Australian Rangeland Society

Dr. Gresley Wakelin-King, Wakelin Associates, Melbourne; La Trobe University, Bundoora.  Email: gresley@wakelinassociates.com.au

 

Hi,  I’m a rangeland geomorphologist. My job is to understand how the Earth’s surface works: the evolution of Australian landscapes, and the processes that maintain them. I got here through a degree in geology and a PhD in desert rivers, and the thing I most enjoy is fieldwork in remote country. I work as a consultant, mostly in western New South Wales and the Lake Eyre Basin; I do research in my own time.

Geomorphology means ‘the shape of the land’. Many people will remember this as part of physical geography in school, where we learned landscapes’ names, shapes (landforms), and character. A meandering river, for example, has a sinuous loopy channel, billabongs, and usually a ridge-and-swale floodplain (Figure 1). Geomorphology tells us about the processes that create the landforms. The river meanders because of inbuilt patterns of turbulence related to the river’s size and sediments. The turbulence creates conditions where the channel migrates slowly, leaving behind a bumpy floodplain where the old banks and bars used to be. Sometimes during channel migration the sides of a loop will meet and join, cutting off the top of the loop and leaving behind a billabong. With this knowledge planners can identify river reaches at risk of sudden change, or distinguish between erosion problems (needing to be fixed) and normal bank retreat (a natural and necessary part of channel migration).

 

Figure 1.   A meandering river: the Murray River at the South Australian-Victorian border.  Source: Google Earth

 

Questions to Ask

During my career I have talked to landholders and residents whenever possible, to find the ways in which geomorphology can be used to support sustainability and productivity. Sometimes this has been during fieldwork, and sometimes during conferences and field days hosted by Landcare, Natural Resource Management groups, or the Australian Rangelands Society. These are the questions I have most often heard: “I’ve seen a great rehabilitation technique, will it work at my place?”, “My landscape is doing [a thing], is that what’s supposed to happen?” and, “Why is this paddock different from the rest of the property?”. For all these, the answer includes geomorphology.

Landforms support habitat.  All ecosystems exist within their physical habitat, which in turn is supported by landscape processes both near and far. An ecosystem can be in good shape locally but be threatened by distant events such as gullying. Monitoring (e.g. vegetation) at point locations may be misleading if landforms across the wider catchment are not considered (Pringle and Tinley 2003). As described so vividly by Hugh Pringle at the 2006 Australian Rangeland Society conference (Renmark), there’s no point monitoring somebody’s breathing by keeping an eye on the feet, because by the time the toenail turns blue the damage is already done.

Different landscapes, different processes. There are so many different types of river and landscape in the Australian rangelands, each operating in their characteristic way. A rehabilitation technique that works well in one place can be an ineffective waste of diesel in another. A particular type of watering point might do well in one catchment but be an erosion trigger elsewhere. In a way, this is like the realisation (~100 years ago) that Australia is not England, and European stocking rates and game animals don’t belong here. In the same way, the Paroo is not the Barrier Ranges is not the Channel Country is not the Gascoyne. On-ground works and river/range assessment schemes need to be a good fit to the landscape that they are being applied to. Nothing works equally well everywhere.

Landscape change (or not). It’s important to know whether the landscape we see today is in its natural condition, or whether it has undergone post-European change. Some Australian rangelands have undergone widespread and pervasive landscape change, some are in original or near-original condition (with respect to landforms; these comments do not apply to plant or animal communities), and some is changed but recoverable, or changed but acceptable. Geomorphology has a particularly important role here, since memories and historical records can be imprecise and ambiguous. If the landscape is in original condition, or is changing in response to its natural landscape processes, it’s likely to be difficult to alter by mechanical means. Furthermore, since the landscape is already evolved to make the best use of its surroundings, mechanical changes may risk unintended poor outcomes. If it’s not broken, it’s likely to be hard to ‘fix’ and easy to break.

Geomorphology is also important in identifying the causes of landscape change. Management action that targets the wrong cause will probably be a waste of resources. Because the world is a complex place, there are often several causes for change; targeting one while ignoring the rest may only resolve part of the problem. An example of this would be an earth tank watering point on a shallow valley that has historically experienced heavy grazing pressure. In the present day the area exhibits devegetated hillslopes and valley-floor incision that has desiccated the previously well-watered flats (Figure 2). Destocking might support hillslope revegetation, however the valley floor is still impacted by the presence of the dam and its bywash (narrowing the flow path and increasing valley’s runoff energy above the erosion threshold).

 

Figure 2.  In its original state, this area was a water lane (an unchannelled valley floor) between two banded vegetation hillslopes. The vegetation has been diminished by historical heavy grazing, and the water lane has experienced multiple episodes of valley-floor incision as a result of dam placement. Source: Annotated Google Earth image.

 

 

Banded Vegetation: a Geomorphology Story

Banded vegetation slopes and plains are widespread landform in Australian and other rangelands (more info in Wakelin-King 1999, Valentin et al. 1999). This nifty biophysical association is a natural water-harvesting system of alternating bare dirt and bands of vegetation occurring on gentle slopes in loamy or clayey soils. From the air or in Google Earth it looks like stripes or elongate dots that follow the contours of the landscape (Figure 3). It occurs in many different plant communities including Mitchell grass, chenopod and mulga.

 

Figure 3.  Banded vegetation in good condition: the darker vegetated bands stand out clearly against the orange bare dirt, and the water lane (top left to bottom just right of centre) is unchannelled. Straight sealed road across the top right corner. Source: Google Earth

 

Rainfall is shed from the bare ground onto the vegetated bands, where it infiltrates and supports the ecosystem. From the plants’ point of view, it’s as if they were growing in a wetter climate. A banded vegetation hillslope has greater productivity than if the vegetation had been evenly distributed. Almost all rainfall stays and grows vegetation on the banded hillslope: only a very little reaches the infilled valleys between one hillslope and the next. These areas, known as water lanes, are more densely vegetated and transmit runoff as shallow low-energy sheetflow (there is no channel).

In the story of banded vegetation, the landscape and the humans aren’t always on the same page. Because banded vegetation doesn’t resemble a river, it is not recognised as a water-carrying landform, so it lacks the regulatory protections and technical support that rivers might have. However, the way it retains water and supports productivity has led it to be valued in post-European pastoral enterprises. Banded vegetation hillslopes are a substantial component of many grazing properties, and earth tank dams are commonly located in water lanes (Figure 2). Despite its broad distribution in Australia, the way banded vegetation works is not widely known. It’s not familiar from temperate-zone Europe, so it’s not described in mainstream geography textbooks, and in Australia detailed research didn’t begin until late last century (e.g. Mabbutt and Fanning 1987). Consequently, landholders may not be aware of why the bare bits (the interbands) are necessary. Attempts to improve natural banded vegetation hillslopes by ploughing or furrowing the “wasted” bare ground (Figure 4) deprives the existing vegetated bands of the runoff water they need, and still won’t grow substantial vegetation in the treated areas. A study commissioned by the NSW Western Catchment Management Authority (Wakelin-King 2011) indicated that in degraded banded vegetation country, furrowing in was more successful if it avoided the naturally bare interbands, and mimicked the natural banding in scale and orientation.

 

Figure 4.  Natural banded vegetation (left) separated by a fence line from treated banded vegetation. Source: Google Earth

 

 

Challenges for Australian Rangeland Geomorphology

Care factor. Many people have never heard of geomorphology, so they might feel that the industry or discipline that they work in has been fine without it. Life’s busy, no one wants to add another step into the workflow. Still, that’s what we used to think about concepts like biosecurity, biodiversity, native vegetation, soil science or TGP (total grazing pressure) management. I don’t think we can fully understand ecosystems without understanding the landscapes that support them. Process-based geomorphology (carried out by suitably qualified and experienced geomorphologists) should be a fundamental step in any project EIS, ecosystem study, or range/river assessment protocol.

Linking to indigenous knowledge. I know that many of the questions I want to ask about past landscape events could be illuminated by tapping into traditional knowledge. I’m aware that those discussions call for time and relationships. I’d like to do that, but I’m bound by the conditions of the contracts I’m employed under, over which I have no control. I don’t know how to change that, but I wish it was different.

Not much accessible knowledge. The Australian drylands are huge, roughly 80% of the main continent. Although there are some places where the geomorphology has been intensively investigated, much of the area is under-researched, lacking even baseline data. This is of particular concern in the drylands rivers, where many of the fluvial landforms or processes are novel and unlike the better-known rivers taught in undergraduate training. Consequently, policies and protocols are being developed on the basis of ‘desktop studies’ using insufficient or inappropriate information. Filling in this information gap is a major focus of my research, but there’s so much more to do.

There are other kinds of landscape geoscience, closely allied to geomorphology, that I refer to when starting a new area. They’ve been written for geologists, so their accessibility and usefulness to land managers is limited. For example, public-sector science investigates regolith and Cainozoic geology, producing technical publications and spatial data. This information is valuable to its intended audience, but further steps are needed to draw out its applications for land managers.

Few resources (research). There should be a research focus on rangeland geomorphology for land management, but there are barriers in the way. There is intense competition for limited funding and a marked decline in working conditions and job security for scientists and academics – that’s a problem for Australian science generally. The funding process also has inbuilt structural factors that can disadvantage new rangelands research: policy-driven research priorities that favour other sectors, and metrics which advantage already-existing successful programs and disadvantage curiosity-driven research. Academics have a punishing workload that makes it difficult to develop new research partnerships; scientists who are not tenured academics aren’t eligible to apply for research funding. Organisations such as catchment management authorities are not meant to be research bodies, and often have specific policies prioritising applied works over research questions.

Almost no resources (documentation and communication). An extensive experimental program of pitting and furrowing took place in western New South Wales from the 1960s to the 1980s, overseen by the New South Wales Soil Conservation Commission. Despite the results being presented at a national and an international rangeland conference, when I was commissioned to investigate the long-term outcomes in 2009, there was almost no information remaining. The conference proceedings were only available on paper (I found them in a filing cabinet in an office slated for closure), and the rest of my information came from geomorphology, or the memories of participants. This isn’t an isolated case; in other projects I have been involved in, my and my colleagues’ technical reports and stakeholder presentations are available at the project conclusion, but in the long term are ephemeral. The memories of conferences fade, and a downloadable report can be just one departmental reorganisation away from becoming unfindable. Similarly, there’s practical geomorphology taking place in landholder-driven rangeland rehabilitation projects across Australia. Aside from the Soils For Life case study collection (https://soilsforlife.org.au), most works are undocumented. Landholders and rehabilitation practitioners are talking to each other, but when the project funding finishes that communication network will disperse. If projects don’t have documentation, communication, and monitoring built into the funding and timelines from the very beginning, knowledge is lost.

 

Wishes

If I had three wishes for the future of rangeland science, this is what they’d be:

  1. There would be strong industry representation to government about the value of geomorphology, so that funding priorities could better reflect that the rangelands represent most of Australia, and that all habitats are hosted by landforms, so there is good reason to invest in rangelands geomorphology.
  2. There would be a university research group specialising in rangelands geomorphology, teaching undergraduate courses to ecologists and land managers, and harnessing postgraduate research projects to systematically analyse and document Australian drylands geomorphology (including developing the applied aspects of the work).
  3. There would be dedicated (funded) programs of science communication, supporting non-academic scientists to convert their in-house research to peer-reviewed publications, assisting landholders to document their rehabilitation works, fostering connections between landholders and researchers, and setting up indexed, securely archived and accessible storage for technical reports.

 

 

References

Mabbutt, J.A. and Fanning, P.C., 1987. Vegetation banding in arid Western Australia. Journal of Arid Environments, 12(1), pp. 41-59

Pringle, H. and Tinley, K., 2003. Are we overlooking critical geomorphic determinants of landscape change in Australian rangelands?. Ecological Management & Restoration, 4(3), pp. 180-186.

Valentin, C., d’Herbès, J.M. and Poesen, J., 1999. Soil and water components of banded vegetation patterns. Catena, 37(1-2), pp. 1-24.

Wakelin-King, G.A. 1999. Banded mosaic (“tiger bush”) and sheetflow plains: a regional mapping approach. Australian Journal of Earth Sciences, 46, pp. 53-60.

Wakelin-King, G.A. 2011. Using geomorphology to assess contour furrowing in western New South Wales, Australia. The Rangeland Journal, 33, pp. 153–171.