Salinity and Biodiversity

CSIRO Discovery Lecture Theatre, Wednesday 13 September at 4 pm

The second seminar in the series discussed the topic of salinity and biodiversity. The event was well attended and sparked a range of interesting questions from the floor.

Speaker: Greg Keighery from CALMScience, WA.

Chair: Rosemary Purdie, Murray-Darling Basin Commission

• Anwen Lovett, National Farmers Federation
• Philippa Walsh, World Wide Fund for Nature
• Kevin Goss, Murray-Darling Basin Commission
• Leith Boully, a grazier and cotton-grower from south-west Queensland, and member of the CSIRO Biodiversity Sector Advisory Committee.

Summary of talk and discussion by Roger Beckmann.

Greg Keighery introduced Australia’s largest state and its 24.5 million hectare agricultural zone (almost entirely in the southwest). About 80-90% of this area has been cleared of its native vegetation, but dotted across it are some 3000 tiny remnants of bushland. The massive clearance since European settlement, by removing deep-rooted vegetation, has raised the water tables and brought salts to the plant root zone and/or the surface. The area is now facing a huge salinity problem, with about 30% of the agricultural zone becoming saline.

WA is famous for its wheatbelt, and Greg and his team at WA’s Conservation and Land Management Biological Survey Group have been concentrating on this area, initiating a four-year study of the region’s biodiversity and the effects of salinity on it.

The team studied 330 sites across the agricultural zone in south-western WA and found considerable diversity that had not been known about before. Estimates are that the entire zone has a vascular plant flora of about 4000 species, of which more than 60% are endemic to the area. The region is the centre of species diversity for many of south-western WA’s (and the continent’s) most species-rich plant groups (Acacia, Dryandra, Eucalyptus, Grevillea and Verticordia). Detailed surveys of just the Lake Muir/Unicup reserves documented almost 1000 vascular plant species.

Of the 700 or so plant taxa that make up the species in the wheatbelt, about half are at risk in the near future. Many of these endemic plants are confined to a very small area and are found nowhere else.

The survey also showed that wetland areas were surprisingly rich in invertebrates, of which about half were undescribed [Arachnids table]. In particular, there was a wealth of endemic microcrustacean fauna, nearly all of which disappear with the onset of salinity.

As well as freshwater wetlands, there are also naturally saline areas. These too have a rich and endemic fauna; unfortunately, tolerance to natural salinity offers little protection from acquired salinity [graph]. The communities are adapted to wet winters and dry summers, but are vulnerable when the area is flooded with saline water all year round. These saline areas are worth protecting, but lack of awareness of the biodiversity in the areas - and a feeling that whatever is living there can cope with any regime of salinity - has meant it is hard persuading people of their value. All too often, such areas are used as a dumping ground for extracted saline groundwater.

One of the major difficulties in documenting biodiversity in the area is that we are losing species before they are described or known about. And, of course, it is not just species that are going. Variation within species is also being lost, and whole communities are vanishing - taking their species assemblages with them.

Wandoo woodland, for example, which normally has about 60 plant species per square metre, is reduced to a meagre 3/m2 when saline-affected.

Greg showed slides with maps of the wheatbelt and its remnants, localities at risk of salinity, and tables showing how many hectares are already affected.

His take-home message was that, to protect biodiversity, we need a broad view of conservation management. To manage effectively, we should foster partnerships and raise awareness of the problem beyond local areas. To the Canberra audience, he warned of the problems to come in eastern Australia.

DISCUSSION

Discussion between the audience and the panel members then ensued, ably chaired by Rosemary Purdie (of the Murray-Darling Basin Commission), who started by asking each of the panel members to nominate a single ‘wish’ that would help in dealing with national salinity.

The general consensus was a desire for national integrated programs, national leadership, more investment, and for moving existing funding from an emphasis on agricultural production (or geophysical mapping) to researching biodiversity.

Continuing the fight

Discussion with the audience revolved around several themes. The first was the question of how hard we should continue to fight against salinity. As one questioner put it, we have already lost 2 million hectares, another 2 million are almost certain to go no matter what we do. Should we allow this to happen and accept the inevitable? Greg Keighery was passionate in his advocacy of continuing the fight., even if we are still losing land. 'We can't start off saying we won't fight, even if we lose a few battles'.

Leith Boully suggested that it was not always clear what should be done, and Kevin Goss thought that the idea of fighting a war was self-defeating. Philippa Walsh felt that we should be carrying out mitigation work while documenting the problems at the same time. She emphasised that we didn't need more knowledge per se (although more is always helpful) but that we need any actions to be properly driven by existing knowledge. Anwen Lovett mentioned the difficulties experienced by rural communities, and the fact that we cannot take people out of the equation, no matter how we fight the problem.

Social implications

Social aspects were raised by another questioner from the floor, who wondered whether communities differ in what they are willing to do. Should actions be dictated by what communities will do, or should communities be told what to do and given funding?

Anwen felt that carrots and sticks were needed. In some catchments, she pointed out, the average age of farmers was about 55. Change was harder here, and the issue of succession weighed on the minds of the farming families. In time, with a new generation of owners and their newer ideas, more could be achieved.

But, of course, there isn't always time available, as Leith pointed out. She felt that we should allow politicians to take the tough decisions and put in place processes and targets to achieve outcomes. It is possible to change prevailing attitudes - for example, it is no longer socially acceptable to pollute water for downstream users.

The issue of change continued to be discussed with one questioner feeling that we were hearing the same old phrases in a tired issue in which there had only been ‘pinpricks of progress’ in the last decade - despite the efforts of Landcare and acts of various Parliaments.

In reply, Leith said that, ten years ago, few farmers knew much about biodiversity. There was now greater commitment to it, although more knowledge had to be broadcast in order to change people. Perhaps the research community needed to generate more knowledge too. However, she felt that the culture in most of the relevant agencies hadn’t changed much, and that responsibility and power needed to be devolved back to the affected communities.

Kevin pointed out that some things have improved. For example, salinity in the Murray had decreased in the last 12 years - mainly as a result of river operations and engineering works. Admittedly this was a bit one-dimensional, but he felt that the thinking now was different to what it had been a decade ago.

In addition, not all salt-affected land is bare, scalded and useless. The definition of ‘salt-affected’ means that agricultural productivity is diminished. Much of this sort of land can still be used for other things.

Greg described the process of declaring a biodiversity recovery catchment in WA. Farmers are amazed that the process is properly resourced. The biggest problem is focal catchments, which are totally community-driven. These only have one year’s funding.

The difficulty of focal catchments with their single concern was discussed at more length. The point was put from the floor that these do not offer integrated solutions. Greg agreed but felt that, for example, a water authority taking over a catchment management was better than nothing. Although the primary concern in this case would be water quality, such an agency could still take on board biodiversity issues. Greg felt that a ‘whole-of-landscape’ and ‘whole-of-government’ approach was desirable but that there were not enough staff available.

The discussion on integrated approaches led on to the point from the floor that too many people were treating salinity as the cause of biodiversity problems rather than a symptom of biodiversity loss. Loss of biodiversity changes ecosystem function and salinity can result. It was therefore argued by this questioner that it was important to engage society and institutions to deal with ecosystem change.

Greg agreed that problems such as salinity were the result of vegetation changes and that many of our current problems with biodiversity declines would still be present in agricultural areas - because of fragmentation and native vegetation clearance - even if the salinity were not. However, he argued that salinity is more visible to people than slow species loss. He felt that salinity was something that people could relate too, that would bring home the extent of the changes we have wrought and the unpleasant consequences of our past actions.

Anwen agreed that salinity is being used as a ‘flag’. The broader issues, she argued, were so nebulous and huge that it is hard for rural communities and urbanised society to focus on them. With salinity, the effects were visible and tangible.

Philippa gave an example of how a WWF group had explained to a somewhat surprised local parliamentarian that salinity is part of a broader package and is best dealt with by management of vegetation.

Leith felt that the informed community understood that the issue was not just salinity. But, at a political level, salinity is the main issue that has penetrated and which continues to drive the agenda.

Other issues - including the participation of traditional owners - were also raised in what was a lively and broad-ranging session that stimulated many questions from an interested audience.

Roger Beckmann