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In dryland environments where rivers have been modified by water resource developments, the use of environmental water provides a management tool to restore or maintain riparian vegetation conditions. Relevant management actions include watering to promote the recruitment of highly valued woody species. However, for many riparian trees, little is known about the watering regimes needed to achieve successful recruitment. We conducted a glasshouse experiment to investigate the early growth of 5-week old seedlings of two Australian dryland riparian tree species, coolibah (Eucalyptus coolabah) and river red gum (Eucalyptus camaldulensis), in floodplain soil cores to provide insights into their requirements for successful establishment in dryland habitats. Both species exhibited similar growth patterns for their above-ground components. E. coolabah root penetration through soil cores was consistent over the 12-week experiment. In contrast, E. camaldulensis root penetration appeared to be considerably slower during the first 6 weeks, but then became more rapid over the following 6 weeks, with similar rooting depths after 12 weeks observed to those of E. coolabah. These findings suggest that coolibah seedlings are more likely to establish under rapidly drying conditions than river red gum seedlings. Such differences in early growth for these iconic species should be considered when determining the provision of environmental water for their management.

Coastal freshwater wetlands (CFWs) are among the most understudied wetlands globally and are highly vulnerable to projected climate changes. To address CFW knowledge gaps in south-east Queensland, Australia, we surveyed the floristic composition and structure of wooded CFWs and explored variation in vegetation patterns in relation to selected environmental drivers. Understorey and shrub assemblages were surveyed using a cover-class scale and stem counts for tree species abundance. Vegetation structure attributes (stem density, basal area) were calculated from survey data. Redundancy analysis was used to investigate drivers of vegetation structure and the species composition of each stratum. Vegetation structure patterns were associated with gradients of rainfall, soil moisture, salinity and pH. Understorey species composition was associated with wallum wetland species, native perennial grass and herb species, and vegetation patterns of the canopy. Common CFW species, namely Melaleuca quinquenervia and Eucalyptus tereticornis, dominated tree assemblage variation. Overall, CFW vegetation exhibited strong associations with gradients of salinity, rainfall, groundwater dependence and disturbance. Alterations to key drivers of vegetation pattern with future climate changes are likely to markedly influence the composition, structure and function of CFW vegetation communities. Action is therefore required to maintain CFW vegetation communities and ecological function in these diverse and unique wetland systems.

Evaluating wetland vegetation responses to flow regimes is challenging because of the inherently complex, variable and dynamic nature of wetland vegetation in space and time. We propose four principles to guide the development of management objectives and evaluation approaches to support adaptive management of wetland vegetation in flow-managed systems. First, we assert a need for more explicit, direct and defensible alignment of management objectives, targets and indicators to reflect broader ecological, sociocultural and economic values, and the underlying ecosystem functions that support them. Second, we propose a framework for indicator selection across multiple spatiotemporal scales and levels of ecological organisation, from individuals to landscape mosaics (vegscapes). Third, we emphasise the need to evaluate vegetation condition and responses to environmental flows in relation to a more nuanced understanding of temporal flow dynamics. Finally, we discuss the importance of considering the effects of non-flow variables that can modify vegetation responses to environmental flows. We highlight key knowledge needs required to support the implementation of these principles, particularly the urgency of improving our understanding of ecological, sociocultural and economic values of wetland vegetation and the attributes and functions that support these values.

Many water scientists aim for their work to inform water policy and management, and in pursuit of this objective, they often work alongside government water agencies to ensure their research is relevant, timely and communicated effectively. A paper in this issue, examining 'Science integrity, public policy and water governance in the Murray-Darling Basin, Australia���, suggests that a large group of scientists, who work on water management in the Murray-Darling Basin (MDB) including the Basin Plan, have been subject to possible ���administrative capture'. Specifically, it is suggested that they have advocated for policies favoured by government agencies with the objective of gaining personal benefit, such as increased research funding. We examine evidence for this claim and conclude that it is not justified. The efforts of scientists working alongside government water agencies appear to have been misinterpreted as possible administrative capture. Although unsubstantiated, this claim does indicate that the science used in basin water planning is increasingly caught up in the politics of water management. We suggest actions to improve science-policy engagement in basin planning, to promote constructive debate over contested views and avoid the over-politicisation of basin science.

Freshwater ecosystems are highly vulnerable to global warming because 1) their chief drivers, water quality and flow regimes, are highly sensitive to atmospheric warming, and 2) they are already extremely threatened by a wide range of interacting anthropogenic pressures. Even relatively modest global warming of 1.5°C poses a considerable threat to freshwater ecosystems and the many critical services these provide to people. Shifts in the composition and function of freshwater ecosystems are widely anticipated with adverse consequences for ecosystem services, including those underpinning water and food security. While the extent and severity of effects is likely to be significantly reduced if global warming is limited to 1.5°C, concerted efforts to implement widely recognised priorities for policy and management are required to mitigate unavoidable impacts and reduce the likelihood of perverse outcomes of climate mitigation and adaptation efforts in other sectors—all of which rely on fresh water supply. Freshwater ecosystems and their services, including provision of fresh water, must therefore be considered first and foremost when developing and implementing any climate action.

Aim: The conservation of plant species biodiversity has been identified as a crucial factor for the resilience of dryland ecosystems in the face of climate change and desertification. Duma florulenta (lignum) is a keystone species that facilitates biodiversity in the floodplains and wetlands of Australia's dryland river systems. This paper explores spatial genetic structure of lignum and investigates factors influencing dispersal and gene flow within and among river catchments of the northern Murray–Darling Basin. Location: Northern Murray–Darling Basin, eastern Australia. Methods: A total of 122 individual plants from subpopulations located on rivers in four adjacent catchments were genotyped using 10 microsatellite markers. Microsatellite data were then analyzed using population genetic techniques to evaluate levels of gene flow and genetic structure and identify factors influencing dispersal. Results: Results suggest high levels of gene flow between lignum subpopulations of the northern Murray–Darling Basin. AMOVA revealed small but significant differences between subpopulations, and STRUCTURE analysis did not detect meaningful structure when sampling information was not provided. However, when sampling information was supplied using the LOCPRIOR model, three genetic clusters were identified. All Lower Balonne subpopulations were assigned to cluster 1 while a number of the other subpopulations showed mixed ancestry. Weak relationships were identified between pairwise genetic distance and geographic as well as river distance, although the R2 value of the former was only half that of the latter. Main conclusions: Patterns of genetic variation suggest frequent long‐distance overland gene flow largely as a result of the movement of seeds via floodwater. Therefore, maintenance of natural variability in flow regime is key both to maintain conditions favorable to recruitment and to promote dispersal and gene flow across the landscape. However, given future climate change projections persistence may be more reliant on the species ability to endure long periods of drought between flood events.

Aim: Riparian ecosystems are regarded as vulnerable to the effects of climate change. Because of their reliance on passive dispersal to migrate from areas where conditions have become unfavourable, plants are particularly susceptible. On dryland river floodplains, the species diversity of herbaceous annuals is often high while that of structurally dominant woody perennials is low. We examined gene flow genetic structure and dispersal in Acacia stenophylla, a small perennial tree widely distributed throughout river systems of inland Australia. The role of the river corridor in shaping patterns of gene flow and genetic structure is also investigated. Location: Murray-Darling Basin, south eastern Australia. Methods: A total of 127 individuals, from 12 subpopulations located on seven rivers were genotyped at 13 microsatellite loci. Several population and landscape genetic tools were applied to the microsatellite data to evaluate spatial patterns of gene flow and genetic structure and make inferences regarding possible modes of dispersal. Results: High gene flow and weak genetic structure was identified for the 12 subpopulations of A. stenophylla sampled, a surprising result given large distances between subpopulations. Pairwise genetic distance between subpopulations was low to moderate and could largely be explained (R2 = 0.68) by two variables: distance along the river and the proportion of no flow days. structure analysis revealed two genetic clusters. Subpopulations located on the Darling and Lower Balonne rivers were dominated by cluster one while subpopulations from the Warrego and Paroo rivers showed largely mixed ancestry with individuals descending from both clusters one and two. Main Conclusions: These results indicate that the river corridor facilitates extensive gene flow between subpopulations of A. stenophylla in this system. Hydrochory appears to be the dominant process; however, upstream movements of propagules most probably via animal movement are sufficient to negate effects expected under unidirectional dispersal.

This chapter presents an overview of the aquatic ecosystems of the Murray–Darling Basin (MDB). Ecosystem types within the Basin are diverse, ranging from small upland streams to the coastal estuary at the river mouth. The vast floodplains and associated rivers and wetlands are the most iconic habitats of the MDB, together with rich communities of plants, birds, fish, and other organisms. The diversity of ecosystem types are summarised, as are each of the major biotic groups making up the Basins’ flora and fauna. The links to hydrology, and, in particular, the role of floods and droughts in the life cycle of these various organisms. Land clearing and flow alteration associated with agriculture and water resource development have had a significant impact on the condition of aquatic ecosystems in the MDB, and climate change is now also emerging as a major threat. These impacts are discussed, together with a brief overview of current efforts to mitigate them and to restore the health of aquatic ecosystems, particularly the more heavily impacted lowland areas and the coastal estuary.

The cities across the northern dry region of China are exposed to multiple sustainability challenges. Beijing-Hebei-Tianjin (BTH) urban agglomeration, for example, experiences severe water shortages due to rapidly expanding urban populations, industrial use, and irrigation-intensive agriculture. Climate change has further threatened water resources security. Overuse of water resources to meet the demand of various water sectors has far-reaching health and environmental implications including ecosystem sustainability. Surface water and groundwater pollution present public health risks. Despite the extraordinary policies and efforts being made and implemented by the Government of China, the BTH region currently lacks coordination among stakeholders leading to poor water governance. Consultation among scientists, engineers and stakeholders on regional water security issues is crucial and must be frequent and inclusive. An international symposium was held in Shijiazhuang in early November 2019 to identify some of the key water security challenges and scope of an idealized future eco-city in the region by developing a sustainability framework. This work drew on experiences from across China and beyond. Scientists agree that integration of science, technology, and governance within an appropriate policy framework was particularly significant for combating the issue of water insecurity, including in the region's newly developed city, Xiong'an New Area. An emerging concept, “Healthy Waterways and Ecologically Sustainable Cities” which integrates social, ecological and hydrological systems and acts as an important pathway for sustainability in the 21st century was proposed in the symposium to tackle the problems in the region. This high level biophysical and cultural concept empowers development goals and promotes human health and wellbeing. The framework on healthy waterways and ecologically sustainable cities can overcome sustainability challenges by resolving water resource management issues in BTH in a holistic way. To implement the concept, we strongly recommend the utilization of evidence-based scientific research and institutional cooperation including national and international collaborations to achieve the Healthy Waterways and Ecologically Sustainable Cities goal in the BTH in future. This article is categorized under: Water and Life > Conservation, Management, and Awareness.

Coastal freshwater supply and demand systems are expected to be significantly affected by changes to both climatic and non-climatic drivers over coming decades. Adapting to these changes to secure adequate freshwater to meet the rising demands of socio-economic development has become a critical task for decision-makers. Whilst a range of adaptation options may be available, the complexity and interconnectedness of water resource systems make it challenging to identify which options are likely to be most feasible and effective. Here, we present a Bayesian decision network (BDN) that was co-developed with local experts to identify appropriate adaptation options for freshwater management under both current and likely future conditions in the Da Do Basin of coastal Vietnam. Potential adaptation options were prioritised according to cost-effectiveness based on relative costs incurred and relative utilities delivered across a range of future scenarios. The BDN model indicated that cost-effectiveness of adaptation options varied between future scenarios. Constructing pumping stations was the most cost-effective option under climate change scenarios, whilst a higher water price was the most cost-effective option under non-climatic changes. Under combined climatic and non-climatic changes, constructing pumping stations in combination with increasing water prices provided the most cost-effective option. The model affords an opportunity for decision-makers in the Da Do Basin to prioritise and evaluate appropriate and feasible adaptation actions under different scenarios with respect to multiple drivers.

Understanding soundscapes, that is, the totality of sounds within a location, helps to assess nature in a more holistic way, providing a novel approach to investigating ecosystems. To date, very few studies have investigated freshwater soundscapes in their entirety and none across a broad spatial scale.In this study, we recorded 12 freshwater streams in South East Queensland continuously for three days and calculated three acoustic indices for each minute in each stream. We then used principal component analysis of summary statistics for all three acoustic indices to investigate acoustic properties of each stream and spatial variation in their soundscapes.All streams had a unique soundscape with most exhibiting diurnal variation in acoustic patterns. Across these sites, we identified five distinct groups with similar acoustic characteristics. We found that we could use summary statistics of AIs to describe daytimes across streams as well. Most difference in stream soundscapes was observed during the daytime with significant variation in soundscapes both between hours and among sites. Synthesis and Application. We demonstrate how to characterize stream soundscapes by using simple summary statistics of complex acoustic indices. This technique allows simple and rapid investigation of streams with similar acoustic properties and the capacity to characterize them in a holistic and universal way. While we developed this technique for freshwater streams, it is also applicable to terrestrial and marine soundscapes., Understanding soundscapes helps to assess nature in a holistic way and provides a novel approach to investigate ecosystems. In unprecedented spatial and temporal resolution, we recorded 12 freshwater streams in south‐east Queensland for multiple days, calculated three acoustic indices and used a principal component analysis to investigate acoustic properties of each stream. While all streams had a unique soundscape, we could also identified five distinct groups with similar acoustic characteristics across all sites, showing our technique allows a rapid investigation of stream soundscape.

Coastal freshwater wetlands are amongst the world’s most modified but poorly researched ecosystems and some of the most vulnerable to climate change. Here, we examine vegetation resilience in coastal wetlands of subtropical Australia to altered salinity and flooding regimes likely to occur with climate change. We conducted field surveys and glasshouse experiments to examine plant diversity and regeneration responses of understorey and canopy species across four habitats. Vegetation composition, but not richness, varied between seaward and inland habitats while soil seed bank diversity was greatest in more inland sites. Experimental salinity and flooding treatments strongly influenced emergence from seed banks with most species germinating under fresh, waterlogged conditions and very few in saline treatments. Composition of emerging seedling assemblages was similar across habitats and treatments but differed considerably from the extant vegetation, indicating a relatively minor role of soil seed banks in sustaining current vegetation structure in this wetland. An exception to this was Sporobolus virginicus (marine couch) which was common in both the vegetation and seed banks suggesting a high capacity for this species to re-establish following disturbances. Seedlings of dominant canopy species also reacted strongly to increased salinity treatments with decreased survivorship recorded. Overall, our findings suggest a high probability of constrained vegetation regeneration in this wetland in response to key projected climate change disturbances with implications for vegetation diversity at a landscape scale including declines in the extent and diversity of more landward vegetation communities and expansion of salt-tolerant marshes dominated by Sporobolus virginicus.

Riparian ecosystems are hotspots for ecological restoration globally because of the disproportionately high value and diversity of the ecological functions and services which they support and their high level of vulnerability to anthropogenic pressures, including climate change. Degraded riparian ecosystems are associated with many serious anthropogenic problems including increased river bank erosion, water quality decline, increased flood risk and biodiversity loss. Conventional approaches to riparian restoration, however, are frequently too narrow in focus – spatially, temporally, ecologically and socially – to adequately or equitably address the goals to which they aspire. Climate change, along with the intensification of other human pressures, means that static, historically oriented restoration objectives focused solely on prior ecological composition and structure are unlikely to be defensible, achievable or appropriate in the Anthropocene. Conversely, open‐ended restoration strategies lacking clear objectives and targets entail substantial risks such as significant biodiversity losses, especially of native species. A functional approach to planning and prioritising riparian restoration interventions offers an intermediate alternative that is still framed by measurable targets but allows for greater consideration of broader temporal, spatial and cultural influences. Here, we provide an overview of major riparian functions across multiple scales and identify key drivers of, and threats to, these. We also discuss practical approaches to restoring and promoting riparian functions and highlight some key concerns for the development of policy and management of robust riparian restoration in the Anthropocene.

Water resources management faces many challenges in coastal areas of developing countries, where climate change coupled with high rates of population growth and urbanization have the potential to cause severe water scarcity. Of particular concern, are sea level rise and altered precipitation regimes that will influence spatial and temporal patterns of river discharge, water levels and saltwater penetration in estuaries. A sound understanding of factors affecting the vulnerability of coastal freshwater systems is therefore needed to mitigate the potential impacts of climatic and non-climatic changes. In this study, a system dynamics modeling approach was employed to explore the vulnerability of the coastal freshwater system in Da Do Basin, Vietnam to projected sea level rise, upstream flow decline and socio-economic development. This system includes the Da Do River and irrigation channels that receive freshwater through sluice gates from the Van Uc and Lach Tray rivers. The model was developed as a learning tool for decision-makers to improve their understanding of the spatial and temporal dynamic behaviors of the system and to inform adaptation decision-making by allowing exploration of plausible future scenarios. The model was developed, calibrated and validated using both historical data and expert knowledge elucidated via stakeholder consultation. Model results indicate that under current conditions, freshwater availability is sufficient to meet existing domestic, industrial and agricultural demands. However, the coastal freshwater system changes significantly and collapses under several plausible future scenarios. Future projections suggest that declining upstream flows will be the strongest threat to the system's vulnerability. System dynamics models enable consideration of the interactive effects of a range of climatic and non-climatic drivers on water resources availability thereby facilitating improved planning for collective and proactive adaptation actions to efficiently secure freshwater resources to support socio-economic development of coastal basins in the face of climate change.

Socio-economic and environmental drivers are causing large scale abandonment of agricultural land worldwide. Simultaneously, there is growing recognition that urgent and widespread revegetation is required in our agricultural landscapes to restore biodiversity, ecosystem services and promote carbon sequestration. The design of effective revegetation strategies, however, can be limited by a lack of knowledge regarding patterns and processes of regeneration. Here, we examine naturally regenerating woody vegetation on 12 old-fields and compare this to paired remnant vegetation across four regions of a semi-arid agricultural area in eastern Australia. We found that naturally regenerating vegetation on old-fields exhibited similarities to remnant vegetation in terms of composition but varied substantially with respect to key structural attributes. Woody vegetation tends to regenerate in these old-fields with relatively high density given sufficient time (~ 30–40 years), but prior to this, very limited structural recovery occurs at all. The composition and richness of tree seedling and shrub assemblages did not differ between remnant and old-field areas. However, tree assemblages in remnant areas differed in composition and had higher species richness. Old-fields had extremely low numbers of exotic trees and shrubs. Simultaneously, most dominant native species present in the remnant vegetation were also observed in regenerating old-fields, contributing to a low degree of compositional difference between old-fields and remnant areas overall. The abundance of paddock trees, time since abandonment and mean annual rainfall are key drivers influencing natural regeneration of these old-fields. We recommend that natural regeneration is a viable form of restoration of old-fields in the northern Murray-Darling Basin given sufficient time.

Climate change is driving shifts in social-ecological systems globally. In response, humans must adapt to altered climatic and environmental conditions. While climate change adaptation is a pressing issue in many sectors and regions, the adaptation of environmental management strategies is particularly urgent because of the severity and extent of risks associated with projected impacts. Robust adaptation of environmental management requires effective spatial and temporal implementation of interventions, with explicit consideration of trade-offs between different socio-economic and environmental objectives. We investigate the critical interface between regional governance systems and spatial planning for climate adaptation by exploring the case of Australia’s Natural Resource Management (NRM) bodies. Australia’s NRM bodies provide an ideal case study for two reasons. First, Australia faces significant threats from current and future climate changes. Second, Australian NRM bodies have recently undertaken a major program of spatial planning and research to explicitly address the need for climate adaptation. We explore the interface between regional governance systems and spatial planning by: 1) reviewing the historical development of institutional arrangements in relation to spatial planning by Australia’s regional NRM bodies; 2) documenting current planning processes with regard to climate adaptation and more generally; and 3) identifying strengths and weaknesses of the existing governance system at various scales with respect to its ability to foster effective spatial planning. We find that the institutional and resource capacity of the Australian regional NRM bodies is currently being eroded and that the national governance system is broadly failing to deliver on the intended outcomes of climate-ready NRM plans. We make recommendations for governance reform and institutional adaptation to improve spatial planning for climate adaptation in Australia and discuss the broader implications of our findings.

Aim: Climate change threatens biodiversity in all ecosystems, and major shifts in species distributions are expected. Freshwater ecosystems are considered particularly vulnerable due to the ectothermic physiology of most freshwater species and their limited habitat extent and capacity to track climate trends. In this study, we examined what broad patterns in freshwater riverine species turnover might be expected under climate change across continental Australia and what are the implications of these patterns for aquatic species and the low aquatic biodiversity of some bioregions? Location: Continental Australia. Methods: We built statistical relationships between bioclimatic environments and the occurrence of species of four freshwater taxa (freshwater fish, crayfish, turtles and frogs) and examined trends in projected species turnover for a ‘business as usual’ climate scenario. We used Maxent to model species distributions and present the median projection across 18 global climate models. A recently derived national stream network was used to generate estimates of mean annual river flow and to produce realistic species distributions and migration options by restricting dispersal and migration opportunities usually available to riverine fauna. Results: High species turnover was driven overwhelmingly by potential local extinctions particularly for stream frogs and crayfish where their current biodiversity is largely confined to higher elevation headwater streams. We predicted high turnover for inland regions of Australia, which are arid and generally support fewer freshwater species. Main conclusions: Our analysis indicates that under the most severe emissions pathway, projected climate change is likely to cause substantial changes to the composition of faunal assemblages in Australian rivers well before the end of this century. While freshwater systems globally are subject to immediate and pressing threats from anthropogenic land and water use, management interventions addressing these pressures need to be considered within the context of climate change.

The Modelling and Simulation Society of Australia and New Zealand Inc. All rights reserved. The management of island water systems in highly developed tourism destinations of developing countries presents many challenges in the face of climate change. Such systems are high levels of uncertainty and complexity driven by dynamic interactions amongst multiple climatic and non-climatic drivers with many feedbacks. Understanding complex interactions and feedbacks in the systems is, therefore, critical to develop a long-term strategy for safeguarding a growing water demand from socio-economic development. In this study, an integrated approach was applied to improved management of scarce water resources in Cat Ba Island under high levels of climate change and socio-economic stressors. Specifically, a range of relevant historical data was collected and examined to identify interrelations among climatic and non-climatic drivers on the island water resources. In addition, 961 households in six communes and one town in the Cat Ba Island were interviewed to understand respondents' perspectives on threats and adaptation options for the management of the island's scarce water system. Results of relevant historical data analysis and respondents' perspectives were used together with focus group discussions to develop a causal loop diagram (CLD) for the Cat Ba Island's scarce water resource system under high levels of climate change and tourism development. The CLD provides a comprehensive representation of the island's scarce water resources driven by multiple relationships and interactions amongst climatic and non-climatic drivers as well as adaptation options, represented by two reinforcing loops (R1 and R2), and ten balancing loops (B1 to B10). These loops provide further information on the potential water scarcity in the island in both current and future conditions. Specifically, water demand has been observed to be significantly increased over time due to high levels of population growth and tourism development, depicted by two reinforcing loops (R1 and R2). However, water supply has been decreasing over time due to sea level rise and precipitation decline. These observations are represented by ten balancing loops (B1 to B10) in which seven balancing loops (B4 to B10) represent a "Drifting goals" system archetype to seek the stability in water availability in the system. The next stage of this study is to apply a system dynamics model (SDM) to assess the vulnerability of the island water system in 47 years, from 2014 to 2050 under climatic and non-climatic changes. Simulations targets the year 2050 because it provides a long-term perspective from which the long-term dynamic behaviour of the island water system and the consequences of the plausible future scenarios could be assessed to inform adaptation decision-making. The key climatic and non-climatic drivers and adaptation options from the CLD will be incorporated into the SDM to assess the vulnerability of the island water system and effectiveness of adaptation options under climate change and socio-economic stressors over time. The SDM will be calibrated using relevant historical data, and validated by local stakeholders for decision-making supports. A contingent evaluation method is also applied to examine the determinant factors influencing respondents' willingness to pay (WTP) for building reservoirs and increasing water price for improved management of scarce water resources in a highly developed tourism island under climate change. The logistic regression models and Bayesian networks will be used to identify determinants of the respondents' WTP for the management of the island's scarce water system. The results of this study will assist decision-makers and water managers to understand dynamics behaviour of the system over time, and respondents' perceptions, thereby applying more effective practices to the management of scarce water resources under high levels of climate change and tourism development in the Cat Ba Island, Vietnam.

Climate change poses significant emerging risks to biodiversity, ecosystem function and associated socioecological systems. Adaptation responses must be initiated in parallel with mitigation efforts, but resources are limited. As climate risks are not distributed equally across taxa, ecosystems and processes, strategic prioritization of research that addresses stakeholder-relevant knowledge gaps will accelerate effective uptake into adaptation policy and management action. After a decade of climate change adaptation research within the Australian National Climate Change Adaptation Research Facility, we synthesize the National Adaptation Research Plans for marine, terrestrial and freshwater ecosystems. We identify the key, globally relevant priorities for ongoing research relevant to informing adaptation policy and environmental management aimed at maximizing the resilience of natural ecosystems to climate change. Informed by both global literature and an extensive stakeholder consultation across all ecosystems, sectors and regions in Australia, involving thousands of participants, we suggest 18 priority research topics based on their significance, urgency, technical and economic feasibility, existing knowledge gaps and potential for cobenefits across multiple sectors. These research priorities provide a unified guide for policymakers, funding organizations and researchers to strategically direct resources, maximize stakeholder uptake of resulting knowledge and minimize the impacts of climate change on natural ecosystems. Given the pace of climate change, it is imperative that we inform and accelerate adaptation progress in all regions around the world.

Ecological character and wise use are central tenets underpinning the Ramsar Convention’s global wetland ambitions. In this paper, we postulate that, given on-going and progressive degradation and destruction of wetlands, these concepts require reframing. So as to overcome the human–nature dualism, which underpins current wetland conservation, we propose that wetlands need to be placed within a social–ecological framing that can accommodate a plurality of worldviews and value systems. This reframing broadens the definition of wetland ecological character and replaces it with a more inclusive and comprehensive term ‘wetland character’. Wise use, consequently, becomes maintenance of wetland character. Further considerations on maintaining wetland character under this construct are presented.

Bayesian belief networks (BBNs) are probabilistic graphical models that can capture and integrate both quantitative and qualitative data, thus accommodating data-limited conditions. This paper systematically reviews applications of BBNs with respect to spatial factors, water domains, and the consideration of climate change impacts. The methods used for constructing and validating BBN models, and their applications in different forms of decision-making support are examined. Most reviewed publications originate from developed countries (70%), in temperate climate zones (42%), and focus mainly on water quality (42%). In 60% of the reviewed applications model validation was based on the expert or stakeholder evaluation and sensitivity analysis, and whilst in 27% model performance was not discussed. Most reviewed articles applied BBNs in strategic decision-making contexts (52%). Integrated modelling tools for addressing challenges of dynamically complex systems were also reviewed by analysing the strengths and weaknesses of BBNs, and integration of BBNs with other modelling tools. The application of BBNs to water resource management was rarely applied in developing countries and in tropical regions.Only 8% reviewed papers explored potential impacts of climate change on water resources.Only 11% and 6% of reviewed articles applied influence diagrams and Object-Oriented Bayesian Networks respectively.Most reviewed articles applied BBNs in strategic decision-making contexts (52%) for water resource management.Results from BBN models were rarely compared or tested against other modelling approaches to validate their performance.

Questions How diverse and resilient is vegetation following a decade of extreme drought along a typical floodplain gradient of semi-arid south-eastern Australia? How do mechanisms of resilience (i.e. persistence and soil seed banks) vary between major plant groups and spatially with respect to habitat type and position along a flood frequency gradient? Location Southern Murray-Darling Basin, Australia. Methods We surveyed understorey vegetation and conducted germination trials to examine responses to re-wetting from soil seed banks of seven major habitat types along a typical floodplain gradient of the southern Murray-Darling Basin. We assessed abundance, species richness, functional diversity and composition, including exotic species, within and between extant and germinating assemblages. Results Understorey vegetation was surprisingly diverse, although low in cover, following a decade of extreme drought, with considerable numbers of plant species (61) and functional plant groups represented. Historically drier habitats, towards floodplain margins, had higher species richness and cover overall and for exotic species. Plant assemblages exhibited high heterogeneity between habitats. Soil seed banks were very dissimilar from extant vegetation, comprising mainly amphibious and damp taxa as well as some terrestrial herbs, mostly annuals. Seed banks were most abundant and diverse in intermediate floodplain habitats, and their composition was very distinct between habitat types. Conclusions Semi-arid floodplain vegetation is likely to be highly resilient to prolonged drought. Plants persisting under dry conditions do not appear to rely on local soil seed banks for regeneration and may either tolerate drying in situ or arrive from neighbouring ecosystems. Soil seed banks allow understorey vegetation to respond to re-wetting, especially in intermediate floodplain habitats. Lake bed assemblages and aquatic/amphibious species lacking soil seed banks appear most vulnerable to drought. Vegetation resilience is promoted by landscape heterogeneity.

Many studies have investigated the effects of human disturbances on floodplain propagule banks, but few have examined how these propagule banks change down the soil depth profile. Changes in soil propagule banks with depth can indicate the state of past vegetation and potentially demonstrate the effects of different land uses on the soil profile. Here, we examined changes in soil propagule banks down the soil-depth profile in an Australian floodplain wetland with five different land-use histories, ranging from a, in this case, relatively minor disturbance (clearing) through to more major disturbance (continuous cultivation). Land use had a larger influence than floodplain geomorphology on the propagule distribution of wetland plant-group numbers. An observed decrease in individuals over the depth profile also altered terrestrial plant groups in fields with longer land-use histories. Overall, soil-propagule profiles for terrestrial plants were not as affected by land use as were those of wetland plants. The geomorphological position on the floodplain also altered the soil propagule bank, with areas subject to the most flooding having the highest number of wetland species and retaining more of these species with greater depths. In conclusion, land-use impacts alter soil-propagule banks down the profile, despite most studies focussing on the top few centimetres.

Environmental flows are a critical tool for addressing ecological degradation of river systems brought about by increasing demand for limited water resources. The importance of basin scale management of environmental flows has long been recognized as necessary if managers are to achieve social, economic, and environmental objectives. The challenges in managing environmental flows are now emerging and include the time taken for changes to become manifest, uncertainty around large-scale responses to environmental flows and that most interventions take place at smaller scales. The purpose of this paper is to describe how conceptual models can be used to inform the development, and subsequent evaluation of ecological objectives for environmental flows at the basin scale. Objective setting is the key initial step in environmental flow planning and subsequently provides a foundation for effective adaptive management. We use the implementation of the Basin Plan in Australia's Murray-Darling Basin (MDB) as an example of the role of conceptual models in the development of environmental flow objectives and subsequent development of intervention monitoring and evaluation, key steps in the adaptive management of environmental flows. The implementation of the Basin Plan was based on the best science available at the time, however, this was focused on ecosystem responses to environmental flows. The monitoring has started to reveal that limitations in our conceptualization of the basin may reduce the likelihood of achieving of basin scale objectives. One of the strengths of the Basin Plan approach was that it included multiple conceptual models informing environmental flow management. The experience in the MDB suggests that the development of multiple conceptual models at the basin scale will help increase the likelihood that basin-scale objectives will be achieved.

Riparian habitats in arid and semi-arid landscapes are characterised by unpredictable flooding and drought with favourable opportunities for seedling establishment limited to short periods following floodwater recession. Tree species persisting under such conditions might therefore be expected to exhibit traits that facilitate seedling growth and survival in the face of unpredictable flooding and drought. We examined seedling growth in response to flooding in two common eastern Australian riparian tree species with contrasting distributions: Acacia stenophylla, common in lowland riparian habitats of the arid and semi-arid interior where average annual rainfall is below 500 mm, and Casuarina cunninghamiana, widespread in upland and coastal catchments with average annual rainfall over 500 mm. We conducted a glasshouse experiment to investigate seedling growth and survival over 90 days under a range of watering treatments including continuous flooding, flooding followed by drying and continuously moist conditions. Seedlings of both species exhibited high levels of flood tolerance, apparently facilitated by a capacity to halt growth and delay development rather than via plastic growth responses. Both species also displayed rapid and opportunistic growth in response to moist conditions; however, this was around three-fold greater in A. stenophylla seedlings. Our results suggest that seedling establishment traits influence the distribution of these widespread riparian species and contribute to the capacity of A. stenophylla to persist under the stressful and unpredictable conditions characteristic of arid and semi-arid riparian habitats.

Questions: Do nurse plant interactions significantly influence understorey vegetation diversity in a large, semi-arid, shrub-dominated wetland? How do the modes and net effects of nurse plant interactions vary spatially along a flood frequency gradient, and temporally in response to drying? Location: Narran Lakes Ramsar site, New South Wales, Australia. Methods: Microhabitat characteristics, understorey vegetation and germinable soil seed banks were investigated in shrub and open habitats across a flood frequency gradient in a large, semi-arid wetland dominated by open shrubland under productive conditions following floodwater recession and again following 6 mo of drought. Split-plot ANOVA and multivariate analyses were used to determine the effects of shrubs on microhabitat character, understorey vegetation cover, species diversity, richness and composition and germinable soil seed banks. Results: Microhabitat characteristics, including canopy cover, litter cover and soil character, all differed between shrub and open habitats, especially in the most frequently flooded sites. Under productive conditions following flooding, lignum shrubs suppressed understorey vegetation cover but increased species richness at the site scale across the flood frequency gradient and, in the most frequently flooded sites, supported higher species density at a microhabitat scale. Under dry conditions, lignum shrubs had a positive effect on understorey vegetation cover, species richness and species density across the flood frequency gradient, but particularly in frequently flooded sites. A significant difference in soil seed bank composition between shrub and open habitats was only observed in frequently flooded sites. Conclusions: Nurse plant interactions appear to play an important role in determining understorey vegetation diversity in the lignum shrubland of the Narran Lakes wetland system. The modes and net effects of these nurse plant interactions vary in space and time in relation to flood history and drying. Positive interactions, probably involving microhabitat amelioration, appear to be particularly important to plant diversity and abundance under dry conditions. Under more favourable wetter conditions, lignum shrubs also contribute to understorey vegetation diversity by facilitating the establishment of different species than those dominating open habitats. Our findings have implications for the management of perennial shrubs and hydrological regimes in such wetlands.

Bayesian networks (BNs) are widely implemented as graphical decision support tools which use probability inferences to generate “what if?” and “which is best?” analyses of potential management options for water resource management, under climate change and socio-economic stressors. This paper presents a systematic quantitative literature review of applications of BNs for decision support in water resource management. The review quantifies to what extent different types of data (quantitative and/or qualitative) are used, to what extent optimization-based and/or scenario-based approaches are adopted for decision support, and to what extent different categories of adaptation measures are evaluated. Most reviewed publications applied scenario-based approaches (68%) to evaluate the performance of management measures, whilst relatively few studies (18%) applied optimization-based approaches to optimize management measures. Institutional and social measures (62%) were mostly applied to the management of water-related concerns, followed by technological and engineered measures (47%), and ecosystem-based measures (37%). There was no significant difference in the use of quantitative and/or qualitative data across different decision support approaches (p = 0.54), or in the evaluation of different categories of management measures (p = 0.25). However, there was significant dependence (p = 0.076) between the types of management measure(s) evaluated, and the decision support approaches used for that evaluation. The potential and limitations of BN applications as decision support systems are discussed along with solutions and recommendations, thereby further facilitating the application of this promising decision support tool for future research priorities and challenges surrounding uncertain and complex water resource systems driven by multiple interactions amongst climatic and non-climatic changes.

Riparian ecosystems in the 21st century are likely to play a critical role in determining the vulnerability of natural and human systems to climate change, and in influencing the capacity of these systems to adapt. Some authors have suggested that riparian ecosystems are particularly vulnerable to climate change impacts due to their high levels of exposure and sensitivity to climatic stimuli, and their history of degradation. Others have highlighted the probable resilience of riparian ecosystems to climate change as a result of their evolution under high levels of climatic and environmental variability. We synthesize current knowledge of the vulnerability of riparian ecosystems to climate change by assessing the potential exposure, sensitivity, and adaptive capacity of their key components and processes, as well as ecosystem functions, goods and services, to projected global climatic changes. We review key pathways for ecological and human adaptation for the maintenance, restoration and enhancement of riparian ecosystem functions, goods and services and present emerging principles for planned adaptation. Our synthesis suggests that, in the absence of adaptation, riparian ecosystems are likely to be highly vulnerable to climate change impacts. However, given the critical role of riparian ecosystem functions in landscapes, as well as the strong links between riparian ecosystems and human well-being, considerable means, motives and opportunities for strategically planned adaptation to climate change also exist. The need for planned adaptation of and for riparian ecosystems is likely to be strengthened as the importance of many riparian ecosystem functions, goods and services will grow under a changing climate. Consequently, riparian ecosystems are likely to become adaptation ‘hotspots’ as the century unfolds.

Vegetation communities in Australia's riverine landscapes are ecologically, economically and culturally significant. They are also among the most threatened ecosystems on the continent and have been dramatically altered as a result of human activities and climate change. Vegetation of Australian Riverine Landscapes brings together, for the first time, the results of the substantial amount of research that has been conducted over the last few decades into the biology, ecology and management of these important plant communities in Australia. The book is divided into four sections. The first section provides context with respect to the spatial and temporal dimensions of riverine landscapes in Australia. The second section examines key groups of riverine plants, while the third section provides an overview of riverine vegetation in five major regions of Australia, including patterns, significant threats and management. The final section explores critical issues associated with the conservation and management of riverine plants and vegetation, including water management, salinity, fire and restoration. Vegetation of Australian Riverine Landscapes highlights the incredible diversity and dynamic nature of riverine vegetation across Australia, and will be an excellent reference for researchers, academics and environmental consultants.

Plant species in temporary wetlands can be subject to dramatic changes in conditions, ranging from prolonged inundation to prolonged drought. Temporary wetland plants exhibit a range of mechanisms which facilitate persistence through periods of extreme dry and/or extreme wet including long-lived soil seed banks which tend to be particularly prevalent in dryland regions. This study examines responses of vegetation and soil seed banks to a managed flood in wetlands on a lowland river floodplain in semi-arid Australia using a Before-After/Control-Impact design (BACI). The main aim of this work was to investigate the role of soil seed banks in vegetation responses to flooding following an extended dry period. Differences in extant vegetation after flooding were clear from the first post-flood survey (approximately 2 months after flooding) and persisted until the final survey almost 12 months after inundation. In contrast, no differences were evident between the germinating assemblages from the soil seed bank of flooded and not flooded sites. Germinating assemblages did however differ significantly from extant assemblages, although this difference reduced over time. We hypothesize that the initial, rapid vegetation response to flooding was facilitated by vegetative reproduction from dormant rhizomes of Eleocharis sphacelata, the dominant taxon in flooded wetlands, which was rare in germinating assemblages. Our results suggest, however, that the contribution of the soil seed bank to the vegetation assemblages of flooded wetlands increased over time, as flood waters receded, and provided the principal source of the gradual increase in plant species richness observed in post-flood vegetation.

We investigated the effects of flooding and drying over 6 months on growth and biomass allocation in seedlings of Muehlenbeckia florulenta Meisn. (tangled lignum), a common and widely distributed shrub of Australia's desert floodplains. We sought to determine if lignum seedlings respond to flooding or drying by altering traits or allocation patterns or instead display fixed patterns of development. Since desert floodplains are highly unpredictable and heterogeneous environments, we hypothesised that adaptive phenotypic plasticity is unlikely to have developed or be advantageous in seedlings of this species as environmental state changes are highly variable in their timing and duration and plants risk being caught out of kilter with environmental conditions. To test this, we conducted a glasshouse experiment in which lignum seedlings, grown in both clay and sandy sediments, were subjected to a range of hydrological conditions over a period of 6 months. Lignum seedlings exhibited considerable tolerance of both flooding and drying in our experiment and no mortality was observed. Growth was significantly reduced by flooding, however, and seedlings displayed extremely delayed development rather than plasticity in overall biomass allocation or any of the specific morphological variables we measured. Lignum seedlings were considerably more tolerant of drying than flooding and responded plastically by reducing leaf area ratios through reductions in specific leaf areas and leaf production and expansion. Sediment type had little effect on seedling development. Our results indicate that surface water hydrology is likely to be a major determinant of recruitment patterns in this ecologically significant species.

Although soil seed banks are understood to be integral to the vegetation dynamics and restoration of many ecosystems, little is known of their role in riparian zones. In this study, we investigated soil seed banks of riparian zones of contrasting condition in an agricultural landscape and evaluated their potential to influence riparian restoration. We examined the composition and structure of germinable soil seed banks along lateral gradients from stream channels in both cleared and wooded riparian zones of three lowland creeks within the Goulburn Broken catchment in temperate southeastern Australia. Environmental correlates of soil seed bank characteristics and similarity to extant vegetation were also examined. We found an abundant and species-rich soil seed bank mostly comprising propagules of perennial rushes and sedges and annual and perennial grasses with many species of annual forbs. While the majority of identifiable germinants and species were native, exotic species were common at all locations. Soil seed bank composition was relatively homogeneous among streams and along lateral gradients from the channel. Riparian condition (i.e. cleared or wooded), however, had a strong influence on soil seed bank composition and structure with cleared reaches containing more species, more germinable annual grasses and higher total numbers of germinable seeds. Soil seed bank composition was correlated with site openness suggesting that extant vegetation structure plays an important role in soil seed bank dynamics. Recruitment from the in situ soil seed bank will help restore only some components of the riparian plant community and may hinder restoration by introducing undesirable species. Copyright © 2008 John Wiley & Sons, Ltd.

Fluvial processes such as flooding and sediment deposition play a crucial role in structuring riparian plant communities. In rivers throughout the world, these processes have been altered by channelization and other anthropogenic stresses. Yet despite increasing awareness of the need to restore natural flow regimes for the preservation of riparian biodiversity, few studies have examined the effects of river restoration on riparian ecosystems. In this study, we examined the effects of restoration in the Ume River system, northern Sweden, where tributaries were channelized to facilitate timber floating in the 19th and early 20th centuries. Restoration at these sites involved the use of heavy machinery to replace instream boulders and remove floatway structures that had previously lined stream banks and cut off secondary channels. We compared riparian plant communities along channelized stream reaches with those along reaches that had been restored 3-10 years prior to observation. Species richness and evenness were significantly increased at restored sites, as were floodplain inundation frequencies. These findings demonstrate how river restoration and associated changes in fluvial disturbance regimes can enhance riparian biodiversity. Given that riparian ecosystems tend to support a disproportionate share of regional species pools, these findings have potentially broad implications for biodiversity conservation at regional or landscape scales.

Summary 1. This paper explores soil seed bank composition and its contribution to the vegetation dynamics of a hydrologically variable desert floodplain in central Australia: the Cooper Creek floodplain. We investigated patterns in soil seed bank composition both temporally, in response to flooding (and drying), and spatially, with relation to flood frequency. Correlations between extant vegetation and soil seed bank composition are explored with respect to flooding. 2. A large and diverse germinable soil seed bank was detected comprising predominantly annual monocot and annual forb species. Soil seed bank composition did not change significantly in response to a major flood event but some spatial patterns were detected along a broad flood frequency gradient. Soil seed bank samples from frequently flooded sites had higher total germinable seed abundance and a greater abundance of annual monocots than less frequently flooded sites. In contrast, germinable seeds of perennial species belonging to the Poaceae family were most abundant in soil seed bank samples from rarely flooded sites. 3. Similarity between the composition of the soil seed bank and extant vegetation increased following flooding and was greatest in more frequently flooded areas of the floodplain, reflecting the establishment of annual species. The results indicate that persistent soil seed banks enable vegetation in this arid floodplain to respond to unpredictable patterns of flooding and drying.

Australian dryland rivers are acknowledged as being among the most variable and unpredictable in the world in terms of their flow regimes. Although renowned for their spectacular floods over vast and complex floodplains, rivers exist for much of the time as discrete waterholes, which are important refugia for aquatic biota. Recent work has shown that waterholes are filled by surface flows and there is little evidence of groundwater contributions. The permanence of these refugia is largely determined by waterhole morphology and evaporative loss, and some waterholes can clearly persist for 2 years or more without surface flow connection. As a consequence, the spatial distribution of refugia for aquatic biota is determined not only by the physical template but also by the duration of dry spells and the timing of flow events. Flow variability also has a major influence on aquatic production in these systems and ultimately influences food availability for fish and other consumers. During dry spells, aquatic food webs in waterholes are largely supported by algal production in the shallow littoral zone. At the other extreme, during floods, the boom of aquatic production on floodplains provides an immense food resource. However, there are many occasions when in-channel flows (flow pulses) result in periods where neither of these sources of production is likely to be available. Although such flow pulses are essential for the physical persistence and connectivity of waterholes, we propose that they may lead to food limitation and stress for populations of fish and other consumers. Water resource development in dryland rivers often leads to an increase in the frequency and duration of flow pulses, due to reduced floods and elevated base flows. This increase in the ‘bits in between’ natural boom or bust conditions may help to explain the observed decline in ecosystem health in dryland river systems with significant water resource development. Copyright © 2006 John Wiley & Sons, Ltd.

Spatial variation in plant community composition and structure in relation to flood frequency was explored on a large hydrologically variable arid floodplain in central Australia. Flooding was found to have an overriding effect on species richness, total cover and cover amongst most major plant groups. At a landscape scale, frequently flooded sites were similar while rarely flooded sites were more divergent from each other, suggesting that local and regional impacts on diversity vary across the flooding gradient. Overall, the results indicate that variable flooding plays an important role in maintaining spatial heterogeneity in plant community composition and structure in this arid floodplain landscape.

The flow regimes of large arid river catchments are amongst the most variable in the world. Plant communities which inhabit arid floodplains typically exhibit high spatial heterogeneity and are temporally dynamic in response to changing flow conditions. It has been suggested that arid floodplain ecosystems, adapted as they are to variability, will be relatively resilient to anthropogenic alterations to flow. This paper argues that floodplain plant communities in arid catchments, as in temperate and tropical regions, are primarily structured by flow regimes despite their inherent unpredictability. Consequently, changes to flood pulses through water extraction can be expected to result in changes in vegetation composition and structure which in turn may have a dramatic effect on wider ecosystem functioning. Results are presented from an ongoing study of the Cooper Creek floodplain in central Australia which illustrate the relationships between plant community dynamics and variable flood pulses. These results indicate that alterations to flow may result in a shift in community structure and an eventual loss of biodiversity. It is essential, therefore, that water resource managers in arid regions consider the requirements of floodplain plant communities when allocating environmental flows.

Hydrology is widely considered to be the dominant driver of understorey vegetation dynamics in arid and semiarid riparian ecosystems. Consequently, environmental watering is often a key approach to restoring and promoting riparian vegetation diversity. Few studies however have considered the role of local factors, for example, shading or litter accumulation, on vegetation responses to flow and how these may influence the outcomes of watering actions. Knowledge concerning modifying effects of local canopy factors on vegetation responses to watering is needed to guide environmental water planning (e.g., setting objectives and targets) and delivery (e.g., timing and duration of managed flows). We conducted a greenhouse experiment to investigate the effects of shade and litter, and their interaction, on plant communities establishing from riparian soil seed banks, collected from the northern Murray–Darling Basin, under a range of hydrological conditions. We found that shade had a positive influence on the abundance, diversity, and reproduction of establishing plant communities under dry conditions but a negative, or null effect, under wet conditions. Litter exerted strong negative effects on plant community metrics under all hydrological conditions. Some understorey species emerged as hardy generalists capable of establishment under a range of conditions whereas others had more specific requirements. Our results highlight the importance of canopy structure for riparian understorey vegetation diversity and dynamics at both local and landscape scales. Land and water management practices seeking to protect or restore vegetation diversity in these systems must therefore take such local factors into account when planning and evaluating interventions.

The concept of environmental water requirements (EWRs) is central to Australia’s present approach to water reform. Current decision-making regarding environmental water relies strongly on the notion that EWRs necessary to meet targets associated with ecological objectives for asset sites can be scientifically defined, thus enabling the ecological outcomes of alternative water management scenarios to be evaluated in a relatively straightforward fashion in relation to these flow thresholds or targets. We argue, however, that the ecological objectives and targets currently underpinning the development of EWRs in the Murray-Darling Basin are insufficient to permit the identification of exact water requirements or flow thresholds. Because of the dynamic and heterogeneous nature of the Murray-Darling Basin and the myriad ways in which it is valued by people, we also assert that it is unlikely that adequate ecological objectives and targets from which to determine EWRs could ever be formulated. We suggest that the current emphasis on the concept of EWRs in environmental water planning conflates science and values, perpetuating a “how much is enough?” myth whereby the significance of the social, cultural and political dimension in environmental decision-making is diminished. We support an alternative paradigm in which the contribution of ecological science to water policy and management decisions focuses on understanding ecological responses of water-dependent ecosystems and their biota to alternative management scenarios and linking these responses to the ecosystem services and human values which they support.

Drawing on the experience and lessons of wetland researchers and managers in Australia and New Zealand, we examined the implications of climate change for wetland policy and management, and identified potential adaptation responses and the information needed to support these. First, we considered wetland vulnerability to climate change, focusing on wetland exposure and sensitivity. We then outlined the existing policy context for dealing with climate change, with an emphasis on the Ramsar Convention on Wetlands. We then considered how the objectives and targets for wetland management can be set in the face of climate change, how management can be adapted to climate change given the uncertainties involved, and how we can monitor and evaluate wetland condition in the face of climate change. We concluded with a set of principles to guide adaptation of wetland conservation and management policy to climate change.

The concepts of ecosystem regime shifts, thresholds and alternative or multiple stable states are used extensively in the ecological and environmental management literature. When applied to aquatic ecosystems, these terms are used inconsistently reflecting differing levels of supporting evidence among ecosystem types. Although many aquatic ecosystems around the world have become degraded, the magnitude and causes of changes, relative to the range of historical variability, are poorly known. A working group supported by the Australian Centre for Ecological Analysis and Synthesis (ACEAS) reviewed 135 papers on freshwater ecosystems to assess the evidence for pressure-induced non-linear changes in freshwater ecosystems; these papers used terms indicating sudden and non-linear change in their titles and key words, and so was a positively biased sample. We scrutinized papers for study context and methods, ecosystem characteristics and focus, types of pressures and ecological responses considered, and the type of change reported (i.e., gradual, non-linear, hysteretic or irreversible change). There was little empirical evidence for regime shifts and changes between multiple or alternative stable states in these studies although some shifts between turbid phytoplankton-dominated states and clear-water, macrophyte-dominated states were reported in shallow lakes in temperate climates. We found limited understanding of the subtleties of the relevant theoretical concepts and encountered few mechanistic studies that investigated or identified cause-and-effect relationships between ecological responses and nominal pressures. Our results mirror those of reviews for estuarine, nearshore and marine aquatic ecosystems, demonstrating that although the concepts of regime shifts and alternative stable states have become prominent in the scientific and management literature, their empirical underpinning is weak outside of a specific environmental setting. The application of these concepts in future research and management applications should include evidence on the mechanistic links between pressures and consequent ecological change. Explicit consideration should also be given to whether observed temporal dynamics represent variation along a continuum rather than categorically different states.