Grey-headed Flying-fox Management Strategy for the Lower Hunter Grey-headed Flying-fox


Vegetation Classification and Map



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15.6.1Vegetation Classification and Map

15.6.1.1Habitat scores - nectar

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.


Scores of total nectar productivity, reliability and wt p*r for each vegetation type are provided in Appendix . These ‘total’ habitat scores do not take seasonal variations into account and so are of limited assistance in assessing the significance of vegetation types for GHFFs. However, they provide a means of summarising patterns of overall habitat quality within the region.
Wt p*r scores are of greatest interest (see Appendix ). Vegetation types having wt p*r scores >0.75 are rare in the Lower Hunter region, making up 2% of vegetation types (n=3) and 0.7% of the area of the region. They primarily comprise small remnants of forest on coastal floodplains dominated by Melaleuca quinquenervia and Eucalyptus robusta. Approximately 8% of the study area supports forests and woodlands with total wt p*r scores >0.50. These vegetation types are primarily found in coastal ranges. Diet plants that feature in these MUs include various species identified as being highly productive, including those above and C. maculata, C. gummifera, E. paniculata, E. pilularis, E. saligna, E. siderophloia and E. tereticornis.
15.6.1.2Bi-monthly nectar scores

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.


A diverse range of MUs in the Lower Hunter region contain species that produce nectar resources for GHFFs from spring to autumn (refer to Table 15.7). A relatively consistent area is productive in each bi-month from October to March, although the dietary species and MUs concerned vary through that time (see Appendix ). A distinct change in habitat characteristics occurs in autumn. The area of productive land in Lower Hunter is notably reduced from April to September, as are indices of productivity.
Approximately 48,000 ha of land that provides nectar resources for GHFFs from March to June are associated with Spotted Gum. This species is productive 1 year in 4, or more seldom. In years when Spotted Gum does not flower, feeding opportunities for GHFFs in the Lower Hunter are highly restricted from April to July. For example, less than 1% of the region produces food for the species in the June–July bi-month (Table 15.7) and foraging habitat is restricted to coastal foredunes containing Banksia integrifolia and sparsely distributed forested wetlands containing E. robusta.
Table 15.7Features of habitat productive in each bi-month in the Lower Hunter region. Values in parentheses are data for June-July when C. maculata does not flower (at least 3 years in 4). Equivalent reductions occur in the April-May bi-month.




Dec-Jan

Feb-Mar

Apr-May

Jun-Jul

Aug-Sep

Oct-Nov

Number of MUs


45

47

22

19 (11)

20

42

Productive area (ha)

172,223

190,296

52,874

52,695 (3,947)

64,708

201,072

% regional area

40%

44%

12%

12% (0.9%)

15%

47%

Area-weighted index*

0.079

0.106

0.038

0.037 (0.004)

0.021

0.078

*Area-weighted indices summarise overall levels of habitat quality across the region to allow comparisons to be drawn through time. They are the sum of products of habitat scores and areas of MUs, divided by the area of the region.
15.7.1.1Habitat scores - fruit

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.


15.7.2Habitat ranks

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 15.8The extent of vegetation types assigned to habitat ranks.

Conservation Value

Rank

Area (ha)

% region

n (MU)

High

1

159,210

37%

57

Moderate

2

83,053

20%

23

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).


We recommend a rule-based, rather than spatially-based, approach is taken in interpreting this work. That is, considerations of the conservation significance of a habitat area should be based on a field assessment of the vegetation communities it contains and the habitat ranks assigned to those communities. The limitations this approach imposes on interpreting these results in light of other map-based assessments are acknowledged. However, the apparently low level of mapping accuracy constrains the value of those assessments.
The GHVM is in the process of being refined. It is recommended that the assessment of conservation priorities of feeding habitat for GHFFs be revised when accurate (80%+) mapping products become available across the Lower Hunter region.

Table 15.10Grey-headed Flying-fox Foraging Habitat Value Ranks based on GHMv4

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



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Conservation Threats

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17.






A range of processes affecting the conservation of the GHFF have been identified. These threats operate at a local, landscape and global scale, and are either natural or anthropogenic in origin. This Section explores the conservation threats to the GHFF in the Lower Hunter. Actions that could be undertaken to improve conservation outcomes for the GHFF are proposed and developed further in Section 20.

Table 17.1Identified Key Threatening Processes

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).


Table 17.2Key Threatening Processes for the GHFF

KTP*

Level of Operation in the Lower Hunter

Past

Current

Future

Loss of foraging habitat

High. The coastal floodplains and alluvial landscapes were heavily cleared. This was followed by extensive clearing for urbanisation.


Moderate, 1,500 ha vegetation cleared 2004-2009^, however some restoration is also underway. As part of LHRS, 32,000 ha have been reserved for conservation^.

High, refer to Section 17.3.1. ~7,300 ha native vegetation occurs within identified development areas^.


Loss and disturbance of roosting sites

High. Many camps have a history of culling. Riparian and alluvial vegetation was most heavily cleared in the past. These areas are favoured for camps.

Moderate, current camp policies discourage dispersal however unauthorised disturbance at contentious locations occurs.

Unknown. Will be strongly influenced by changes in policy and legislation.

Unregulated shooting

High. Regular culling in orchards and at camps. Reported as recently as the late 1990s at Black Hill.

Unknown – reporting of these events is unlikely.

Unknown. Would be influenced by strength of regulatory activity.

Electrocution on powerlines and entanglement in netting and barbed-wire fencing

Unknown, but likely to have been low.

Moderate. Inappropriate netting in use. No regulation of use of barbed-wire. Low implementation of CCT overhead powerlines or underground power.

No change anticipated. Banning of sale and use of netting harmful to wildlife is recommended.

Education about wildlife-friendly fencing is recommended.



Competition for resources with the Black Flying-fox

Non-existent.

Not fully understood. Black Flying-foxes occur in some camps across the Lower Hunter.

Threat may increase if Black Flying-fox increases numbers and extent in Lower Hunter.

Negative public attitudes and conflict with humans

High.

Reducing as information about bats and their management becomes more readily available.

Unknown. Dependent on sound management of conflict and continued community education.

Impacts from climate change

As dictated by natural shifts in climate patterns.

Severe weather events such as storms and heat waves affect GHFF. However other factors may have influenced outcomes.

Yes and increasing if projected increases in extreme weather events happen.

Disease

Unknown.

Unknown#.

Unknown.

Source: *OEH 2012, ^DECCW 2009b, #studies required of mass abortion events.

Table 17.3Foraging Habitat Loss

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).


These patterns are evident in the Lower Hunter, with observations of GHFF dropping over winter when nectar and native fruit productivity in this region is low (refer to Table 10.4), and a large increase in numbers when mass flowering associated with Spotted Gum occurs. An example of the latter was a peak in numbers of GHFF at Tocal of over 100,000 animals during a recent Spotted Gum flowering event (pers. obs. April 2012).
17.3.1Identified Potential Future Development

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.


The foraging habitat value of vegetation occurring in the LRHS identified development areas is provided in Table 17.5. Of the 7,416 ha of vegetation identified for development, 7,047 ha provide foraging habitat for GHFFs, with most (6,588 ha) comprising high conservation value foraging habitat (rank 1). As a significant portion of the proposed development areas contain high conservation value GHFF foraging habitat (89%), strategies are required to reduce the impacts of the loss of this vegetation if there is to be an ‘improve or maintain’ outcome in terms of the GHFF foraging habitat availability in the Lower Hunter.

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


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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:


  • accurately quantify the loss of foraging habitat (using Appendix D and formulae provided in Section 6);

  • define where this loss will occur; and

  • 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.


17.5.1LEP Zoning

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.


However, clearing in these areas and outside of the LHRS process, could negatively impact on the conservation of the GHFF in the Lower Hunter, as the volume of foraging habitat is much greater in these areas than within LHRS identified development sites. Areas within the Lower Hunter that are not zoned for conservation purposes contain 81,504 ha of high conservation value GHFF foraging habitat (rank 1) and 35,184 ha moderate conservation value habitat (rank 2).

Table 17.6Loss and Disturbance of Roost Sites

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.


Buffers such as public open space between vegetated riparian areas and residential yards would provide distance between any new GHFF camps, would contribute to bushfire Asset Protection Zones and provide access and amenity to the new residential / urban areas.
Eight GHFF camps occur in developable LEP zones: Millfield, East Cessnock, Hannan Street, Lorn, Tocal, Bobs Farm, Raymond Terrace and Black Hill. Italia Road camp occurs in a developable zone under the Port Stephens LEP 2000; however it is located in a State Forest and therefore not likely to become a conflict site affected by inappropriate future development.


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