VEGETATION MANAGEMENT PLAN for Bidjigal Reserve - Land

Vegetation Management Plan - Bidjigal ReserveCRITERION BACKGROUND METHODOLOGY FOR FIELD RANKING LIMITATIONSEcological and Heritage Conservation Significance3) Moderate infestation - high percentage of weeds in ground layer andmoderate percentage in mid. No weeds in upper layer (1.6)4) High infestation - high percentage of weeds in lower and mid layers(1.8)5) High-extreme infestation, high percentage of weeds in lower and midlayers, moderate percentage in upper layer (2.3)6) Extreme infestation in all layers, severe management issue (2.8)Threatened Flora andFauna SpeciesLevel of Management Assessment: UnitPriority was given to the sites with the highest number of listed threatenedspecies (TSC Act, EPBC Act) recorded in the site/locality to ensure that anylocal populations of these threatened species are protected and maintained.However, it should be noted that the removal of dense weed thickets suchas those created by Lantana will need to be undertaken progressively, asthese provide habitat for some native fauna, particularly small birds. Broadscale clearance may result in the displacement of threatened and otherfauna if it is not undertaken in a staged manner, which allows thereinstatement of habitat (through natural regeneration or planting).In order to retain populations of small birds in Lantana-infested habitats(which generally are slow to regenerate because the chemical compositionof the underlying soils have been altered), the removal of the vegetationshould be carried out in small (< 20 sq metres) patches and these thicketsreplaced with native plantings of similar structure and form.This criterion analysis was based on threatened species records providedby DECC and records made in the field survey. The occurrence of athreatened species within each Management Unit was recorded.Records of the number of individuals were not used in the priorityranking assessment.A ranking of priority was given for categories of threatened speciesoccurrence (see below). The threshold number of sightings for eachscore were determined to form a fairly even spread of the sites over thescores, thereby creating a high level of score differentiation between thesites.1) Known occurrence of 1 threatened species2) --3) Known occurrence of 2 threatened species4) --5) Known occurrence of >3 threatened speciesNote: the Powerful Owl is known to occur or very likely along allcreeklines within the Reserve and therefore was included in everyRiparian Management Unit. Other sightings of the Powerful Owl werealso included where UBM has been informed by members of the Trust.Highly mobile threatened fauna species are likely to utilise all of theManagement Units within Bidjigal Reserve however only those units wherethreatened species have been previously observed or were recorded duringthe current survey were included in this assessment.Threatened EcologicalCommunitiesLevel of Management Assessment: UnitThe presence of a threatened plant community determines a high priorityfor protection, rehabilitation and maintenance. Left untreated, over time,weed invasion may alter the habitat to such an extent that the survival ofthe significant plant community is unlikely.Therefore, the highest priority was given to sites where a threatenedecological community occurred.This criterion was based on Tozer et al. (2006) and follow-up groundtruthing during surveys. The area of any of the following communitieswithin the Management Unit were calculated: Sydney Turpentine-Ironbark Forest and Cumberland Shale/Sandstone Transition Forest;1) Threatened communities occupy < 1 ha of site2) Threatened communities occupy 1 - 1.5 ha of siteThe level of rarity/threat to threatened ecological communities was notconsidered. All threatened ecological communities were considered equallyfor this criterion.Catchment ManagementPosition on Slope/LandscapeLevel of Management Assessment: UnitSites that are located on ridges are generally given priority for weed controlas weeds spread from their origin downslope and/or downstream. If weedysites lower in the landscape are worked first, they are more likely to bereinfested from upslope sources. Working from ‘top to bottom’ is oftendescribed as the Total Catchment approach to bushland rehabilitation.A visual assessment was made during the field survey which was thenchecked against contour data. The following list identifies the criteria forpriority assessment:1) Gully2) --3) SlopeEach position in slope category was not quantifiably defined, which mayhave caused errors in the assigned score.Some sites filled the entire range of categories (i.e. gully to ridge).Did not give an accurate measure of what sites occur upslope from others(e.g. if 2 sites occurred in the same gully, it did not give priority to theUBM Ecological Consultants Pty Ltd 41