Skip to main content

Kirstie Fryirs

Macquarie University, Environment & Geography, Faculty Member

Followers

88

Following

10

Co-authors

11

Public Views

For full profile:
http://web.science.mq.edu.au/directory/listing/person.htm?id=kfryirs

and on LinkedIn:
au.linkedin.com/pub/kirstie-fryirs/15/73a/685/

less

Anne-magali Seydoux-guillaume

Michael E. Böttcher

Leibniz Institute for Baltic Sea Research Warnemuende

Johannes Gutenberg-Universität Mainz

J. Stephen Daly

University College Dublin

Georges Beaudoin

Laurence Maurice

Institut de Recherche pour le Développement (IRD - France)

Anastassia Borisova

Université Paul Sabatier de Toulouse

GANNABOINA MACHENDERR

Mahatma Gandhi University

Interests

Uploads

Papers by Kirstie Fryirs

Vegetation over hydrologic control of sediment transport over the past 100,000 yr

by Kirstie Fryirs, Paul Hesse, and Anthony Dosseto

AGU Fall Meeting Abstracts, Dec 1, 2008

Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr... more Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr) oxides (FMO) by factors of~ 5000-50000, much higher than any other element including its chemical homologue, Se. We have attempted to investige the mechanism (s) of Te incorporation and its enrichment in FMOs by probing in atomic enviroment using X-ray Absorption Fine Structure (XAFS) spectroscopy and compare the result to that of Se. We report the preliminary findings of the XAFS studies done on a FMO sample and laboratory ...

Vegetation over hydrologic control of sediment transport over the past 100,000 yr

by Kirstie Fryirs and P. Hesse

AGU Fall Meeting Abstracts, Dec 1, 2008

Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr... more Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr) oxides (FMO) by factors of~ 5000-50000, much higher than any other element including its chemical homologue, Se. We have attempted to investige the mechanism (s) of Te incorporation and its enrichment in FMOs by probing in atomic enviroment using X-ray Absorption Fine Structure (XAFS) spectroscopy and compare the result to that of Se. We report the preliminary findings of the XAFS studies done on a FMO sample and laboratory ...

Seed banks as a source of vegetation regeneration to support the recovery of degraded rivers: A comparison of river reaches of varying condition

Science of The Total Environment, 2016

Anthropogenic disturbance has contributed to widespread geomorphic adjustment and the degradation... more Anthropogenic disturbance has contributed to widespread geomorphic adjustment and the degradation of many rivers. This research compares for river reaches of varying condition, the potential for seed banks to support geomorphic river recovery through vegetation regeneration. Seven river reaches in the lower Hunter catchment of south-eastern Australia were assessed as being in poor, moderate, or good condition, based on geomorphic and ecological indicators. Seed bank composition within the channel and floodplain (determined in a seedling emergence study) was compared to standing vegetation. Seed bank potential for supporting geomorphic recovery was assessed by measuring native species richness, and the abundance of different plant growth forms, with consideration of the roles played by different growth forms in geomorphic adjustment. The exotic seed bank was considered a limiting factor for achieving ecological restoration goals, and similarly analysed. Seed bank native species richness was comparable between the reaches, and regardless of condition, early successional and pioneer herbs, sedges, grasses and rushes dominated the seed bank. The capacity for these growth forms to colonise and stabilise non-cohesive sediments and initiate biogeomorphic succession, indicates high potential for the seed banks of even highly degraded reaches to contribute to geomorphic river recovery. However, exotic propagules increasingly dominated the seed banks of moderate and poor condition reaches and reflected increasing encroachment by terrestrial exotic vegetation associated with riparian degradation. As the degree of riparian degradation increases, the resources required to control the regeneration of exotic species will similarly increase, if seed bank-based regeneration is to contribute to both geomorphic and ecological restoration goals.

Prospects for, and Challenges of, Research Design and Training in Cross-Disciplinary Environmental Management Research

Geographical Research, 2015

ABSTRACT Research in coupled human and natural systems can be quite a cross-disciplinary endeavou... more ABSTRACT Research in coupled human and natural systems can be quite a cross-disciplinary endeavour, requiring the combination of diverse concepts, methods, and approaches. While there is a wide recognition of the importance of incorporating different viewpoints, perspectives, and disciplines in achieving positive environmental and social outcomes, the methods through which such research is designed, specifically the processes engaged in, are largely absent from the literature. This presents challenges in research training for students in the field. This paper uses the example of a recent student project examining the management of Temperate Highland Peat Swamps on Sandstone to consider how research training might address project design, conceptual challenges, and methodological choices. The goal of this project was to build improved understanding of the role of context in the adaptive management of these endangered ecological communities from Commonwealth to micro-local scales. The paper explores the complexities of integrating approaches and methods drawn from both social sciences and environmental sciences. Rather than providing a definitive ‘how to guide’ for conducting integrative cross-disciplinary research, it offers food for thought on the processes involved in creating a research project which transcends boundaries between social science and environmental science that are easily entrenched in research training that is compartmentalised along discipline lines.

Rehabilitating Upland Swamps Using Environmental Histories: A Case Study of the Blue Mountains Peat Swamps, Eastern Australia

Geografiska Annaler: Series A, Physical Geography, 2014

16 Sediment organisation along the upper Hunter River, Australia: a multivariate statistical approach

Developments in Earth Surface Processes, 2007

Freely adjusting gravel-bed rivers are subject to recurrent input of material and frequent, but i... more Freely adjusting gravel-bed rivers are subject to recurrent input of material and frequent, but irregular, reworking of bedload materials. In contrast, many Australian rivers are characterised by low-bedload input and infrequent mobilisation of bedload materials. In this study, the influence of these boundary conditions upon surface bedmaterial organisation are analysed through application of extensive field sampling and multivariate statistics based on a range of bed-material parameters along an 8 km reach of the Upper Hunter River in New South Wales. The Hunter River is a mixedload, gravel-bed river that has been subjected to significant disturbance since European settlement. Since European settlement, the channel in the study reach has been transformed from a passive meandering river to a configuration in which the low-flow channel locally adjusts around various bar and bench features. Channel capacity has enlarged locally by a factor of 3, channel alignment has changed via cut-offs (both natural and human-induced), and channel-floodplain relationships have been altered. The multivariate statistical analyses performed in this study provided a very useful tool for identifying surface facies and the way in which sediment is organised. Bedload surface facies do not demonstrate an equivalent degree of organisation to that documented for fully self-adjusting rivers. A conceptual model is developed that relates the variability and spatial arrangement of differing classes of bed material to the type of geomorphic unit, elevation above the low-flow channel and ease of reworking (i.e., frequency of potential mobilisation). Spatial variability in the sediment mix of the study reach, appraised in light of long-term changes to sediment flux, prompts the need for refinement of bedload transport models for this kind of river.

What are we monitoring and why? Using geomorphic principles to frame eco-hydrological assessments of river condition

The Science of the total environment, 2010

Monitoring and assessment are integral components in adaptive management programmes that strive t... more Monitoring and assessment are integral components in adaptive management programmes that strive to improve the condition of river systems. Unfortunately, these procedures are generally applied with an emphasis upon biotic attributes and water quality, with limited regard for the geomorphic structure, function and evolutionary trajectory of a river system. Geomorphic principles convey an understanding of the landscape context within which ecohydrologic processes interact. Collectively, geo-eco-hydrologic understanding presents a coherent biophysical template that can be used to frame spatially and temporally rigorous approaches to monitoring that respect the inherent diversity, variability and complexity of any given river system. This understanding aids the development of management programmes that 'work with nature.' Unless an integrative perspective is used to monitor river condition, conservation and rehabilitation plans are unlikely to reach their true potential.

The relationship between geomorphic river adjustment and management actions over the last 50 years in the Upper Hunter Catchment, NSW, Australia

River Research and Applications, 2009

The installation of 517 river works in the upper Hunter catchment, New South Wales over the last ... more

How Does Restoration of Native Canopy Affect Understory Vegetation Composition? Evidence from Riparian Communities of the Hunter Valley Australia

Restoration Ecology, 2012

Abstract Restoration of native vegetation often focuses on the canopy layer species, with the ass... more Abstract Restoration of native vegetation often focuses on the canopy layer species, with the assumption that regeneration of the understory elements will occur as a consequence. The goal of this study was to assess the influence of canopy restoration on the composition and abundance of understory plant species assemblages along riparian margins in the Hunter Valley, NSW, Australia. We compared the floristic composition (richness, abundance, and diversity) of understory species between nonrevegetated (open) and canopy revegetated ...

Did humid-temperate rivers in the Old and New Worlds respond differently to clearance of riparian vegetation and removal of woody debris?

Progress in Physical Geography, 2005

Clearance of riparian vegetation and removal of woody debris are perhaps the most pervasive of al... more Clearance of riparian vegetation and removal of woody debris are perhaps the most pervasive of all forms of human disturbance to river courses. Geomorphic consequences of these impacts have varied markedly from river system to river system, a result of variations in catchment setting, climate, geology, sediment supply and evolutionary history. In this paper, geomorphic responses of rivers to rapid, systematic clearance of riparian vegetation in New World (colonial) societies are contrasted with changes associated with gradual, piecemeal, yet progressive clearance of riparian forests in northern Europe (the Old World). It is postulated that the dramatic nature of river metamorphosis experienced in landscapes such as southeastern Australia records the breaching of fundamental geomorphic thresholds in a different manner to that experienced in Old World landscapes.

Catchment-scale (dis)connectivity in sediment flux in the upper Hunter catchment, New South Wales, Australia

Geomorphology, 2007

... The distribution of riverine sediment stores and sinks, and the frequency with which sediment... more

Variability in sediment delivery and storage along river courses in Bega catchment, NSW, Australia: implications for geomorphic river recovery

Geomorphology, 2001

In many catchments in southeastern Australia, alluvial stores have been the dominant source of se... more In many catchments in southeastern Australia, alluvial stores have been the dominant source of sediments mobilised in the period since European settlement. In Bega catchment, on the South Coast of New South Wales (NSW), this has been reflected by dramatic changes to river morphology. Extensive volumes of material have been released and efficiently flushed to the lowland plain, with a

Sediment tracing in the upper Hunter catchment using elemental and mineralogical compositions: Implications for catchment-scale suspended sediment (dis)connectivity and management

Geomorphology, 2013

ABSTRACT River bed colmation layers clog the interstices of gravel-bed rivers, impeding the verti... more ABSTRACT River bed colmation layers clog the interstices of gravel-bed rivers, impeding the vertical exchange of water and nutrients that drives ecosystem function in the hyporheic zone. In catchments where fine-grained sediment supply has increased since human disturbance, understanding sediment provenance and the (dis)connectivity of supply allows practitioners to target sediment source problems and treat them within catchment management plans.Release of alluvial fine-grained sediment from channel bank erosion since European settlement has resulted in the formation of a colmation layer along the upper Hunter River at Muswellbrook, eastern Australia. X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD) are used to determine the elemental and mineralogical signatures of colmation layer and floodplain sediment sources across this 4480 km2 catchment. This sediment tracing technique is used to construct a picture of how suspended sediment supply and (dis)connectivity operates in this catchment. In this system, the primary source areas are subcatchments in which sediments are stored largely in partly confined floodplain pockets, but from which sediment supply is unimpeded and directly connected to the receiving reach. Subcatchments in which alluvial sediment storage is significant — and which contain large, laterally unconfined valleys — are essentially ‘switched off’ or disconnected from the receiving reach. This is because large sediment sinks act to trap fine-grained sediment before it reaches the receiving reach, forming a buffer along the sediment conveyor belt. Given the age structure of floodplains in the receiving reach, this pattern of source area contributions and (dis)connectivity must have occurred throughout the Holocene.

Climatic and vegetation control on sediment dynamics during the last glacial cycle

Geology, 2010

As climate is changing rapidly, there is an increasing need to understand how water and soil reso... more As climate is changing rapidly, there is an increasing need to understand how water and soil resources respond to climate change. Soil and sediment dynamics are sensitive to several external factors such as climate, vegetation type and distribution, human activity, and tectonic activity. However, the relationship between erosion and changes in these factors is diffi cult to constrain with current available approaches. Here we show that uranium isotopes in sediments from river paleochannels can be used to reconstruct variations in the residence time of sediments in a catchment over the past 100 k.y. We fi nd that sediment residence times increase by an order of magnitude during interglacials compared to glacial periods. This is interpreted as a change in sediment stores in the landscape that are tapped by catchment erosion: young, upland soils during glacial periods, reworking of old alluvial sediments during interglacials. A direct correlation is found between the sediment residence time and climatic parameters (sea-surface temperature, atmospheric carbon dioxide content, and paleorainfall estimates), suggesting that during a glacial cycle, sediment dynamics closely follow variations in climate. However, this relationship is not simple because there is no correlation between sediment residence time and paleodischarge estimates. Because sediment residence time variations correlate with changes in vegetation inferred from pollen data, it is hypothesized that the infl uence of climate on erosion over a glacial cycle may be indirect, and operates via the infl uence of climate on the type of plant ecosystems within a catchment. If verifi ed elsewhere, this conclusion would emphasize the important role of biology in the physical evolution of Earth's surface, here observed over a 100 k.y. time scale.

The Geographic Basis of Geomorphic Enquiry

Geography Compass, 2011

Geomorphic enquiry ranges from interpretations of landscape evolution framed within geological sc... more Geomorphic enquiry ranges from interpretations of landscape evolution framed within geological sciences to contemporary process-form analyses that build upon engineering applications. Geographic discourse blends these perspectives, emphasizing spatio-temporal relationships across a range of scales. Following a brief historical overview, this article highlights how emerging themes in geomorphic enquiry emphasize nonlinear, emergent aspects of geomorphic systems. Such understandings extend beyond traditional conceptualizations of landscapes that were based upon notions of deterministic stability and predictability. The unique configuration and temporal sequence of drivers, disturbances and responses of each landscape, along with the historical imprint, result in system-specific behavioural and evolutionary traits wherein landscape forms and processes are contingent upon a multitude of factors. This place-based perspective of landscapes is an inherently geographical approach to enquiry. Such geomorphic thinking provides a coherent template for a range of environmental management applications, especially in interdisciplinary fields such as landscape ecology and landscape engineering.

Has river rehabilitation begun? Social perspectives from the Upper Hunter catchment, New South Wales, Australia

Geoforum, 2010

Recognition of the degraded state of rivers across the world has prompted the development of mana... more Recognition of the degraded state of rivers across the world has prompted the development of management programmes which promote river repair through rehabilitation practices. Efforts to date have emphasised concerns for biophysical attributes of rivers to the relative exclusion of socio-cultural values. Ultimately, the process of river repair must move beyond this technical focus and incorporate collective societal engagement, participation and ownership. However, the inherent complexities of informing and managing this process limit the prospects that engagement will be translated into an effective and sustained practice. This qualitative case study research analyses the community's knowledge, views and opinions regarding geomorphic river change and river works projects undertaken in the Upper Hunter catchment, New South Wales, Australia. The responses and views expressed by the participants highlight how ineffective communication and limited understanding of past river work practices has inhibited the connection and ownership between the people and their river. Essentially, historical river management was viewed as a technical process that failed to incorporate social values and aspirations, and which gave inadequate consideration to local knowledge and experience. Participants identified the need to address both diversity and commonality in vision-building and the need for greater confidence and transparency in river science and management. In light of these responses, this paper argues for the adoption of a geosocial, transdisciplinary approach to river rehabilitation.

Post-European changes to the fluvial geomorphology of Bega catchment, Australia: implications for river ecology

Freshwater Biology, 1999

1. Within a few decades of European disturbance in the mid-nineteenth century, river character an... more 1. Within a few decades of European disturbance in the mid-nineteenth century, river character and behaviour were transformed in Bega catchment on the south coast of New South Wales, Australia. Ecological impacts of geomorphic changes to river structure and function throughout the catchment are assessed. 2. At the time of European settlement, many water courses in Bega catchment were discontinuous, with extensive swamps along middle and upper courses. Following a series of direct and indirect human impacts, channels became continuous in the middle and upper parts of the catchment, as extensive valley fills at the base of the escarpment were incised. Along the lowland plain, the channel widened by over 300%, fundamentally altering the relationship between the channel and its adjacent floodplain. 3. Geomorphic changes to river structure have modified habitat availability throughout Bega catchment. The impacts have been least pronounced in headwater streams, but have been dramatic along virtually all river courses beyond the base of the escarpment. 4. Changes in river structure have been directly related to altered riparian vegetation cover, and vice versa. As a consequence of changes to river structure, bed substrate calibre (and supply volume/rate) has been modified along most streams. 5. A series of indirect, secondary impacts have modified habitat viability along river courses. Lateral, longitudinal and vertical linkages within the river system have been altered, affecting the transfer of water, sediment, organic matter, nutrients and other biotic interactions. 6. These direct and indirect consequences of geomorphic changes in river structure suggest that ecologists need to adopt a longer-term, catchment-framed view of human disturbance to river ecosystems. 7. Effective, sustainable ecological rehabilitation of river courses is dependent on an understanding of geomorphic processes and determination of appropriate river structure at differing positions in catchments.

Don’t Fight the Site: Three Geomorphic Considerations in Catchment-Scale River Rehabilitation Planning

Environmental Management, 2009

Three geomorphic considerations that underpin the design and implementation of realistic and stra... more Three geomorphic considerations that underpin the design and implementation of realistic and strategic river conservation and rehabilitation programs that work with the nature are outlined. First, the importance of appreciating the inherent diversity of river forms and processes is discussed. Second, river dynamics are appraised, framing the contemporary behavioral regime of a reach in relation to system evolution to explain changes to river character and behavior over time. Third, the trajectory of a reach is framed in relation to downstream patterns of river types, analyzing landscape connectivity at the catchment scale to interpret geomorphic river recovery potential. The application of these principles is demonstrated using extensive catchment-scale analyses of geomorphic river responses to human disturbance in the Bega and Upper Hunter catchments in southeastern Australia. Differing implications for reach-and catchment-scale rehabilitation planning prompt the imperative that management practices work with nature rather than strive to 'fight the site.'

Post-European settlement response gradients of river sensitivity and recovery across the upper Hunter catchment, Australia

Earth Surface Processes and Landforms, 2009

EARTH SURFACE PROCESSES AND LANDFORMS Earth Surf. Process. Landforms 34, 897918 (2009) Copyright... more

Use of ergodic reasoning to reconstruct the historical range of variability and evolutionary trajectory of rivers

Earth Surface Processes and Landforms, 2012

Applications of ergodic reasoning (or location for time substitution) aid efforts at environmenta... more Applications of ergodic reasoning (or location for time substitution) aid efforts at environmental reconstruction and prediction, providing a useful tool to analyse and communicate stages of landscape evolution. Analysis of the historical range of behaviour and change that a river system has experienced can be used to interpret thresholds that have been breached, and underlying controls and/or triggers for adjustment and change. This information can be used to forecast future trajectories of adjustment and provide target conditions for management activities. This paper uses a case study from upper Wollombi Brook, New South Wales, Australia to demonstrate how ergodic reasoning can be used to assess river behaviour, change and responses to natural and human-disturbances. The 'river evolution diagram' developed by Brierley and Fryirs (Geomorphology and River Management: Applications of the River Styles Framework. Blackwell Publishing: Oxford, 2005) is presented as a means for depicting the range of behaviour and evolutionary variability of this river. These approaches can be readily applied in other systems. Implications for approaches to analysis of river evolution and management are outlined. Figure 4. Ergodic matrix of river evolution for Wollombi Brook. The sequence of changes is summarized in schematic timeslices from the work of Erskine (2008) and Erskine and Melville . Four representative sites within the four process zones were chosen to depict the main changes that have occurred since European settlement. The timing of transition in river type is also noted.

Vegetation over hydrologic control of sediment transport over the past 100,000 yr

by Kirstie Fryirs, Paul Hesse, and Anthony Dosseto

AGU Fall Meeting Abstracts, Dec 1, 2008

Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr... more Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr) oxides (FMO) by factors of~ 5000-50000, much higher than any other element including its chemical homologue, Se. We have attempted to investige the mechanism (s) of Te incorporation and its enrichment in FMOs by probing in atomic enviroment using X-ray Absorption Fine Structure (XAFS) spectroscopy and compare the result to that of Se. We report the preliminary findings of the XAFS studies done on a FMO sample and laboratory ...

Vegetation over hydrologic control of sediment transport over the past 100,000 yr

by Kirstie Fryirs and P. Hesse

AGU Fall Meeting Abstracts, Dec 1, 2008

Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr... more Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr) oxides (FMO) by factors of~ 5000-50000, much higher than any other element including its chemical homologue, Se. We have attempted to investige the mechanism (s) of Te incorporation and its enrichment in FMOs by probing in atomic enviroment using X-ray Absorption Fine Structure (XAFS) spectroscopy and compare the result to that of Se. We report the preliminary findings of the XAFS studies done on a FMO sample and laboratory ...

Seed banks as a source of vegetation regeneration to support the recovery of degraded rivers: A comparison of river reaches of varying condition

Science of The Total Environment, 2016

Anthropogenic disturbance has contributed to widespread geomorphic adjustment and the degradation... more Anthropogenic disturbance has contributed to widespread geomorphic adjustment and the degradation of many rivers. This research compares for river reaches of varying condition, the potential for seed banks to support geomorphic river recovery through vegetation regeneration. Seven river reaches in the lower Hunter catchment of south-eastern Australia were assessed as being in poor, moderate, or good condition, based on geomorphic and ecological indicators. Seed bank composition within the channel and floodplain (determined in a seedling emergence study) was compared to standing vegetation. Seed bank potential for supporting geomorphic recovery was assessed by measuring native species richness, and the abundance of different plant growth forms, with consideration of the roles played by different growth forms in geomorphic adjustment. The exotic seed bank was considered a limiting factor for achieving ecological restoration goals, and similarly analysed. Seed bank native species richness was comparable between the reaches, and regardless of condition, early successional and pioneer herbs, sedges, grasses and rushes dominated the seed bank. The capacity for these growth forms to colonise and stabilise non-cohesive sediments and initiate biogeomorphic succession, indicates high potential for the seed banks of even highly degraded reaches to contribute to geomorphic river recovery. However, exotic propagules increasingly dominated the seed banks of moderate and poor condition reaches and reflected increasing encroachment by terrestrial exotic vegetation associated with riparian degradation. As the degree of riparian degradation increases, the resources required to control the regeneration of exotic species will similarly increase, if seed bank-based regeneration is to contribute to both geomorphic and ecological restoration goals.

Prospects for, and Challenges of, Research Design and Training in Cross-Disciplinary Environmental Management Research

Geographical Research, 2015

ABSTRACT Research in coupled human and natural systems can be quite a cross-disciplinary endeavou... more ABSTRACT Research in coupled human and natural systems can be quite a cross-disciplinary endeavour, requiring the combination of diverse concepts, methods, and approaches. While there is a wide recognition of the importance of incorporating different viewpoints, perspectives, and disciplines in achieving positive environmental and social outcomes, the methods through which such research is designed, specifically the processes engaged in, are largely absent from the literature. This presents challenges in research training for students in the field. This paper uses the example of a recent student project examining the management of Temperate Highland Peat Swamps on Sandstone to consider how research training might address project design, conceptual challenges, and methodological choices. The goal of this project was to build improved understanding of the role of context in the adaptive management of these endangered ecological communities from Commonwealth to micro-local scales. The paper explores the complexities of integrating approaches and methods drawn from both social sciences and environmental sciences. Rather than providing a definitive ‘how to guide’ for conducting integrative cross-disciplinary research, it offers food for thought on the processes involved in creating a research project which transcends boundaries between social science and environmental science that are easily entrenched in research training that is compartmentalised along discipline lines.

Rehabilitating Upland Swamps Using Environmental Histories: A Case Study of the Blue Mountains Peat Swamps, Eastern Australia

Geografiska Annaler: Series A, Physical Geography, 2014

16 Sediment organisation along the upper Hunter River, Australia: a multivariate statistical approach

Developments in Earth Surface Processes, 2007

Freely adjusting gravel-bed rivers are subject to recurrent input of material and frequent, but i... more Freely adjusting gravel-bed rivers are subject to recurrent input of material and frequent, but irregular, reworking of bedload materials. In contrast, many Australian rivers are characterised by low-bedload input and infrequent mobilisation of bedload materials. In this study, the influence of these boundary conditions upon surface bedmaterial organisation are analysed through application of extensive field sampling and multivariate statistics based on a range of bed-material parameters along an 8 km reach of the Upper Hunter River in New South Wales. The Hunter River is a mixedload, gravel-bed river that has been subjected to significant disturbance since European settlement. Since European settlement, the channel in the study reach has been transformed from a passive meandering river to a configuration in which the low-flow channel locally adjusts around various bar and bench features. Channel capacity has enlarged locally by a factor of 3, channel alignment has changed via cut-offs (both natural and human-induced), and channel-floodplain relationships have been altered. The multivariate statistical analyses performed in this study provided a very useful tool for identifying surface facies and the way in which sediment is organised. Bedload surface facies do not demonstrate an equivalent degree of organisation to that documented for fully self-adjusting rivers. A conceptual model is developed that relates the variability and spatial arrangement of differing classes of bed material to the type of geomorphic unit, elevation above the low-flow channel and ease of reworking (i.e., frequency of potential mobilisation). Spatial variability in the sediment mix of the study reach, appraised in light of long-term changes to sediment flux, prompts the need for refinement of bedload transport models for this kind of river.

What are we monitoring and why? Using geomorphic principles to frame eco-hydrological assessments of river condition

The Science of the total environment, 2010

Monitoring and assessment are integral components in adaptive management programmes that strive t... more Monitoring and assessment are integral components in adaptive management programmes that strive to improve the condition of river systems. Unfortunately, these procedures are generally applied with an emphasis upon biotic attributes and water quality, with limited regard for the geomorphic structure, function and evolutionary trajectory of a river system. Geomorphic principles convey an understanding of the landscape context within which ecohydrologic processes interact. Collectively, geo-eco-hydrologic understanding presents a coherent biophysical template that can be used to frame spatially and temporally rigorous approaches to monitoring that respect the inherent diversity, variability and complexity of any given river system. This understanding aids the development of management programmes that 'work with nature.' Unless an integrative perspective is used to monitor river condition, conservation and rehabilitation plans are unlikely to reach their true potential.

The relationship between geomorphic river adjustment and management actions over the last 50 years in the Upper Hunter Catchment, NSW, Australia

River Research and Applications, 2009

The installation of 517 river works in the upper Hunter catchment, New South Wales over the last ... more

How Does Restoration of Native Canopy Affect Understory Vegetation Composition? Evidence from Riparian Communities of the Hunter Valley Australia

Restoration Ecology, 2012

Abstract Restoration of native vegetation often focuses on the canopy layer species, with the ass... more Abstract Restoration of native vegetation often focuses on the canopy layer species, with the assumption that regeneration of the understory elements will occur as a consequence. The goal of this study was to assess the influence of canopy restoration on the composition and abundance of understory plant species assemblages along riparian margins in the Hunter Valley, NSW, Australia. We compared the floristic composition (richness, abundance, and diversity) of understory species between nonrevegetated (open) and canopy revegetated ...

Did humid-temperate rivers in the Old and New Worlds respond differently to clearance of riparian vegetation and removal of woody debris?

Progress in Physical Geography, 2005

Clearance of riparian vegetation and removal of woody debris are perhaps the most pervasive of al... more Clearance of riparian vegetation and removal of woody debris are perhaps the most pervasive of all forms of human disturbance to river courses. Geomorphic consequences of these impacts have varied markedly from river system to river system, a result of variations in catchment setting, climate, geology, sediment supply and evolutionary history. In this paper, geomorphic responses of rivers to rapid, systematic clearance of riparian vegetation in New World (colonial) societies are contrasted with changes associated with gradual, piecemeal, yet progressive clearance of riparian forests in northern Europe (the Old World). It is postulated that the dramatic nature of river metamorphosis experienced in landscapes such as southeastern Australia records the breaching of fundamental geomorphic thresholds in a different manner to that experienced in Old World landscapes.

Catchment-scale (dis)connectivity in sediment flux in the upper Hunter catchment, New South Wales, Australia

Geomorphology, 2007

... The distribution of riverine sediment stores and sinks, and the frequency with which sediment... more

Variability in sediment delivery and storage along river courses in Bega catchment, NSW, Australia: implications for geomorphic river recovery

Geomorphology, 2001

In many catchments in southeastern Australia, alluvial stores have been the dominant source of se... more In many catchments in southeastern Australia, alluvial stores have been the dominant source of sediments mobilised in the period since European settlement. In Bega catchment, on the South Coast of New South Wales (NSW), this has been reflected by dramatic changes to river morphology. Extensive volumes of material have been released and efficiently flushed to the lowland plain, with a

Sediment tracing in the upper Hunter catchment using elemental and mineralogical compositions: Implications for catchment-scale suspended sediment (dis)connectivity and management

Geomorphology, 2013

ABSTRACT River bed colmation layers clog the interstices of gravel-bed rivers, impeding the verti... more ABSTRACT River bed colmation layers clog the interstices of gravel-bed rivers, impeding the vertical exchange of water and nutrients that drives ecosystem function in the hyporheic zone. In catchments where fine-grained sediment supply has increased since human disturbance, understanding sediment provenance and the (dis)connectivity of supply allows practitioners to target sediment source problems and treat them within catchment management plans.Release of alluvial fine-grained sediment from channel bank erosion since European settlement has resulted in the formation of a colmation layer along the upper Hunter River at Muswellbrook, eastern Australia. X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD) are used to determine the elemental and mineralogical signatures of colmation layer and floodplain sediment sources across this 4480 km2 catchment. This sediment tracing technique is used to construct a picture of how suspended sediment supply and (dis)connectivity operates in this catchment. In this system, the primary source areas are subcatchments in which sediments are stored largely in partly confined floodplain pockets, but from which sediment supply is unimpeded and directly connected to the receiving reach. Subcatchments in which alluvial sediment storage is significant — and which contain large, laterally unconfined valleys — are essentially ‘switched off’ or disconnected from the receiving reach. This is because large sediment sinks act to trap fine-grained sediment before it reaches the receiving reach, forming a buffer along the sediment conveyor belt. Given the age structure of floodplains in the receiving reach, this pattern of source area contributions and (dis)connectivity must have occurred throughout the Holocene.

Climatic and vegetation control on sediment dynamics during the last glacial cycle

Geology, 2010

As climate is changing rapidly, there is an increasing need to understand how water and soil reso... more As climate is changing rapidly, there is an increasing need to understand how water and soil resources respond to climate change. Soil and sediment dynamics are sensitive to several external factors such as climate, vegetation type and distribution, human activity, and tectonic activity. However, the relationship between erosion and changes in these factors is diffi cult to constrain with current available approaches. Here we show that uranium isotopes in sediments from river paleochannels can be used to reconstruct variations in the residence time of sediments in a catchment over the past 100 k.y. We fi nd that sediment residence times increase by an order of magnitude during interglacials compared to glacial periods. This is interpreted as a change in sediment stores in the landscape that are tapped by catchment erosion: young, upland soils during glacial periods, reworking of old alluvial sediments during interglacials. A direct correlation is found between the sediment residence time and climatic parameters (sea-surface temperature, atmospheric carbon dioxide content, and paleorainfall estimates), suggesting that during a glacial cycle, sediment dynamics closely follow variations in climate. However, this relationship is not simple because there is no correlation between sediment residence time and paleodischarge estimates. Because sediment residence time variations correlate with changes in vegetation inferred from pollen data, it is hypothesized that the infl uence of climate on erosion over a glacial cycle may be indirect, and operates via the infl uence of climate on the type of plant ecosystems within a catchment. If verifi ed elsewhere, this conclusion would emphasize the important role of biology in the physical evolution of Earth's surface, here observed over a 100 k.y. time scale.

The Geographic Basis of Geomorphic Enquiry

Geography Compass, 2011

Geomorphic enquiry ranges from interpretations of landscape evolution framed within geological sc... more Geomorphic enquiry ranges from interpretations of landscape evolution framed within geological sciences to contemporary process-form analyses that build upon engineering applications. Geographic discourse blends these perspectives, emphasizing spatio-temporal relationships across a range of scales. Following a brief historical overview, this article highlights how emerging themes in geomorphic enquiry emphasize nonlinear, emergent aspects of geomorphic systems. Such understandings extend beyond traditional conceptualizations of landscapes that were based upon notions of deterministic stability and predictability. The unique configuration and temporal sequence of drivers, disturbances and responses of each landscape, along with the historical imprint, result in system-specific behavioural and evolutionary traits wherein landscape forms and processes are contingent upon a multitude of factors. This place-based perspective of landscapes is an inherently geographical approach to enquiry. Such geomorphic thinking provides a coherent template for a range of environmental management applications, especially in interdisciplinary fields such as landscape ecology and landscape engineering.

Has river rehabilitation begun? Social perspectives from the Upper Hunter catchment, New South Wales, Australia

Geoforum, 2010

Recognition of the degraded state of rivers across the world has prompted the development of mana... more Recognition of the degraded state of rivers across the world has prompted the development of management programmes which promote river repair through rehabilitation practices. Efforts to date have emphasised concerns for biophysical attributes of rivers to the relative exclusion of socio-cultural values. Ultimately, the process of river repair must move beyond this technical focus and incorporate collective societal engagement, participation and ownership. However, the inherent complexities of informing and managing this process limit the prospects that engagement will be translated into an effective and sustained practice. This qualitative case study research analyses the community's knowledge, views and opinions regarding geomorphic river change and river works projects undertaken in the Upper Hunter catchment, New South Wales, Australia. The responses and views expressed by the participants highlight how ineffective communication and limited understanding of past river work practices has inhibited the connection and ownership between the people and their river. Essentially, historical river management was viewed as a technical process that failed to incorporate social values and aspirations, and which gave inadequate consideration to local knowledge and experience. Participants identified the need to address both diversity and commonality in vision-building and the need for greater confidence and transparency in river science and management. In light of these responses, this paper argues for the adoption of a geosocial, transdisciplinary approach to river rehabilitation.

Post-European changes to the fluvial geomorphology of Bega catchment, Australia: implications for river ecology

Freshwater Biology, 1999

1. Within a few decades of European disturbance in the mid-nineteenth century, river character an... more 1. Within a few decades of European disturbance in the mid-nineteenth century, river character and behaviour were transformed in Bega catchment on the south coast of New South Wales, Australia. Ecological impacts of geomorphic changes to river structure and function throughout the catchment are assessed. 2. At the time of European settlement, many water courses in Bega catchment were discontinuous, with extensive swamps along middle and upper courses. Following a series of direct and indirect human impacts, channels became continuous in the middle and upper parts of the catchment, as extensive valley fills at the base of the escarpment were incised. Along the lowland plain, the channel widened by over 300%, fundamentally altering the relationship between the channel and its adjacent floodplain. 3. Geomorphic changes to river structure have modified habitat availability throughout Bega catchment. The impacts have been least pronounced in headwater streams, but have been dramatic along virtually all river courses beyond the base of the escarpment. 4. Changes in river structure have been directly related to altered riparian vegetation cover, and vice versa. As a consequence of changes to river structure, bed substrate calibre (and supply volume/rate) has been modified along most streams. 5. A series of indirect, secondary impacts have modified habitat viability along river courses. Lateral, longitudinal and vertical linkages within the river system have been altered, affecting the transfer of water, sediment, organic matter, nutrients and other biotic interactions. 6. These direct and indirect consequences of geomorphic changes in river structure suggest that ecologists need to adopt a longer-term, catchment-framed view of human disturbance to river ecosystems. 7. Effective, sustainable ecological rehabilitation of river courses is dependent on an understanding of geomorphic processes and determination of appropriate river structure at differing positions in catchments.

Don’t Fight the Site: Three Geomorphic Considerations in Catchment-Scale River Rehabilitation Planning

Environmental Management, 2009

Three geomorphic considerations that underpin the design and implementation of realistic and stra... more Three geomorphic considerations that underpin the design and implementation of realistic and strategic river conservation and rehabilitation programs that work with the nature are outlined. First, the importance of appreciating the inherent diversity of river forms and processes is discussed. Second, river dynamics are appraised, framing the contemporary behavioral regime of a reach in relation to system evolution to explain changes to river character and behavior over time. Third, the trajectory of a reach is framed in relation to downstream patterns of river types, analyzing landscape connectivity at the catchment scale to interpret geomorphic river recovery potential. The application of these principles is demonstrated using extensive catchment-scale analyses of geomorphic river responses to human disturbance in the Bega and Upper Hunter catchments in southeastern Australia. Differing implications for reach-and catchment-scale rehabilitation planning prompt the imperative that management practices work with nature rather than strive to 'fight the site.'

Post-European settlement response gradients of river sensitivity and recovery across the upper Hunter catchment, Australia

Earth Surface Processes and Landforms, 2009

EARTH SURFACE PROCESSES AND LANDFORMS Earth Surf. Process. Landforms 34, 897918 (2009) Copyright... more

Use of ergodic reasoning to reconstruct the historical range of variability and evolutionary trajectory of rivers

Earth Surface Processes and Landforms, 2012

Applications of ergodic reasoning (or location for time substitution) aid efforts at environmenta... more Applications of ergodic reasoning (or location for time substitution) aid efforts at environmental reconstruction and prediction, providing a useful tool to analyse and communicate stages of landscape evolution. Analysis of the historical range of behaviour and change that a river system has experienced can be used to interpret thresholds that have been breached, and underlying controls and/or triggers for adjustment and change. This information can be used to forecast future trajectories of adjustment and provide target conditions for management activities. This paper uses a case study from upper Wollombi Brook, New South Wales, Australia to demonstrate how ergodic reasoning can be used to assess river behaviour, change and responses to natural and human-disturbances. The 'river evolution diagram' developed by Brierley and Fryirs (Geomorphology and River Management: Applications of the River Styles Framework. Blackwell Publishing: Oxford, 2005) is presented as a means for depicting the range of behaviour and evolutionary variability of this river. These approaches can be readily applied in other systems. Implications for approaches to analysis of river evolution and management are outlined. Figure 4. Ergodic matrix of river evolution for Wollombi Brook. The sequence of changes is summarized in schematic timeslices from the work of Erskine (2008) and Erskine and Melville . Four representative sites within the four process zones were chosen to depict the main changes that have occurred since European settlement. The timing of transition in river type is also noted.