent loss of biodiversity, coupled to the threat posed by climate change, has led to a requirement for sustainable forest systems. Large-scale monocultures supply timber that can no longer be harvested in sufficient quantity from natural forests in subtropical and tropical regions. However, there is a general perception that forest systems need to be managed to provide multiple production and environmental services, including carbon (C) sequestration, restoration of soil fertility, and biodiversity. Overall, traditional plantation monocultures cannot meet all of these new objectives, and native and mixed-species plantations may provide an alternative, when provision of ecosystem services, besides timber, becomes a priority. The objective of this thesis was twofold. Firstly to assess C storage in native rainforest tree (hoop pine, Araucaria cunninghamii) plantations, planted as monocultures in subtropical Australia. Plantations were examined to evaluate their potential as a sustainable forest system for provision of high-value timber products and C sinks. The second objective was to contrast the traditional monoculture system with a multi-species system, and a mixed-species rainforest tree plantation was studied. These systems are receiving substantial attention from private forest growers as they could provide economic benefits, including greater productivity, coupled to biologically desirable outcomes, such as higher biodiversity. The focus of the second objective was to improve the design of mixtures for maximum wood production and C sequestration, so that other ecological benefits could be realised. Subtropical native hoop pine monocultures did not store soil C into long-term storage pools as rapidly as adjacent native rainforest or pastures. In addition, substantial amounts of soil nitrogen were lost from tree plantations, indicating that with current management, these systems may not be sustainable in the long-term. Overall, total C storage, including soil and aboveground biomass C, was higher in tree plantations than pastures highlighting the potential of native tree plantations for C sequestration. The mechanisms behind lower soil C storage of native hoop pine plantations, compared with rainforest and pasture, may be related to differences in soil C stabilization. While native forest and pasture systems stored C within soil aggregates and through organo-mineral interactions, tree plantations did not show a strong aggregate hierarchy and most soil C was associated with mineral-sized particles. Because soil minerals have a limited capacity to adsorb soil organic C, they may limit the C storage capacity of the studied tree plantations. We conclude that changes to management of hoop pine monocultures, such as increasing plant diversity in tree plantations, may create conditions similar to the native forest and promote greater C sequestration in plantation soils by stabilization through both soil aggregation and organomineral interactions. Since traditional monoculture forest production systems may not provide the multiple benefits needed for sustainable forestry, an alternative mixed-species tree plantation was investigated. We examined the dominant paradigm that mixtures of two fast growing species (Grevillea robusta and Elaeocarpus angustifolius) compete for site resources, while mixtures of shade tolerant (Castanospermum australe) and shade intolerant (G. robusta or E. angustifolius) species are complementary. Contrary to predictions, there was evidence for complementary interactions between the fast-growing species in terms of nutrient uptake, nutrient use efficiency and nutrient cycling. Preliminary model simulations of interactions between species for light indicated that G. robusta maintained the highest rates of photosynthesis under different light conditions and may be combined with C. australe and the more light demanding E. angustifolius in mixtures. Overall there was evidence for tree species combinations which could potentially sequester more C, in addition to other benefits including higher biodiversity and improved use of soil resources, in mixed-species plantations. Such knowledge is useful to encourage implementation of these new timber production systems.
|
287 |
Carbon sequestration in native rainforest tree plantationsRichards, A. Unknown Date (has links)
The recent rapid decline in tropical and subtropical forests and subsequent loss of biodiversity, coupled to the threat posed by climate change, has led to a requirement for sustainable forest systems. Large-scale monocultures supply timber that can no longer be harvested in sufficient quantity from natural forests in subtropical and tropical regions. However, there is a general perception that forest systems need to be managed to provide multiple production and environmental services, including carbon (C) sequestration, restoration of soil fertility, and biodiversity. Overall, traditional plantation monocultures cannot meet all of these new objectives, and native and mixed-species plantations may provide an alternative, when provision of ecosystem services, besides timber, becomes a priority. The objective of this thesis was twofold. Firstly to assess C storage in native rainforest tree (hoop pine, Araucaria cunninghamii) plantations, planted as monocultures in subtropical Australia. Plantations were examined to evaluate their potential as a sustainable forest system for provision of high-value timber products and C sinks. The second objective was to contrast the traditional monoculture system with a multi-species system, and a mixed-species rainforest tree plantation was studied. These systems are receiving substantial attention from private forest growers as they could provide economic benefits, including greater productivity, coupled to biologically desirable outcomes, such as higher biodiversity. The focus of the second objective was to improve the design of mixtures for maximum wood production and C sequestration, so that other ecological benefits could be realised. Subtropical native hoop pine monocultures did not store soil C into long-term storage pools as rapidly as adjacent native rainforest or pastures. In addition, substantial amounts of soil nitrogen were lost from tree plantations, indicating that with current management, these systems may not be sustainable in the long-term. Overall, total C storage, including soil and aboveground biomass C, was higher in tree plantations than pastures highlighting the potential of native tree plantations for C sequestration. The mechanisms behind lower soil C storage of native hoop pine plantations, compared with rainforest and pasture, may be related to differences in soil C stabilization. While native forest and pasture systems stored C within soil aggregates and through organo-mineral interactions, tree plantations did not show a strong aggregate hierarchy and most soil C was associated with mineral-sized particles. Because soil minerals have a limited capacity to adsorb soil organic C, they may limit the C storage capacity of the studied tree plantations. We conclude that changes to management of hoop pine monocultures, such as increasing plant diversity in tree plantations, may create conditions similar to the native forest and promote greater C sequestration in plantation soils by stabilization through both soil aggregation and organomineral interactions. Since traditional monoculture forest production systems may not provide the multiple benefits needed for sustainable forestry, an alternative mixed-species tree plantation was investigated. We examined the dominant paradigm that mixtures of two fast growing species (Grevillea robusta and Elaeocarpus angustifolius) compete for site resources, while mixtures of shade tolerant (Castanospermum australe) and shade intolerant (G. robusta or E. angustifolius) species are complementary. Contrary to predictions, there was evidence for complementary interactions between the fast-growing species in terms of nutrient uptake, nutrient use efficiency and nutrient cycling. Preliminary model simulations of interactions between species for light indicated that G. robusta maintained the highest rates of photosynthesis under different light conditions and may be combined with C. australe and the more light demanding E. angustifolius in mixtures. Overall there was evidence for tree species combinations which could potentially sequester more C, in addition to other benefits including higher biodiversity and improved use of soil resources, in mixed-species plantations. Such knowledge is useful to encourage implementation of these new timber production systems.
|
288 |
Repositioning human resource management in a global airline : the struggle for legitimacy.Wilcox, Tracy Patricia, Organisation & Management, Australian School of Business, UNSW January 2009 (has links)
This thesis presents a study of intra-organisational legitimation of the Human Resource function in a large Australian airline. Major changes in senior management and strategy, under tumultuous circumstances for the industry and the firm, saw a repositioning of human resources in the organisation. The study draws on empirical ethnographic research conducted within a large global airline over approximately fourteen months, focusing on 2001. Using a longitudinal and processual research strategy, the study adopted enabled the close examination of the interrelationships between institutional structures and organisational action, embedded in an organisational setting. In particular, it considers the loss of legitimacy and agency of managers in a corporate human resources department and their response in re-establishing legitimacy in a new institutional context. Legitimacy implies the actions and existence of these actors and their sub-unit are both valued and considered valid by their constituencies. In the analysis of the unfolding multi-layered processes of legitimation, I employed elements of neo-institutional theory and critical realist ontology and applied this analysis to a modified conception of structuration, mapping out the HR managers' experience of the inner context and how it came to position their practices and constrain their agency. The study found that the human resource actors in the airline were able to re-form and regain the legitimacy of their sub-unit and of their major strategic initiative, by drawing on their stock of political relationships and on the plurality of logics, values and norms available within the large, diverse firm" Their reflexive awareness of their contextual positioning enabled them to alter their legitimation strategies and regain legitimacy" This thesis makes a contribution to our understanding of processes of deinstitutionalisation and legitimation and ongoing structuration in organisational settings. It also expands our conceptualisation of legitimacy, by focusing on legitimation as an act of becoming, and developing the notion of legitimacy struggles as institutional politics. Finally, the thesis contributes to critical human resource management research and our understanding of human resource managers' capacity for agency within broader institutional contexts.
|
289 |
Models and frameworks that enhance systematic planning for coral reef biodiversity conservationBeger, Maria Unknown Date (has links)
The global decline of coral reef biodiversity requires rapid, efficient and practical solutions. No-take marine reserves and reserve systems and other managed marine conservation areas are currently considered one of the most effective management methods to deal with this ongoing decline. Although the effects, design, and establishment of coral reef reserves have been widely debated in the literature, few examples of systematic approaches to the design of reserve systems exist. Systematic conservation planning is a procedure to prioritise sites for their inclusion in reserve systems based on data and a set of conservation principles. For coral reefs the systematic design of reserve systems has been hampered by the lack of spatially explicit data, and the lack of practical recommendations to resource managers of how to apply new scientific findings. This thesis fills critical gaps at the interface between theory, planning, and implementation of coral reef reserve systems, and provides practical guidance to reef managers. In the first chapter, literature on marine reserves is discussed and the implications for coral reef reserves are considered. Chapter 2 discusses the lessons learned in the design and implementation of a community-based marine reserve in the Philippines. Reviewing relevant literature, a framework of ‘lessons learnt’ during the establishment of local protected areas is presented, highlighting the importance of a number of factors that are vital to the success of these reserves: (a) an island location; (b) small community population size; (c) minimal effect of land-based development; (d) application of a bottom-up approach; (e) an external facilitating institution; (f) acquisition of title; (g) use of a scientific information database; (h) stakeholder involvement; (i) the establishment of legislation; (j) community empowerment; (k) alternative livelihood schemes; (l) surveillance; (m) tangible management results; (n) continued involvement of external groups after reserve establishment, and (o) small-scale project expansion. To manage coral reef species it is important to understand the processes that influence their distribution. Chapter 3 identifies the environmental factors most influential in determining coral reef fish species distributions on a regional scale. Logistic regression models for 227 fish species related presence-absence data to four remotely determined environmental predictor variables: depth 500 m away from a reef, presence of a land-sea interface, exposure, and the distance to the nearest estuary. A novel method of evaluating model significance identified suitable models for 134 species. All four predictor variables were important for the distributions of the chosen suite of fishes. Depth was the most frequently significant variable in single variable models, and the proximity of a reef to an island was the least frequently important variable. For combinations of two predictor variables, depth and exposure as well as depth and distance from the nearest estuary were the prevalent predictors of fish distributions. Several fish species responded to the combination of the distance from an estuary and the presence of the terrestrial-marine interface, indicating that these species depend on intact coastal reef habitat, which is in decline near the main sediment-laden rivers. Significant models were predominantly developed for habitat specific species. These habitat specific species are of greater conservation concern than widespread species because of their restricted range, or because threats affect them more severely if they are selectively affecting their habitat. For this reason, species distribution modelling may be an efficient method to inform reserve design. The relevance of cross-taxon congruence to the suitability of taxa as conservation representation surrogates of coral reef biodiversity across the Indo-Pacific is tested in Chapter 4, using species lists of fishes, corals, and molluscs. Congruence is identified with a linear regression analysis of dissimilarity values. The utility of a surrogate was determined by the degree to which each taxon can represent the others in a marine reserve network using a greedy reserve selection algorithm. None of the taxonomic groups examined was capable of acting as a general conservation representation surrogate. Even a data-rich taxon like fishes could be severely under-represented in reserve systems designed based on a surrogate taxon such as corals, implying that data-deficient taxa are unlikely to be represented adequately where surrogate taxa are used for planning. Despite the high cross-taxon congruence between fishes and corals, and between corals and molluscs for some regions, cross-taxon congruence was not always a reliable indicator of conservation representation surrogacy. Consequently, in Indo-Pacific coral reef ecosystems one can only be sure that a target taxon is represented fully in a marine reserve network when data on this taxon are used to select reserve sites. The fifth chapter provides a theoretical and practical framework for incorporating ecological processes that span terrestrial, marine, and freshwater environmental realms into systematic conservation planning. Firstly the types of processes are classified as interactions that exist: a) on narrow interfaces such as inter-tidal zones; b) on broad interfaces such as mangrove swamps; c) along constrained connections such as corridors used by amphibian movements between natal ponds and adult habitat; and d) through diffuse connections like bird migrations. A framework of conservation planning approaches to promote the persistence of these types of processes and examples of how they might be implemented is developed. The framework focuses both on problem formulations consistent with existing decision support tools, such as the conservation planning software MARXAN, and on new methods. The review is aimed at a broad audience of scientists, planners, and managers and takes a practical and illustrative approach, providing examples of existing work and pointing readers to tools that are available to enhance conservation planning across realms. In the concluding chapter ideas from all chapters are synthesised. This chapter discusses how the approaches and frameworks presented here could be extended, and profitable areas for future research are suggested. Overall this thesis provides new insights, concepts, and tools that can assist reef managers and scientists struggling to minimise the loss of coral reefs.
|
290 |
Carbon sequestration in native rainforest tree plantationsRichards, Anna Elizabeth Unknown Date (has links)
The recent rapid decline in tropical and subtropical forests and subsequent loss of biodiversity, coupled to the threat posed by climate change, has led to a requirement for sustainable forest systems. Large-scale monocultures supply timber that can no longer be harvested in sufficient quantity from natural forests in subtropical and tropical regions. However, there is a general perception that forest systems need to be managed to provide multiple production and environmental services, including carbon (C) sequestration, restoration of soil fertility, and biodiversity. Overall, traditional plantation monocultures cannot meet all of these new objectives, and native and mixed-species plantations may provide an alternative, when provision of ecosystem services, besides timber, becomes a priority. The objective of this thesis was twofold. Firstly to assess C storage in native rainforest tree (hoop pine, Araucaria cunninghamii) plantations, planted as monocultures in subtropical Australia. Plantations were examined to evaluate their potential as a sustainable forest system for provision of high-value timber products and C sinks. The second objective was to contrast the traditional monoculture system with a multi-species system, and a mixed-species rainforest tree plantation was studied. These systems are receiving substantial attention from private forest growers as they could provide economic benefits, including greater productivity, coupled to biologically desirable outcomes, such as higher biodiversity. The focus of the second objective was to improve the design of mixtures for maximum wood production and C sequestration, so that other ecological benefits could be realised. Subtropical native hoop pine monocultures did not store soil C into long-term storage pools as rapidly as adjacent native rainforest or pastures. In addition, substantial amounts of soil nitrogen were lost from tree plantations, indicating that with current management, these systems may not be sustainable in the long-term. Overall, total C storage, including soil and aboveground biomass C, was higher in tree plantations than pastures highlighting the potential of native tree plantations for C sequestration. The mechanisms behind lower soil C storage of native hoop pine plantations, compared with rainforest and pasture, may be related to differences in soil C stabilization. While native forest and pasture systems stored C within soil aggregates and through organo-mineral interactions, tree plantations did not show a strong aggregate hierarchy and most soil C was associated with mineral-sized particles. Because soil minerals have a limited capacity to adsorb soil organic C, they may limit the C storage capacity of the studied tree plantations. We conclude that changes to management of hoop pine monocultures, such as increasing plant diversity in tree plantations, may create conditions similar to the native forest and promote greater C sequestration in plantation soils by stabilization through both soil aggregation and organomineral interactions. Since traditional monoculture forest production systems may not provide the multiple benefits needed for sustainable forestry, an alternative mixed-species tree plantation was investigated. We examined the dominant paradigm that mixtures of two fast growing species (Grevillea robusta and Elaeocarpus angustifolius) compete for site resources, while mixtures of shade tolerant (Castanospermum australe) and shade intolerant (G. robusta or E. angustifolius) species are complementary. Contrary to predictions, there was evidence for complementary interactions between the fast-growing species in terms of nutrient uptake, nutrient use efficiency and nutrient cycling. Preliminary model simulations of interactions between species for light indicated that G. robusta maintained the highest rates of photosynthesis under different light conditions and may be combined with C. australe and the more light demanding E. angustifolius in mixtures. Overall there was evidence for tree species combinations which could potentially sequester more C, in addition to other benefits including higher biodiversity and improved use of soil resources, in mixed-species plantations. Such knowledge is useful to encourage implementation of these new timber production systems.
|
Page generated in 0.0908 seconds