Our research focuses on the population dynamics of plants and how they are influenced by impacts of natural disturbances and global environmental change. We are particularly interested in the interactive effects of fire, grazing and drought in grasslands and woodlands in southern Australia, and how climate change, fragmentation and shrub encroachment affect ecosystems.

Tuesday, 11 February 2014

The earliest evidence for widespread declines in native grasslands in Australia??

Something a little different this week.

Native grasslands in southern Australia have undergone a massive transformation since European settlement. But the evidence for the speed of that transformation has been hard to come by. It's hard to guess whether people noticed the changes, or simply realised one day that grasslands were gone.

The following is an extract of an article from The Australasian, dated 18th October 1878. It shows that within 50-80 years of  settlement, an understanding of the impacts of agriculture on native grasses was already obvious. And, interestingly, there were already calls to develop a native grassland "seed industry". It's worth noting this type of information - perhaps the earliest record of grassland transformation in Australia - because we are still grappling with the same issues in 2014 in many respects.

It should make us reflect on what we now know, and yet how little has changed in some respects. We're still thinking about grazing regimes that promote native grasses & still grappling with how to best produce large quantities of seed. Enjoy.

"The deterioration of our native pastures as regards their fattening powers .... is due not only to the removal from the soil of certain proportions of the elements of fertility in the form of bone, flesh, and wool, but in some degree also to the loss of the best and most nutritious grasses, which inevitably occurs under the system of depasturing commonly practised in the whole of these colonies. Whether the grasses are only annuals or are those known as perennials, they must soon die out unless measures are taken to ensure a re-seeding of the ground at certain intervals.

Even the longest lived grasses must be renewed from seed occasionally; the old stools become enfeebled by continuous grazing, and the sorts that are most relished by sheep are actually eaten down into the soil, so that in the course of a few years they disappear altogether from the ground. Of this the common kangaroo grass is a familiar example; it will not bear the constant nibbling of stock, especially of sheep, and as it is often the only green feed, in hot dry weather, the plants are eaten completely out.  Within unstocked or lightly stocked enclosures, as between railway fences, native grasses of all kinds continue to thrive as formerly. They have the opportunity of renewing themselves from seed annually, and as they are rarely fed down they grow far more vigorously than grasses of the same species depastured in the ordinary way.

Here is a lesson of which graziers great and small may take note, if they have any desire to preserve the native grasses from extinction. The question whether it is desirable to preserve them at such cost and trouble as may be needed to effect that object is one upon which old and experienced graziers agree. They all affirm that no exotic grasses fatten so quickly as the native pasturage used to do, and there is an equally general agreement of opinion that the stock are far less healthy on " English grasses " than on the native pasturage of the country.
It is a principle in English husbandry, when laying down lands in permanent pasture, to employ as large a number as possible of species. In this they only imitate nature, for on examining a square yard of well-grassed ground it is found that the number of species thereon usually varies from 50 to over 200. In this country the number of species is not so great upon the plains, but there is a very considerable variety of pasture plants in districts having a name for fattening. In attempting to imitate nature, and replace the lost natural pasturage by sowing down, as in England, general mixtures of grasses, colonists have met with little success.
In the course of a few years the greater number of the grasses are found to have disappeared, leaving only the most robust, or those which by growing all the year round eventually extinguish the more delicate, which, are, usually, also the most desirable. Whilst, therefore, pastures of English grasses can be easily formed, they are found wanting in variety of food—an element of the greatest importance in maintaining the health of the stock. They supply a great abundance of rank and watery food, instead of the more moderate quantity of sweet and healthful food afforded by the native pasturage.

Seeing, then, the importance of maintaining the health, of our stock, the preservation of the native grasses becomes a matter of the first moment, especially to residents in the warmer districts, in which the so-called English grasses will not thrive. It has been remarked that when once the native grasses are gone a full sward can never again be established. Graziers, therefore, should conserve the pastures, and in order to succeed in doing this they will find it necessary to give some little attention to the habits of the several species as regards longevity and time of seeding. The winter grasses, for example, seed in spring; the summer ones later in the season, and at different periods of the summer and autumn. Unless these points are known and regarded, some important grasses will very soon become extinct, even in pastures which are allowed a season of rest from stock, with the object of permitting them to shed a crop of seed. It is obvious that unless the latter plan be adopted the alternative one of sowing native grass seeds must be pursued, and hitherto this has been out of the question, no such article having been upon the market.

The business of growing Australian grass seeds might surely afford profitable work for many farmers in different districts. Harvesting would, for the most part, take place before the grain harvest commenced; the late grasses would not be ready until after that work had been concluded. We can hardly imagine any line in which more could be made with certainty than in growing crops of native grasses specially for seed. Men of intelligence and good powers of observation would readily determine what species ripen simultaneously, and might, therefore, be grown together. The first matter is to collect sufficient seed by hand, and the present time is the season for commencing."

You can see the original article at http://trove.nla.gov.au/ndp/del/article/2982085

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