WfHC - cover page (not to be used with pre-printed report ... - CSIRO

een uninhabited during the wet season during recent times, people are not present in this
model.
A second major feature of this model relates to the movement of animals, as the water has
different impacts on different species. The animals are classified according to two categories,
whether they are native or introduced, in addition to the level of significance water has for
their movement and distribution. Although not comprehensive or always accurate, this
generates four useful working categories at the height of the wet season:
Aquatic animals – these are able to move and migrate freely up and down
watercourses during the wet season. Therefore movement is highly enabled by
abundant surface water.
Cattle and horses – Although initially able to take advantage of fresh feed and more
abundant water at the start of the wet season, these large, heavy, hard-footed,
introduced animals must avoid boggy ground. Therefore at the height of the wet they
must leave the area or remain on high ridges, including the homestead site.
Therefore movement is heavily constrained by boggy ground.
Other introduced land animals – this category is primarily oriented to pigs, which are
less constrained by boggy ground than cattle and horses above, but nevertheless
have a landscape impact. It also includes adult cane toads 36 and cats. Movement by
these animals can be mildly restricted by boggy or flooded ground and/or mildly
enabled by abundant surface water depending on the circumstances.
Native land animals – primary focus of this category is animals like kangaroos,
goannas, dingoes and birds. This group is separated from category three because of
category three are non-natives and may have consequent negative effects. In terms
of movement, this category is similar to the other land animal category - movement is
mildly restricted by boggy or flooded ground and/or mildly enabled by abundant
surface water.
This model suggests patterns and relationships between animals and water at the most
general and functional level. The onset of the wet season sparks an initial dispersal of all
terrestrial animals, but then the boggy ground has particular implications for some introduced
species; they are re-concentrated on high ground or leave the area completely. Physically
lighter and/or more water tolerant species have different patterns of movement, having a less
constrained and distinct pattern (and in some cases, no major discernible change at all). In
terms of erosion processes, rainfall and surface runoff are the main source of soil erosion,
but the presence of animals, particularly cattle, pigs, and horses, can initiate erosion or
increase its effects during the wet season, and this process is incorporated into the model.
Other factors contributing to soil erosion (inappropriate fires, road use, weed dispersal, etc.)
are incorporated more fully the dry season models of subsequent sections.
36 No grouping system can be entirely adequate, and it should be noted that juvenile cane toads in
particular are aquatic animals and may be transported during high flow periods. Foxes are an
important introduced predator in many areas of Australia, but dislike boggy ground. Rabbits are also
not found in significant numbers.
Working Knowledge at Oriners Station, Cape York
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