Biology Reference
In-Depth Information
Box 2.3.
Is fallen timber on a farm good or bad?
Prior to European settlement, temperate woodlands naturally supported large vol-
umes of fallen logs, sometimes exceeding 200 cubic metres per hectare. 3, 23 As
discussed in this chapter, many native species have evolved to use this habitat
resource. Some people believe that having fallen timber on a farm is a problem that
should be 'cleaned up'. After all, isn't it fuel for fires and a haven for pests like the
European Rabbit and the Red Fox? Large logs are not fine fuels that readily ignite
and spread fires. Rather, they often act as micro fire-breaks and can limit the spread
of fire. It is true that large logs can shelter rabbits and foxes; but addressing this
problem requires the destruction of these pests through approaches other than
removing logs, such as laying poison baits and ripping warrens (but see Box 5.3 in
Chapter 5). Controlling pests like foxes will not only benefit native wildlife, but have
benefits like increasing the survival of lambs. Fallen timber can also provide impor-
tant shelter for stock, particularly ewes and lambs.
Another way to promote the development of an
understorey layer is to deliberately establish it by
underplanting. We have established an understorey layer
of shrubs and trees in a series of remnants on the South
West Slopes of New South Wales as part of a partnership
project between local landholders, The Australian
National University and the Murrumbidgee Catchment Management Authority (see
Figure 2.6). This underplanting work was done because previous work had indicated
that the absence of a natural understorey was a factor limiting populations of native
birds, and a trial program was instigated to test the response of a number of bird
species of conservation concern. Such shrubs are best established in thickets, leaving
some open areas between the thickets. The experiment has not yet been running
long enough for there to be definitive results, but early indications are that there are
positive conservation outcomes from this work.
Limiting overgrazing by
livestock and rabbits is
a good way to manage
the understorey layer of
woodland remnants
Box 2.4.
Wattles and worms
The value of understorey vegetation for many native animal species has been well
established. Wattles, however, have many other surprising roles that can influence
farm enterprises. Because wattles are nitrogen-fixing plants they can promote the
growth of surrounding trees such as eucalypts. A particularly unexpected effect of
wattle has emerged from work conducted in Brazil, which has shown that con-
densed tannins from the Black Wattle significantly reduce the numbers of intestinal
parasites in sheep. 24
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