Vegetation Classification and Map

Of the 105 MUs described in the Lower Hunter by the GHVM, 70 (67%) contain plants in the nectar diet of GHFFs. Forests and woodlands that potentially produce nectar for the animals cover 56% of the region, or approximately 91% of extant vegetation.

When habitat nectar scores are calculated using only the species that flower in each bi-monthly interval, distinctive seasonal patterns become apparent in the extent, distribution and nectar characteristics of productive habitat. These patterns are consistent with the observed seasonal occupancy of camps in the region.

Plants in the fruit diet of GHFFs are found in 18 MUs, covering 4.4% of the region. Eleven of the MUs are classified as warm-temperate or dry-rainforest types, five are layered wet-sclerophyll or swamp-forest types that contain a sub-canopy with substantial rainforest elements and two are MUs dominated by Avicennia marina (Grey Mangrove). The species richness of dietary plants identified in vegetation profiles is notably low in all 16 MUs (Sommerville 2009). None contains >6 dietary species and the majority contain <4.

The highest bi-monthly rank for each of the nectar-producing MUs was taken as the final nectar rank for that type. Fruit-bearing MUs were allocated habitat score of 2 due to the poor diversity and low density of diet species they contain. Rank 2 habitats identify moderate conservation value foraging habitat for the GHFF. Moderate conservation value foraging habitat occurs over 20 % of the Lower Hunter and contributes significantly to the diversity of food available for the GHFF. Rank 1 habitats are considered as having high conservation value and cover 37 % of the Lower Hunter. These areas are the most productive and reliable foraging areas for the GHFF and the reason why GHFF can persist in the Lower Hunter. The data are summarised in Table 6.5 and the approximate distribution of ranked habitat is shown in Illustration 6.1. Bi-monthly ranks are shown in Illustration 6.2 and depict the general pattern of increased foraging resources in the warmer months between October and March. A complete set of data describing each MU appears in Appendix D.

Table 15.9Accuracy of GHMV Spatial Layer and Implications for the Assessment

Vegetation classifications and digital map layers are essential elements in the method used to assess foraging habitat for GHFFs. The classifications provide the template for quantifying the distribution and relative densities of dietary species across the landscape. Maps of ranked habitat allow areas of conservation significance to be identified spatially. This provides the capacity for data to be analysed in relation to a range of parameters relevant to land management and conservation planning, such as political boundaries, tenure, zoning and the outcomes of conservation assessments undertaken under other jurisdictions.

The accuracy of vegetation classifications and maps varies and none are perfect representations of extant vegetation. During the course of this work, issues with the accuracy of the GHVM spatial layer became apparent. The implications for mapping the locations of foraging habitat significant to GHFFs were tested using a sample of fixes from satellite-collared animals known to be feeding on Spotted Gum in the study area during May and June 2012 (J. Martin RBGS unpublished data). MUs associated with feeding fixes were identified from the GHVMv4 map and their vegetation profiles were scrutinised for the presence of Spotted Gum. A total of 38 feeding localities were assessed; 16 (42%) were associated with MUs containing Spotted Gum. Spotted Gum was not mentioned in the vegetation profiles attributed to 58% of localities. This can only be considered a superficial and notably incomplete assessment of the spatial accuracy of the map in the Lower Hunter study area. However, it introduces a level of doubt regarding the accuracy of spatial depictions of ranked habitats (Table 15.10 and Table 15.11).

Table 15.11Bi-Monthly Grey-headed Flying-fox Foraging Habitat Ranks based on GHMv4

Conservation Threats

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17.

Under the TSC Act and EPBC Act, several key threatening processes for the GHFF have been identified. An assessment of these processes was made with regard to their relevance to the Lower Hunter (refer to Table 17.2).

Food availability for the GHFF is reduced wherever clearing of forests occurs. In NSW clearing has been most extensive within the fertile coastal floodplains, with less easily accessible and arable lands in steep and mountainous areas often reserved for timber production and conservation. The Hunter Valley floor is the most heavily cleared area in the Lower Hunter, with 80% of native remnant vegetation now cleared and only 3% protected in formal reserves (DECCW 2009b). Similarly in northern NSW and southern QLD, clearing of the fertile coastal floodplains has impacted upon the availability of winter flowering resources, creating food shortages over winter that affect the entire GHFF population (Eby & Law 2008).

It is not possible to predict accurately how much GHFF habitat would be removed or impacted as a result of development associated with the LHRS (refer to Table 17.4). Design and assessment processes associated with development proposal approval would likely result in the retention of some of the extant vegetation within the proposed development areas. Complete development of LHRS identified areas could impact up to 7,416 ha of vegetation (based on GHMv4 mapping product). A full list of impacted vegetation types is provided in Appendix Table 24.1.

Table 17.4LHRS Identified Potential Development

Table 17.5GHFF Foraging Habitat Value within LHRS Development Areas

Rank	Across the Lower Hunter			Proposed for Development
	area (ha)	% region	n (MU)	area (ha)	% rank available	n (MU)
1	159,210	37%	57	6,588	8%	31
2	83,053	20%	23	459	3.1%	10

All vegetation mapping products carry some degree of spatial error and some accuracy issues have been identified with the GHMv4 mapping product (refer to Section Table 15.9; see also Kuginis et al. 2012, Sivertsen et al. 2011). Development of measures to reduce the loss of GHFF foraging habitat should be supported by field verification and correction of vegetation types mapped in the GHMv4 product, enabling analysis that would:

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  accurately quantify the loss of foraging habitat (using Appendix D and formulae provided in Section 6);
  
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  define where this loss will occur; and
  
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  through comparison of the loss to locally available foraging resources, predict the impacts to the GHFF.
  

The LHRS will also be updated over the next few years and alternative development areas may be identified. As a result of improved mapping products, field verification of the GHMv4 product or revisions of identified development areas arising from a review of the LHRS, the analyses provided in this study would require updating.

Development outside of LHRS identified areas has potential to impact on habitat availability for the GHFF. There are 276,934 ha of land within the Lower Hunter that, under respective LEPs, have social or economic values as management priorities. Within these areas, 139,247 ha are currently vegetated. A range of controls regulate clearing in these areas, including the Native Vegetation Act 2003 on rural land, and the Environmental Planning and Assessment Act 1979, in conjunction with the TSC Act and EPBC Act across all land. In some cases Council approval would also be required.

17.6.1Impact on Existing Camps

The GHFF can roost in urban areas, resulting in conflict with humans when close to residential or other sensitive development (e.g. schools, hospitals). Residents living within 100 m of a GHFF camp experience significant negative impacts associated with flying-foxes, whilst those located further are more likely to respond positively to a local flying-fox camp (Larsen et. al. 2002). Many camp management policies now recommend a buffer of at least 300 m between flying-fox camps and residential areas (SEQ 2012, Eby pers comm. in Roberts 2006, DSE 2011). Experience from management of conflict associated with urban camps across Australia clearly demonstrates that future development should avoid areas known to be used by roosting flying-foxes. This includes areas that have historically been used by roosting GHFFs, but show no sign of contemporary use.
Most of the areas identified for future development in the LHRS are further than 300 m from the nearest known GHFF camp. The only exception is land planned for residential development across Maitland Road, south of the East Cessnock camp. This camp currently occurs approximately 200–250 m from the proposed future urban area, however there is potential for the camp to move or expand south-easterly, until it reaches Maitland Road. At this point, the camp would be approximately 80 m away from the proposed residential area. Careful vegetation management, and the implementation of a supporting buffer between Maitland Road and the start of any residential dwellings, should be considered early during the design and planning of the development of this site. Contemporary urban design of the buffer areas could include areas where management would exclude trees reaching over 3 m in height. Examples include waterways landscaped with sedges and rushes and walkways, bicycle paths, outdoor exercise stations or sports fields. A discussion of the appropriateness of this location for development should be undertaken. Consideration of future management actions potentially required for the East Cessnock camp could be included in these discussions.
A study of the historical locations of flying-fox camps would provide further information about the future risks of conflict between residents and roosting flying-foxes. Sites used historically as camps could be revegetated and appropriately buffered to attract roosting flying-foxes if contemporary surrounding land uses are compatible. Alternatively, if contemporary land use surrounding a historic camp site is now incompatible with a GHFF camp site, landscaping at the site should avoid use of trees over 3 m in height. Future development within these sites should be avoided, or stringent vegetation control measures applied through planning controls such as Development Control Plans.
17.6.2Potential for Future Camp / Human Conflict

It is not possible to predict where flying-fox camps may establish. However, we can assess current and potential site attributes for proposed development sites and identify areas that could potentially satisfy criteria associated with flying-fox camp sites (refer to Section Table 12.3). Alongside the risk of creating a new conflict site at East Cessnock (refer to Section 17.6.1), there is potential for GHFF camps to establish adjacent to, or within, other areas targeted for future urban expansion. These areas are described in Table 17.8.