Biodiveristy_State of Environment report - Mission Beach Cassowaries

2.1.1 Representation andRestorationPressureLand clearing is still occurring acrossall habitat types on land of more gentletopography. The rate is negligiblecompared to the original deforestationof the Shire for agriculture and timber.Table 2.1.1a describes land-clearingrates since 1995. Land clearing hascontinued to slow over the last twelveyears. Whilst clearing for crops hasslowed, there is a slight increase inclearing for cattle pasture. Nativevegetation covers 62.06% of the Shire. This is becauselarge areas are under protection by the WHA, which has anarea of 47% of the Shire. Approximately 15% of nativevegetation exists outside the WHA on private land; the rest(38%) has been cleared. Compared to other areas inQueensland these figures are very good. However, thereare problems with the representation of some endangeredecosystems.Isolation, Fragmentation and ConnectivityThe figures in the Table 2.1.1a do not detail the furthereffects associated with land clearing - isolation,fragmentation, and connectivity.The isolation of islands of vegetation amongst cleared landlimits the movement of many flora and fauna betweenareas of remnant vegetation. These species are then subjectto pressure from inbreeding, and where localised 'disasters'occur there are no new colonists to replace a lost species.This further affects other species 'on the island' when a lostspecies was an important part of the ecosystem.Fragmentation is similarly associated with land clearing.Fragmented vegetation results where in-roads have beenmade into what used to be a consistent area, resulting in amosaic of vegetation, much like the strands and patchesholding together a very worn piece of cloth. Fragmentationenhances the 'edge effect' on remnant vegetation. Edgeeffect describes the vulnerability of vegetation to externalinfluences. Some of these influences include; weedinvasion, cyclone damage and effects from the adjacentland use. Edge effect is worst where the remnantvegetation has a small area with a long boundary, i.e.where it is thin and spidery as opposed to fat and solid.Connectivity describes how well the remaining vegetationis linked. Connectivity problems are common in thefoothills west of Innisfail where topography has limitedland clearing to the flatter areas that are more suitable foragriculture; leaving many of the steep ridges, deep gulliesand rocky areas vegetated. Connectivity affects flora andfauna when large areas of cleared land exist, which speciesare unable to bridge in order to colonise or utilise nearbyareas. A lack of connectivity has resulted from landclearing, most obvious in separating the coastal ecosystemsfrom the range. Low connectivity affects genetic exchangebetween fragmented ecosystems, and can form a barrier inlifecycle events such as the dispersal of progeny ormigration.ConditionRepresentation of Regional EcosystemsWhilst there are large areas of protected vegetation in theShire, there are also a large variety of ecosystem typespresent. Not all of these ecosystems are representedequally, and some are classified as endangered becausethere are only small areas left throughout the State.The EPA has classified native vegetation throughout theState into groups based upon the ecosystem's floristiccomposition, the underlying geology, and climate.The types of regional ecosystems and their conservationstatus are defined under the Queensland VegetationTable 2.1.1a - Land Clearing in the Shire Source: NR&M (2003)Total Area ~164,000 ha % Wooded vegetation cover 2001(WHA = 47%)Year New Pasture Crops Forest Mining InfrastructurewoodyregrowthSettlementTotalCleared% Woodedvegetation cover2001(WHA = 47%)01-03 nd 22 2 0 0 1 0 25 62.06 2 (15.06) 0.0099-01 0 15 8 0 0 2 0 25 62.41 (15.41) 0.004397-99 2 7 21 1 0 0 0 30 62.43 (15.43) 0.00795-97 5 7 86 0 0 0 3 96 62.49 (15.49) 0.02891-95 1 0 0 120 0 0 2 1 123 62.56 (15.56) 0.042nd – not determined1 Double time period2 Updated accuracy of satellite imagery also contributing to this revised figure% Totalclearing inQld27