Spatial scale of influence of riparian and catchment land use on stream ecosystem health. Human activities at the landscape scale comprise one of the greatest threats to the ecological integrity of river ecosystems. Government and community groups across Australia are making significant efforts in riparian protection and rehabilitation in an attempt to improve the health of degraded waterways but are hampered in their goal to maximise the environmental gains for every dollar or unit effort inve ....Spatial scale of influence of riparian and catchment land use on stream ecosystem health. Human activities at the landscape scale comprise one of the greatest threats to the ecological integrity of river ecosystems. Government and community groups across Australia are making significant efforts in riparian protection and rehabilitation in an attempt to improve the health of degraded waterways but are hampered in their goal to maximise the environmental gains for every dollar or unit effort invested. The proposed research on understanding the spatial scale of influence of land use and the aggregative effects on stream ecosystems will provide a robust framework to assess various options and optimise benefits from management actions. Read moreRead less
Enhancing nutrient retention in soils through management of microbial biomass. Soil microbial-processes are generally studied in relation to mineralisation of nutrients but rarely for their potential to retain nutrients and reduce nutrient leaching. We hypothesise that management of microbial immobilisation will enhance nutrient retention in nutrient enriched soils during seasonal rains. This hypothesis will be tested under strongly seasonal environments of southwest Australia where nutrient lea ....Enhancing nutrient retention in soils through management of microbial biomass. Soil microbial-processes are generally studied in relation to mineralisation of nutrients but rarely for their potential to retain nutrients and reduce nutrient leaching. We hypothesise that management of microbial immobilisation will enhance nutrient retention in nutrient enriched soils during seasonal rains. This hypothesis will be tested under strongly seasonal environments of southwest Australia where nutrient leaching from soils degrades quality of surface and groundwater. We will first investigate pathways and conditions leading to microbial immobilisation. We will then explore the regulation of substrate and nutrient conditions to promote such retention, and subsequently develop management interventions based on microbially-mediated nutrient retention.Read moreRead less
Rapid evolution, and the dynamics and stability of ecological communities. Population sizes of species go up and down and often we do not know why. This is a problem because changes in population size underpin more complex ecological change, and understanding why population sizes change affects our ability to manage environmental impacts, and threatened, harvested and pest species. The aim of this project is to discover how rapid evolution – evolution occurring over just a few generations – driv ....Rapid evolution, and the dynamics and stability of ecological communities. Population sizes of species go up and down and often we do not know why. This is a problem because changes in population size underpin more complex ecological change, and understanding why population sizes change affects our ability to manage environmental impacts, and threatened, harvested and pest species. The aim of this project is to discover how rapid evolution – evolution occurring over just a few generations – drives changes in population sizes of plants in Australian freshwater ecosystems. By focusing on this fundamental yet poorly understood process, our results promise to rewrite our understanding of the causes of change in ecological communities, while highlighting a unique and little studied component of Australia’s biota.Read moreRead less
Toad vs Toad: Innovative approaches to understand and control an invasive species. Understanding the ecology of an invasive pest species can be a powerful tool for developing control methods. Cane toads pose a major threat to Australian native species, and are spreading increasingly rapidly through the Australian tropics. Unfortunately, we still know very little about the biology of invasion-front populations of toads. This project will provide that understanding, and will explore new ideas a ....Toad vs Toad: Innovative approaches to understand and control an invasive species. Understanding the ecology of an invasive pest species can be a powerful tool for developing control methods. Cane toads pose a major threat to Australian native species, and are spreading increasingly rapidly through the Australian tropics. Unfortunately, we still know very little about the biology of invasion-front populations of toads. This project will provide that understanding, and will explore new ideas about ways to control toad populations. For example, if we can reduce the survival of feral animals by increasing the intensity of competition within their own popualtions rather than relying on effects of other species, we may be able to use the toads to control their own populations.Read moreRead less
How effective are environmental flows? Novel approaches for monitoring and assessing ecological responses to large-scale flow alteration. Australia has begun a multi-billion dollar program to return water to stressed rivers as environmental flows. However, during times of unprecedented water scarcity, such an investment in the environment can be controversial because the ecological benefits of released water are mostly poorly understood. This project will demonstrate the effectiveness of environ ....How effective are environmental flows? Novel approaches for monitoring and assessing ecological responses to large-scale flow alteration. Australia has begun a multi-billion dollar program to return water to stressed rivers as environmental flows. However, during times of unprecedented water scarcity, such an investment in the environment can be controversial because the ecological benefits of released water are mostly poorly understood. This project will demonstrate the effectiveness of environmental flows, and promote greater understanding of the links between flow patterns and river health. The project will build upon existing knowledge to create a sound framework for planning, monitoring, and evaluation of environmental watering decisions across regional Australia, greatly improving our ability to sustainably manage rivers into the future.Read moreRead less
How does flow regulation affect food web linkages between juvenile and larval fish and aquatic invertebrates in a coastal river? River regulation to supply water for human demands has altered flow regimes in many Australian rivers. These changes in flow impact on native invertebrate and fish community composition. Environmental flow allocations seek to alleviate these impacts but managers are hampered by lack of data on the effects of flow on food web linkages, particularly for juvenile and lar ....How does flow regulation affect food web linkages between juvenile and larval fish and aquatic invertebrates in a coastal river? River regulation to supply water for human demands has altered flow regimes in many Australian rivers. These changes in flow impact on native invertebrate and fish community composition. Environmental flow allocations seek to alleviate these impacts but managers are hampered by lack of data on the effects of flow on food web linkages, particularly for juvenile and larval fish (JLF). We aim to compare food webs of invertebrates and JLF in six tributaries of the Hunter River, three of which are regulated, to determine how flow regulation changes trophic linkages. A flow release in one tributary will let us test the hypothesis that river regulation restricts food availability to JLF, reducing their viability, growth rates, and abundance.Read moreRead less
Predicting the ecological impact of cane toads on native fauna of northwestern Australia. At current rates of spread, cane toads will invade the Kimberley region of northwestern Australia within a few years. We urgently need to be able to predict which native species will be at risk from toads, and which will be relatively unaffected either because they are not killed by toads, or because they can rapidly learn, or evolve, in ways that reduce this impact and thus allow population recovery. We ....Predicting the ecological impact of cane toads on native fauna of northwestern Australia. At current rates of spread, cane toads will invade the Kimberley region of northwestern Australia within a few years. We urgently need to be able to predict which native species will be at risk from toads, and which will be relatively unaffected either because they are not killed by toads, or because they can rapidly learn, or evolve, in ways that reduce this impact and thus allow population recovery. We will obtain these data by exposing native animals to toads and recording the results; and thus, can identify the most important priorities for conservation efforts.Read moreRead less
Transformations of catchment nutrients in southeast Queensland. Human activity in catchments throughout southeast Queensland has increased nutrient loads in receiving waters. However, until recently there has been a lack of accurate quantification of these loads, and little understanding of their role in stimulating algal blooms. This proposal will examine the links between catchment nutrient inputs to waterways, their transformations and effects on stimulating algal growth in freshwater systems ....Transformations of catchment nutrients in southeast Queensland. Human activity in catchments throughout southeast Queensland has increased nutrient loads in receiving waters. However, until recently there has been a lack of accurate quantification of these loads, and little understanding of their role in stimulating algal blooms. This proposal will examine the links between catchment nutrient inputs to waterways, their transformations and effects on stimulating algal growth in freshwater systems. The outcomes from this research will be information on how catchment nutrients are affecting water quality, thus providing a vehicle for targeting management strategies designed to reduce nutrient loads.Read moreRead less
Species redundancy in response to multiple disturbances. This project aims to elucidate how the context within which disturbances occur affects food web linkages and how these map to responses in ecosystem function. There is a critical need to test the common assumption in environmental management that high biodiversity makes ecosystems resilient to disturbances. Studies that merely observe biodiversity change after disturbance cannot identify ecological processes connecting high diversity and e ....Species redundancy in response to multiple disturbances. This project aims to elucidate how the context within which disturbances occur affects food web linkages and how these map to responses in ecosystem function. There is a critical need to test the common assumption in environmental management that high biodiversity makes ecosystems resilient to disturbances. Studies that merely observe biodiversity change after disturbance cannot identify ecological processes connecting high diversity and ecosystem function, making experiments that manipulate identical disturbances in ecosystems with different biodiversity essential. This project will use field experiments that manipulate disturbances in streams replicated in low and high biodiversity regions and across gradients of chronic background stress to show how biodiversity sustains functional ecosystems, and how much diversity can be lost before ecosystems collapse.Read moreRead less
Setting rehabilitation targets for regulated floodplain wetlands: linking system structure and function. Limited understanding of ecosystem processes in floodplain wetlands impedes adaptive management strategies for combating the decline in aquatic productivity and biodiversity. This project addresses three knowledge gaps critical for effective floodplain wetland management: 1) hierarchical spatial and temporal patterns of structural diversity; 2) correspondence between patterns of structural d ....Setting rehabilitation targets for regulated floodplain wetlands: linking system structure and function. Limited understanding of ecosystem processes in floodplain wetlands impedes adaptive management strategies for combating the decline in aquatic productivity and biodiversity. This project addresses three knowledge gaps critical for effective floodplain wetland management: 1) hierarchical spatial and temporal patterns of structural diversity; 2) correspondence between patterns of structural diversity, rates of system production, and food web structure, and 3) conceptual models of relationships between hydrologic regime and wetland structure and function. The project will improve understanding of the impacts of regulation on floodplain wetlands, contribute to adaptive management, and set rehabilitation targets for delivery of environmental flows for ecosystem sustainability.Read moreRead less