Dealing with salinity in Wheatbelt Valleys - Department of Water

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• buffering remnant vegetation with fringe
plantings;
• revegetation of drainage lines and other features,
thus connecting and expanding habitat;
• numerous other actions to start restoring a
benign hydrology (see Table 1).
However, actions to maintain diversity could be
improved. For example, revegetation within the
Toolibin Lake Nature Reserve concentrated on
establishing trees of local provenance that have high
water use. It was intended that understorey species
would also be introduced, but this has not yet been
undertaken. It is interesting to speculate whether
introduction of understorey would decrease current
problems with parrot and insect damage to
revegetation. This shows that while the broad aims
of actions are sound, they can be better targeted to
achieve diversity, biological control, and resilience.
Also, many plantings in the catchment are not based
on local or regional species. Thus revegetation
works have not always been undertaken in a way
that maximises biodiversity conservation values.
Similar comments apply to diversity of farming
enterprises in that, while a much greater range of
farming systems is being tested, general application is
limited. The goals are correct, but research,
development and adoption are far from adequate.
Also, the commercial potential of revegetation has
not always been maximised.
Manage water, energy and nutrient cycles
While implementation has only begun and there is a
long way to go, we can claim that we are moving
towards a much more benign hydrological system.
The challenge is to ensure that this happens with
sufficient speed to be effective in recovering nature
conservation and production values. In contrast, we
poorly understand energy and nutrient cycles. A sign
that these cycles need management attention was
the first outbreak of waterbird poisoning at Toolibin
as a result of eutrophication in March 1993.
Recognise that our environment is one of extremes, and
manage accordingly
To date we have only achieved this in a very limited
way. The best example is that our most recent
engineering structures have been designed to fail,
during large or extreme events, in a way that
minimises damage to structures and associated land
uses. This is an important step, but there is much
– 6 –
further to go. As suggested above, we could
increase the resilience of the system by diversifying
our revegetation systems, for example, by
introducing more understorey species. It can be
expected that ecological resilience will also favour
the economic resilience of agriculture.
Manage according to natural boundaries
There are no concrete data on changes in farming
practice within the Toolibin Catchment. However,
Jenny Crisp (pers. comm.) estimates (1996) that:
• 50% of farmers in the catchment are working to
contour, and that many grade and interceptor
banks have been constructed;
• 50% of landholders are working towards full
farming to soil types, however, this will take
many years to implement; and
• 90% of landholdings are covered by a farm plan.
These range from being rudimentary to those
that are sophisticated. Implementation and use
of plans is also highly variable.
Social, cultural and economic systems congruent with
achieving long term goals
This topic can be separated into those socio-cultural
and economic factors external to the catchment, and
those within the catchment (including stakeholders,
such as agencies, that live outside the catchment but
work within it).
External socio-cultural factors are beyond the scope
of this paper, and are not considered further here.
External economic factors have a profound impact,
mostly by determining, for example through farm
profitability, the level of resources that may be
applied on the ground. It is useful to note that
changes in relative profitability of farm products may
have very important influences on the ground. For
example, with the current (1998) drop in wool prices
and increased profits from cereal crops, revegetation
is indirectly favoured by decreased farm flocks and
increased cropping. This is because farmers are
more likely to plant seedlings and withhold paddocks
from grazing to protect the seedlings. However, the
same factors will also increase soil disturbance and
nutrient imbalances are likely to increase!
External factors will be similar across most of the
case studies covered in this publication. Of more
direct interest here are relevant socio-cultural factors
within the catchment. These are briefly considered