Wetlands in drylands: science, research and collaboration
In late October 2017, during their annual MSc student fieldtrip to Spain (see stephentooth.wordpress.com/2014/10/27/the-rain-in-spain/), Andrew Thomas and Stephen Tooth presented at the Instituto Pirenaico de Ecología (IPE), located near Zaragoza, northeast Spain. IPE is a research centre belonging to the Natural Resources section of the Spanish National Research Council (Consejo Superior de Investigaciones Científicas), and this year is celebrating its 75th anniversary. Over the years, IPE has produced high-quality research on many aspects of the Spanish environment (e.g. ecology, geomorphology, Quaternary history) and has been instrumental in translating much of this research into environmental policy and practice.
Tooth opened and closed the presentation with a contribution entitled ‘Wetlands in drylands: science, research and collaboration’, which provided some of the rationale for studying wetlands in drylands, outlined the development of the WiDs Research Network, and invited opportunities for collaboration (for instance, how about a Spanish translation of the ’10 Reasons why the Geomorphology of Wetlands is Important’ brochure?). The research element of the presentation was provided by Thomas, who examined whether some wetlands in drylands could be hidden hotspots of carbon (C) sequestration and storage. In line with a recent Nature Geoscience article claiming that closed (endorheic) desert basins may represent a substantial, global inorganic C sink (Li and others, 2017, v.10, doi: 10.1038/ngeo2972), preliminary data from the Kalahari and Spain seem to show that under certain environmental conditions, ephemeral pans and playas can act as C sinks, with net C uptake occurring in the saline sediments.
There was significant interest in the talk from the IPE staff present, as evidenced by a large number of perceptive comments and questions. Many of these revolved around the identification, sampling and quantification of the geochemical and microbial controls on the drawdown, transformation, storage, and release of organic and inorganic C. Clearly, this is a topic ripe for further research and will form part of a forthcoming European Commission/Welsh Government-funded project by Thomas and others entitled ‘Microbial photosynthesis and carbon stores in dryland pan sediments (MicroCarb)’.
[Footnote: IPE’s own blog of the talk (in Spanish) is at: https://divulgaipe.com/2017/10/27/tooth-thomas-secuestro-carbono-humedales-zonas-aridas/]
Resilience and nonresilience of wetlands in drylands
In mid October 2017, Stephen Tooth attended the 48th Annual Binghamton Geomorphology Symposium at Texas State University, San Marcos, USA. The symposium started at Binghamton in New York in 1970 and has been held annually ever since, expanding beyond its northeast USA origins to other parts of the USA and, on occasion, even being held farther afield (e.g. Canada, Italy). Sawyer and others (2014) have traced the development of the symposium series (see Geomorphology, v.223, doi: 10.1016/j.geomorph.2014.06.022), showing how many of the symposium themes and publications have helped to shape the direction and focus of subsequent geomorphological research. The 2017 theme was entitled ‘Resilience and Bio-Geomorphic Systems’, the justification being that resilience thinking is a rapidly-emerging concept that is being used increasingly to frame how we approach the study and management of biophysical systems but that geomorphological inputs so far have been limited.
The symposium comprised a one-day fieldtrip around the catchment of the San Marcos River to examine resilience against the backdrop of catastrophic flood disturbance, riparian restoration efforts, and environmental education initiatives (see images), and two days of oral presentations, posters, and discussions.
Wetlands are archetypal bio-geomorphic systems, and Tooth’s invited talk focused on the resilience concept in the context of wetlands in drylands. Starting with the contention that most examinations of wetland resilience have focused on wetlands in coastal and/or more humid regions, the talk summarized more than two decades of research into the geomorphology of South African wetlands, and examined whether these wetlands have shown resilience or nonresilience to drivers including landscape denudation, regional climatic changes, shorter term weather extremes, and human activities. Over the late Quaternary, South African wetlands have exhibited both resilience and nonresilience to these sorts of drivers: some have shown remarkably little change in geomorphological processes and form over many thousands of years (i.e. resilience), but others have undergone profound changes in channel-floodplain structure that are effectively nonreversible on the timescale of centuries of even thousands of years (i.e. nonresilience). The take home message was that geomorphologists can help apply the resilience concept in wetland management, but greater consideration needs to be given to how geomorphological resilience interfaces with other resilience dimensions, especially ecological resilience and socioeconomic resilience, the latter commonly being defined in terms of ecosystem service delivery.
Given the more common focus on the resilience of coastal, fluvial and hillslope systems, Tooth’s talk helped to raise the profile of research into wetlands in drylands and the associated activities of the WiDs Research Network. A full set of articles from the symposium will be published in a special issue of Geomorphology (anticipated late 2017 or early 2018), with many already available from the ‘Articles in press’ section of the journal’s website.
An outline of the themes arising from the post-meeting fieldtrip to the Macquarie Marshes is now available at:
WIDS2017 Day 3
Day 3 of WIDS2017 featured a morning session devoted to Indigenous knowledge and management of wetlands in drylands.
Dr Emily O’Gorman chaired a session wherein Uncle Phil Duncan shared some of his extensive experience working in natural resource management, and set an agenda for strong and productive partnerships with Indigenous people and their communities.
Uncle Phil Duncan presents an original artwork to Dr Tim Ralph as a gift in recognition for organising the WIDS2017 conference.
Danielle Flakelar outlined ways in which Wayilwan people are using the ’empowerment model’ to assert their voices in decision-making concerning water planning and management, and shared personal reflections on working across cultures.
Dr Emilie Ens described her ‘two-way’ approach to cross-cultural wetland science in Arnhem Land in northern Australia, and shared some of the social, cultural and environmental successes that have stemmed from this work.
In closing the conference, Professor Stephen Tooth and Dr Tim Ralph reflected on the ideas, opportunities and challenges emerging from the presentations and workshops. The need to facilitate knowledge transfer between science and management, as well as broader environmental education, came through in the proceedings, along with the need to address important knowledge gaps in areas such as biogeochemistry and carbon storage. Finally, research on wetlands in drylands was placed in a global context in terms of its potential to contribute meaningfully to meeting global challenges, such as climate change, food and agriculture, water and human health.
WIDS2017 Day 2
Day 2 was focused on ecology, resilience and sensitivity. Engaging keynotes by Dr Denise Schael, Dr Phumulele Gama and Max Finlayson stimulated productive discussions on vulnerability and dynamic landscapes.
Dr Peter Berney and Tim Hosking shared their experiences in land and water management. They emphasised the importance of building and maintaining strong relationships between scientists, managers and other stakeholders to meet challenges facing wetlands in drylands.
— Kirstie Fryirs (@Kirstie_F) July 25, 2017
Following the keynotes and workshops, discussions continued in a more social setting at the bar. Day 3 will explore Indigenous knowledge and management, and look towards the future for research on – and management of – wetlands in drylands. WIDS2017 Day 1 WIDS2017 is off to a cracking start at Macquarie University, Sydney, Australia. After a Acknowledgment of Country performed by Uncle Phil Duncan, Professor Lesley Hughes placed a climate change lens over the Wetlands in Drylands theme in her opening address to the conference.
Keynotes by Professor Stephen Tooth, Dr Mirela Tulbure and Emeritus Professor ‘Spike’ McCarthy formed a basis for workshopping key opportunities and challenges in smaller groups.
Stephen Tooth discussed global challenges facing wetlands in drylands and encouraged delegates to consider the bigger picture. Mirela Tulbure presented on advances in basin-scale hydrological modeling and the opportunities provided by big data. Spike McCarthy gave insights into the complex geochemistry of the Okavango Delta, drawing on over 30 years of research in this dynamic environment.
In the afternoon, postgraduate students competed in a ruthless round of ‘Three-minute Thesis’ in which they briefly summarised their research. The session was supported by the Oceania Chapter of the Society of Wetlands Scientists. Zacc Larkin and Mackenzie Austin were the joint winners for their talks on avulsion in the Okavango Delta and fire mapping in wetlands, respectively.
WIDS2017 Second Circular: Wetlands in Drylands Research Network Conference, Macquarie University (Sydney, Australia), 24-26 July 2017
WIDS2017 is the second meeting of the WIDS Research Network, to be held at Macquarie University (Sydney, Australia) from 24-26 July 2017.
Participation by international scientists, practitioners, managers, and early career and postgraduate researchers is encouraged and highly valued.
The program will include seven core interactive sessions that will combine formal keynote presentations with panel and group discussions framed around the following topics:
- Hydro-geomorphological dynamics (e.g. inundation regimes, river channel change, landscape evolution)
- Ecological dynamics (e.g. aquatic ecosystem metabolism, vegetation succession, aquatic biota)
- Biogeochemical dynamics (e.g. nutrient cycling, carbon dynamics, fire regimes)
- Socio-cultural dynamics (e.g. changing perspectives on wetlands, adaptive and inclusive management approaches)
- Sensitivity and resilience (an integrative session)
- Linking science and management (an integrative session)
- Future outlooks
Another research paper on the Tshwane floodplain wetlands, northern South Africa
Another round of congratulations is owed to Zacc Larkin, a Macquarie University PhD student (see ‘Student Spotlight’ page), who has just had another paper based on part of his MRes thesis accepted for publication. The paper by Larkin and others is entitled ‘Timescales, mechanisms, and controls of incisional avulsions in floodplain wetlands: insights from the Tshwane River, semiarid South Africa’ and will be published in the international journal ‘Geomorphology’ (doi: 10.1016/j.geomorph.2017.01.021).
Building on the broad scale treatment of river channel and floodplain wetland characteristics in the Tshwane and Pienaars catchments (see the allied ‘Earth Surface Processes and Landforms’ paper highlighted in the news item below), this paper focuses on the avulsion history of a 4 km-long reach of the vertically aggrading lower Tshwane River. Aerial imagery, geomorphological and sedimentological data, and optically stimulated luminescence (OSL) dating is used to establish that three avulsions have occurred along the reach in the last 650 years. Avulsions occur through an incisional mechanism, whereby a headcutting channel on the floodplain extends upvalley during periods of overbank flow, ultimately diverting flow and sediment from the original channel, which is then abandoned. The last avulsion occurred between 1950 and 1972, and led to abandonment of one highly sinuous reach and formation of a new, straighter reach on the western floodplain margin. Recent aerial imagery (see below) also shows clearly that other sinuous reaches of the river are being primed for avulsion through a similar incisional mechanism. The strong implication is that individual avulsion events are driven by intrinsisic (autogenic) processes as a natural outcome of meander belt development, rather than necessarily being related to changing hydroclimates.
The findings from the Tshwane River support the assumption that avulsion frequency and sedimentation are broadly correlated, and demonstrate that incisional avulsions can occur even in settings with relatively rapid aggradation. Attempts to undertake global comparisons, however, reveal just how few OSL- or radiocarbon-constrained avulsion datasets exist, especially for wetlands in drylands. In South Africa, there is now a sample size of two, namely the Klip River (Tooth and others, 2007, 2009) and the Tshwane River (Larkin and others, 2017). Additional studies are badly needed so that we can build on this work and further clarify the timing, mechanisms, and controls of avulsion in a wider range of wetlands in drylands.
As a start, and if seeking out remote field sites is enticing, how about these examples of avulsive rivers in floodplain wetlands in the drylands of Argentine Patagonia?
Stephen Tooth noticed these valleys during a flight from El Calafate to Ushuaia last spring. Google Earth imagery (oriented with south to the top to reflect the flight line) reveals that the meander bend, anabranch and avulsion dynamics are taking place within underfit valleys. In many places, these valleys bear the unmistakable hallmarks of former braided channel networks that were probably conveying major floods during the late Pleistocene deglaciation of this part of South America.
World Wetlands Day 2017, 2nd February 2017
Given the title of this Ramsar cartoon (‘Some Dry Facts About Wetlands’), how could we not feature this on a site dedicated to wetlands in drylands?
New research paper on the Tshwane-Pienaars floodplain wetlands, northern South Africa
Congratulations to Zacc Larkin, a Macquarie University PhD student (see ‘Student Spotlight’ page), who has just had a paper based on part of his MRes thesis accepted for publication. The paper by Larkin, Ralph, Tooth and McCarthy is entitled ‘The interplay between extrinsic and intrinsic controls in determining floodplain wetland characteristics in the South African drylands’ and will be published in the international journal ‘Earth Surface Processes and Landforms’ (doi: 10.1002/esp.4075).
Using analysis of aerial imagery, geological maps and field data, the study investigated floodplain wetland characteristics in the Tshwane and Pienaars catchments, northern South Africa. These impressive floodplain wetlands remain in near-pristine condition but have not been studied in detail previously.
Original research results from the two rivers are combined with the findings from previous research to develop a new conceptual model that highlights the influence of variations in aridity on flow, sediment transport, and channel-floodplain morphology. Similar to the findings of Grenfell, Grenfell and Ellery (2014) in other parts of South Africa, the paper demonstrates how floodplain wetland characteristics vary along a subhumid to semiarid climatic gradient. Increasing aridity tends to be associated with a reduction in the ability of rivers to maintain through-going channels and an increase in the propensity for channel breakdown and floodout formation. The paper concludes by suggesting that improved understanding of the interplay between climate, hydrology and geomorphology may help to anticipate and manage pathways of floodplain wetland development under future drier, more variable climates, both in South African and other drylands.
First Circular: Wetlands in Drylands Research Network Conference, 24-25 July 2017
WIDS2017 is the second meeting of the Wetlands in Drylands (WIDS) Research Network, and will take place at Macquarie University in Sydney, Australia, from 24-26 July 2017. Follow the link below for further information.
Visit to Hohai University, Nanjing, 22nd-23rd September 2016
Following the running of a successful special session on ‘Wetlands in drylands’ at the INTECOL conference (see news item below), Stephen Tooth and Andrew Thomas visited Hohai University in Nanjing. Aberystwyth University and Hohai University have an articulation agreement to run a 2+2 degree scheme in Environmental Science, with the Chinese students studying the equivalent of Aberystwyth’s Year 1 curriculum over two years and then having the option of coming to Aberystwyth for Years 2 and 3 of the degree. Tooth and Thomas’s visit to Hohai was part of an attempt to facilitate this relationship, and while present, they gave talks on their research and teaching interests, which – as you might easily guess – revolve around wetlands and drylands. Near the start of Tooth’s talk, the assembled staff and students were asked to write down 3, 4 or 5 keywords (in English and Chinese) that they associate with wetlands and with drylands. Some of the responses are below (click image for enlargement), and provide insight into the common perceptions of these environments.
In time, Tooth plans to undertake similar exercises with staff and students in the UK and other academic contexts. This might provide some basis for assessing cross-cultural differences in perceptions of wetland and dryland environments. But what are the first 3 to 5 keywords that you would associate with wetlands in drylands?
10th INTECOL International Wetlands Conference, Changshu, China, 18-24th September 2016
Several members of the WiDs Network (Fred Ellery, Donovan Kotze, Zacc Larkin, Andrew Thomas, Stephen Tooth) are currently at the latest INTECOL meeting. All are giving talks, some co-authored with other Network members (Tim Ralph, Erwin Sieben). Many of the talks will be given in a special session convened by Fred Ellery, Stephen Tooth and Tim Ralph entitled: “Wetlands in drylands: enigmatic but neglected ecosystems that are essential for human wellbeing”.
Along with a wide array of plenary keynote talks, symposia, workshops and poster sessions, there is an excellently presented wetlands exhibition that showcases the best of Chinese wetland management, protection, restoration and creation.
WiDs Network members have been happy to sign the Declaration (see below), but are also taking the opportunity to draw attention to our own Parys Declaration (see the ‘Downloads’ tab). The act of signing has provided amusement among some locals, leading to some photobombing.
Channel dynamics in the Okavango Delta, 17-27th August 2016
Several members of the WiDs Network are currently busy in the Okavango Delta, Botswana. Tim Ralph, Zacc Larkin, Marc Humphries and Stephen Tooth are collaborating with other colleagues from Macquarie University, University of the Witwatersrand, and the Okavango Research Institute on a project that is investigating channel and wetland dynamics in the Panhandle region of the Delta. Particular focus is on the changes to river flow, sediment transport and vegetation associated with an ongoing avulsion of the Okavango River near to Sepopa. Following up on work started by Spike McCarthy and colleagues in the mid 1990s, evidence suggests that an increasing proportion of flow and sediment transport is being diverted away from the named Okavango channel into the neighbouring Filipo channel to the east, potentially heralding a wholesale relocation of the channel. Other work will focus on collecting samples for optically stimulated luminescence dating from the abundant large palaeochannels in the Panhandle. Are these channels potentially the upvalley equivalents of the 7-4 ka age palaeochannels preserved near Xugana in the Fan region? Or are they older or younger? Providing an answer will form part of Zacc Larkin’s ongoing PhD thesis.
Making space for wetlands …. or not?
Two contrasting articles about wetlands in drylands have featured on websites over the last few months.
1) Research by Tim Ralph and colleagues into channel-floodplain dynamics in the Macquarie Marshes, Australia, has featured on the ‘Riverspace’ website. This website is funded by two non-profit organisations (the Australian River Restoration Centre and Murray-Darling Wetlands Working Group), both of which hope to inspire and support people to care for Australia’s rivers and wetlands. The work by Tim and colleagues draws attention to the long history of channel-floodplain change in Macquarie Marshes, and the fact that small changes to the landforms, or the processes that create landforms, can have a large impact on patterns of water movement and associated ecological responses. These ‘wandering wetlands’ are dynamic, and so conservation and management strategies need to be dynamic as well:
2) The deMilked website highlights the work of photographer Johnny Miller and his project entitled “Unequal Scenes”. The Cape Town-based photographer used an Unmanned Aerial Vehicle (UAV, sometimes termed a ‘drone’) in areas around the city to provide a bird’s eye view on physical lines of social inequality. Although the project is intended as social commentary, some of the photographs and the footage from the UAV overflight at the foot of the webpage show just how pressurised are many of these peri-urban wetlands. Here, there is little or no scope to allow wandering wetlands, and the management challenges are quite different:
Petition for creation of iconic outback Kidman National Park, central Australia
This petition was started by Rod Moffatt, and calls on the Australian Commonwealth and relevant State Governments to acquire the S Kidman & Co Ltd pastoral leases in the lower Channel Country and lower Lake Eyre basin in order to create a new and iconic outback national park that will rival the achievements of Uluru and Kakadu. Currently, cattle grazing is conducted in areas that are not ecologically sustainable, including internationally significant Ramsar wetlands, riparian corridors, and desert dunefields. At a time when many rivers and wetlands in drylands are under severe pressure, and even existing conservation measures are often poorly implemented (see the Parys Declaration under the ‘Downloads’ tab), creating this national park would help to buck the trend.
Further information and comments from supporters can be see at the petition website:
As of 20th July 2016, the petition had attracted 661 supporters. Another 339 is needed for the petition to reach 1000.
A Wetland in a Dryland in Iran
Stephen Tooth’s flight to the Linyanti-Chobe-Zambezi floodplain wetlands (see below) involved flying via the Middle East. The flight path from Birmingham to Dubai passed over the spectacular mountainous desert scenery of Turkey and Iran. One particular salt lake near Tabriz in northwest Iran provided good views of rivers terminating in a complex of distributaries, splays and floodouts on the edge of a large salina. Google Earth imagery tags this part of the world as Garegoshon Wetlands International. Nope, me neither. Never heard of them. Does anyone know anything about these wetlands?
The Coupled Dynamics of Human-Dryland River Systems: Linkages and Feedbacks Between Human and Environmental Drivers of Water Quality and Human Health Pt II, 10-20 June 2016
Stephen Tooth has returned to the Linyanti-Chobe-Zambezi floodplain wetlands for follow-up fieldwork on this National Science Foundation-funded project (see earlier post). The annual flood has peaked and water levels have been falling since early May, which happens to coincide with the latest Google Earth imagery. The image below shows part of the Chobe River upstream of Kasane, and reveals a number of small channels that have served as conduits for water and probably small amounts of sediment draining from the floodplains back to the channel. I’m not sure if there is a technical term for these distinctive but likely short-lived, ephemeral features …. does anyone know of a term? If not, how about ‘reverse splays’ as an informal proposition?
10th INTECOL International Wetlands Conference, forthcoming Sept 2016
Several members of the WiDs Research Network will be attending the 10th INTECOL International Wetlands Conference in Changshu, China (http://temp.intecol-10iwc.com/EN/HelpCenter/HelpInfo.aspx?nid=14). Fred Ellery, Stephen Tooth and Tim Ralph are convening a special session entitled: “Wetlands in drylands: enigmatic but neglected ecosystems that are essential for human wellbeing”.
Abstracts have been submitted by Stephen Tooth, Tim Ralph, Donovan Kotze, Erwin Sieben and Andrew Thomas. Individually and collectively, these abstracts cover a diverse range of topics and perspectives germane to the analysis of wetlands in drylands and their ecosystem service delivery, and will help to raise the profile of the WiDs Research Network and its activities.
The Coupled Dynamics of Human-Dryland River Systems: Linkages and Feedbacks Between Human and Environmental Drivers of Water Quality and Human Health Pt I, 29 Feb-9 March 2016
Stephen Tooth has joined a team of researchers looking at the Linyanti-Chobe-Zambezi system, a vast area of floodplain wetlands located near the borders of Botswana, Namibia, Zimbabwe and Zambia. The project is funded by the National Science Foundation, USA, and led by Kathleen Alexander at Virginia Tech. A press release is at: http://www.vtnews.vt.edu/articles/2015/09/093015-cnre-nsfcnhgrant.html
The project is investigating the underlying processes that link the environment, wildlife, domestic animals, and humans in wetlands in drylands, particularly those processes that drive the accumulation and movement of waterborne disease across the landscape. The project is focusing on three significant problems: 1) basic knowledge of the coupled dynamics of fluvial processes and water quality in drylands and the influence of anthropogenic and natural influences on pathogen pollution and health; 2) sociocultural and economic variables that influence waterborne disease dynamics and system feedbacks; and 3) appropriate tools to monitor indicators of system change and intra-annual forecasting ability.
Tooth’s role is to help outline how the complex interactions between hydrological, geomorphological, sedimentary, and ecological processes particular to floodplain wetlands in drylands have an influence on faecal microbial dynamics, water quality, and human waterborne disease risk.
South African National Wetlands Indaba, Rawsonville, Western Cape, 20-23 October 2015
The South African National Wetlands Indaba is an annual gathering of scientists, practitioners, consultants, government personnel, and members of NGOs, who share an interest in wetlands. The 2015 meeting was attended by more than 300 people representing more than 30 organisations. Session topics included ‘Urban and Constructed Wetlands’, ‘Wetland Biodiversity’, ‘Wetland Origins, Drivers and Dynamics’, ‘Wetland Plants, Climate and Climate Change’, ‘Wetland Mapping, Monitoring and Assessment’, and ‘Wetland Rehabilitation’.
The Wetlands in Drylands Research Network was well represented at the meeting, with network members and their students presenting 20 papers or posters (amounting to 25% of the scientific programme), including a keynote presentation by Fred Ellery on wetland geomorphology. Abstracts and presentation PDFs are available for download at:
To access a presentation PDF, click on the hyperlinked presentation title. This will take you to the Abstract page. The last line of the Abstract is a link to “Download presentation”. The 2016 Indaba will take place at Swadini, Mpumalanga Province, in October.