Natural regeneration of wetlands under climate change

Wetlands are increasingly valuable under climate change in terms of their ecological functions, ecosystem services, and biodiversity. Simultaneously, wetlands are hotspots for anthropogenic activity due to their high soil fertility and water supply, and have been subject to significant modification, degradation, and staggering losses. With climate change having increasing impacts on ecosystems globally, the need for wetland restoration is rapidly growing. Natural regeneration, whereby vegetation is allowed to regrow via propagules already present within the landscape, provides a cost-effective and large-scale approach to restoration for many, but not, all wetlands. This paper emphasises the importance of natural regeneration of wetland ecosystems as an effective restoration approach under climate change. We discuss drivers and barriers of natural regeneration of wetlands under climate change along with implications for management approaches. Drivers of wetland natural regeneration are depicted along with their interactions, displaying a range of abiotic and biotic factors that influence ecosystem change. Key adaption approaches to maintain and promote natural regeneration of wetlands under climate change include integrated land and water management, protecting and promoting key relevant biotic and abiotic processes within landscapes, and reconsidering current exotic species management strategies. Most importantly, however, natural regeneration should be recognised as an important and viable restoration approach under climate change in order to meet restoration demand and promote landscape resilience to changing conditions

Natural regeneration of wetlands under climate change

Wetlands are increasingly valuable under climate change in terms of their ecological functions, ecosystem services, and biodiversity. Simultaneously, wetlands are hotspots for anthropogenic activity due to their high soil fertility and water supply, and have been subject to significant modification, degradation, and staggering losses. With climate change having increasing impacts on ecosystems globally, the need for wetland restoration is rapidly growing. Natural regeneration, whereby vegetation is allowed to regrow via propagules already present within the landscape, provides a cost-effective and large-scale approach to restoration for many, but not, all wetlands. This paper emphasises the importance of natural regeneration of wetland ecosystems as an effective restoration approach under climate change. We discuss drivers and barriers of natural regeneration of wetlands under climate change along with implications for management approaches. Drivers of wetland natural regeneration are depicted along with their interactions, displaying a range of abiotic and biotic factors that influence ecosystem change. Key adaption approaches to maintain and promote natural regeneration of wetlands under climate change include integrated land and water management, protecting and promoting key relevant biotic and abiotic processes within landscapes, and reconsidering current exotic species management strategies. Most importantly, however, natural regeneration should be recognised as an important and viable restoration approach under climate change in order to meet restoration demand and promote landscape resilience to changing conditions

Transforming Environmental Water Management to Adapt to a Changing Climate

Environmental water management has become a global imperative in response to environmental degradation and the growing recognition that human well-being and livelihoods are critically dependent on freshwater ecosystems and the ecological functions and services they provide. Although a wide range of techniques and strategies for planning and implementing environmental flows has developed, many remain based on assumptions of hydrologic stationarity, typically focusing on restoring freshwater ecosystems to pre-development or “natural” conditions. Climate change raises major challenges to this conventional approach, in part because of increasing uncertainties in patterns of water supply and demand. In such a rapidly changing world, the implementation of, and capacity of water managers to deliver flow regimes resembling historical hydrological patterns may be both unfeasible and undesirable. Additionally, as emphasis shifts from species-focused water allocation plans toward a greater appreciation of freshwater ecological functions and services, many of which will be influenced by climate change, a thorough re-evaluation of the conventional objectives, planning, delivery and monitoring of environmental water, including its role in the broader context of water and environmental management, is essential. Here, we identify the major challenges posed by climate change to environmental water management and discuss key adaptations and research needed to meet these challenges to achieve environmental and societal benefits and avoid maladaptation

Applications of Bayesian Networks as Decision Support Tools for Water Resource Management under Climate Change and Socio-Economic Stressors: A Critical Appraisal

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. View Full-Tex

Different Conceptualizations of River Basins to Inform Management of Environmental Flows

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

The politicisation of science in the Murray-Darling Basin, Australia:discussion of ‘Scientific integrity, public policy and water governance’

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

Plant community responses to wetting and drying in a large arid floodplain

ABSTRACT 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

Soil seed banks of degraded riparian zones in southeastern Australia and their potential contribution to the restoration of understorey vegetation

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

Beyond a ‘just add water’ perspective:environmental water management for vegetation outcomes

Practitioners of environmental water management (EWM) operate within complex social-ecological systems. We sought to better understand this complexity by investigating the management of environmental water for vegetation outcomes. We conducted an online survey to determine practitioners’ perspectives on EWM for non-woody vegetation (NWV) in the Murray-Darling Basin, Australia with regards to: i) desirable outcomes and benefits; ii) influencing factors and risks; iii) challenges of monitoring and evaluation, and iv) improving outcomes. Survey participants indicated that EWM aims to achieve outcomes by improving or maintaining vegetation attributes and the functions and values these provide. Our study reveals that EWM practitioners perceive NWV management in a holistic and highly interconnected way. Numerous influencing factors as well as risks and challenges to achieving outcomes were identified by participants, including many unrelated to water. Survey responses highlighted six areas to improve EWM for NWV outcomes: (1) flow regimes, (2) vegetation attributes, (3) non-flow drivers, (4) management-governance considerations, (5) functions and values, and (6) monitoring, evaluation and research. These suggest a need for more than ‘just water’ when it comes to the restoration and management of NWV. Our findings indicate more integrated land-water governance and management is urgently required to address the impacts of non-flow drivers such as pest species, land-use change and climate change. The results also indicate that inherent complexity in EWM for ecological outcomes has been poorly addressed, with a need to tackle social-ecological constraints to improve EWM outcomes.</p