{"id":54,"date":"2015-02-08T01:00:48","date_gmt":"2015-02-07T14:00:48","guid":{"rendered":"http:\/\/pcap.org.au\/?p=54"},"modified":"2017-03-26T19:26:12","modified_gmt":"2017-03-26T08:26:12","slug":"landcare-biodiversity-soil-water","status":"publish","type":"post","link":"https:\/\/pcap.org.au\/index.php\/2015\/02\/08\/landcare-biodiversity-soil-water\/","title":{"rendered":"Landcare for biodiversity, soil and water"},"content":{"rendered":"

by Malcolm McDonell
\nhttps:\/\/www.facebook.com\/malcolm.mcdonell<\/a><\/p>\n

Australia\u2019s environment<\/strong><\/p>\n

Measures of sustainability show Australia\u2019s rural landscape is in poor shape. One popular movement to address the situation is \u2018landcare\u2019 – focussed on revegetation of the natural bush. Landcare that is focussed can be part of a sustainable future. Any plans to address the problem has to deal with soil, water and care of biodiversity of plants and animals.<\/p>\n

I want to look at the temperate south-east corner of the land in Australia, the most user-friendly part from a productivity perspective, and with a point of focus on Adelaide at the tail end of this territory.<\/p>\n

Historical and geographical considerations<\/strong><\/p>\n

We are challenged by lack of water \u2013 exacerbated by its variability. To make way for agriculture much of the land has been cleared of its vegetation cover. The aboriginal owners were swept aside quickly, and no regard was shown for their management ways. Australia has a different biotic assemblage to other parts of the world; Charles Darwin contrasted it with the northern biota \u2013 \u201cTwo distinct Creators must have been at work\u201d. He was not aware, as we are, that Australia is a unique remnant of the Gondwana heritage.<\/p>\n

The soils are poor. Geoffrey Blainey\u00a0 claims Australia is the “world\u2019s great museum of soil deficiencies”. What soils we have are thin, and the practice of deforestation for agriculture has left soils exposed which were then able to be stripped by rain and wind. The outcome is that across much of the arable land of the country a large fraction of the topsoil is gone.<\/p>\n

The early colonists struggled for many years to produce food sufficient for the colony. Eventually subsistence was achieved. And in time the agricultural export economy grew with wheat, wool, and later meat production. Today corporate agriculture is concerned with exports and shows little concern for the discussion of sustainability, (beyond the public relations considerations) but the conservation minded (\u2018greenies\u2019) do. The conservation movement goes in two different directions.<\/p>\n

Sustainability<\/strong><\/p>\n

Two streams of sustainability are apparent \u2013
\n– firstly, the conservation of biodiversity; and
\n– secondly, organic agriculture (dealing with soil and water),
\nand these agendas can be in conflict \u2013 such is our enigmatic land! Native plants thrive in the poor native soils, and agriculture looks to build a rich soil profile for fertility and production. The two do not sit happily in the same immediate environment.<\/p>\n

Sustainability 1 \u2013 Conservation of Biodiversity\u00a0<\/em><\/strong><\/p>\n

All species have a right to existence each for its own sake, but some species would also have value for some qualities that we may never know – if they are driven over the brink to extinction.<\/p>\n

Loss of species<\/em><\/p>\n

The demands of agriculture saw large areas of land cleared, and so many plants and animals were under threat. Many species of animals and plants were actually\u00a0driven to extinction \u2013 and many more are now endangered. Endangered species should be given the highest priority in our management of the land. We may yet not even know their utility value to an ecosystem.<\/p>\n

European colonial society has made two mistakes in terms of the Australian environment. One is to regard the native bush as inferior and to seek to replace it. The other is to ignore aboriginal land management. Cultural attitudes are sentimental. In the late 20th century Australians saw fault with their earlier attitudes and turned in favour of \u2018the bush\u2019 but this sentiment is not discerning and it accepts a simple answer where more analysis is needed. So our attitudes to the bush are simplistic. Likewise our attitude to aboriginal ways has changed, and here also there is a lack of rational analysis, as yet we have not understood much of their knowledge.<\/p>\n

In the management of our sprawling landscape some land is taken up for settlement, more is given over to agriculture and some is retained as reserves. This reserve land is maintained by a low maintenance methodology \u2013 as far as possible it is left alone. In the popular imagination this is seen as \u2018natural\u2019 and \u2018like it was before colonization\u2019, however those two are not at all the same.<\/p>\n

Numerous writers have pointed out the way parts of the Australian landscape were constrained by aboriginal communities. Forests were controlled such that the land was like a park with lots of open space. Closed forest was not the norm at all. And when we talk about forests in this Australian context we are talking about forests of (predominantly) eucalyptus trees.<\/p>\n

Although this perspective would not be new to students of environment, at the cultural level this is not readily accepted today, as we have come to think of our best reserves as the ones we leave undisturbed.\u00a0 However, the reality, it seems, is that to leave the land alone is to profoundly change it! I believe our problematic, bushfire prone reserve areas demand a stronger approach, to keep them appropriately in check.<\/p>\n

We know that the forests were controlled in this way, but I do not think we know for sure why they were thinned. Some writers have (glibly?) speculated that it was done to facilitate hunting of kangaroos, but was that the only reason? From a modern perspective there is more to be said about eucalypts. European land use has made their presence unstable to the soil.<\/p>\n

About eucalypts<\/em><\/p>\n

1. Eucalypts are fire-prone. Who would doubt it? They have flammable bark and flammable leaves and are ecologically adapted to thrive with fire \u2013 which drives out other species. The terrible destructive bushfires that happen at times even close to our cities are fires thriving on a eucalypt fuel-load\u00a0\u2013 the devastating crowning fires in particular. In 2007 we saw huge forest-fires in Los Angeles and it is Australian eucalypts that are to blame. They are not good companions for a sedentary populace.<\/p>\n

2. Eucalypts are thirsty. In many places around the world where there is a low rainfall eucalyptus trees have been planted. They have proven valuable in drying out a swamp, and have been used in that way in other countries. But in Spain they are removing them because of the aggressive deep roots which are killing off forests of cork-oak trees. Even in suburban plantings we can easily see that the amount of undergrowth under the trees canopy is minimal \u2013 they out-compete all others.<\/p>\n

3. The impact of eucalypts on the ecology is detrimental to the rest of the flora. Tim Flannery says \u201cthey like to get rid of nutrients out of soils\u201d and further: \u201cthere is maybe only a hundredth as much protein available in those ecosystems as was available in the earlier systems. So it\u2019s an impoverished system which is stable to a certain extent \u2013 but not nearly as productive.\u201d<\/p>\n

If not eucalypts then what?<\/em><\/p>\n

The vegetation of the 18th century was not \u2018natural\u2019 it was also interacting with human beings and an artefact \u2013 aboriginal farmland. It begs the question what was it like before human occupation (50,000 years ago)? Might it have been a Gondwana vegetation, not characterized by eucalypts at all? The landscape has certainly changed since then \u2013 it is only about 11,000 years ago since Australia was under the influence of an ice-age. We have some knowledge of individual species that were around in earlier eras, but no clear picture of the species at the time of first human settlement, and certainly not of the spread of species across the landscape.<\/p>\n

For instance, a useful street tree of today is the White Cedar (Melia Azedarach) which is a subspecies of an Indian tree \u2013\u00a0possibly a Gondwana link. In the present day, other available local native species of trees include she-oaks, native pine and blackwoods, but there are not many other options from the current assemblage.<\/p>\n

The answer in the early 20th century was to plant exotics \u2013 and slowly make a European and American (northern) species mix. The trees planted in Canberra during that era illustrates it \u2013 poplars, plane trees\u2026etc.\u00a0 Do we go back to that option? I think the rationale for planting indigenous shrub species still stands. We can still do a lot with understorey plants. However these species are of course fire-adapted, as the companions of the eucalypts \u2013 subject to fire on a regular basis. Remove fire from the ecology and surely we change the ecology markedly.<\/p>\n

The environmental demand to find an assemblage of plants that is stable in the long term with minimal management is elusive.\u00a0 Just what landcare bush structure can we put in place and maintain with a low manpower management system? (Meaning we can look after it by basically leaving it alone).<\/p>\n

It might be that just as aboriginal people found they could not leave it alone, we cannot take that path either. Could it be that we keep a restricted population of eucalypts as was done in pre-colonial times? With our present day housing situation the forest maintenance might have to be done more with a chainsaw than with fire!<\/p>\n

But this issue is not dealt with until we consider the situation of soil and water.<\/p>\n

Sustainability 2.1 \u2013 Soil<\/strong><\/em><\/p>\n

Early colonial farmers cleared the land and erosion by wind, rain and running water carried a lot of soil away. We have to plant to look after our soil. This might be native plants but it must be successful \u2013 and might require exotic plants.<\/p>\n

Conflicting strategies<\/em><\/p>\n

The challenge is not easy. Soil enrichment is antagonistic to native plants, so weeds may thrive the more. And runoff from rich soils may find its way into the creeks and dams \u2013 promoting algal blooms. This could even be a threat to endangered species in the creeks, estuaries and coastlines! So care must be taken.<\/p>\n

As I have just been arguing, native vegetation, especially eucalypts, robs the soil of water, so less is available for agricultural needs. On the other side soil improvement, enriching the soil with fertilizer, (inorganic or organic) for the sake of agriculture means the water that runs off can be high in nitrogen and phosphorus, and thus make for algal blooms in the creeks and ponds. Certainly some endangered species of fish and\/or crustaceans could be lost due to this effect.<\/p>\n

Sustainability\u00a02.2 \u2013 Water<\/strong><\/em><\/p>\n

Australia has a population now of over 22 million people. Two hundred years ago the population was \u00bd to 1 million according to anthropologists. The population of Australia needs food. Which is to say that we need agriculture, and agriculture needs water. (I am not talking about the agriculture that is focussed on exports).<\/p>\n

Adelaide<\/em><\/p>\n

In Adelaide water is problematic. The state is largely desert and semi-desert. The well-watered part – Adelaide and the Mount Lofty Ranges – is an area of about ten thousand square kilometres, and it is home to a population of over one million people. That is a population density comparable to Indonesia and France. It is a very different picture to the situation of the eastern states of Australia.<\/p>\n

In the early 20th century the growing city of Adelaide recognized the need for more water resources. The problem was dealt with by accessing the Murray River. Since then utilisation and exploitation of the water throughout the Murray-Darling Basin means that there is no longer any summer flow in the river, and the reliability of winter flows is not assured. We might well lose the support of the River Murray and be forced again to utilise local rainfall.<\/p>\n

In recognition of this matter the state of South Australia\u00a0has built a desalination plant to make a backup supply of water. However the desal-plant is coal fired, and if called on to supply water it would make a very large carbon footprint \u2013 just at the time we are trying to reduce our carbon use for sustainability. The logical end\u00a0of it is clear we have to maximise our capacity to harvest the yield of water from the rain that falls on the Adelaide Hills \u2013 the Mount Lofty Ranges from Cape Jervis to Mount Remarkable.<\/p>\n

As we have seen eucalypts are not a good choice for hills where rain is to be collected. Neither is bare ground. We would do well to create an ecology that supports water harvesting. Trees for shade, cooling the understory, vegetation cover and layers of humus on the soil, making a sponge of soil, capable of holding soil and allowing it to travel slowly across the landscape \u2013 eventually to creeks, then to be stored in thousands of ponds and dams over the landscape.<\/p>\n

From this point of view what is the right choice of species for the Adelaide Hills \u2013 which is the catchment for that much needed water? An understorey of local native plants might be good, but what is the climax species? I think it probable that we will need some imported species as well. It might be reliance on\u00a0Australian natives like the Moreton Bay Fig which does quite well in Adelaide, but it might be that we should use some exotic species too, like the Mediterranean Oaks \u2013 ready to thrive in Adelaide\u2019s winter rain and summer heat and aridity.<\/p>\n

We should also plant to enhance rainfall!\u00a0 Some vegetation does induce rain as shown by the research of Lyons\u00a0who noted the 30% better rainfall on the vegetated side of the rabbit proof fence in Western Australia. And it is widely accepted that loss of vegetation is a cause of the growth of deserts in Australia and elsewhere.<\/p>\n

For consideration<\/em><\/p>\n

Further, some plants are claimed to be more rain attracting than others. For example, P.R. Sarkar directed, and with local support made a change-of-landscape plantation in a run-down area of rural India, by the\u00a0use of oaks (Quercus species) and ferns (and others) for promoting rain and water retention in the organic materials in the soil. This project at Anandanagar (West Bengal, India) now has running rivers, where dry stream beds were 40 years ago. When water is such a key for the Australian landscape this type of approach\u00a0should surely be the focus of trials and experiment.<\/p>\n

Conclusion<\/strong><\/p>\n

We need to care for endangered plants directly, and we need to care for endangered animal species with suitable habitat \u2013 be it native plants or otherwise. We need to plant to care for soils \u2013 to stop soil erosion, which might also be done by native or exotic plants. And we need to plant to maximise our water yield \u2013 to make rain, to shade the soil and understorey, to create a spongy soil receptive to moisture.<\/p>\n

In Adelaide today there is sentiment and there is rhetoric, but there is no commitment \u2013 there is not even any analysis \u2013 towards a plan which can deliver a sustainable environment for the generations ahead.\u00a0 I hope we can formulate a plan that makes for a healthy environment into the future.<\/p>\n

\u00a0References<\/strong><\/p>\n

1. Triumph of the Nomads<\/em>, Geoffrey Blainey, 1975.
\n2. The Biggest Estate on Earth<\/em>, Bill Gammage, 2012.
\n3. http:\/\/www.abc.net.au\/radionational\/programs\/earthbeat\/landclearing–rainfall-in-wa\/3640228<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

by Malcolm McDonell https:\/\/www.facebook.com\/malcolm.mcdonell Australia\u2019s environment Measures of sustainability show Australia\u2019s rural landscape is in poor shape. One popular movement to address the situation is \u2018landcare\u2019 – focussed on revegetation of the natural bush. Landcare that is focussed can be part of a sustainable future. Any plans to address the problem has to deal with…<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[33],"tags":[18,37,34,36],"class_list":["post-54","post","type-post","status-publish","format-standard","hentry","category-sustainability","tag-forests","tag-soils","tag-sustainability","tag-water"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/posts\/54","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/comments?post=54"}],"version-history":[{"count":5,"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/posts\/54\/revisions"}],"predecessor-version":[{"id":148,"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/posts\/54\/revisions\/148"}],"wp:attachment":[{"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/media?parent=54"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/categories?post=54"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pcap.org.au\/index.php\/wp-json\/wp\/v2\/tags?post=54"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}