What is biodiversity?
Biodiversity is the variety of all life forms – the different plants, animals and microorganisms, the genes they contain, and the ecosystems of which they form a part. The level of diversity is not fixed, but rather dynamic, increased by genetic changes and evolutionary processes, and decreased by extinction and habitat degradation (DEH 2004).
Impacts on biodiversity
Population growth in the region, particularly on the coast, continues to result in greater demand for development. This causes subsequent pressure on biodiversity due to land clearing for residential and rural residential developments. Land clearing and modification for rural activities, including agriculture (primarily cattle grazing) also apply direct pressure on biodiversity.
Further pressures placed on biodiversity in the Shire include the prevalence of exotic weed species and feral animals. Introduced plants that result in weed infestations including noxious weeds and garden escapees are a major threat to biodiversity in the Kempsey Shire. Exotic species of particular concern especially in riparian zones include Camphor Laurel, Willow, Large-Leaved Privet, Small-Leaved Privet, Wandering Jew, Blackberry, and particularly Lantana that was prevalent at all sites surveyed within the Shire. Exotic species applying the most significant pressure in biodiversity in high conservation areas of National Parks estate, primarily in the coastal region, are Bitou Bush and Lantana.
Feral animals apply a significant amount of pressure on native fauna and flora and therefore the overall biodiversity in the region. Some have been listed under the TSC and EPBC Acts as Key Threatening Processes (KTPs). KTPs occurring (or likely to be occurring) in the region in relation to introduced animals include:
- Competition and land degradation by feral goats;
- Competition and land degradation by feral rabbits;
- Predation by feral cats;
- Predation by the European Red Fox;
- Predation, habitat degradation, competition and disease transmission by feral pigs;
- Competition from feral honey bees; and
- Predation by Gambusia holbrooki (Plague Minnow or Mosquito Fish).
Feral animals of particular significance known to exist in the Shire, include; hares, rabbits, foxes, black rat, brown rat, common mouse, feral cats, starlings, Indian Myna birds, house sparrows, mosquito fish, goldfish/carp, trout, European honey bees and feral dogs and cross-bred dingoes.
The Indian Myna Acridotheres tristis is a medium-sized, dark brown bird with a black head and neck, and a yellow beak, eyepatch and legs. White wing patches are obvious in flight.
Mynas were introduced to Australia in the 1860s to control insects in market gardens. Since their introduction, Myna populations have spread along the east coast of Australia and to New Zealand. They are aggressive, territorial, and compete with native birds for food. They attack smaller birds and animals.
Macleay Landcare is running an Indian Myna Control Project with the help of a grant from the NSW Environmental Trust. For help with trapping Indian Mynas or to assist with the monitoring program contact:
Ph: 0428 864 465
- Wanted - The Indian/Common Myna - poster (PDF - 161 KB)
- Indian Myna Control Program - poster (PDF - 201 KB)
Bushfires also impact on the biodiversity of the Shire. Fire is a natural process to which native animals and plants have adapted to. Groups of animals and plants that constitute an ecosystem respond similarly to fire according to the characteristics of their life-history. Many small mammals and most birds breed in Spring and Summer (commonly the fire period). As burned areas regenerate, different species find suitable habitat at the various levels of regeneration. Changing fire regimes have been associated with the decline of many biological communities. The correct management of fire is thus essential to avoid disruption of ecosystems and extinction of species.