The Vertebrate Fauna of Jenolan Karst Conservation Reserve: Final

6.4.6 Environmental degradation, competition and disease transmission by pigs
Pigs are known to depredate and
compete with many native species.
Significant environmental damage is
caused by pigs excavating food sources
on waterways. Pigs are currently in
medium densities in JKCR and are
capable of reaching high densities in the
absence of control. Erosion,
sedimentation and water eutrophication
caused by pigs can have an indirect
impact on cave-dwelling species and
the cave system and this is discussed
further in the cave-dwelling fauna
section 9.
6.4.7 Weed invasion
Invasive introduced plant species
impact on fauna by degrading habitat,
reducing forage, polluting water and
blocking cave entrances. Leaf litter from
exotic plants has been shown to support
a different invertebrate assemblage at
JKCR to leaf litter from native plants
(Hills et al. 2008).
Piglets, pig damage and a red-bellied black snake caught on a
remote camera at Surveyor’s Creek Weir. Photo © OEH
There are many escaped garden plants that are causing problems at JKCR that originated from the
exotic gardens around Caves House. A key problematic species is the sycamore maple in the
Surveyors Creek catchment. These trees form a dense monoculture, providing substandard habitat for
fauna when compared to native forests. As an alien deciduous species, heavy leaf fall may also
change the chemistry of the water in Surveyors Creek, potentially impacting on aquatic fauna, the
karst and Blue Lake. Removal of sycamore maple presents a challenge due to the steep slopes and
erosion risk once trees have been removed. Furthermore, the adjoining pine plantations mean that
invasion by radiata pine is an ongoing threat.
Riparian weeds also occur in high densities at JKCR. Riparian weeds change the habitat values of an
area and may impact on water quality. Dense riparian weeds, such as periwinkle are infesting areas
downstream from the brush-tailed rock-wallaby population and may reduce the availability of foraging
habitat and ability for this colony to expand.
6.4.8 Environmental degradation and competition by feral goats
Goats remove large volumes of vegetation and disturb soil, resulting in erosion, slope destabilisation
and other environmental damage. Goats are able to access and overgraze steep rocky slopes which
are particularly prone to erosion. Goats are currently in medium densities within JKCR with ongoing
control programs aiming to keep numbers to a minimum. Key potential impacts in JKCR are on the
brush-tailed rock-wallaby with which they compete for food and shelter. Erosion and sedimentation
can have an indirect impact on cave-dwelling species and the cave system and this is discussed
further in the cave-dwelling fauna section 9.
6.4.9 Environmental degradation and competition by feral deer
The spread and establishment of feral deer in JKCR will result in environmental degradation and
competition with native herbivores. Red and fallow deer are currently uncommon at JKCR with
ongoing regional control programs. Deer impact on native fauna both directly and indirectly as follows:
through the degradation of vegetation by grazing; by trampling of fragile habitats; by interfering with
brush-tailed rock-wallaby or bat roosts in caves (rusa deer shelter in overhangs) and through the loss
of viability of plant populations through the curtailment of seed production and seedling recruitment
(Keith and Pellow 2005). Furthermore, overgrazing can cause erosion and sedimentation which may
have an indirect impact on the cave system - discussed further in the cave-dwelling fauna section 9.
6.4.10 Environmental degradation and competition by rabbits
Rabbits remove vegetation both above and below the ground, disturbing soil and causing
environmental damage. At JKCR rabbit numbers fluctuate though they are mostly confined to
disturbed grassy areas. Rabbits have been identified as competing for food with the brush-tailed rock-
The Vertebrate Fauna of Jenolan Karst Conservation Reserve 95