Resource patchiness, dispersal and species co-occurrence: an experimental and levels-of-evidence approach in some lowland streams. Millions of dollars are being spent on rehabilitating river ecosystems that have often been highly simplified by human activities. It is important that such rehabilitation be well-grounded in sound ecological knowledge. We will test how the availability of essential resources of food and living space affect the identity and density of species present. We expect to p ....Resource patchiness, dispersal and species co-occurrence: an experimental and levels-of-evidence approach in some lowland streams. Millions of dollars are being spent on rehabilitating river ecosystems that have often been highly simplified by human activities. It is important that such rehabilitation be well-grounded in sound ecological knowledge. We will test how the availability of essential resources of food and living space affect the identity and density of species present. We expect to provide practical advice allowing managers to enhance biodiversity in streams surrounded by, and serving, agricultural areas. Likewise, we will be able to advise on the consequences of excessive water extraction on the likely success of such rehabilitation in rivers with highly variable flows.Read moreRead less
Transformation of vegetation by big herbivores, from the Pleistocene to now. The project aims to provide a coherent understanding of the effects of extinct and extant large herbivores on ecosystems over space and time. The structure and distribution of vegetation types is determined not only by climate and soils, but also by the impacts of herbivores and fire as consumers of plant biomass. Recent research has shown how fire shapes the large-scale distribution of vegetation types, but we do not h ....Transformation of vegetation by big herbivores, from the Pleistocene to now. The project aims to provide a coherent understanding of the effects of extinct and extant large herbivores on ecosystems over space and time. The structure and distribution of vegetation types is determined not only by climate and soils, but also by the impacts of herbivores and fire as consumers of plant biomass. Recent research has shown how fire shapes the large-scale distribution of vegetation types, but we do not have an equivalent understanding of the effects of large ground-dwelling herbivores. The project plans to test the effects of such animals on vegetation structure in the Pleistocene, when mega-herbivores were common, and today, and thus to compare the impacts of fire and herbivores on the distribution of vegetation types.Read moreRead less
Change ecology - gaining broad-scale, timely biodiversity knowledge in a time of uncertainty. Australians are confronted daily with the consequences of changes wrought by human over-exploitation of natural resources. Our capacity to track and respond to change is very limited and slow. Thus, rapid deterioration of ecologically important aspects is detected late and is not reflective of the general state because knowledge is derived from small-scale measurements that are difficult to generalize. ....Change ecology - gaining broad-scale, timely biodiversity knowledge in a time of uncertainty. Australians are confronted daily with the consequences of changes wrought by human over-exploitation of natural resources. Our capacity to track and respond to change is very limited and slow. Thus, rapid deterioration of ecologically important aspects is detected late and is not reflective of the general state because knowledge is derived from small-scale measurements that are difficult to generalize. We will build a capacity for providing large-scale knowledge of vegetation condition and flow-on effects on biodiversity, which also will allow us to make informed assessments of the ecological consequences of some existing (climate change, drying) and imminent (biofuel plantings) drivers of change.Read moreRead less
The importance of edge effects in determining the value of seagrass landscapes as fish nurseries. Seagrasses are a conspicuous element of Australian marine environments, and are crucial in the conservation and maintenance of biodiversity. Degradation of seagrass ecosystems from climatic extremes, increased sediment and nutrients in the water, and other pollutants results in loss and fragmentation of meadows. These changes to seagrass are linked with increased coastal erosion, severe loss of bio ....The importance of edge effects in determining the value of seagrass landscapes as fish nurseries. Seagrasses are a conspicuous element of Australian marine environments, and are crucial in the conservation and maintenance of biodiversity. Degradation of seagrass ecosystems from climatic extremes, increased sediment and nutrients in the water, and other pollutants results in loss and fragmentation of meadows. These changes to seagrass are linked with increased coastal erosion, severe loss of biodiversity, and collapse of fisheries. Increased understanding of how biological processes such as predation and food availability influence animal associations with seagrasses, and how these effects change with landscape structure, will have important applications in the sustainable management of Australia's threatened coastal habitats.Read moreRead less
Reconstructing landscapes for biodiversity: From predictive modelling to future scenarios. Many landscapes around the world have been effectively denuded of natural vegetation, causing precipitous declines in native biodiversity. Mitigation of such effects in the near/medium-term future requires substantial ecological advice. We will employ our skills developed in modelling distributions of species across landscapes based on terrain, soils and climate to assess alternative landscape-reconstructi ....Reconstructing landscapes for biodiversity: From predictive modelling to future scenarios. Many landscapes around the world have been effectively denuded of natural vegetation, causing precipitous declines in native biodiversity. Mitigation of such effects in the near/medium-term future requires substantial ecological advice. We will employ our skills developed in modelling distributions of species across landscapes based on terrain, soils and climate to assess alternative landscape-reconstruction scenarios. This links use of existing data sets for initial modelling, a validation phase for testing model reliability and for refining models, and a subsequent GIS-based modelling phase in which alternative options for reconstructing landscapes are evaluated for their effectiveness in sustaining landscape-scale native biodiversity.Read moreRead less
Landscape level effects on dispersal behaviour and gene flow in the logrunner, a rainforest restricted bird. Dispersal is thought to be critical for the persistence of small avian populations in fragmented landscapes. However, our knowledge of dispersal is limited. I will combine behavioural observations on radiotagged birds and powerful genetic markers to examine the effects of habitat fragmentation on the dispersal behaviour of a rainforest restricted bird, the logrunner. This study will deter ....Landscape level effects on dispersal behaviour and gene flow in the logrunner, a rainforest restricted bird. Dispersal is thought to be critical for the persistence of small avian populations in fragmented landscapes. However, our knowledge of dispersal is limited. I will combine behavioural observations on radiotagged birds and powerful genetic markers to examine the effects of habitat fragmentation on the dispersal behaviour of a rainforest restricted bird, the logrunner. This study will determine how landscape structure influences the movement of juvenile logrunners, investigate the causes and consequences of variation in juvenile dispersal behaviour, and use molecular data to determine how connectivity between habitats effects the genetic structure of logrunner populations.Read moreRead less
Leaf economics, and the acquisition and use of water and nitrogen for photosynthesis. Successful and sustainable management of both natural and human-modified ecosystems flows from advances in our understanding of the fundamentals of plant ecology. Improved understanding of acquisition and use of water and nutrients by plants should lead not only to better management in the present day, but better-founded management decisions under possible future scenarios such as global warming, higher atmosph ....Leaf economics, and the acquisition and use of water and nitrogen for photosynthesis. Successful and sustainable management of both natural and human-modified ecosystems flows from advances in our understanding of the fundamentals of plant ecology. Improved understanding of acquisition and use of water and nutrients by plants should lead not only to better management in the present day, but better-founded management decisions under possible future scenarios such as global warming, higher atmospheric CO2 concentrations or altered rainfall regimes. High-impact publications resulting from this project will sustain Australian leadership in environmental plant biology.Read moreRead less
Ecophysiological limitations that affect water and carbon balance within large tree canopies: a comparative investigation. Supply of water to forest canopies is a major control of hydrological, atmospheric and biotic processes that impinge on groundwater stability, catchment yield, the fate of pollutants and plant productivity. Fundamental aspects of water transport and distribution within plant tissues remain obscured by conflicting experimental data and conflicting theoretical models that des ....Ecophysiological limitations that affect water and carbon balance within large tree canopies: a comparative investigation. Supply of water to forest canopies is a major control of hydrological, atmospheric and biotic processes that impinge on groundwater stability, catchment yield, the fate of pollutants and plant productivity. Fundamental aspects of water transport and distribution within plant tissues remain obscured by conflicting experimental data and conflicting theoretical models that describe physiological functioning.
Potential hydraulic constraints to the exchange of water and carbon between leaf and atmosphere require investigation before accurate models and informed decisions can be made with respect to the role of forests in biosphere-atmosphere processes. I will use large trees to investigate physiological and morphological determinants of hydraulic function and consider relationships between tree size, water requirements and water supply.
This project will foster comparative analyses of hydraulic functioning in large angiosperm and conifer species to elucidate universal principles that relate form to function and explain relationships between trees and their environment.
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Refining Restoration Ecology: Is Range of Historical Variability an appropriate concept to guide ecosystem management and restoration? Ecosystem restoration is an urgent task in many Australian landscapes. Range of Historical Variability (RHV) theory provides an influential but largely untested framework to guide restoration activities. We will test the RHV proposition that biodiversity conservation is enhanced if the structure of altered ecosystems is restored within the pre-settlement range. P ....Refining Restoration Ecology: Is Range of Historical Variability an appropriate concept to guide ecosystem management and restoration? Ecosystem restoration is an urgent task in many Australian landscapes. Range of Historical Variability (RHV) theory provides an influential but largely untested framework to guide restoration activities. We will test the RHV proposition that biodiversity conservation is enhanced if the structure of altered ecosystems is restored within the pre-settlement range. Plants, vertebrates and invertebrates will be compared between ?unrestored? Callitris woodlands dominated by post-settlement regrowth, and ?restored? stands where regrowth has been reduced within the RHV. This will be the first test of RHV theory to encompass a range of taxonomic and functional groups at both local and landscape scales.Read moreRead less
Landscape-scale population dynamics of open forests in the Australian monsoon tropics. Over the last century there has been a trend of increasing tree cover in many landscapes. Yet the causes of this globally important ecological phenomenon are poorly understood, but may include the effects of climate, fire, grazing and CO2. We will determine how an area of forest has changed over 50 years in Kakadu National Park, linking forest demography with remote sensing techniques, re-measurement and analy ....Landscape-scale population dynamics of open forests in the Australian monsoon tropics. Over the last century there has been a trend of increasing tree cover in many landscapes. Yet the causes of this globally important ecological phenomenon are poorly understood, but may include the effects of climate, fire, grazing and CO2. We will determine how an area of forest has changed over 50 years in Kakadu National Park, linking forest demography with remote sensing techniques, re-measurement and analysis of long-term tree demography datasets, and simulation models of tree population dynamics on a landscape scale. This will provide a scientific framework to develop sustainable land management and the conservation of Australia's forest biodiversity.Read moreRead less