Biodiversity Strategy - Gosford City Council - NSW Government

Almost thirty key threatening processes are now identified at a State and Commonwealth level.
These include predation by introduced species such as the European red fox, feral cat and by
plague or Mosquito Fish (Gambusia holbrooki). Others are competition and land degradation
from introduced species (such as feral rabbits, goats and honey bees), clearing and degradation
of native vegetation including riverbank vegetation, invasion by introduced plants (such as bitou
bush and exotic grasses), entanglement and ingestion of debris such as plastics by marine
animals, high frequency fire and human induced climate change. Finally, it is noted that
pressures that have been identified may alter in level of threat and new issues may emerge,
especially as scientific knowledge develops. These are some of the major challenges for
Council in its role of managing and protecting biodiversity in Gosford City.
Figures 7.4-7.6
Stormwater channel in Somersby area that leads to Piles Creek, weed invasion by
climbers in bushland area and a degraded natural creekline.
A - 7.2
Habitat Loss and Fragmentation of Native Vegetation
Increasing fragmentation and loss of remaining bushland areas increases the pressure on
native species. This occurs both directly from loss of habitat and food resources and from more
indirect pressures such as the inability to migrate to other suitable areas in times of fire and
drought, or for species to interbreed. New bushfire regulations have also resulted in the need for
greater cleared areas around properties, leading to more habitat loss.
Vegetation mapping recently undertaken for GCC by Bell (2004) demonstrates the increasingly
fragmented nature of bushland areas, particularly in the coastal parts of the City. As
development pressures and property values increase native vegetation in the Central Coast is
continually being lost. Increasing fragmentation including tracks and roads through or adjacent
to vegetated areas also leads to declining health of remnant vegetation through impacts such as
edge effects and increased weed invasion. “Edge effects” are also the result of fragmentation
whereby bushland areas close to urbanisation are more vulnerable to impacts such as weed
invasion. Roads, particularly major roads and freeways, railways powerline and other
easements generally contribute to a loss of biodiversity. Foxes, for example, favour roads and
tracks as movement corridors. As well as the direct loss of animals killed on roads, road kills
may also impact significantly on native species as they attract predators such as foxes to feed
on roadkill.
Some vegetation communities are also more vulnerable to impacts from fragmentation, edge
effects and increased frequency of bushfire. Also many areas of remnant vegetation occur on
private lands and often do not have an appropriate landuse zoning. Eventually these remnants
will be lost through gradual incremental losses associated with development and landuse. Even
properties that are largely vegetated or have a good canopy of mature trees over time are
degraded through clearing and modification for land uses associated with residential use. These
include landscaping around houses, horse or other grazing on rural properties, construction of
sheds and other structures around the dwelling, paving, swimming pools and tennis courts and
the like. Unauthorised underscrbbing and unauthorised grazing also occurs on Conservation
(7a) zoned lands.
Biodiversity - Technical Report Page 154