Submission to DEH. Response to SIS 2005, Cumberland Ecology for Clarence Valley Council
by Patricia Edwards
Clarence Valley Regional Water Scheme
Brushtailed Rock-wallaby (Petrogale penicillata)
Endangered - TSC Act
Vulnerable - EPBC Act
Cumberland Ecology's 8-part test for rock-wallaby clearly points out in 3 separate volumes (Vols A, B & C) that the brush-tailed rock-wallaby is "...highly territorial and remains in the same place permanently..." ( pB.203). The test also admits that rock-wallaby requires specific habitat features such as aspect, slope, number of shelter sites and accessibility, and that these have to be a right balance to avoid predation by foxes.
This is supported by other research. Other known facts about rock-wallabies are :
These permanent home ranges are not broad. Individual animals inhabit overlapping home ranges of approximately 15ha each (Archer 1985)
"Steep narrow routes to cliff tops and grassy feeding areas close to daytime refuges are essential (Eldridge & Close 1995).
"Within their home range, rock-wallabies habitually use the same refuges, feeding areas and pathways (Joblin 1983).
A study of central eastern NSW populations found that a wallaby's range comprised on average a rectangular 700m strip along a cliff line, with up to 5ha dispersal during night time foraging.
Yet, despite this recognition of the rock-wallabies' limited range and territory, Cumberland Ecology (CE) determines by the 8-part test, (Part d - whether known habitat is likely to become isolated..) that this Shannon Creek population can move via "... forested eastern and western escarpments and slopes of the Shannon Creek catchment into a larger vegetated corridor extending from Nymboida in the south to Ramornie National Park in the north. Much of this area also features rocky escarpments and rugged terrain and would be expected to provide corridor movement potential for Rock-wallabies." (All Vols, pB.207)
The major part of this statement was also cut and pasted for 15 other species in 3 separate volumes.
As far as this 'potential' movement corridor goes, much of it may provide rocky escarpment and rugged terrain suitable, and may be available for displaced and dispersing rock-wallabies. Cumberland Ecology is vague in his assessment because the area is unknown to him. What can be ascertained, however, by simple examination of an aerial regional map (GIS) and measuring distances, that much more of it does not, and the habitat certainly does not form a constant connected corridor.
Ramornie National Park is 12km away, as the crow flies, with a minimum of over a kilometre of cleared farmland to a minimum 1,200m to be crossed.
There are no escarpments at all along the western bank of Shannon Creek beyond 500m north of the spillway site
The eastern side of Shannon Creek, north of the access road alignment and including the Chambigne Nature Reserve East, consists of a shallow broken ridge with little suitable habitat. This has been proven to be unused by rock-wallaby (Lewis survey, 2004 - below)
Chambigne Nature Reserve North has been accepted as unsuitable for long term habitat
Koukandowie Nature Reserve is separated and surrounded by lengthy tracts of cleared farmland, and is acknowledged as insecure rock-wallaby habitat
By all of the above features it cannot be claimed, until positively proven, that the Shannon Creek catchment is a corridor for rock-wallaby.
Even if it was possible for individuals of the Shannon Creek population to decamp, there is no estimation of numbers, nor any survey of suitable habitat or consideration of already use by rock-wallabies in any of the closest reserves. The Koukandowie Nature Reserve, although closest, is not likely to be a destination for Shannon Creek wallabies isolated by construction activity and inundation on the eastern side of the escarpment. The Blaxland Creek valley comprises broad >800m tracts of grassland, while the shortest route across the valley leads into unsuitable rock-wallaby terrain on the eastern slopes. From that point a similar length of cleared land would have to be negotiated before entry into the Reserve.
Together with a 40m cleared Transgrid easement aiding separation of the Shannon Creek and Koukandowie wallaby terrotories, it seems quite possible that the scant sightings of rock-wallabies to the extreme south of Lot 90 Blaxland Parish could already be an isolated population. This possibility should be further examined. Local knowledge could easily confirm the population's viability - ie whether females are seen with young.
There is no proof presented by CE that the Shannon Creek population is, or might be, currently connected to other populations outside the area. Yet CE concludes by his 8-part test (All Vols, B.209) that "There is no need to vary from the original prediction, and the habitat for the species that occurs within the study area is predicted to remain largely intact. It is predicted that Brushtailed Rock Wallaby will be able to continue to disperse around the eastern, western and southern rims of the Shannon Creek Valley and that they will also be able to continue to disperse between the eastern and western escarpments to the north of the storage.
This comment exhibits a distinct lack of understanding of the species and its available habitat within the immediate vicinity. By maps and sighting records of brush-tailed rock-wallaby there clearly never has been, nor is ever likely to be, any dispersal around the western or southern rims of the Shannon Creek valley. Similarly nor of the eastern escarpments, which fail north of the proposed access road alignment.
These above details alone should sound a warning bell for this development proposal within rock-wallaby habitat, and should automatically dictate extreme caution where these animals are concerned.
Brush-tailed rock-wallaby is already under severe threat by alteration, loss, fragmentation and destruction of habitat through land clearing; introduced predators, especially fox, but also by cats and dogs; competition for food resources, and destruction of refuge habitat by goats, sheep and rabbits. By CE's 8-part test (All Vols, B.207) it is admitted that :
M shelter habitat will be destroyed by all components of the project - access road, pipeline, spillway and dam wall construction
M currently used grassland browsing areas will be destroyed and/or inundated
M there is a recognised high potential for the project to introduce foxes, the major threat
M the dam will to some extent have a barrier effect to animals on the eastern and western escarpments
M the modified designs will have a greater impact on the wallabies than the earlier plan
M the workers' compound will 'temporarily' (ie read 3-5 years) interfere with "potential" rock-wallaby movement across the Shannon Creek Valley
MThe management plan for the now introduced Phytophthora cinnamomi concedes a risk to the health of the wallaby, without being sure of the outcome (Table 3.6 p3.19).
MConcerns have been raised over local declines (Archer 1985; Kennedy 1992; Bayne 1996; Dovey 1997 - [All Vols, B.204]). (Note: By these research dates it would appear that rock- wallaby populations could indeed be declining, and constantly)
Yet despite all these significant necessities, threats and uncertainties, and even though this species is protected under federal law, CE concludes with confidence by his 8-part test that "...the approved project components, access road, design modifications, power supply and upgrade of existing roads are unlikely to have a significant impact upon this species."
CE's confidence is even more surprising in light of the fact that the only plans proposed to save this population is to "monitor foxes and to see whether or not fox incursion takes place more frequently within the study area following during and after construction of the access road and pipeline..." and also to revegetate a section of the valley (where there is no suitable shelter habitat for rock-wallabies. See below). This while acknowledging that rock-wallabies are territorial and maintain a permanent home range.
There is no consideration whatsoever, and no earlier research was undertaken (therefore no data was presented in the EIS) of the actual degree of disturbance and its likely effects, either immediately by habitat invasion and destruction, or by prolonged (3-4 year) of high activity directly within and destroying core habitat and historic valley crossing point, including by blasting. Nor is there any scientific prediction as to where the wallabies might in fact disperse to in the immediate short term, for shelter, safety and breeding purposes.
Previous research has shown these animals to be timid and shy, prone to respond to disturbance by moving away from their refuge or foraging sites (R Close). With suitable habitat in the Shannon Creek area limited, any disturbance will inevitably lead to fragmentation of the population in a quest for quieter sites for breeding purposes, resulting in further threat by predation, particularly of vulnerable at foot joeys and females with pouched young if they transfer to less suitable habitat.
It can be judged by the topographic map (Coutts Crossing, 9438) that, no secure shelter habitat within the limited confines of Shannon Creek will be free from disturbance by construction noise and activity.
Nor is there any predicted outcome for the population, such as how long a colony might endure if breeding fails due to constant disturbance, or vulnerable females and young are heavily predated, should the wallabies fail to disperse far from their familiar home territory.
Research has shown that historically rock-wallaby are unlikely to voluntarily cross the Shannon Creek valley in any place other than the proposed dam site, owing to >300m stretches of open grassland, or lack of suitable habitat (Lewis Report 2004, see below). Although the northern valley loop is expected to be revegetated, even if this proves successful, the situation will still remain the same for the wallabies for an estimated 5 years at least from the end of activities.
CE makes no note of the prolonged impact by the prolonged construction activity on rock-wallaby (3 years best scenario). During that time it has to be considered likely that the population will be fragmented and separated. There is also no consideration of impediments and impacts by:
the extensive workers compound to be constructed in the valley loop adjoining the spillway and dam wall loop
the length of time it will take for this compound to be dismantled and the valley to restore to its former condition, or be revegetated as planned
future use of this valley loop (possible human recreation)
Planned construction and public use of an historic walking trail
the mesh fences proposed to be installed around the spillway, worker's compound and other infrastructure for the safety of visitors
ongoing disturbance across the area by visitors; bushwalkers; rock-climbing enthusiasts; campers (even though illegal); general public recreational use of the area; and pumping and dam maintenance.
cleared roadways across and within the valley
the length of time between revegetation of the downstream loop, and useful safe cover
the further prolonged human incursion into the northern valley loop for revegetation purposes
The greatest concern, though, expressed frequently as a major concern by all parties in all relevant documents, is predation by foxes. Yet the only management plan suggested to prevent elimination of the rock-wallaby by red fox is to monitor both the wallabies and the incoming foxes. Nothing else is suggested. Baiting was recommended in the Access Road DA, but proved an unpopular option with DEC and has subsequently been deleted. Simply watching the ensuing impacts of the activity on the rock-wallaby population is so transparently inadequate it would be laughable if not so serious. Fox records within the isolated Shannon Creek valley are at present rare, due in the main to lack of cleared access. There is a claim of a sighting on farmland to the east (Miller), and a mange infested fox was seen crossing Shannondale Road, also over considerably modified grazing country (Edwards & Edwards c1990). Greenloaning Biostudies recorded fox in similar pastural land to the west of the Shannon Creek valley (2003). Foxes have never yet been seen on Lot 2 Shannondale Estate, adjoining CVC's eastern Lots 119/59, nor on Lot 119 itself (Edwards 1979-2005).
CE admits that brush-tailed rock wallaby "... is not necessarily secure within many of existing reserves, principally due to predation by foxes..." (SIS p6.7 all volumes)
It would seem that the population at Shannon Creek, being isolated by considerable tracts of native forest and lack of encroaching development, is at present quite possibly the largest and most secure population in NSW, specifically in that it is relatively free from fox predation.
By reason of rock-wallabies' extreme vulnerability to change and predation, this should not be allowed to alter!
The Lewis Report (Lewis BD, Clarification and Assessment of Impacts on the Shannon Creek Brush-tailed Rock-wallaby Population, 2004)
Independent field surveys by Lewis Ecological Surveys (2004) of the proposed activity areas, with dawn to dark and night-time spotlight studies of the dam wall/spillway site, and of the ridges and escarpments both up and downstream of the site, confirmed that although rock-wallaby is known to occasionally pass along the NW side of the northern valley-loop proposed to be revegetated, this area is generally unsuitable habitat for wallaby (Lewis report, Fig 3, p4). The report concludes that the suggested mitigative measures to provide a crossing point by revegetation of the downstream valley will be ineffective for rock-wallabies.
The Shannon Creek Restoration Plan, therefore, although not disputed as a likely benefit to wildlife, will prove unworkable for rock-wallaby, at least by the initial northern loop planting program.
In the understanding that a rock-wallaby's foraging and refuge territory is contained within an approximate range of <>200m, the Lewis studies also confirmed that the area surrounding the proposed dam wall and spillway sites are the key nodal area, which is unquestionably an important component of the rock-wallaby habitat within the area.
The report confirmed corridor habitat for rock-wallaby. Specifically, by this and a previous study for the EIS (Rowheder, Goldingay & Lewis 1998), it was reconfirmed that rock-wallaby does not in any way utilise the eastern rock ridge north of the proposed access road, at least as far as NCW's land boundary with Kelly. The survey also confirmed that the ridgeside of the Chambigne Nature Reserve (East) continues the general failure of habitat provision. This is supported by Cumberland Ecology, (Figures 3.25 and 3.25a, SIS ABC Vol 3, elect p 493), although a single rock-wallaby has been recorded near the SW boundary corner.
126.96.36.199 The Vertebrate Pest Management Plan, recognises the possible (potential?) impacts on the rock-wallaby population by foxes, dogs and cats, and puts forward the revegetation plan as the only mitigation strategy. This is unlikely to help the rock-wallabies by reason of :
The usefulness of the revegetated area as a crossing point for rock-wallaby is disproved (above)
A newly forested area will fail in discouraging feral predators, when the predators will have 2 (possibly 3), easy entry routes into the dam site and core rock-wallaby habitat via the access road, pipeline and eventual flood time access.
The access road across the valley actually utilises the boundary of the current wallaby movement corridor, for a distance of approximately 1.5km
SIS Volume C (p7) Design Modifications, admits that the proposed new spillway design will extend further to the north along the valley than the approved spillway design and has implications for the movement of rock-wallabies between the eastern and western escarpments. It also suggests that several hundred metres of "potential" movement corridor will remain after construction of the new spillway, and that dispersal is likely to take place between the escarpments after the dam is built.
The Lewis report affirms just 300m of suitable protective values for rock-wallaby below the dam site (p5).
The Lewis survey also resulted in grave concerns, regarding:
the direct impact by modification and destruction of rock-wallaby refuge and foraging habitat
the modified spillway design will remove as much as 4ha of known nodal brush-tailed rock-wallaby habitat
the likelihood of further extension of habitat disturbance at least 500-750m beyond and around the spillway site (by workmen and associated recreational incursions and activities)
a questionable approach to previous surveys for rock-wallaby would have failed to gain any meaningful conclusion
the lack of mitigation measures proposed to address issues associated with key threatening processes, division of the population into 2 sub-populations, and the implications for the long-term viability of the population
the initial separate addressing of the various works components, without assessment of cumulative impact on rock-wallaby by all proposed works
the impact of change from current and past benign land use to the high activity of construction, public assess roads, road cuttings and physical barriers
the likelihood of division and isolation of the <100 wallaby population
the facilitation of exotic predators such of red-fox into the area
* Note: In regard to the latter threat, the Lewis Report recommends that "more effective mitigation measures such as a reduction in the number of easements which access the site from three to one may alleviate these impacts". (Lewis report, Executive summary p iv). This suggestion is endorsed by all environmental groups, and by DEC.
SIS All volumes, 6.5.4 Director General's Requirements, Consideration of Corridors (p6.46) admits, a) that the proposed design modifications to the spillway, and the relocated workers' compound, will extend for a considerable distance along areas that could otherwise afford movement by the rock wallabies, and b) that fencing around the spillway and storage wall for human security is expected to further restrict wallaby movement across the storage wall/spillway area. The revegetation of the downstream valley loop is again put forward as a mitigation measure, but here at least there is an admission that the strategy is not guaranteed to work.
It would be thought that in dealing with the future of a highly restricted and endangered animal, something better than guesswork and hope would be a better plan. The Shannnon Creek Restoration Plan goes as far as to suggest that ... "radio tracking of rock wallabies and other species might present a good opportunity to further research projects in management of rare and threatened species in conjunction with vegetation management, providing funding was to be made available."
This has to be strongly protested, and will be resisted. Once again it must be pointed out that this suggestion is put forward for human benefit, and will not only impact directly on trapped and stressed animals, but indirectly, by further human incursion of the area set aside solely to ensure the ongoing health and continuance of threatened fauna species. It is to be sincerely hoped that no such funding will ever be arranged - or requested.
The Lewis report makes particular note of the caution by Greenloaning Biostudies (Flora and Fauna Impact Assessment for Design Revisions, Shannon Creek Storage Part A, 2004a) that there is "... potential for significant adverse impacts on the Brush-tailed Rock Wallaby if the Vertebrate Pest Management Plan is ineffective and fox numbers in particular substantially increase in association with increased assess to the western escarpment."
Lewis suggests the consultants should indicate occasions where fox control has proven successful, and that they be required to demonstrate the relevant skills to implement a fox control strategy.
This is strongly endorsed by the authors of this submission
The Shannon Creek Restoration Plan, CE again comments on the disappearance of rock-wallaby from many parts of its range since the introduction of the fox, and that, "Essentially, this agile species of wallaby is thought to be limited principally by the occurrence of an introduced predator and not by its inability to disperse."
Apparently the ability for the Shannon Creek rock-wallabies' to disperse ahead of a predator is considered by CE to be higher than those in other areas.
CE still confirms that the sole plan for mitigating this significant key threatening process at Shannon Creek is to continue a monitoring program, which is scheduled to run for five years after completion of dam construction. Although monitoring was a concurrence condition set down by the Director-General, it is unlikely that the aim of this condition was solely to provide a job for the ecologists, and that a specific plan was expected to be devised if the monitoring proves that activities are having a detrimental impact.
It is highly likely that once the dam is built, when the activity ends and the wildlife starts to settle down again, that is when the foxes will come in, easily channeled into fragmented rock-wallaby habitat by a number of cleared and constructed roads and service tracks through current native bushland
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