Colin Finlayson

Current state of knowledge regarding the world’s wetlands and their future under global climate change: a synthesis

Wetlands cover at least 6xa0% of the Earth’s surface. They play a key role in hydrological and biogeochemical cycles, harbour a large part of the world’s biodiversity, and provide multiple services to humankind. However, pressure in the form of land reclamation, intense resource exploitation, changes in hydrology, and pollution threaten wetlands on all continents. Depending on the region, 30–90xa0% of the world’s wetlands have already been destroyed or strongly modified in many countries with no sign of abatement. Climate change scenarios predict additional stresses on wetlands, mainly because of changes in hydrology, temperature increases, and a rise in sea level. Yet, intact wetlands play a key role as buffers in the hydrological cycle and as sinks for organic carbon, counteracting the effects of the increase in atmospheric CO2. Eight chapters comprising this volume of Aquatic Sciences analyze the current ecological situation and the use of the wetlands in major regions of the world in the context of global climate change. This final chapter provides a synthesis of the findings and recommendations for the sustainable use and protection of these important ecosystems.

The status of wetlands and the predicted effects of global climate change: the situation in Australia

The condition of many wetlands across Australia has deteriorated due to increased water regulation and the expansion and intensification of agriculture and increased urban and industrial expansion. Despite this situation, a comprehensive overview of the distribution and condition of wetlands across Australia is not available. Regional analyses exist and several exemplary mapping and monitoring exercises have been maintained to complement the more general information sets. It is expected that global climate change will exacerbate the pressures on inland wetlands, while sea level rises will adversely affect coastal wetlands. It is also expected that the exacerbation of these pressures will increase the potential for near-irreversible changes in the ecological state of some wetlands. Concerted institutional responses to such pressures have in the past proven difficult to sustain, although there is some evidence that a more balanced approach to water use and agriculture is being developed with the provision of increasing funds to purchase water for environmental flows being one example. We identify examples from around Australia that illustrate the impacts on wetlands of long-term climate change from palaeoecological records (south-eastern Australia); water allocation (Murray-Darling Basin); dryland salinisation (south-western Australia); and coastal salinisation (northern Australia). These are provided to illustrate both the extent of change in wetlands and the complexity of differentiating the specific effects of climate change. An appraisal of the main policy responses by government to climate change is provided as a basis for further considering the opportunities for mitigation and adaptation to climate change.

Policy considerations for managing wetlands under a changing climate

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.

Understanding change in the ecological character of Ramsar wetlands: perspectives from a deeper time – synthesis

The Convention for Wetlands was signed in 1971 as part of a global measure to mitigate the loss and degradation of the world’s wetlands. Signatory nations nominate wetlands as internationally important and commit to maintaining their ‘ecological character’. In many cases the character that has been maintained was that occurring at the time of nomination with scant attention to the variability and change that occurs over longer periods. Palaeoclimate and palaeoecological research now reveals a diverse array of conditions in wetlands in the past and attests that any recently identified condition may be transient. The research further reveals the considerable magnitude and antiquity of the impact of people on wetlands. Hence the site description used by wetland managers would benefit from the provision of a longer-term perspective of change. The changing state of wetlands provides a dilemma for wetland managers. In response, a workshop on understanding change in wetlands was held in Queenscliff, Australia, in November 2013 to draw together perspectives of change from neo- and palaeoecological sources to enable the formulation of new pathways of assessment to better accommodate the dynamic nature of wetlands. A synthesis of the information provided at the workshop is provided in this paper.

An integrated risk-assessment framework for multiple threats to floodplain values in the Kakadu Region, Australia, under a changing climate

The internationally important river–floodplains of the Kakadu Region in northern Australia are at risk from invasive species and future sea-level rise–saltwater inundation (SLR–SWI), requiring assessments of multiple cumulative risks over different time frames. An integrated risk-assessment framework was developed to assess threats from feral animals and aquatic weeds at three SLR-scenario time frames (present-day, 2070 and 2100) to natural (magpie goose habitats), cultural (indigenous hunting–fishing sites) and economic (tourism revenue less invasive species control costs) values. Probability density functions (pdfs) were fitted to spatial data to characterise values and threats, and combined with Monte Carlo simulation and sensitivity analyses to account for uncertainties. All risks were integrated in a Bayesian belief network to undertake ‘what if’ management-scenario analyses, and incorporated known ecological interactions and uncertainties. Coastal landscapes and socio-ecological systems in the region will be very different by 2100 as a result of SLR; freshwater ecosystems will transform to marine-dominated ecosystems and cannot be managed back to analogue conditions. In this context, future invasive-species risks will decrease, reflecting substantial loss of freshwater habitats previously at risk and a reduction in the extent of invasive species, highlighting the importance of freshwater refugia for the survival of iconic species.

Global extent and distribution of wetlands: trends and issues

Herein we review estimates of global and regional wetland area from ‘bottom-up’ approaches of site or national wetland inventories and ‘top-down’ approaches from global mapping and remote sensing. The trend for increasing wetland extent reported in the literature over time is a consequence of improved mapping technologies and methods rather than a real increase in wetland area, because a continuing trend for natural wetland loss and conversion is documented over the same time period. The most recent high-resolution estimate of global wetland area is in excess of 12.1×106km2, of which 54% is permanently inundated and 46% is temporarily inundated. Globally, 92.8% of continental wetland area is inland and only 7.2% is coastal. Regionally, the largest wetland areas are in Asia (31.8%), North America (27.1%) and Latin America and the Caribbean (Neotropics; 15.8%), with smaller areas in Europe (12.5%), Africa (9.9%) and Oceania (2.9%). It is likely that estimates of global wetland area published to date persist in underestimating the true wetland area. The ‘grand challenge’ of a global inventory integrating all types of permanent and temporary wetlands at high spatial resolution has yet to be fully achieved.

Managing freshwater protected areas in the global landscape

Freshwaters contain a disproportionately high level of biodiversity, yet have experienced very high levels of loss over the last few decades: Protected Areas (PAs) play a critical role in reducing and reversing this decline.Five high level ecological principles common to all freshwater ecosystems are presented. Although they have different ramifications for each ecosystem type these principles are fundamental to the design and management of all freshwater Protected Areas (PAs) and the conservation of aquatic biodiversity.

Introduction to the Wetland Book 1: Wetland Structure and Function, Management, and Methods

The Wetland Book 1 is designed as a first port-of-call reference work for information on the structure and functions of wetlands, current approaches to wetland management, and methods for researching and understanding wetlands. Contributions by experts summarize key concepts, orient the reader to the major issues, and support further research on such issues by individuals and multidisciplinary teams. The Wetland Book 1 is organized in three parts - Wetland structure and function; Wetland management; and Wetland methods - each of which is divided into a number of thematic sections. Each section starts with one or more overview chapters, supported by chapters providing further information and case studies on different aspects of the theme.

The Wetland Book, Volume I: Structure and Function, Management and Methods

The Wetland Book is a comprehensive resource aimed at supporting the trans- and multidisciplinary research and practice which is inherent to this field. Aware both that wetlands research is on the rise and that researchers and students are often working or learning across several disciplines, The Wetland Book is a readily accessible online and print reference which will be the first port of call on key concepts in wetlands science and management. This easy-to-follow reference will allow multidisciplinary teams and transdisciplinary individuals to look up terms, access further details, read overviews on key issues and navigate to key articles selected by experts.

Linking Science to International Wetland Policy - the Ramsar Convention on Wetlands

This Research Front comprises three papers that address the links between science and international wetland policy as shown through formal decisions taken by the Ramsar Convention on Wetlands. The papers cover three very different topics – water quality, ecosystem services and wetland monitoring. The Convention is an inter-governmental treaty, signed in 1971, that provides a framework for national and international cooperation for the conservation and wise use of wetlands and their resources, and is built around three areas of activity: the wise use of all wetlands; designation and management of Wetlands of International Importance (Ramsar Sites); and international cooperation (Gardner and Davidson 2011). At the centre of the Convention’s philosophy is the ‘wise use of wetlands’ as shown in the mission statement, namely ‘the conservation and wise use of all wetlands through local and national actions and international cooperation, as a contribution towards achieving sustainable development throughout the world’ (www.ramsar.org, accessed 18 April 2014). Wise use of wetlands is specifically defined as ‘the maintenance of their ecological character, achieved through the implementation of ecosystem approaches, within the context of sustainable development’. As such, wise use comprises the conservation and sustainable use of wetlands and their resources, for the benefit of humankind (Finlayson et al. 2011). The Convention has 168 Contracting Parties (member countries) who meet every three years to review administrative arrangements, review national reports on the implementation of the Convention, and consider guidance for the wise use of wetlands. Formal decisions made by the Contracting Parties are adopted through consensus. Observers frommany organisations also attend these meetings and until 2012 were able to intervene in all discussions. Partway through the 2012 meeting, observers were prevented from intervening in order to recoup time spent on earlier issues. Implementation of the Convention between meetings is managed by a Standing Committee and a permanent Secretariat with technical advice being provided by a subsidiary expert body, the Scientific and Technical Review Panel (STRP). The meetings of Contracting Parties have made 289 formal decisions, with technical information for wetland management derived from these decisions being compiled in 21 handbooks for the wise use of wetlands (Secretariat of the Ramsar Convention 2010). The program of each meeting (referred to as a Conference of Parties, CoP) includes several technical sessions that enable ongoing and emerging issues for wetland conservation and wise use, including the interpretation and development of key concepts, to be addressed, and guidance adopted for the wise use of wetlands. Ramsar meetings have gained the reputation of being highly effective events, generally allowing active participation of the non-governmental and academic communities. The STRP provides technical input to the meetings through the provision of draft decisions on technical issues and the facilitation of technical discussions, in particular when it is necessary to form sub-groups to work through complex or contentious issues. The STRP comprises members appointed for their expertise in wetland conservation and wise use as well as experts chosen specifically to provide advice on priority topics. These members are chosen on the basis of their technical expertise and not to represent specific organisation or countries. They are supported by several observer organisations, including the Society of Wetland Scientists (SWS; http://www.sws.org/), which itself has formed a Ramsar section to support networking and the promotion of activities that address wetland topics ranging from science to policy. In 2012 and 2103, the SWSRamsar section organised sessions at the Society’s annual conferences, with the respective themes of Linking Science to International Policy and on Understanding How Wetland Science Supports International Wetland Policy. These sessions had the dual purpose of introducing policy issues to wetland scientists and receiving feedback on the science supporting those policy issues. In this way it was anticipated that the nexus between wetland scientists and policy makers could be better understood and strengthened. In a further step to support the aims of the SWS-Ramsar section,Marine and Freshwater Research has compiled a short collection of papers dealing with technical topics and how they contribute to or have been undertaken in response to wetland policy adopted by the Convention. McInnes (2014) assesses the ecosystem services provided by wetlands in urban settings. This assessment was undertaken in response to formal decisions being agreed by UN-Habitat in 2011 and the Ramsar Convention in 2012. The latter in particular provided principles for the planning and management of urban and periurban wetlands and invited countries to CSIRO PUBLISHING