VEGETATION MANAGEMENT PLAN for Bidjigal Reserve - Land

Vegetation Management Plan - Bidjigal Reserveother invaders that are capable of rapidly displacing native species and destroying habitat, evenwhere the bushland has not been disturbed or unduly impacted. The latter are described as‘ecosystem modifiers’ and for the purposes of this Report are termed ‘keystone’ or ‘primary target’weeds (see Section 7.7 Weed Ecology).Survey results set out in Section 5 of the VMP provides a list of keystone weeds for the individualManagement Units surveyed, while Appendix 10 provides species-specific recommendations forcontrol techniques.6.5 Edge EffectsSmall urban remnants are often linear in shape and with extended edge sites, and are usually badlyimpacted by weeds and other disturbances, and the more extensive the edge, the higher theimpacts are likely to be (see Table 3.2). Fragmentation of bushland by tracks and trails or servicecorridors produces much the same effect – i.e. a high edge to core ratio. Degradation at thebushland edge may result from inappropriate recreational activities, planting on neighbouringproperties, encroachments for gardens, storage or vehicle parking or access, dumping, disposal oflawn clippings and garden debris, as well as overzealous under-scrubbing or clearing for bushfirehazard purposes.Where grassed parkland meets bushland (e.g. around sporting ovals or managed parkland), mowercreep - where the operator moves progressively, and usually unintentionally, further into thebushland over time - is another common cause of degradation on edge sites. This is of particularconcern as regenerating seedlings of shrubs and trees are continually destroyed, and communitystructure is altered over time. The shading canopy is gradually lost and the ground layer is subject toincreasing light levels. This encourages the invasion of light-tolerant grasses and herbs.Fragmentation of bushland and the resultant increase in edge to core ratio also has implications fornative fauna. In suburban areas, species such as Noisy Miners (Manorina melanocephala), Magpies(Gymnorhina tibicen) and Pied Currawongs (Strepera graculina) are common. These aggressive birdsexploit disturbed sites, and may exclude other bird species. Other urban tolerant species such assome of the bat species and the Brushtail and Ringtail Possums (Trichosaurus vulpecular &Pseudocheirus peregrinus) increase in numbers as the availability of habitat sites increases, so thatthey often congregating in residential areas and (for some residents at least) cause a nuisanceand/or damage the urban amenity.Apart from this direct impact on avifauna biodiversity (as well as other interdependent species), treehealth can also be affected, as the smaller birds are effective controllers of insects (e.g. leaf lerp).Therefore, attenuation of fragmentation and edge effects and the restoration of habitat complexityshould be one of the principle objectives of any bushland restoration.6.6 Creation of Buffers and Interface ZonesThe establishment of vegetated buffers at the interface between bushland and managed open space(e.g. parks/recreational or sporting fields) is strongly recommended. Such buffers are proposed inUBM Ecological Consultants Pty Ltd 121