When planning to revegetate an area, it is
worth visiting patches of remnant bush, to get an idea how the trees,
shrubs and ground plants have changed on your land over the past 200
years. In the mountain and foothills in the east of the guide area, one
can easily find patches of bush which contain lots of native plants, and
without too much trouble, we can develop a mental picture of what
reasonably ‘natural’ bush looks like. On the plains, however, it can be
hard to find a natural looking remnant, and it can sometimes be almost
impossible to determine how much the land has changed over the past 200
years, as very little is left to indicate changes in the past.
Woodland remnants on public and private land
serve many important functions, including soil and water conservation,
habitat for plants and animals, sources of native seeds for future
revegetation, and to provide a model to guide revegetation efforts. These
remnants are also important for our local history and heritage, as they
are the only places where our children can see what the region looked like
when the first white explorers and settlers entered, and how we have
altered the landscape since then.
So where can such sites be found on the
plains? Most of the best woodland remnants are small, hidden between the
extensive crops and grazed paddocks. Not surprisingly, most native plants
tend to survive in places which have escaped past development, and which
have not been ploughed, fertilised or continuously grazed. Typical sites
include small cemeteries, along railway lines and little-used travelling
stock reserves, and on some stream frontages. Often the grassy areas
within country airports and race tracks contain many plants which have
vanished from the surrounding region.
A number of botanists have studied the plains
and have described general changes in the landscape. They have found that
the most important activities which have caused losses of native plants
are continual grazing or grazing at high stocking rates, soil disturbance,
fertilisation and water run-on, all of which deplete native species and
promote exotics, including many weeds.
When an area which has rarely been grazed by
stock gets grazed more intensively, the first species to disappear are
those which the stock prefer to eat (the palatable species), and which
cannot survive being continuous grazed down. Gradually, other species
decline and disappear, and at the same time many introduced species
become more abundant. As most native woodland plants are perennials and
many exotics are annual, the overall effect of increasing grazing is to
change a woodland remnant dominated by perennial species to a degraded
site dominated by introduced annuals. Many palatable native shrubs also
disappear, removing habitat for nesting birds. Most people are so used to
seeing roadsides and neglected paddocks dominated by tall weeds, that it
is a surprise to discover that many small, undisturbed patches of bush
actually are very good at resisting weed invasion, until the remnants get
disturbed, after which the weeds then move in.
Because of the magnitude of the landscape
changes over the past 200 years, it is often difficult to be confident
about which native species originally grew in a particular place 200 years
ago. Over most of the White Box woodlands, the landscape appears to have
been relatively open originally, with scattered shrubs and a grassy
understorey. The original grasses were not the Oats and Phalaris which now
dominate most roadsides in the region, but the native Kangaroo Grass and
Tussock-grass. Kangaroo Grass is rapidly eaten out under moderate stocking
levels, and has disappeared from all but small areas. Many of the native
grasses which are most often observed nowadays, such as Red-grass and
Purple Wire-grass, probably became more common as Kangaroo Grass and
Tussock grass were eliminated.
To many people, the simplest way to identify a
high quality woodland remnant is the wealth of native wildflowers which,
in a good season, can cover the ground in a carpet of colour. It is a pity
such species have disappeared from our roadsides as they would make a
colourful display, far more preferable to the bands of Paterson’s Curse
and Capeweed. In spring, many small cemeteries are bejewelled with the
yellow Everlastings and Scaly Buttons, erect spikes of Creamy Candles,
Purple Donkey-orchids, nodding yellow Yam-daisies, and sprays of Native
Bluebells. Not surprisingly, many gardeners and local councils are using
many of these plants in colourful garden beds.
The south-west slopes region does not contain
a large number of species which are nationally rare or threatened.
Instead, the extensive foothill and plains land systems contained many
widespread species which also occurred in many other regions. Nowadays, it
is important not to focus too much on Nationally rare or threatened
species, simply because (by definition) these plants occur in very few
places and are absent from many otherwise important remnants. In most
places, a more important focus is the large group of species which
tenuously survive in many cemeteries, railway easements, stock routes and
the odd, lightly grazed paddock, because these species represent the core
natural heritage of the woodlands of the south-west slopes region.
Regrettably, many of these species are still slowly declining throughout
the region (an in many other regions as well), as many small remnants are
unwittingly degraded or destroyed.
By appreciating and protecting the small
remnants which survive in the region, we can save our own local history
and natural heritage, plus the seed supplies and natures models for future
revegetation efforts. Fortunately, most remnants can be protected very
simply, by ensuring that the soil is not disturbed or dug, that fertiliser
and water run-on are excluded, and that grazing levels are not increased.
No doubt, future revegetators will doubly respect our efforts to conserve
these natural seed sources now.
Species mentioned above
Creamy Candles - Stackhousia
monogyna
Common Everlasting -
Chrysocephalum apiculatum
Kangaroo Grass - Themeda
triandra
Native Bluebells - Wahlenbergia
species
Purple Donkey-orchid - Diuris
dendrobioides
Purple Wire-grass - Aristida
ramosa
Red-grass - Bothriochloa
macra
Scaly Buttons - Leptorhynchos
squamatus
Tussock-grass - Poa
sieberiana
White Box - Eucalyptus
albens
Yam-daisy - Microseris
scapigera
Further
reading
McBarron, E. J. (1955). An enumeration of
plants in the Albury, Holbrook, and Tumbarumba districts of New South
Wales. Contributions from the New South Wales National Herbarium
2, 89-247.
Moore, C. W. E. (1953). The vegetation of the
south-eastern Riverina, New South Wales. I. The climax communities.
Australian Journal of Botany 1, 485-547.
Prober, S. M. and Thiele, K. R. (1995).
Conservation of the grassy white box woodlands: relative contributions of
size and disturbance to floristic composition and diversity of remnants.
Australian Journal of Botany 43, 349-366.
This article was first published as:
Lunt, I. (1998).
Protecting our wonderful woodland remnants. In: From Little Things Big
Things Grow ... South-west Slopes Revegetation Guide. (Ed F.
Stelling), pp. 12-14. (Murray Catchment Management Committee and
Department of Land and Water Conservation: Albury).