The duality of wetlands in drylands: deluge and drought

Thursday 3rd August 2017

The 2nd Wetlands in Drylands (WiDs) meeting took place at Macquarie University in Sydney, Australia, between 24-26th July 2017.  Organised by Tim Ralph, the meeting involved presentations and breakout group discussions, and was followed by a four-day excursion to the Macquarie Marshes in inland central New South Wales.  Following on from the inaugural WiDs meeting held near Parys, South Africa in November 2014, a meeting that led to formation to formation of the Wetlands in Drylands Research Network (see, this post is an attempt to cast a perspective over the activities.  The activities provided an opportunity not only to assess progress in wetlands in drylands research since the Parys meeting, but also to place these activities against the backdrop of more than two decades of research and management in the Macquarie Marshes in particular.

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Tim Ralph giving the opening address at the WiDs 2017 meeting at Macquarie University (Photo: Will Farebrother)

A day-by-day outline of activities at Macquarie University is provided elsewhere (see  Stepping back a little, it is noteworthy that compared to the Parys meeting, which was specifically for 16 UK and South African wetland researchers alone (this was a stipulation of the catalysing funding scheme), the Macquarie meeting was larger (~50 attendees) and more diverse.  A common lament at the Parys meeting was the absence of involvement from other people whose social and professional lives revolve around wetlands in drylands (e.g. representatives of local community groups, subsistence and commercial farmers, wetland managers and policy makers).  Most wetlands in drylands are living and working landscapes, such that the relatively new term ‘social-ecological system’ can be readily applied.  While blue-skies wetland research remains important, in many instances this can benefit from, and dovetail with, additional perspectives.  But thanks to Tim’s sterling organisational efforts, the Macquarie meeting and the associated excursion was blessed with inputs not only from wetland researchers spread across four continents but also from additional constituencies: wetland managers and policy makers, wetland landholders, and – importantly – representatives of the Traditional Owners of the Macquarie Marshes (the Aboriginal Wayilwan nation).  As befitted the meeting theme of ‘Dynamic Landscapes’, specialist sessions focused on hydrogeomorphological, biogeochemical and ecological dynamics, and the resilience and sensitivity of wetlands in drylands, but later sessions were set aside to consider the interactions between science and management, and indigenous knowledge and management.

As a consequence of this diverse involvement and structure, discussions following presentations and in the breakout groups were considerably enriched, with particular attention focusing on how best to build and maintain strong relationships between scientists, managers and other stakeholders to address the many challenges facing wetlands in drylands.  What are the main barriers to, and opportunities for, communication and sharing of wetland knowledge and insights?  How best can wetland researchers translate findings into forms that can be assimilated by wetland managers?  To what extent should management concerns help to shape wetland research priorities?  Can environmental water flow releases from reservoirs work in synergy with ‘cultural flows’ to enable maintenance of local customs associated with water (e.g. fishing)?  And how can cultural perspectives on wetlands – oral histories and the like – be dovetailed with scientific perspectives?

The excursion – dubbed the ‘Macquarie Marshes Research Outreach Event’ – provided an opportunity to continue such discussions in a specific field setting.  This is one of Australia’s iconic wetlands in drylands, known especially for its diverse aquatic and semi-aquatic habitats that occur amidst the otherwise dusty, semi-arid plains of inland New South Wales.  Internationally, these wetlands are best known for their periodic profusion of waterbird populations, which in large part led to their 1986 listing as a Ramsar Wetland of International Importance (  Fed largely by seasonal rainfall gathered in its southern headwaters, historically the Macquarie River flowed freely northwest and north past towns such as Wellington, Dubbo and Warren, eventually disgorging its water and sediment amongst a confusing tangle of active and abandoned channels, marshlands, swamplands, floodplains, woodlands and lagoons.  In particularly wet years, the extent of flood inundation could expand to around 3000 km2 (300 000 ha) – an area roughly fifty-five times the size of Sydney Harbour or 1% of the total area of the United Kingdom – only to shrink back to much smaller areas of more-or-less permanently wet, ‘core wetlands’ during drier years.  Such a wetting-and-drying dynamic is the natural norm in inland Australia’s highly variable climate, and is associated with a well-adapted boom-and-bust ecology.  The local Aboriginal peoples would have known these rhythms well, adapting their cultural practices accordingly.  But European explorers and colonists took far longer to appreciate them.  In 1818, John Oxley arrived at the edge of the marshes in flood and turned around, concluding that he had arrived at an inland sea.  A decade later, Charles Sturt came during a drought and found largely dry floodplains, albeit ones dotted with small waterbodies, concluding instead that only in very heavy rains could the marshes and adjacent lands be inundated.  Even with the benefit of nearly 200 years of collective hindsight, fleeting visits still colour many people’s perceptions of the value of wetlands in drylands.  The marshes offer a very different personal experience in a wet year compared to a dry year, but both are needed for a fuller comprehension of the system’s workings.

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Winter low flows in the middle Macquarie River between Dubbo and Warren (Photo: Stephen Tooth)

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The southern part of the Macquarie Marshes Nature Reserve in times of drought (late September 2008) and flood (late November 2010) (Photos: Tim Ralph)

And like many other wetlands in drylands around the globe, the absence of this longer-term perspective has been partly culpable for a steady decline in the health of the Macquarie Marshes, whether this be measured in terms of tree deaths, reduced diversity of vegetation and fish communities, or declining waterbird numbers.  Upstream dam construction and associated flow regulation, urban and agricultural flow extractions, and creeping encroachment from irrigated lands have all taken their toll on the marshes.  To this toxic mix, add complications from river and floodplain engineering schemes, marsh-dissecting roadworks, and greater flow variability resulting from climate change, and their declining health should come as no surprise.  In short, apart from a few areas of the marshes where inundation is now more-or-less permanent (and somewhat ironically can result in tree deaths and adverse soil geochemical changes), in many other parts, flooding events are now less frequent and less extensive, while desiccation events are becoming more frequent and more severe.

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Swamp stomping in Buckiinguy Swamp (Photos: Stephen Tooth)

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Willancorah Swamp in the southern marshes (Photo: Stephen Tooth)

Roughly 90% of the Macquarie Marshes is now in private ownership, with the remaining 10% in protected areas, most notably the Ramsar-listed Macquarie Marshes Nature Reserve, but even these sorts of designations have not provided immunity from the overall health decline.  The two main portions of the reserve (southern and northern) are not accessible to local people or visitors from farther afield, so many of the deleterious changes that have taken place within the southern portion especially – desiccation, tree deaths, channel erosion, and so forth – have gone largely unnoticed.  In itself, this lack of public awareness is part of the problem.  In a 1992 commentary in the National Parks Journal, Bill Johnson (a former ranger with the NSW National Parks and Wildlife Service) argued that that while there was a need to halt many of the processes contributing to their decline and to begin restoration, the long-term viability of the Marshes is “totally dependent upon the involvement of the wider community in the management of the wetlands and the Macquarie River”.  An Australian Geographic article from March 1996 provided a snapshot of conditions in the marshes, highlighting the rich birdlife in particular, but not shying away from reporting some of the negative ecological changes, including tree deaths, waterbird declines, and the spread of invasive species such as the European carp and feral pigs.  It also sampled a wide range of local community views on the management of the marshes, including a quote from a now-departed local resident: “If people can’t visit the marshes, they won’t care about them”.  In this respect too, personal experience is vital for influencing perceptions of the value of wetlands in drylands.

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The entrance to the dominantly dry southern portion of the Nature Reserve (Photo: Stephen Tooth)

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Mobs of roos within the Nature Reserve (Photo: Stephen Tooth)

Johnson’s commentary and the Australian Geographic article both focused on the key issue facing the marshes, namely the diverse views regarding the provision of water for urban, agricultural, environmental, and cultural purposes.  In a 1998 article in the Australian Geographer, Philippa Brock (then-time member of the Macquarie Marshes Catchment Committee) provided an overview of the declining physical status of the marshes and the evermore complex water allocation and distribution framework that was trying to balance the competing demands.  She highlighted the need for scientists and managers to work together to develop expertise in addressing natural and artificial changes in the marshes, concluding that the best that we could hope to achieve was: “… management of this unique ecosystem in a manner as close as possible to a ‘natural state’.  In an already regulated river system … this may require some degree of intervention and ‘active management’.”

These articles were published during the 1990s when La Niña conditions were still generating moderate rainfall and flooding.  In retrospect, this decade might be referred to as the last heyday of the marshes.  Ecological health worsened dramatically during the ‘millennium drought’ (c. 2001-2010), but has improved slightly in recent years, as a new La Niña phase has led to the return of moderate flows.  Intense competition for water has remained, however, and the policies and practices for water allocation and distribution have undergone further evolution.  So two decades or more later, where do we stand against the views and opinions expressed by an earlier generation of marshes managers and residents?  Has any progress been made against the calls for greater community involvement, and for closer working between scientists and managers?  Has scientific research provide any traction with the issues of negative ecological change?  Have channel and floodplain restoration efforts succeeded or failed?  Are there improved policies to balance the competing demands for water?  And how have local community perspectives fared within the negotiating rooms?

The excursion to the Marshes provided an opportunity for myself and others to ponder these sorts of issues.  And it’s mixed news.  Thanks especially to the work of Tim Ralph, his academic colleagues and students, our knowledge of the geomorphology, sedimentology, and environmental history of the Marshes has improved considerably.  Along with important contributions from other research groups, the links between landforms, earth surface processes, and ecological functioning in the marshes are now much better known, albeit still incomplete.  There is, for instance, much greater cognisance of the intrinsic dynamism of these ‘wandering wetlands’ and how lateral channel shifts, erosion and sedimentation can lead naturally to changes in wetland location and extent, regardless of conservation boundaries (  Suggestions that the degraded and drying southern portion of the Nature Reserve should be abandoned in favour of focusing efforts on the wetter northern portion can be rebuffed with the argument that a longer term perspective is needed: wait for the next lateral channel shift, keep patient during the drought, and wetter conditions will likely return.

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Chewing the fat at Willie Retreat (Photo: Stephen Tooth)

Some of these insights have been implemented in management policies and practices.  Some attempts at restoration of parts of the marshes have failed, even threatening the Ramsar status of the Nature Reserve (see, but lessons have been learned and are being incorporated into management practices (e.g. improving the design of channel-spanning weirs).  Some private landowners are fully on board with attempts to better understanding the landscapes and ecosystems of the marshes, and readily facilitate scientific research efforts.  While the Nature Reserve is still not publically accessible (a decision that seems to be based mainly on attempts to exclude unwelcome visitors such as illegal pig hunters), local community (including Wayilwan) perspectives are now given greater prominence in round-table discussions about the management plans for the reserve and the marshes more widely.

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Discussing the long history of Aboriginal occupation and use of the marshes.  A degraded mound (lower right) provides evidence of a ceremonial site alongside the old Macquarie River (Photo: Stephen Tooth)

Progress on other issues remains unclear, at least to me.  In a short visit of only two full days, it was impossible for me to get my head around the intricacies of the current marshes water allocation and distribution system, let alone its long and complex history.  Each year, many tens or hundreds of thousands of megalitres of water are released from the Burrendong Dam, but this is divided between environmental flows, irrigation flows, by pass flows and so on …. it’s a complex terminology with complex definitions that is coupled with complex demands competing in a complex social web.  All that is best left for others to elaborate on (see  Similarly, local issues of environmental management and social justice can’t be debated and resolved in a few quick conversations: for instance, just when do we intervene – or not intervene – in natural process such as channel abandonment and flow diversion, and how do we compensate those downstream users who may be deprived of water, or inconvenienced by changing flood patterns?  But the main point is that rarely can science and management be divorced from social context and consequence.

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Debating the options for channel and floodplain wetland restoration in the southern portion of the Nature Reserve (Photo: Stephen Tooth)

Even if answers can’t be provided immediately, approaches to a search for solutions can be outlined, at least in theory: namely, the need to facilitate ongoing communication, dialogue, and exchange of ideas between different scientists, managers, local community groups, and other stakeholders.  There is no simple recipe for doing so, but discussions at the meeting and on the excursion provided anecdotes and case studies to highlight at least some best practice principles.  Building trusting relationships by taking the time to listen to people’s views, engaging with environmental education projects in local communities, and organising open field visits such as the Macquarie Marshes Research Outreach Event …. none of these are magic bullets, but they can help lay the foundations for moving forward.  And in the Macquarie Marshes, many of the foundations are there already, not least because there seems to be sufficient shared concern about the future of the marshes for people to be open to ongoing communication.

Maintaining and building on these foundations is a constant challenge.  As discussions in the field, around the campfire, and on the bus home unfolded, it struck me that people within living and working wetland social-ecological systems enter and depart the scene, much like many of the waterbirds come and go with floods and droughts.  Like stately River Red Gums that line the Macquarie River banks, some individuals, families, social groupings and institutions provide continuity across the decades, persisting through cycles of flood and drought and withstanding the changing water allocation and environmental management frameworks.  But like Bill Johnson and others that frequented the Macquarie Marshes in the 1980s and 1990s, many move on or pass away.  Other people take their place, but with each entry and departure, knowledge and wisdom has to be re-learned and trusting, working and social relationships have to be rebuilt.

Of course, such issues are not unique to the Macquarie Marshes.  Institutional policies and practices can provide some sort of inherited memory and learning to enable ongoing progress, regardless of individual involvements.  In environmental management circles, ‘adaptive management’ is now the mantra.  Adaptive management practices acknowledge that despite uncertainty, decisions must be made and actions implemented, but emphasise learning from the outcomes to inform future decision making.  The Macquarie Marshes has its own adaptive management plan (written by Bill Johnson in a new role – see, something that may well be essential in managing for a future that seems to be getting just a little more uncertain with each passing year.  Let’s hope that in two decades or more, a retrospective similar to the one attempted here will provide positive rather than negative commentary on the state of the Macquarie Marshes social-ecological system.


Footnote: I gratefully acknowledge sponsorship from the NSW Office of Environment and Heritage (OEH) and Macquarie University for the Macquarie Marshes Research Outreach Event.  I also thank OEH staff, local landholders and representatives of the local community for their support and participation.  I thank Tim Ralph in particular for additional discussions and suggestions.  While informed by discussions on the excursion, the views expressed in this post are of course my own.


Wetlands in drylands: how good is the service?

Monday 17th November 2014

The Vaal River, South Africa: an important ecosystem service provider in a dryland setting

The Vaal River, South Africa: an important ecosystem service provider in a dryland setting

Around 1800, the world’s population reached one billion for the first time.  Just over 200 years later, this figure exceeds seven billion … and is still rising.  With such explosive growth, human activities such as agriculture, mining, dam building, manufacturing and urbanization have had profound, long-lasting, negative impacts on the natural environment.  Decades-old worries over air pollution, soil contamination, and the hole in the ozone layer almost seem quaint by comparison with ever-more-urgent concerns over issues such as groundwater depletion, species extinctions, and a warming planet.  At the same time, there is growing recognition that human wellbeing is partially dependent on a healthy natural environment.  Wellbeing includes the obvious physical aspects, but also more subtle mental aspects.  As an example, the term ‘nature deficit disorder’ has arisen amid growing concerns that humans, especially children, are spending less time outdoors, resulting in a wide range of behavioural problems (see

Against this backdrop, the term ‘ecosystem services’ has entered the scientific domain, and is defined as the benefits that people obtain from ecosystems.  The Millennium Ecosystem Assessment (MEA) – a four-year (2001-2005) collaboration involving more than 1360 experts worldwide – provided a state-of-the-art appraisal of the condition of the world’s ecosystem services, and assessed the consequences of ecosystem change for human wellbeing (  The MEA classified ecosystem services into four main types: provisioning, regulating, supporting, and cultural.  It also noted that although the human species is buffered against environmental changes by culture and technology, it remains fundamentally dependent on the flow of ecosystem services.

Diagram from the Millennium Ecosystem Assessment illustrating how many aspects of human wellbeing are dependent on provisioning, regulating, cultural and supporting ecosystem services

Diagram from the Millennium Ecosystem Assessment illustrating how many aspects of human wellbeing are dependent on provisioning, regulating, cultural and supporting ecosystem services

Alongside coverage of various terrestrial and marine ecosystems, the world’s wetlands (defined broadly by the MEA) received special consideration.  The marshes, fens, swamps, peatlands, shallow water bodies and rivers in tropical, temperate and arctic regions were noted as delivering a wide range of ecosystem services, such as fish and fibre, water supply and purification, flood and climate regulation, coastal protection, and recreational and tourism opportunities.  But within the voluminous MEA volumes (the specific ‘Wetlands and Water’ synthesis volume alone runs to 68 printed pages), just how comprehensive was coverage of wetlands in drylands?  Drylands are the world’s extensive hyperarid, arid, semiarid and dry subhumid regions, and so while ‘wetlands in drylands’ sounds like a contradiction in terms, wetlands in fact can form and persist wherever a positive water balance exists for at least part of the year.  In many drylands, this most commonly occurs where river inflows combine with other factors that serve to impede drainage, including tectonic faulting, swelling soils, and ponding by wind-blown sediments.  Many individual wetlands in drylands may be relatively small compared to some tropical, temperate and arctic wetlands, but collectively they can form across a diverse range of dryland settings.  More importantly, by dint of their presence in otherwise largely dry environments, the MEA recognised that wetlands in drylands may be disproportionately important in terms of biodiversity and other ecosystem services.

Critical reading of the MEA volumes, however, reveals that hard facts about wetlands in drylands are in short supply, and many assumptions remain untested.  For instance, given that many wetlands in drylands desiccate on seasonal or longer bases, how similar are they to their more-or-less permanently-saturated tropical, temperate and arctic cousins?  Do wetlands in drylands necessarily serve to improve water quality for downstream users, or might there be situations where water quality actually decreases downstream of wetlands (e.g. where dry season grazing increases fecal contamination of the desiccating water bodies)?  Are wetlands in drylands really stores of carbon and therefore important contributors to global climate regulation (e.g. through incorporation of atmospheric carbon dioxide into vegetation and ultimately organic-rich soils), or might dry season fires simply burn off the vegetation and organics, thus returning carbon dioxide straight back to the atmosphere?  And to what extent are the provisioning, regulating, supporting and cultural services actually compatible, or might there be potential for conflict, especially where wetlands are the subject of competing human interests?

To examine these and other related questions, colleagues and I recently convened a three-day workshop entitled “Wetlands in Drylands: Past, Present and Future Trends in Ecosystem Service Provision” near Parys, Free State Province, South Africa.  The workshop was funded as part of the Royal Society’s UK-South Africa Scientific Seminars Scheme.  The overarching objective was the establishment of a network of researchers to advance the science of wetlands in drylands, and to translate scientific findings into forms that can be assimilated by those charged with wetland conservation, rehabilitation and management.

The scheme paid for four UK and twelve South Africa participants to convene at the magnificent Stonehenge in Africa conference venue (, located 6-7 km west of Parys.  Situated close to the epicentre of the World Heritage-listed Vredefort Dome – arguably the world’s oldest (2.02 billion years) and largest (greater than 300 km wide) meteorite impact crater – and with a lawn that slopes down to the north bank of the Vaal River, the venue was never going to disappoint.  While the visual impact of the surrounding impact crater is somewhat muted on account of its vast age and size (one really needs an aerial perspective and geomorphologist’s eye to fully appreciate its grandeur), the permanently-flowing pools and rapids, and the green, tree-lined islands of the Vaal present a magnificent sight, especially as they contrast so starkly with the surrounding, usually much drier, browner terrain.  In the MEA’s terms, surely the Vaal must rank as one of South Africa’s most important riverine wetlands, providing good service for locals and visitors alike?

Bedrock rapids and boulders along the Vaal River at Stonehenge

Bedrock rapids and boulders along the Vaal River at Stonehenge

The journey to the conference venue was trouble free.  During preparations for landing at OR Tambo airport, I caught glimpses of some of the wetlands around Johannesburg’s sprawling peri-urban fringe, many of which purify poor quality water emanating from malfunctioning sewerage systems and gold mine dumps.  The plane had landed on time, and we breezed through customs.  After meeting some other workshop participants, we piled into a minibus for the two hour-drive drive southwest to Stonehenge.  As we trundled ever nearer, there was an African welcome typical of November: an ever-darkening sky, followed by spectacular lightning bolts and a torrential downpour.  Wet season thunderstorms were arriving in a land parched by an eight month-long dry season … over the coming weeks, river flows would increase, wetland water bodies would fill, and green shoots would lighten dampened soil.  In this instance, the downpour didn’t last longer than about 10 minutes, but the dark sky, lightning and thunder hung around, providing a constant threat of rain.

And over the next three days, torrential rain did return several times, often accompanied by lightning and thunder.  We didn’t see much sun, which at this time of year normally makes a welcome visit between thunderstorms.  These meteorological conditions lead to some sleep-disturbed nights and one short-lived power outage, while leaking roofs caused inconvenience in a few bedrooms and communal areas.  But these conditions didn’t affect the torrent of ideas emanating from the workshop activities, which included short presentations, small group discussions and round table debates.

Attentive participants during one of the session talks

Attentive participants during one of the session talks

Following some introductory sessions, the first two days considered wetlands in drylands and their ecosystem services from the perspective of the past, present and future.  To what extent did wetlands in the past serve as key hominin habitats and migration routes from Africa to other parts of the world?  How can we best translate wetland science into current wetland management policy?  Which wetland ecosystem services are most threatened by projected future climate changes?

At the end of day two, I arranged for the participants to visit two local contacts of mine, whose house is located along the margins of the Vaal just a few kilometers upriver of Stonehenge.  To complement a generous provision of wine and snacks, our hosts took us for a walk on one of the numerous river islands, and we chatted about the Vaal and other important South African rivers.  A lifetime of kayaking South Africa’s rivers, coupled with more than 10 years living by the Vaal, has sharpened their awareness of the quality of river and wetland ecosystem service provision, even if this is not a term that they would use.  And in most instances, the service is declining as a result of human activities, including active mismanagement.  In the case of the Vaal, as with many other river and wetland ecosystems, factors such as flow regulation, raw sewage disposal, and invasive vegetation have dealt severe body blows, precluding optimal service provision.

Worse still are some of the threats facing the Vaal’s larger sibling, the Orange River.  Having long researched the landscapes of the lower Orange valley, I had already become aware of the proposed run-of-the-river hydropower developments for some of the most scenic, pristine and inaccessible reaches, including the supposedly protected, much visited Augrabies Falls and the downstream, lesser known Ritchie (Oranje/!Gariep) Falls (  If a green light is given, the developments will divert water from some of the Orange’s bedrock channels, waterfalls and gorges so that it can be run through turbines.  Relatively small amounts of electricity will be generated, much of which is destined for consumption by Namibia.  The threats to river ecology, geoheritage, and the sense of wilderness in these reaches is being given lip service – at best – by the developers and their consultants.  Potentially, this represents yet one more body blow to an already weakened ecosystem.

The final day considered how new scientific techniques can best be employed in the study of wetlands in drylands and their ecosystem services, and concluded with a discussion of the way forward for our nascent research network.  Plans are for state-of-the-art publications, an online presence to support network activities, and a future workshop.  Much more needs to be done to promote research into wetlands in drylands and their ecosystem services, so that the types of questions posed above can be answered.

A busy agenda and a long list of ideas for post-meeting activities

A busy agenda and a long list of ideas for post-meeting activities

But during preparation for the final session – partly done during the middle of night as I lay awake listening to yet another thunderstorm – I had already found an answer to at least one of those questions.  A definitive ‘no’.  The various ecosystem services provided by rivers and wetlands in drylands are not necessarily compatible.  It struck me that the provisioning, regulating and supporting services often take centre stage, effectively sidelining the cultural services.  In the case of the lower Orange River, certain interest groups are listing hydropower generation among the provisioning services, and are prioritising this service to the virtual exclusion of all others, particularly the cultural services that include aesthetic, spiritual, educational and recreational opportunities.  The installations and infrastructure associated with hydropower developments will undoubtedly detract from all these cultural services, so one has to question this prioritisation.  Cultural services may be more nebulous than electricity generation, and less easy to monetise than megawatts, but in a world where a sense of wilderness is rapidly disappearing and ‘nature deficit disorder’ is now a recognized condition, what are the hidden costs?