Byron Flora and Fauna Study 1999 - Byron Shire Council

A GREENPRINT FOR A SUSTAINABLE FUTURE
Further monitoring showed that several more species disappeared 10-20 yrs after fire including Leptomeria
acida and Twisted Parrot-pea. All the shorter-lived species dropping out of the community were obligate
seeders with soil seedbanks. By 30 years soil seedbanks would probably be starting to decline (perhaps
significantly). Therefore, 25-30 years was suggested as a suitable threshold (maximum interval between
fires) for the majority of heath species. Recommended fire thresholds were being exceeded for some vegetation
types in some parts of the Reserve, resulting in a change from open heath communities to closed vegetation.
With a general trend to greater fire control and fire suppression in rural farming lands, State Forest and
National Park, society is probably causing a fundamental change in a fire regime which has existed for
thousands of years. Overall, we are witnessing a reduction in fire frequency and intensity in the landscape.
At the same time frequent fuel reduction burns particularly around human habitation now occur far too
frequently to be compatible with the maintenance of biodiversity. These changes in fire regimes are occurring
for pragmatic reasons, generally without consideration of the ecological consequences. A great deal more
research is needed into fire and its effects on flora and fauna communities and biodiversity generally, to
achieve scientifically informed fire management planning.
7.5 GRAZING
Ecological problems associated with pastoral activity may include increased nutrient run-off and contamination
of surface water run-off from pastures, particularly improved pastures which are regularly fertilized. These
problems are exacerbated when the riparian zone has been disturbed, degraded or destroyed by clearing
and/or grazing. When stock are permitted access to river banks, riparian ecosystems may be further degraded.
Long term native vegetation and fauna habitat loss may occur in paddocks where isolated trees or clumps of
vegetation fail to regenerate because of grazing in the understorey (Christoff and Wishart 1994).
Where stock have access to remnant vegetation, weed invasion may be severe as a result of the seeds of
pasture weeds being carried into the forest by grazing animals, and because the disturbance created provides
ideal conditions for weed establishment. Regeneration of native vegetation is reduced or prevented. Grazing
removes the seedling bank in the understorey, and the soil is compacted.
While there are no local quantitative data on the impact of grazing, the range of effects described is apparent
wherever unrestricted grazing occurs throughout the Shire. Vegetation of high conservation significance
requires fencing. Trees such as figs should be planted, and together with other regeneration sites in grazed
areas should be fenced so that replacement occurs as trees in paddocks senesce.
7.6 PREDATION BY INTRODUCED ANIMALS
Predation by introduced animals has been identified as a major cause for declines in native fauna populations.
In Byron Shire the Cane Toad, feral/domestic Cat Felis catus, the Fox Vulpes vulpes and the domestic Dog Canis
familiaris have contributed in varying degrees to local population declines in many vertebrate species. Those
which have suffered the greatest impact include the large snakes, terrestrial frogs, ground-foraging and
nesting birds and small and medium-sized terrestrial mammals.
The establishment of introduced and feral predators in an area is usually facilitated by human activities.
These include roading through previously intact areas, patch clearing within stands of native vegetation and
simplification of vegetation structure by removal of understorey, together with the removal of logs, rocks
and vines.
With respect to Threatened species Cats are known predators of the Common Planigale (Redhead 1995)
and Common Blossom-bat (S. Phillips pers. comm.) and are also likely to be a threat to slow-flying, lowforaging
microchiropteran bat species such as the Eastern Long-eared Bat (Hoye 1995). Domestic Dogs are
considered one of the principal causes of Koala population decline in and adjacent to urban areas (Smith
and Smith 1990) with more than 50% of Koalas attacked by domestic Dogs being fatally injured
88