Our economy and society ultimately depend on natural resources: land, water, material (such as metals) and energy. But some scientists have recognised that there are hard limits to the amount of these resources we can use. It is our consumption of these resources that is behind environmental problems such as extinction, pollution and climate change.

Even supposedly 'green' technologies such as renewable energy require materials, land and solar exposure, and cannot grow indefinitely on this (or any) planet.

Most economic policy around the world is driven by the goal of maximising economic growth (or increase in gross domestic product – GDP). Economic growth usually means using more resources. So if we can’t keep using more and more resources, what does this mean for growth?

Most conventional economists and policymakers now endorse the idea that growth can be 'decoupled' from environmental impacts – that the economy can grow, without using more resources and exacerbating environmental problems.

Even the then US president, Barack Obama, in a recent piece in Science argued that the US economy could continue growing without increasing carbon emissions thanks to the rollout of renewable energy.

But there are many problems with this idea. In a recent conference of the Australia-New Zealand Society for Ecological Economics (ANZSEE), we looked at why decoupling may be a delusion.

The Decoupling Delusion

Given that there are hard limits to the amount of resources we can use, genuine decoupling would be the only thing that could allow GDP to grow indefinitely.

Drawing on evidence from the 600-page Economic Report to the President, Obama referred to trends during the course of his presidency showing that the economy grew by more than 10% despite a 9.5% fall in carbon dioxide emissions from the energy sector. In his words:

…this 'decoupling' of energy sector emissions and economic growth should put to rest the argument that combating climate change requires accepting lower growth or a lower standard of living.

Others have pointed out similar trends, including the International Energy Agency which last year – albeit on the basis of just two years of data – argued that global carbon emissions have decoupled from economic growth.

But we would argue that what people are observing (and labelling) as decoupling is only partly due to genuine efficiency gains. The rest is a combination of three illusory effects: substitution, financialisation and cost-shifting.

Substituting the Problem

Here’s an example of substitution of energy resources. In the past, the world evidently decoupled GDP growth from buildup of horse manure in city streets, by substituting other forms of transport for horses. We’ve also decoupled our economy from whale oil, by substituting it with fossil fuels. And we can substitute fossil fuels with renewable energy.

These changes result in 'partial' decoupling – that is, decoupling from specific environmental impacts (manure, whales, carbon emissions). But substituting carbon-intensive energy with cleaner, or even carbon-neutral, energy does not free our economies of their dependence on finite resources.

Let’s get something straight: Obama’s efforts to support clean energy are commendable. We can – and must – envisage a future powered by 100% renewable energy, which may help break the link between economic activity and climate change. This is especially important now that President Donald Trump threatens to undo even some of these partial successes.

But if you think we have limitless solar energy to fuel limitless clean, green growth, think again. For GDP to keep growing we would need ever-increasing numbers of wind turbines, solar farms, geothermal wells, bioenergy plantations and so on – all requiring ever-increasing amounts of material and land.

Nor is efficiency (getting more economic activity out of each unit of energy and materials) the answer to endless growth. As some of us pointed out in a recent paper, efficiency gains could prolong economic growth and may even look like decoupling (for a while), but we will inevitably reach limits.

Moving Money

The economy can also appear to grow without using more resources, through growth in financial activities such as currency trading, credit default swaps and mortgage-backed securities. Such activities don’t consume much in the way of resources, but make up an increasing fraction of GDP.

So if GDP is growing, but this growth is increasingly driven by a ballooning finance sector, that would give the appearance of decoupling.

Meanwhile most people aren’t actually getting any more bang for their buck, as most of the wealth remains in the hands of the few. It’s ephemeral growth at best: ready to burst at the next crisis.

Shifting the Cost onto Poorer Nations

The third way to create the illusion of decoupling is to move resource-intensive modes of production away from the point of consumption. For instance, many goods consumed in Western nations are made in developing nations.

Consuming those goods boosts GDP in the consuming country, but the environmental impact takes place elsewhere (often in a developing economy where it may not even be measured).

In their 2012 paper, Thomas Wiedmann and co-authors comprehensively analysed domestic and imported materials for 186 countries. They showed that rich nations have appeared to decouple their GDP from domestic raw material consumption, but as soon as imported materials are included they observe 'no improvements in resource productivity at all'. None at all.

From Treating Symptoms to Finding a Cure

One reason why decoupling GDP and its growth from environmental degradation may be harder than conventionally thought is that this development model (growth of GDP) associates value with systematic exploitation of natural systems and also society. As an example, felling and selling old-growth forests increases GDP far more than protecting or replanting them.

Defensive consumption – that is, buying goods and services (such as bottled water, security fences, or private insurance) to protect oneself against environmental degradation and social conflict – is also a crucial contributor to GDP.

Rather than fighting and exploiting the environment, we need to recognise alternative measures of progress. In reality, there is no conflict between human progress and environmental sustainability; well-being is directly and positively connected with a healthy environment.

Many other factors that are not captured by GDP affect well-being. These include the distribution of wealth and income, the health of the global and regional ecosystems (including the climate), the quality of trust and social interactions at multiple scales, the value of parenting, household work and volunteer work. We therefore need to measure human progress by indicators other than just GDP and its growth rate.

The decoupling delusion simply props up GDP growth as an outdated measure of well-being. Instead, we need to recouple the goals of human progress and a healthy environment for a sustainable future.

James Ward, Lecturer in Water & Environmental Engineering, University of South Australia; Keri Chiveralls, Discipine Leader Permaculture Design and Sustainability, CQUniversity Australia; Lorenzo Fioramonti, Full Professor of Political Economy, University of Pretoria; Paul Sutton, Professor Department of Geography and the Environment, University of Denver, and Robert Costanza, Professor and Chair in Public Policy at Crawford School of Public Policy, Australian National University

This article was originally published on The Conversation. Read the original article.

Ku-ring-gai Council is anticipating that there will be a strong demand for biodiversity offsets once biodiversity legislation comes into operation in August. At the council meeting on 13 June a decision will be made whether to support the adoption of the Biodiversity Banking and Offsets Scheme (BioBanking) as an ongoing biodiversity management approach within council owned or managed land classified as Community Land under the Local Government Act 1993. Public consultation to assess the community’s acceptance of the ongoing creation of BioBanking sites will take place before the scheme is finalised.

So far there is one BioBanking site at Rofe Park, Sheldon Forest and Comenarra Creek Reserve and a decision has been made for another site yet to be determined in respect of land clearing by the North Connex project. Ongoing BioBanking within council-owned or managed land will strengthen the protection of biodiversity values and increase the funds available for management activities which improve biodiversity conservation.

As pointed out in the council meeting papers and in the article about offsetting on changes under the Biodiversity Conservation Act 2016, the impacts of development within Ku-ring-gai could be offset elsewhere in NSW. This could be circumvented if offset lands are made available.

Also the new system is weaker in its requirements for like-for-like offset requirements. Plant Community Types (PCTs) which don’t exist within Ku-ring-gai could in some circumstances be offset with different PCTs occurring within Ku-ring-gai, creating further offsetting opportunities.

The selection of potential BioBanking sites in Ku-ring-gai will seek:

• to maximise landscape connectivity;
• to protect sites of high ecological value and resilience, as directed by council’s 2015–17 bushland prioritisation matrix; and
• to align with regional conservation priorities, including the Office of Environment and Heritage’s Biodiversity Investment Opportunities Map – this map identifies areas for investment within the Cumberland subregion, which include either core areas or biodiversity corridors of state or regional significance.

If you are interested in obtaining further information look out for developments on council’s website.

The Australian and Queensland governments are still pushing for the Adani mine to go ahead and are bending over backwards to make this possible. The local native title holders are opposed but the Australian government is trying to legislate away the aboriginal rights.

We still haven’t heard if the Northern Australia Investment Facility will provide a concessional loan of $1 billion to finance the rail line from the Carmichael Basin to the port at Abbot Point on the Great Barrier Reef.

Queensland has offered financial inducements such as the deferral of royalty payments and no payment will be required for the mega litres of water that will be drained from the Great Artesian Basin. Local farmers are concerned about the effect on their water supplies.

Adani has announced a decision to go ahead in principle. But where will the finance come from when already 16 major banks have declined to participate? They can see that the project is not viable. When will reality hit the politicians?

There are many reasons why the mine will be a disaster:

• Adani has a dubious record that is hard to pin down due to complicated corporate structures and use of offshore tax havens.
• The chief benefit being promoted is jobs, jobs, jobs but realistic figures are for only about 1,500 full-time equivalent direct and indirect jobs as against the hype of 10,000 jobs.
• The Minister for Resources and Northern Australia, Matt Canavan, claims that the coal will bring the Indian peasants out of poverty. But solar energy has been shown to be more affordable.
• The mine is a total environmental folly. The opening of the Adani mine and construction of the railway line will open up the whole Galilee Basin that contains enough coal which, if burned, could blow away any hope of keeping global warming within 2°C and undermine any national and state action to tackle climate change.
• The mine threatens the Great Barrier Reef not only because of the increase in sea temperatures from climate change. The recent heavy rains led to coal washing into wetlands next to Abbot Point, the coal loader leased to Adani. Is this an example of worse to come?
• The mine would harm the economy of other coal mining states. The massive increase in production would reduce the coal price for coal mined in the Hunter Valley.
• The current rapid move to renewable energy is likely to reduce demand for coal to the extent that the coal market will collapse. The governments’ support could well be wasted.

Lord Howe Island is a magnificent island about 600 km off the coast of NSW. Its unique landform as an eroded volcanic peak and endemic biodiversity led to its classification as a World Heritage site. The southern end is dominated by the basalt peaks of Mt Gower (875 m) and Mt Lidgbird (777 m) covered in dense forests. The northern end is undulating and partially cleared for settlement. Lord Howe’s crescent shape embraces a sheltered lagoon and the southernmost coral reef on the planet.

The number of residents and visitors is limited by its small size and mountainous topography. Its economy depends on tourism and propagation and export of the kentia palm. The maximum number of tourists on the Island at any one time is constrained to 400 and the number of residents is about 350.

When I last visited the island in 2002 there was talk of a project to eradicate rodents. Rats and mice arrived in 1918 as escapees from a grounded ship. Rodents have contributed to the extinction of a number of species and are recognised as a threat to at least 13 bird species, 2 reptiles, 51 plant species, 12 vegetation communities and numerous threatened invertebrates.

The problem is that there is no native mammal species on the island that can compete with, or predate, on the rats and mice. Any impact on the natural values of the island diminishes tourism and recreation values since these are inextricably linked to the islands unique biodiversity and World Heritage values. (Attempts have been made to bring in other predators that are another example of the problems humans can cause when we interfere with nature – see the end of this article.)

Predation by rodents on kentia palm production reduces values associated with this commercial activity, via reduced production and added costs. In addition, rodents impose costs to residents and tourism operators via the need to bait to reduce visual presence of rodents, the spoiling of food stuffs and potentially health impacts to residents and tourists alike.

There has been a long process of investigation and consultation with concerned residents and I understand that the issues are still not resolved. The main problem is the acceptance of widespread use of poison baits. It is hoped that final approval will be granted later this year. The ABC Radio National Off Track program had two episodes on Lord Howe Island’s ecology during early June including discussion of the project and the damage being done by rats.

I recently discovered one of the reports on the project. The Economic Evaluation of the Lord Howe Island Rodent Eradication Project prepared by Gillespie Economics (November 2016). It is an interesting example of cost benefit analysis, the sort of analysis expected by government. As expected with an economic evaluation the report covers the financial aspects of the project. But it is also tries to quantify other community and environmental effects that cannot be directly related to money using some of the techniques of environmental economics.

Cost Benefit Analysis

Cost benefit analysis (CBA) provides a comparison of the additional costs and benefits with the rodent eradication project (REP), relative to without the REP. Provided the present value of additional benefits exceed the present value of additional costs, a project is considered to improve the wellbeing of society and hence is desirable from an economist’s point of view.

The net present value of a benefit or cost arising in the future takes into account the value of time through the process of discounting. The discount rate is a huge area of controversy. Business and government usually use commercial interest rates while society may consider a much lower rate is appropriate so that the interests of future generations are not discounted using the questionable theory that they will be better off than current generations.

A prime example is the issue of climate change – some argue that the costs borne in transitioning to renewable energy sources now do not justify the benefits of avoiding the loss of crops, bushfires, heat stress, sea level rise 50 or 100 years hence. If the benefits of avoiding costs in the long term are discounted at commonly used interest rates then the costs of transition today may exceed these benefits. Part of the problem is the broad assumptions needed to value loss of biodiversity and other environmental assets. The REP project analysis provides some examples of surrogate methods that are used. I will leave the reader to decide on the validity of the methods.

Scope of the REP

The Lord Howe Island Board currently implements a limited rodent control program at a cost of $85,000 per year. However, it is not reducing the rodent population sufficiently to limit landscape scale ecological impacts and there is a risk that continuation of the current approach will result in bait shyness and/or resistance in the rodent population.

The Lord Howe Island REP will use cereal baits laced with the anticoagulant Brodifacoum dispersed from helicopters in the uninhabited areas, and a combination of hand broadcasting, bait stations and bait trays in the settled area. Preparation is required to ensure some species are not killed by the baits. The iconic woodhens that were rescued from extinction and the local currarongs will have to be captured and caged for the period the baits are potent.

Without the REP, the current rodent control program would continue but this can only cover accessible areas of the island. The rodents have plenty of food sources all over the island. There would be continued presence of poison in the environment, continued impacts on the kentia palm and nursery industry, further degradation of World Heritage values (including endemic and threatened species) and the potential for Lord Howe Island to be inscribed on the List of World Heritage in Danger.

Cost Benefit Analysis Results

The analysis calculates that the present value of costs of the project and follow up management including measures to return species that are currently extinct from the island over 30 years is $9 million. By contrast the value of the benefits is $150 million. Hence this analysis shows that the economic value of the project is obvious.

Just looking at the cost of the project compared with ongoing costs of the current methods of control the net cost is about $8 million. Funding commitments have already been received from the NSW and Australian governments.

The removal of the effects of rodents on the kentia palm industry and vegetable production is valued at $1 million.

Some of the valuing of the benefits would be subject of much debate, for example:

• The improvement in biodiversity is deemed to increase visitor numbers. In warmer months when accommodation is already fully booked, increased demand is assumed to increase prices by 35%. In cooler months the accommodation demand is assumed to increase by 20% and prices by 7%. All this is assumed to have a present value over 30 years of $80 million.
• It is estimated that seven future extinctions will be avoided. The value of extinction prevention is based on several studies of community willingness to pay for the protection and recovery of threatened species. On an Australia-wide measure of community willingness to pay they are valued at $8 million each adjusted for a chance that the REP makes no difference to the chance of extinction to give a total of $40 million.
• There are also four species that are locally extinct, the Kermadec petrel, the white-bellied storm petrel, phasmid (stick insect) and wood-feeding cockroach. The return of these species is valued similarly with a deduction for the possibility of failure to reestablish the species at $27 million. One wonders if the general public would value the return of a species population by a transfer from another island in the same way as prevention of extinction of the only population of a species.

Even though some of these figures are debatable it is clear that the REP is worthwhile from an economic point of view. It is hoped that the local residents can be convinced of the benefits.

A Further Complication – the Masked Owl

Not long after rats became a problem the authorities thought it was a good idea to introduce various owl species to control the rats. There is still a large population of Tasmanian Marked Owls. After the REP is completed their major food source will have disappeared so it is likely they will turn to other species. We don’t want more extinctions so a removal program will be required of these Masked Owls.

There has been much media interest in the report that Sydney's population has reached 5 million. What has also been reported is that Melbourne’s population is growing faster than Sydney’s and may soon exceed it.

Sydney

The problem I have with this is that Sydney includes the Central Coast and the Blue Mountains, but not Wollongong. I don't advocate including Wollongong but leaving out the other two plus the Wollondilly Shire (Picton) we have 5.25 – 0.33 – 0.08 – 0.05 = 4.79 million. We could go further and leave out the farther reaches of Hornsby, Baulkham Hills and other local government areas.

Melbourne

Melbourne includes the Mornington Peninsular (0.16 million) which is debatable. Other areas should also be removed (allow 0.05 million). So, 4.67 – 0.16 – 0.05 = 4.46 million which is 93% of Sydney’s population.

Distortions

Part of the problem for the Australian Bureau of Statistics is that the outer suburban local government areas cover large areas of peripheral rural land. The Sydney map at a guess is at least 75% rural and this leads to massive distortions when people try to compare densities.

This data below (from Population Australia) is rubbish. Population Australia is a website specialising in research for Australia population growth trends and estimation. It is not clear who is behind this group but the data seems to be coming from the Australian Bureau of Statistics.

More on this some other time.

Jim Wells has been delving into published statistics that are more than meets to eye.

STEP is supporting a great initiative by organised by Forestmedia, a small not-for-profit organisation that is aiming to increase community awareness of the plight of our threatened species and help to develop the next generation of environmental leaders. The children’s art competition is supported by a number of organisations including the National Parks Association, the Nature Conservation Council, WIRES, Featherdale Wildlife Park, Humane Society International, Animals Australia and Taronga Zoo.

The competition is open from 5 June to 4 August to all primary aged children in NSW and the ACT. Fifty finalists’ works will hang in a two week exhibition in September at the Botanic Gardens and Surry Hills Community Centre, with winners announced on 7 September, Threatened Species Day.

There will be prizes in several categories. STEP is sponsoring a prize for a nocturnal animal artwork. Last year’s prize winners are shown on the website. They are very impressive.

In May the NSW government released regulations and codes that provide some of the detail on how the biodiversity legislation will operate in practice. But it is not complete so there is still a lot of uncertainty. The call for submissions is an opportunity to express a view on what should be in the areas that are missing as well as the available drafts.

There is a large volume of information to digest. The most useful one is the Submission Guide: Ecological Sustainable Development.

Consistent with STEP’s interests we focus on the aspects that relate to the management and preservation of urban bushland. Refer to our article on the issues regarding the Biodiversity Offsets Scheme.

The major areas that are missing are the Vegetation State Environment Planning Policy (Vegetation SEPP) and some of the maps that will underpin the decision-making process. This is most unsatisfactory! The legislation is due to come into force on 25 August. It is an abuse of due process to be conducting consultation on incomplete information.

The Vegetation SEPP will regulate clearing of vegetation in urban areas and environmental conservation/management zones where clearing does not otherwise require development consent under the main planning act, the Environmental Planning and Assessment Act. So the zones that are covered include E2, E3 and E4 zones.

The major concern is the inclusion of E2 zones in the clearing provisions. This zone is for areas with high ecological, scientific, cultural or aesthetic values outside national parks and nature reserves. The zone provides the highest level of protection, management and restoration for such lands whilst allowing uses compatible with those values.

E3 (environmental management) and E4 (environmental living) zones accommodate low-impact residential development but contain, or are near, bushland so have particular environmental or risk factors.

So why is the Vegetation SEPP regulating clearing on E-zone land, in particular E2 land? Clearing should not be allowed except for bushfire safety and other protection reasons.

Examples of land that could come under the new regulations are near the Blue Gum High Forest area in Dalrymple Hay Reserve and the area between Berowra Heights and Cowan near the Great North Walk. Most people assume the latter is national park but much of the natural scenery enjoyed by walkers is zoned E2, E3 and even RE1 (public recreation) and would have little protection under the proposed SEPP. Some E2 land is protected by being a BioBanking site or part of a conservation agreement, but not all.

Sensitive Biodiversity Values Land

There are certain areas, regardless of land area, that will require a biodiversity assessment (and offsetting if clearing is approved) if they are mapped in a Sensitive Biodiversity Values Lands map. The definition of areas included is very restricted.

Comment for submissions

The final map is not available and we understand many parts of NSW have not been properly assessed yet.

The resolution of the draft map on the website is too low to identify particular sites.

Areas that don’t meet the definition and should be included are endangered ecological communities (e.g. Sydney Turpentine Ironbark Forest and Duffys Forest EECs), buffer zones around EECs and areas of critical habitat, e.g. Ku-ring-gai Flying Fox Reserve.

Will it be possible to nominate areas for inclusion? Local land managers should be able to have a say on what is Sensitive Biodiversity Values Land.

There is a real danger that clearing of EECs such as STIF could rapidly turn it into critically endangered. A council’s discretionary DCP would be the only protection. It takes some time for a change in classification of vegetation communities to be finalised. In the meantime will they be cleared beyond hope of recovery?

Clearing Provisions

The clearing provisions are determined by categories of development.

Development consent required

Development consent is required (under the Environmental Planning and Assessment Act) for larger developments and infrastructure.

The Biodiversity Assessment Method (BAM) applies to clearing and the flawed offset provisions will apply.

Development consent NOT required

When development consent is NOT required, e.g. clearing of undeveloped land, the Biodiversity Offset Scheme (BOS) thresholds apply as prescribed below:

The thresholds are high.

For clearing above the threshold the BOS applies and approval will be determined by the Native Vegetation Panel. A biodiversity offset obligation will be imposed. Local councils could be given authority to do this assessment. We don’t know who will be appointed to the Native Vegetation Panel.

Clearing below the threshold will be regulated under the local council’s Development Control Plan (DCP) through a permit system. This will be the most likely situation in urban areas,

There is currently wide variation in the standards of DCPs, for example in relation to individual trees. Ku-ring-gai requires a permit for clearing of most native trees and vegetation and non-native trees while Hornsby only controls clearing of locally endemic native trees or trees in heritage zones. It is possible that the government will impose standard clauses in DCPs. Indeed would these be desirable if a high standard is applied?

Comment for submissions

It is essential that the objectives of clause 5.9 of the standard LEP are carried over to DCPs under the new scheme that is ‘to preserve the amenity of the area, including biodiversity values, through the preservation of trees and other vegetation’.

Submissions should explain desirable standards for the DCP regulations. One area that has not been covered is how the DCP clearing codes will fit in with the need for wildlife corridors and the Greater Sydney Commission’s guidelines for the Green Grid and minimum tree canopy cover.

Other Impacts of Clearing Regulations

A major issue with the local regulation of clearing is that there will be no monitoring of loss of vegetation communities and assessment of cumulative impacts. There needs to be a database of regional clearing approvals.

There is uncertainty about the legal status of DCP regulations and the ability to prosecute if breaches occur.

Areas of western Sydney that will be subject to the greatest amount of new development need as much protection as possible of native vegetation and habitat. The Cumberland Plain Woodland has already had large areas cleared. The allowable clearing and the use of offsets under the proposed regulations will further reduce the area of remaining native vegetation and habitat.

Conclusion

Given the limited areas of bushland in urban areas, it is inevitable that there will be more losses of irreplaceable biodiversity. The offsets provisions do not adequately factor in the scarcity of suitable offsets in urban areas (see article below). The rules must be amended to ensure maximum protection of native vegetation in urban and E zones, particularly areas containing threatened species.

Please Send a Submission

Closing date: Wednesday 21 June. Lodge online or post to Land Management and Biodiversity Conservation Reforms, Office of Environment and Heritage, PO Box A290, Sydney South, NSW 1232.

Over the past 200 years NSW has lost almost half of its bushland through land clearing and only 9% of what is left is in good condition. Clearing of native vegetation and habitat modification are the greatest threats to the survival of the majority of species on the threatened list.

The biodiversity laws that the government passed in late-2016 place a great deal of emphasis on offsetting as a means of allowing development to occur. The theory is that biodiversity lost when clearing for a development can be replaced by providing for restoration or protection of biodiversity in another place.

The Nature Conservation Council recently published a report on the operation of NSW’s biodiversity offset schemes, called Paradise Lost: The Weakening and Widening of NSW Biodiversity Offsetting Schemes, 2005–16. This article outlines the key findings of the report.

As you can tell from the title, the principles of offsetting have been severely compromised. We can expect worse to come under the new laws.

Concept of Biodiversity Offsetting

Biodiversity offsetting has been in use in NSW since 2005 under various pieces of legislation.

One example is the money that was paid by NSW Transport Infrastructure Development Corporation to compensate for the loss of 0.33 ha of Blue Gum High Forest when the railway station at Hornsby was expanded. The money was used to help purchase land to expand the area of protection of Blue Gum High Forest next to Dalrymple-Hay Nature Reserve.

We have written before about the theoretical difficulties of using offset schemes to compensate for lost vegetation and habitat loss and the measures that should be taken to counteract these difficulties.

The basic principles that should be observed are given below.

Offsets hierarchy

Offsets should only be used after appropriate avoidance and minimisation measures have been taken according to the mitigation hierarchy. A biodiversity offset is a commitment to compensate for significant residual adverse impacts.

No net loss

A biodiversity offset should be designed and implemented to achieve measurable conservation outcomes that can reasonably be expected to result in no net loss and preferably a net gain of biodiversity.

Some areas should be off limits – red flags

There are situations where residual impacts cannot be fully compensated for by a biodiversity offset because of the irreplaceability or vulnerability of the biodiversity affected.

Consider whether restoration is possible

Biodiversity offsetting assumes ecosystems and habitats can be re-created. This is often not the case, particularly if offset sites have been highly degraded and lost essential characteristics. In Australia, a number of studies have shown revegetated areas rarely resemble the ecosystem it was intended they would replicate.

Timing mismatch

It takes some time for species to establish a viable population in a new habitat. Offsetting should allow for a phased-in approach to prevent the total loss of species that are already threatened. The loss of hollow-bearing trees is a particular example.

Stakeholder participation

In areas affected by the project and by the biodiversity offset, the effective participation of stakeholders should be ensured in decision-making about biodiversity offsets. All stages including their evaluation, selection, design, implementation, monitoring and communication of results to the public should be undertaken in a transparent and timely manner.

Long-term management

The design and implementation of a biodiversity offset should be based on an adaptive management approach, incorporating monitoring and evaluation, with the objective of securing outcomes that last in perpetuity.

Case Studies

There are five types of offsets schemes operating in NSW. The performance of each of these schemes was examined through the lens of eight case studies:

• Namoi catchment property vegetation management plans – approval for land clearing under the Native Vegetation Act
• Kellyville in northwest Sydney – creation of credits under the BioBanking scheme
• Wagga Wagga local environment plan – biodiversity certification for strategic planning
• Albury local environment plan – biodiversity certification for strategic planning
• Huntlee development in Hunter Valley – Office of Environment and Heritage principles for biodiversity offsetting
• Boggabri and Maules Creek coal mines – development consent – Office of Environment and Heritage principles for biodiversity offsetting
• Warkworth mine extension – Office of Environment and Heritage principles for biodiversity offsetting
• Mt Owen mine expansion – NSW biodiversity offsets policy for major projects

The report provides a detailed description of the features of each case study and compares them with the expected standards. The criteria for the analysis were:

• be a last resort after avoidance and mitigation (including appropriate ‘red flags’)
• deliver biodiversity equivalence (like-for-like)
• provide security and achieve benefits in perpetuity
• deliver a net gain in biodiversity
• be additional to conservation measures already in place
• be enforceable, resourced and well-managed
• be subject to a rigorous monitoring and evaluation framework
• be open and transparent

 It was demonstrated that biodiversity offsetting is failing to deliver the environmental outcomes promised. No case studies resulted in outcomes deemed ‘good’ and the outcomes were:

• ‘disastrous’ in one study (Boggabri/Maules Creek)
• ‘poor’ in five studies (Warkworth, Mount Owen, Huntlee, Albury, Kellyville)
• ‘adequate’ in two studies (Namoi, Wagga Wagga)

For more details read the report.

Comparison of Offset Schemes

The report considers that a scheme should have the following features:

• excludes discounting of offset credits
• excludes supplementary measures
• excludes mine rehabilitation
• clear standard for environmental outcomes
• does not allow payment in lieu of offsets
• red flags
• impacts on water quality and soil are taken into account
• like-for-like offsetting

The case studies demonstrate the features of the five biodiversity offset schemes in operation. It was found that the later models contained fewer best-practice principles and standards than the earlier ones:

• only the first offsets scheme (the Environmental Outcomes Assessment Methodology under the Native Vegetation Act) contained all eight features
• the Biodiversity Offsets Policy for Major Projects introduced by the Baird government in 2014 contained only one of the eight features

Overall, biodiversity offsetting schemes have failed to deliver the promised outcomes and they have become weaker as standards have slipped.

Draft Biodiversity Offset Scheme is Even Worse

The latest Draft Biodiversity Offset Scheme (BOS) and the Biodiversity Assessment Methodology (BAM) that will be used to determine offsetting does not include any of the features described above.

The BAM is a metric-based tool that allows biodiversity impacts and improvements to be assessed and quantified in terms of ecosystem credits and species credits, collectively known as biodiversity credits that will need to be offset.

The proponent can choose to between three methods of meeting their offset obligation:

• buying credits for a suitable site under the offset rules from the market, or they can establish a Biodiversity Stewardship Agreement on their own land and retire the credits generated
• make a payment to the Biodiversity Conservation Trust that will source the offsets
• paying for conservation actions as approved by the consent authority

Key points for submissions

The key points on the features that should be in the offsetting legislation and the changes that are needed are listed below.

1. Discounting of biodiversity credits should not be permitted

The government proposes introducing ‘discounting’ that will allow offset credit requirements to be ‘discounted’ based on claimed social and economic benefits. Economic prioritisation policies are likely to contribute to the incremental and permanent loss of significant biodiversity in NSW, and undermine the credibility of the policy.

2. Supplementary measures should not be included

The BOS allows the use of ‘biodiversity conservation actions’ that may include research or surveys into the biodiversity under threat. This is not a genuine offset. The Scientific Committee stated in a report on this idea that this:

… is clearly a case of developers being able to buy themselves out of any obligation to protect biodiversity in any meaningful way.
NSW Scientific Committee (2014) Submission on the Draft NSW Biodiversity Offsets Policy for Major Projects

3. Allowance of mine rehabilitation

Numerous critics have questioned whether degraded mine sites can be effectively restored and in any case mine site rehabilitation should be an obligation of the mining company. Recently, developers have been permitted to use mine rehabilitation sites to generate biodiversity offset credits. The government proposes continuing this practice under the draft BOS.

4. Clear standards

The Biodiversity Conservation Act requires that the biodiversity assessment method should adopt a standard that result in no net loss but the draft BAM does not have a clear objective to protect biodiversity.

5. No payment in lieu

The draft BOS would allow proponents to discharge offset requirements simply by paying money into Biodiversity Conservation Trust. The development could proceed without certainty that the required offset is possible.

6. Red flags

The BOS does include some restrictions on proposals that cause ‘serious and irreversible impacts’ (SAII) but the criteria for defining SAII are too weak. It includes only the most endangered and restricted area species and ecological communities. In the case of major projects the SAII risks can be ignored. The net effect will be that EECs and endangered species not listed in the list of SAIIs, e.g. STIF and Duffys Forest, could be cleared without offset requirements if the land area is below the clearing thresholds. A council’s discretionary DCP would be the only protection.

7. Other impacts on water and soil

Other impacts should be considered in the BAM. The assessment methodology covers only a limited range of biodiversity values such as vegetation integrity and habitat suitability but not soil health and water quality and availability.

8. Like-for-like principle

The like-for-like principle that offsets should replace the values being lost is undermined in several aspects. For example:

• Offsets can be found from a radius of 100 km. It will be easier and cheaper to find offsets outside urban areas undermining preservation of biodiversity and threatened species and EECs such as STIF. The loss of existing geographic distribution if sites in urban areas are lost will undermine species resilience and long term adaptation to climate change.
• Offsets can be used for species across similar vegetation classes or between species. This even applies to threatened species; a koala can be swapped for a wallaby.

Conclusion

The government is proceeding with this model despite warnings expressed by leading scientists, lawyers and conservationists. The government basically has ignored the advice of the experts because it is wants to deliver development at any cost. Implementing the BOS will in fact add extinction pressures to the very species and ecological communities it is supposed to protect by facilitating the more rapid and widespread destruction of threatened species habitat across NSW.

Please Send a Submission

Closing date: Wednesday 21 June. Lodge online or post to Land Management and Biodiversity Conservation Reforms, Office of Environment and Heritage, PO Box A290, Sydney South, NSW 1232.

Hollows as Homes

The Australian Museum has joined the Royal Botanic Garden Sydney and Sydney University in launching a new citizen science project called Hollows as Homes. Funding support is provided by the Australian government.

The project builds on the Cockatoo Wingtags project and involves the same researchers, led by Dr John Martin.

In urban and agricultural areas large, hollow-bearing trees are in decline, but many species of animal rely on tree hollows for shelter and breeding.

In NSW, hollow-dependent species include at least 46 mammals, 81 birds, 31 reptiles and
16 frogs. Of these, 40 species are listed as threatened with extinction. This is why the ‘loss of hollow-bearing trees’ has been listed as a Key Threatening Process to biodiversity throughout Australia.

One reason that their loss is significant is the length of time that it takes for a tree hollow to form (often more than 100 years). More hollow-forming trees are needed to replace the losses that have occurred already. The solution being trialled is to create artificial hollows and nest boxes.

The Hollows as Homes project aims to conduct the first landscape scale assessment of tree/nest box/cut-in hollow distribution, type and wildlife use. Data generated will inform council plans for retaining important habitat trees, planting future habitat trees and supplementing missing habitat.

The project will harness the enthusiasm of local residents to report, measure and monitor tree hollows in their backyards, streets and parks.

Participating is easy – check the trees in your backyard, street, park, paddock or the bush, and report the hollow(s) online.

FeralScan

Feral animals cause over $720 million damage each year in Australia and threaten our native wildlife. FeralScan allows you to help reduce feral animal damage by mapping feral animal sightings, damage and control activities in your local area.

Ferals covered by the program include Indian Mynas, foxes, rabbits, feral cats and many more invasive species.

Following the serious power blackouts that occurred in South Australia and near misses in other states, gas-fired power stations have been touted as the one of the best means to transitioning away from our aging coal-fired electricity generation system. This is short-term, simplistic thinking that will be detrimental in the longer term, and the Climate Council has just released a report explaining why. The report is called Pollution and Price: The Cost of Investing in Gas.

The Climate Council is the crowd funded organisation led by Tim Flannery that replaced the Climate Commission that was abolished by the Abbott Government shortly after they came into power. They aim to provide independent, expert information on climate change issues.

Here is a brief summary of the main findings.

Use of gas does not reduce emissions sufficiently

Australia must reduce greenhouse gas emissions down to zero by 2050 in-line with international goals. Fossil fuels (coal, oil and gas) all produce greenhouse gas emissions driving climate change. Limiting global temperature rise requires that they are all phased out. Gas is not sufficiently less polluting than coal to garner any climate benefit.

Greenhouse gas emissions are produced both from gas power stations and gas production (for instance, methane from gas leaks). Methane is 86 times more potent as a greenhouse gas than carbon dioxide over a
20-year period.

New gas power plants are less polluting than coal. However, when the entire supply chain of gas production is considered, gas is not significantly less polluting than coal. Current levels of reliance on gas power in Australia must be reduced to play our role in limiting global temperature below 2°C. Expanding gas usage is inconsistent with tackling climate change as it locks in emissions for decades into the future.

Greater reliance on gas will drive higher power prices

Australia’s liquefied natural gas exports are pushing up the price of gas power as domestic gas prices are now inextricably linked to world market prices for oil. This will continue into the foreseeable future.

The most economic and accessible reserves are now being exported. Further gas expansion will drive increased reliance on unconventional gas, which is expensive. Reliance on gas power is also driving power price spikes, particularly in South Australia, Queensland and increasingly in New South Wales, due to lack of competition among gas power companies.

Investment in new gas plants is financially risky

The large increases in future gas prices and volatility resulting from liquefied natural gas exports together with domestic gas prices controlled by relatively few producers, make investments in new power plants using gas very risky. New gas power plants would rely on ageing gas production infrastructure (e.g. processing plants and high pressure pipelines) that is increasingly vulnerable to failure. Costs of updating this infrastructure and accounting for methane leakage must be factored into policy and investment decisions.

New gas infrastructure locks in carbon emissions for decades. Future regulations may impose higher costs or stricter limits on emissions in the future, impacting on the economic viability of gas production and electricity generation, stranding investments.

Significant development of new gas plants is unfeasible without a massive expansion of unconventional gas

The sheer volume of gas required, the cost, the lock in of long-term emissions, environmental risks and lack of support from communities near gas wells makes this unrealistic. Currently the emissions from unconventional gas in Australia are unknown due to a lack of measurement and data. This presents a long term carbon risk to investors as high emissions fossil fuel infrastructure faces the possibility of future regulation due to climate change. Development of new unconventional gas is entirely out of step with meeting the Australian government’s climate change goals.

Renewable energy can provide a secure, affordable alternative to new fossil fuels

New renewable energy is cost competitive with new gas. The cost of renewable power and storage, particularly solar, wind and batteries, continues to fall and has no associated fuel costs. This contrasts with rising and volatile gas prices.

Technologies such as solar thermal, hydro and biomass plants can meet demand for electricity at all times of the day as well as meeting technical requirements for grid stability. Combining these technologies with wind, solar PV, and large-scale energy storage, can meet electricity demand round-the-clock. Using existing gas-fired generators and supply infrastructure prudentially to complement wind and solar power while scaling up a range of renewable energy technologies, energy storage and energy efficiency measures could deliver a limited benefit, provided the end goal is phasing out the use of all fossil fuels as quickly as possible.

Conclusion

The report concludes that Australia should not provide policy support for new gas power plants or gas supply infrastructure. Existing gas plants should be thought of as a short-term, expensive, emergency backup as renewable energy and storage is rapidly scaled up.

Every day there’s an outdoor event to celebrate or commemorate something or other, and balloons will be released. It looks spectacular for a moment or two, but they’re soon forgotten. What happens to them? Most end up in our seas, where they are eaten by marine wildlife, including seabirds. It sounds frivolous, but it’s become a major conservation problem.

BirdLife Australia has thrown its support behind a campaign by Zoos Victoria and the Phillip Island Nature Parks to shine a spotlight on this issue.

Most people aren’t even aware that the simple act of releasing balloons into the air poses a major danger to wildlife. However, the facts are startling. A CSIRO study found that balloons are in the top three most harmful pollutants threatening marine wildlife – along with plastic bags and bottles.

Albatrosses, cormorants, penguins and pelicans are all affected by this, but of all Australia’s seabirds, shearwaters, or muttonbirds, are the most badly affected when it comes to ingesting plastic debris.

For example, the decline of Flesh-footed Shearwaters on Lord Howe Island has been directly linked to the ingestion of debris, with balloons and their plastic attachments, one of the most prevalent and readily identifiable items found inside them. Further, two separate studies have found that 100% of Short-tailed Shearwaters contain plastic in their digestive systems.

The balloons fill the birds’ digestive tracts while offering no nutrition, and slowly poison them as toxic chemicals leach into the birds’ tissues.

Birdlife Australia is joining Zoos Victoria and Phillip Island Nature Parks to encourage Australians to make their outdoor events wildlife-friendly. The best way to do this is by choosing to use bubbles instead of balloons to reduce this source of harmful waste.

Help spread the word to use bubbles instead of balloons at outdoor events. It’s a simple act but it can make such a big difference.

This information comes from Birdlife Australia.

Further reading:

• https://www.zoo.org.au/get-involved/act-for-wildlife/balloons
• https://www.zoo.org.au/get-involved/act-for-wildlife/balloons/about
• https://www.csiro.au/en/Research/OandA/Areas/Marine-resources-and-industries/Marine-debris

Ku-ring-gai Council has commissioned a report on developing the tourism potential of the municipality. Ku-ring-gai Destination Management Plan 2017 to 2020 is open for submissions until Friday 12 May.

The report focuses on a plan:

… to redevelop the St Ives precinct to achieve a ‘wow factor’ to attract visitors, benefit residents and help grow the local visitor economy.

The aspirations presented in the report are:

• to develop the precinct as a distinctive destination for nature-based and Aboriginal cultural tourism experiences
• to establish the precinct as a unique trekking hub and gateway for adjoining national park trails and Hawkesbury River to Sydney Harbour linkages to achieve similar iconic status as the Three Capes Track in Tasmania
• to develop events infrastructure and supporting facilities to position the precinct as centre for international-standard performances similar to those staged at the Hope Estate in the Hunter Valley for music, cinema and performing arts
• to rebrand the precinct to reflect its competitive advantage and world-class potential (e.g. Centennial Parklands and Western Sydney Parklands)
• to commission a revised master plan to balance existing recreational and community activities with a new tourism focus under a trust governance model used elsewhere
• to achieve the precinct’s full potential as a seven day a week, four seasons integrated mixed-use destination for international and domestic visitors

Accommodation Proposals

The possible developments described are more prosaic. Many of the suggestions are for the upgrading of existing facilities but STEP would be concerned by proposals for:

… unique accommodation experiences that complement these experiences (e.g. a five-star eco-tourism lodge sited near the boundary of the national parks escarpment, hostel accommodation for education and recreation groups and flash-camping).

Details are needed on how this sort of development can be achieved without damaging the environmentally sensitive E2-zoned land including endangered the Duffys Forest Ecological Community. The map at the top of the page also seems to show some national park land as being within the precinct. STEP will be looking at these plans very closely.

The report does acknowledge the environmental constraints:

It should be recognised that the recommended strategy, focused on nature based and Aboriginal cultural tourism, has environmental protection and enhancement at its core. There are numerous examples around the world of sensitively designed accommodation and infrastructure within and adjacent to national parks and areas of high ecological value. It is proposed that all new development in the St Ives precinct will be sensitively designed, constructed and operated in accordance with best practice and there should be a net improvement to environmental performance on site such as increased biodiversity, improved drainage runoff, Aboriginal cultural interpretation and signage. It should also be appreciated that many parts of the St Ives precinct are in a degraded environmental condition.

Walking Tracks

Proposals to upgrade walking tracks within the precinct and links to Ku-ring-gai Chase and Garigal National Parks are welcome. Many of the existing tracks are degraded and unattractive because of weed infestations. Funding has always been a problem, both for council and National Parks and Wildlife Service. This highlights the perennial problem, where will the money come from? It seems that public private partnerships and commercial leases are the only hope.

National Parks Development

The report (p19) states that the NSW government is about to release a new master plan for national parks covering partnerships with nature-based tourism stakeholders. A draft new Plan of Management for Ku-ring-gai Chase National Park is due to be released this year. It is going to be another busy year for preparing submissions.

Old Nursery Site

The plan for an indoor sports centre at the site of the nursery does not get a mention. Has that idea fizzled out? Instead there is mention of a native wildflower nursery funded by the private sector.

Road Links and Parking

The report highlights the need for traffic lights and a pedestrian crossing at the main entrance on Mona Vale Road. It also suggests that the exit at the Wildflower Garden be closed with internal roads being used to gain access via the main showground. There is a suggestion for overflow parking on the other side of Mona Vale Road. The effects of car parking on the Duffys Forest vegetation and soils has always been a problem and is currently controlled by the use of bollards and parking restrictions. If the number of visitors is to increase significantly the control of parking will be more important than ever.

Firstly, some history; in 2003 UTS decided to vacate the site and sought a rezoning for residential development with 560 buildings. Ku-ring-gai Council refused the application so the state government intervened and declared the site to be a Part 3A project under the EPAA Act. The Minister for Planning became the decision maker.

STEP was a member of a community consultative committee established to demonstrate that the community had been consulted. The committee opposed many aspects of the development plan. There were some wins in the transfer of 9 ha of the land to management by Lane Cove National Park and some improvements including a reduction in the number of dwellings approved for the site, the retention of a full-sized oval for community use and the retention of heritage buildings.

Of course there are no additional funds available to the NPWS to manage the additional national park land. A significant area of bushland has been modified to establish the asset protection zone and of course there will always be traffic and parking problems especially when the new school is operating. The management of stormwater and the risk of weed encroachment will need to be closely monitored.

Crimson Hill – Defence Housing Australia (DHA)

Crimson Hill estate was designed along simple, environmentally sound principles aimed to establish a new integrated community connected by bushland trails and elevated walkways. The objective was to promote community interaction and well-being. It has 345 dwellings occupying a portion of the 12.6 hectare site of rezoned land that DHA purchased from UTS in March 2011.

A significant area of this land, including publicly accessible bushland and nature trails for bushfire management, is in the care of the new residents via a Community Management Association.

It is DHA’s first multi-residential housing project and is being constructed in five phases. The name is a salute to the colour of the ribbon on the Victoria Cross medal. Each residential precinct is named after one of the five recipients of the VCs awarded for bravery on a single day during the battle of Lone Pine in 1915:

• Burton’s Place – Alexander Stewart Burton
• Dunstan Grove – William Dunstan
• Tubb’s View – Frederick Harold Tubb
• Hamilton’s Corner – John Hamilton
• Shout Ridge – Alfred Shout

The estimated 700 residents, expected to occupy Crimson Hill eventually, comprise a mix of Defence personnel and civilians. There are many owner-occupiers and tenants.

DHA is an Australian government enterprise established by the Defence Housing Act 1987 to supply housing and related services to Australian Defence Force members, in-line with operational requirements. Launched in 1988 as a statutory authority, DHA is now a commercially-funded organisation that has projects all over Australia. During 2015–16, DHA managed 18,767 properties for ADF members and civilians.

Before construction commenced in 2013, the brownfield site had significant areas of native remnant bushland around the university campus. A detailed ecological assessment was done before any clearing started.

Indigenous seeds were collected from endemic species and these were replanted. It is estimated that over 90% of plants on the site now are native and the majority are locally occurring species.

The centrepiece of the estate is Charles Bean Sports Field, opened in December 2013. It was developed by DHA with Ku-ring-gai Council and the Northern Suburbs Football Association. The purpose-built, publicly-accessible sports field has received FIFA 2-star certification, the highest accreditation an artificial grass field can receive. There are football teams coming and going continually and it is rare to see the field without players on the evergreen surface.

Rainwater is harvested within the buildings for re-use and some have solar panels to reduce main-grid energy usage. Environmental consultancy Cundall, estimates the buildings will use 60% less energy and water than standard multi-residential developments. The residential development was designed by two architectural companies: Bates Smart and Architectus. Construction was by two building companies: Grindley and Ganellen.

The recently finished Shout Ridge is the first apartment building in Australia to receive a prestigious 6-Star Green Star – Multi Unit Residential Design V1 certified rating for environmentally sustainable design from the Green Building Council.

New School on the Horizon

The latest good news for Lindfield residents is that planning is underway for a major refurbishment of the empty UTS building that remains from its previous use as a university. The building is earmarked to become a new K to 12 school.

The large concrete building was handed over to the NSW Education Department as part of a land swap with UTS. Eventually 2,000 primary and secondary students are anticipated to attend the new school. It hopes to have high quality technical spaces for science, engineering, hospitality, visual and performing arts, as well as music and film. And there will be a childcare facility.

The former UTS building has architecturally heritage because it won the prestigious Sulman Medal for architecture in 1978. This is the highest award given in Australian architecture.

New Walking Track

NPWS and DHA, with the assistance of Friends of Lane Cove National Park, are building a new track from Crimson Hill to Lane Cove National Park. Locals will be able to walk along this bushland track and stroll among wonderful angophora, wattle and eucalypt trees to get down easily to Lane Cove National Park all without any need to get into a car. At a construction cost of more than $220,000, the track will be one more amenity for the residents of Crimson Hill and other locals.

Note:  As it is, the track is not shown on our new map, Walking Tracks of the Lane Cove Valley. An example of how hard it is to keep up-to-date.

Lots More Development

As President of the Friends of Lane Cove National Park, Tony Butteriss points out in Regenavitis, wherever you look in Sydney now, there is more development and if feels as if it is getting closer to Lane Cove National Park. There are numerous projects coming right on the edge of the Park including the old UTS site, old Screen Australia site (adjacent) and redevelopment of the Acoustic Laboratory. However, the development that makes all the others look as if they are only playing, is the one at the Epping Road end of Delhi Road. Strictly speaking it is not one but at least three different developments planned to have a total of more than 2,200 units. This will have an impact of (at least) 5,000 people.

This particular development is a worry but consider the cumulative effect of all of them. Each development reduces habitat surrounding the Park. Each brings more hard surfaces and increases the speed of run-off after storms. And each brings visitor overcrowding to the Park. What can local groups do about this? The Friends hope to persuade the developers to fund some restoration projects.

The February edition of Regenavitis, the newsletter of the Friends of Lane Cove National Park, included the following update on the development of the former UTS (Ku-ring-gai) site in Lindfield that is now called Crimson Hill. We thank them for permission to reprint.

Click here for more information on the campaign.

Thirlmere Lakes lie in an area that was subject tectonically to weak uplift and gentle monoclinal warping at the ill-defined southern end of the Lapstone Structural Complex, a feature that is highlighted further north by the bold escarpments of the Lapstone Monocline and the Kurrajong Fault. The chain of five shallow, swampy lakes lies in the remnants of an alluvium-filled, mature, incised-meandering river system that ancestrally drained westwards into the Wollondilly catchment. However, as a consequence of the gentle upwarping plus relative subsidence of the adjoining Cumberland Basin, the drainage direction in the north-east sector of the chain has been reversed due to headwater capture by Cedar Creek, which flows via Stonequarry Creek south-eastwards to the Nepean. The lakes are essentially stranded on a gentle watershed between two drainage systems.

The catchment area of the lakes is relatively small, roughly 10 km² of Hawkesbury Sandstone spurs and side-valleys, and there is no long distance drainage flow-through along the dismembered ancient river course. But they overlie a substantial thickness of water-saturated alluvium whose water leaks away very slowly, and are in one sense the surface manifestation of its rising and falling water table.

Rises and Falls in Water Level

Latter day fluctuations in the water levels in these ancient lakes have been the subject of much recent debate centred around the possible effects on aquifers of longwall coal mining in nearby Tahmoor Colliery, operated by Xstrata. Other suggested factors have been the pumping of aquifers for local agricultural purposes.

Levels were particularly low in June 2010 (photo bottom left) and then rose quite slowly – below many people’s expectations (photo at the top of the page was taken in May 2015). However, the lakes now (March 2017) are as full as they’ve been in recent decades (photo bottom right).

You can easily access the rainfall data of the Bureau of Meteorology’s automatic rain gauge located near Buxton 3 km to the south, and from it you can deduce some interesting correlations.

The low water levels of 2010 following the exceptionally dry year of 2009 (photo bottom left) occurred when only 588 mm was recorded against a mean of 856 mm. In strong contrast, in 2017 (photo bottom right) is a hangover from the massive east coast low falls of June 2016 when 387 mm was recorded at Buxton, including a one day fall of 188 mm (contrast the wettest monthly total for 2009 of only 97 mm). Rains from east coast lows can overwhelm everything over huge areas, create massive floods, and fill and sometimes overflow our storage reservoirs. The plants don't need all that extra water, especially in winter, and what doesn't run off will bypass their root systems and swell the aquifers, including those that feed the lakes.

And what of the gradual rise in lake levels from 2010 onwards that had many people puzzled? Well, four out of the six years from 2010 to 2016 brought above average rainfall, peaking at 971 mm in 2013, and the other two were only slightly below – 736 mm in 2011 and 841 mm in 2014. The maximum one day fall in that period was 133 mm in January 2013 and January and February of that year scored a combined total of 326 mm. This was thus a slightly wetter than average time and the photo at the top of the page shows Lake Werri Berri recovering, roughly half full, in May 2015, a year in which the preceding month of April was the wettest one with a total of 164 mm.

Are we still pointing a finger at Xstrata's longwall mine system? Well this is a personal opinion and don't quote me as an expert, but I believe it can only be a minor factor at most; rainfall versus evaporation is demonstrably the major control, as has been the case from historical records and one which is built into the conclusions of the report cited below. How climate change will affect things in the future is unknown, though there is already evidence of increasing intensity within rainfall events. More ones like June last year can only be good for the lakes.

Recommended reading: Thirlmere Lakes Inquiry Final Report of the Independent Committee, 23 October 2012

John Martyn recently visited Thirlmere Lakes to see how the area has fared during the recent period of freak weather. In STEP Matters 186 we wrote about concerns that the significant drop in water levels since the mid-1980s was due to longwall mining. It seems the picture has changed considerably.

The name Wianamatta is familiar through the loose usage of the term ‘Wianamatta Shale’ to embrace the Triassic rocks that overlie the Hawkesbury Sandstone. This is an informal term, distinctly woolly in its definition, and should be avoided, but if it must be used, ‘shale’ or ‘shales’ should always be spelt lower-case.

Wianamatta Group, derived from the Aboriginal name for South Creek, was established formally in 1952, fully documented in 1954 and further revised in 1979. The group consists of three formations: the Ashfield Shale, Minchinbury Sandstone and Bringelly Shale. It occupies the centre of the Sydney Basin, lapping onto the lower Blue Mountains and extending southwards to the Southern Highlands. It has been defined largely from drillhole data because outcrop is mostly limited to road and railway cuttings and quarries.

The thickest stratigraphic section drilled was encountered in hole DM Razorback DH1 on
Mt Hercules near Picton. This passed through 304 m of Wianamatta Group strata consisting of 257 m of Bringelly Shale, 2 m of Minchinbury Sandstone and 45 m of Ashfield Shale.

The Ashfield Shale and Minchinbury Sandstone correlate well across much of the 50 km long area covered by the same Department of Mineral Resources drill program, whereas the Bringelly Shale is much less uniform, its variability enhanced by the presence of many scattered sandstone lenses of limited lateral extent but up to more than 40 m in thickness that are hard to correlate.

The Wianamatta Group was deposited on a coastal lowland subject to early minor marine incursions. The depositional environment evolved upwards into lagoonal or marshy lowland crossed by meandering rivers that brought surges of sand that filled channels and created the sandstone lenses.

Ashfield Shale

The Ashfield Shale has a maximum drilled thickness of 61.6 m at Erskine Park near the centre of the basin and has been subdivided into four members consisting of alternating layers of dark ferruginous shale and laminite.

All of these members were once incompletely exposed in the Thornleigh brick pit but this has since been filled in. Now, the most viewable Ashfield Shale faces can be found along the North Shore and Northern railway lines and Bells Line of Road, and in a number of other road cutting exposures such as Horace Street, St Ives and in the Picton–Campbelltown area.

The best natural exposure is the river-cliff in Mulgoa Nature Reserve south of Penrith which exhibits dark coloured Mulgoa Laminite Member, and also the river-cliff opposite the Parramatta ferry wharf (see photo). The Mulgoa cliff is visible from Mulgoa Road through gaps in a screen of riparian forest but is difficult to access on foot.

An important feature of the Ashfield Shale is its relatively high phosphorus content of between 0.1 and 0.9% P₂O₅. This is in strong contrast to the negligible amounts of phosphorus in the underlying Hawkesbury Sandstone and is also significantly higher than levels in the Bringelly Shale. Phosphorus values in Ashfield Shale measured from drill core tend to be spiky with prominent peaks, and it appears the element resides in thin beds rich in phosphatic siderite nodules.

Minchinbury Sandstone

The Minchinbury Sandstone is a widespread but thin (less than 6 m) marker band of fine-grained, bluish-grey, brown-weathering rock that is rarely seen in surface outcrop and is known mainly from drill intersections. It is a quartz lithic sandstone with grains mostly of quartz with about 10% of rock grains. It also contains calcite, plus micas, notably muscovite which can be seen sparkling on broken surfaces. Another very similar, intermittent sandstone bed lies immediately above in the lower Bringelly Shale. Both sandstones weather deeply to a crumbly or flaky condition and surface expressions are subtle, or the sandstone outcrops are smoothed over by soil profiles or pasture.

Minchinbury Sandstone at Minchinbury is more than 100 m deep in a borehole, and finding its outcrops elsewhere, especially natural ones, is a challenge. Near the top of the Mulgoa shale cliff there is a thin (less than 1 m) band of very fine-grained flaggy sandstone which has been interpreted as Minchinbury. In Lansdowne Park (see photo) there is a train of large, disjointed sandstone slabs whilst other small outcrops and floaters are scattered along a low, hillside bench. There are a few others, but if you happen to know of any more, please let me know.

Bringelly Shale

The Bringelly Shale is the uppermost formation of the Wianamatta Group and also the youngest Triassic sedimentary unit in the Sydney Basin. Reaching more than 250 m in the south, it is also one of the thickest.

The commonest rock type exposed is a mixture of finely-bedded shale, laminite and siltstone. Seen in road cuttings this differs from the dark, almost black, clay-mineral-rich Ashfield Shale, being more variable, often accompanied by disconnected sandstone lenses that become thicker and more prominent from Western Sydney Regional Park southwards, forming most of the hilly country between Campbelltown and Picton. Driving south or into the Picton area you can't miss them. They form intricate escarpments up to 200 m high, and the sandstone cliffs along the old Hume Highway near Picton (see photo) are of the two thickest ones, the Mt Hercules and Razorback Sandstone Members (see photo at the top of the page).

Such sandstones have been described as lenses and stacked multiple lenses and have been interpreted as infill deposits in channels created by rivers meandering across the swampy lowland. Their lateral extent is not great and they are difficult or impossible to correlate with one another across distances of more than a few kilometres, but they are important in defining the landscape, their scarps and hollows nurturing sub-types of endangered Cumberland Plain Woodland floras.

Ashfield Shale Floras

Ashfield Shale outcrop extends to higher elevations and into higher rainfall areas than Bringelly Shale. These include the North Shore where rainfall zones exceeding 1000 mm, and similarly the Bilpin–Mountain Lagoon area. Where the shale forms cappings that fringe the Illawarra escarpment the mean annual falls may exceed 1500 mm by a significant amount.

Blue Gum High Forest is familiar to most STEP members and needs little description here. Most members live within 10 min drive of Dalrymple-Hay and Sheldon Forest or can easily reach more far flung localities like the Blackbutt forest of Galaringi Reserve or the Blue Gum, Grey Ironbark forests of Rapanea Community Forest, both in the Carlingford area. But even more diverse treats are in store in the Blue Mountains where the Mountain Blue Gums Eucalyptus deanei and Monkey Gums E. cypellocarpa grow tall and stately in the endangered Blue Mountains Shale Cap Forest of the Bilpin area. These two are members of a cornucopia of eucalypt species as the community grades laterally into Sydney Turpentine Ironbark Forest and Shale Sandstone Transition Forest. Appearing are Grey Ironbark, Mountain Mahogany E. notabilis, Grey Gum, White Stringybark, Sydney Peppermint, and of course not forgetting Turpentine.

Have you visited the Illawarra Fly Treetop Walk at Knights Hill near Robertson? If not it's worth an outing, rounded off by a pie at the Robertson Pie Shop. The walk meanders through the crowns of two tall eucalypt forest species,
Gully Gum Eucalyptus smithii and Brown Barrel E. fastigata. Ashfield Shale sits atop a sheer cliff of Hawkesbury Sandstone protected by a large capping of Cenozoic basalt. The weather station at the pie shop records a mean annual rainfall of nearly 1600 mm.

Scheyville National Park near Pitt Town is perhaps the best place to look at lower rainfall communities on Ashfield Shale. It includes part of the former Pitt Town Common grazing lands whose pasture merges into tracts of quite dense woodland and forest. The dominant plant community is the critically endangered Cumberland Plain Woodland whose principal tree species are Grey Box Eucalyptus moluccana, Forest Red Gum E. tereticornis and Narrow-leaved Ironbark E. crebra. The forest floor is often grassy and may be sprinkled with quite delicate wildflowers like Blue Trumpet Brunoniella australis in spring and summer. Cumberland Plain flora shares many herb and shrub species with the tablelands and slopes of NSW but in the grassy ground flora you'll also be reminded of aspects of Blue Gum High Forest.

Bringelly Shale Floras

The Minchinbury Sandstone is so thin and it weathers so readily that, vegetation-wise, it is inseparable from the Bringelly Shale (or for that matter the underlying Ashfield Shale).

The Bringelly Shale supports a more varied range of Cumberland Plain plant communities than the Ashfield Shale described earlier. Because of the presence of sandstone beds and lenses, its country can be quite hilly, with sheltered slopes and valleys, and this has led to the creation of Shale Hills as distinct from Shale Plains woodlands as Cumberland Plain Woodland subtypes. Sheltered valleys and steep slopes have also nurtured additional communities such as Western Sydney Dry Rainforest and Moist Shale Woodland, both also listed endangered. However, rainfall nowhere reaches levels that would support tall blue gum forests like those on Ashfield Shale in Sydney’s upper North Shore or the lower Blue Mountains.

Reserves carrying native vegetation on Bringelly Shale are relatively small, widely scattered and often subject to weed invasion especially by African Olive, Lantana, privet species and African Lovegrass. They include Lansdowne Park, remnant pockets within Mt Annan Botanic Gardens, Mulgoa Nature Reserve, Shanes Park, and Wianamatta and Western Sydney Regional Parks including Kemps Creek.

In Western Sydney Regional Park you can wander from the main park areas into quite dense Spotted Gum forest, and into sheltered niches below escarpments formed by sandstone lenses which carry Moist Shale Woodland and Western Sydney Dry Rainforest, with odd ring-ins like White Mahogany Eucalyptus acmenoides amongst the Spotted Gums and Forest Red Gums. Understory species include Mock Olive Notelaea longifolia and Hairy Clerodendrum Clerodendrum tomentosum. Climbing plants are particularly diverse and include native Grape Cayratia clematidea and Gum Vine Aphanopetalum resinosum (from personal experience, too aggressive to grow in the garden).

Main reference: Herbert, C. (1979) The Geology and Resource Potential of the Wianamatta Group, Geological Survey of NSW Bulletin 25

This is the fourth in a series of articles by John Martyn on Sydney’s geology.

The Australian Association of Bush Regenerators was established in 1986 out of concern for the continuing survival and integrity of bushland and its dependent fauna.

The AABR recently put on a lunch for what they called the pioneers of bush regeneration, those visionary and committed people who took the concept from the Bradley sisters, developed it, sat on committees, turned it into a tech course, wrote text books and generally created a new approach to bushland management. Apart of course from working in the bush themselves.

Sydney's Blue Gum High Forests built colonial Sydney. By the 1850s most had gone. However a few patches survived. The largest one was in St Ives. It was so rare, that Richard Dalrymple-Hay, NSW’s first Commissioner of Forests, acquired it as a demonstration forest. This became known as the Dalrymple-Hay Nature Reserve.

In 1934 Annie Wyatt – later to become the founder of the National Trust – led a community campaign to save this endangered forest.

Then again in 2007, the community led another campaign to acquire two privately owned blocks of land into public ownership and so protect the forest. To celebrate the tenth anniversary of this campaign, Friends of Ku-ring-gai Environment (FOKE) and STEP have organised some walks which highlight the beauty of Blue Gum High Forest and Janine Kitson is presenting a talk entitled The Battle of the Blue Gums.

FOKE Walk on Sunday 7 May – Dalrymple-Hay Nature Reserve

Time: 9:45 for a 10 am start (finish noon)
Meet: entrance to Dalrymple-Hay Nature Reserve (cnr Rosedale Road and Vista Street, St Ives)
Book: Janine Kitson (0428 860 623, 9498 2402, This email address is being protected from spambots. You need JavaScript enabled to view it.)

Nancy Pallin, one of the leaders of the campaign, will lead a walk demonstrating the unique features of this outstanding forest.

FOKE Walk on Sunday 14 May – Sheldon Forest from Turramurra to Pymble

Time: 9:45 for a 10 am start (finish noon)
Meet: ticket office, Turramurra Station
Bring: hat, water, snack and good walking shoes (involves walking up some steep hills)
Book: Janine Kitson (0428 860 623, 9498 2402, This email address is being protected from spambots. You need JavaScript enabled to view it.)

Sheldon Forest is one of Sydney’s rarest urban forests. It is within walking distance of not one, but two, railway stations – Turramurra and Pymble. The North Shore railway line forms a wildlife corridor that connects Sheldon Forest to other remnant forests in reserves and gardens. This ecologically focused heritage walk explores the unique relationship between the natural and built heritage of Ku-ring-gai and Sydney's forest history. It reveals layers of history – indigenous, colonial, federation, interwar, as well as revealing Australia’s rich biodiverse natural history. Discover why the resilience and protection of this magnificent Blue Gum High Forest is so important during a time of climate disruption and biodiversity extinction.

NPA Talk on Saturday 10 June – The Battle of the Blue Gums

Time: 10 to noon
Tutor: Janine Kitson
Book: https://www.weasydney.com.au/course/TBBG

During the 1930s, two forests were under threat – the Blue Gum Forest in the Blue Mountains and the Blue Gum High Forest in suburban Sydney. Discover how pioneer conservationists like Myles Dunphy and Annie Wyatt successfully rallied to protect these forests. How did these forest battles contribute to the modern Australian conservation movement? How are these forests faring today – at a time of burgeoning population increase, habitat loss and climate change?

STEP Walk on Sunday 18 June – Blue Gum Walk in Hornsby Valley

Click here for more information

It’s a rare week when natural resource management policy penetrates the national news cycle not once, but twice.

Nonetheless, last Thursday the federal government struck a deal with the Greens to increase funding to Landcare programs by $100 million in exchange for their support on other matters. No one quite seems to know yet how this money will be spent – presumably in ways that support the thousands of volunteer community Landcare groups dotted around Australia.

Then on Sunday, the Australian Financial Review reported that the government will abolish the Green Army program as part of its mid-year budget update later this month.

Introduced in 2014 as a signature policy under the then prime minister, Tony Abbott, the Green Army aimed to mobilise 15,000 young and unemployed people to work on conservation projects and receive complementary training. Axing the program would deliver budget savings of around $350 million.

Abbott took to Facebook on Monday to criticise the move. His main concern seems to be the implication that the Greens’ policy priorities are more important than the Coalition’s. That’s a bad look, he argues, for a 'centre-right government'.

Yet the move would arguably be very much in keeping with centre-right values. By reinvigorating Landcare’s model of personal responsibility and self-regulation, the government could reduce pressure to regulate land use or to pay landholders financial incentives to improve their environmental management.

But consistency with any particular political philosophy is not the issue here. The hyper-polarised political landscape of recent years, particularly on environmental policies, encourages parties to differentiate on any grounds they can. Thus, the cross-party support long enjoyed by Landcare can perversely work against it. Incoming governments believe they need new programs to claim as their own, diverting attention and resources from those already in place.

The $484 million cut to Landcare in the 2014 budget needs to be remembered in this context. Both Coalition and Labor governments have made changes over the years that either reduced the financial support available to community Landcare groups, or imposed more top-down modes of decision-making.

The 2015 Senate inquiry into the National Landcare Program revealed considerable community concern about the impacts of budget cuts on Landcare’s activities and on private commitment to natural resource management. Every dollar of public money invested in Landcare is believed to leverage between $2.60 and $12.00 of community and landholder investment.

When the Green Army was launched, many people questioned whether it would deliver this kind of value for money. With a three-year review of the Green Army due for release early next year (subject to ministerial approval), we might have expected to see some answers.

So why is the Green Army is being cut before the review? Perhaps the government is sparing itself the embarrassment of defending a program that is failing to meet its objectives. Perhaps, despite the critics, the findings would have been positive and the government is avoiding having to explain why the Green Army is being killed off anyway. Perhaps it’s just looking for easy budget savings.

Strategic plan?

Whatever the motivation, the biggest concern is the absence of a strategic and coherent approach to natural resource management policy in Australia. Major program changes are being made with limited consultation and transparency, and precious little evidence of planning.

At the same time, some policies and programs appear to be working at cross purposes. For example, tree clearing is increasing in much of Australia at the same time that some landholders are being paid through the Emissions Reduction Fund to conserve native vegetation.

Questions need to be asked about the genuine impacts of existing policy, about the way in which regulations intersect with voluntary programs, and about coordination between Commonwealth and state governments, among other issues.

The recent Senate inquiry into Landcare called for long-term investment and stability in natural resource management programs. Achieving this will require a return to genuine cross-party support coupled with broader community and industry support. The key to achieving this, I suspect, is less wheeling and dealing among political parties and more consultation and planning with all interested stakeholders.

It might be time to consider a white paper process to inform the next phase of natural resource management policy. At least that would give us some confidence policy is not being decided on the run.

Stewart Lockie, Director, The Cairns Institute, James Cook University

This article was originally published on The Conversation. Read the original article.

STEP is delighted that our secretary has received Ku-ring-gai Council’s Australia Day Award for Outstanding Service to the Ku-ring-gai Community (Individual).

Helen has been the key engine-room of STEP as a committee member since 1990 and secretary since 1997. She has devoted many hours applying her comprehensive skills to the operation of STEP. Her work has included maintaining the membership records, creating communication material, editing our newsletter and publications, promoting and selling our books and maps. More recently she has been the brains behind the modernisation of our website and the transformation of our newsletter distribution into the digital age.

Without Helen’s selfless devotion STEP could not have functioned successfully.

The geology of the Sydney Basin changes dramatically at the top of the Hawkesbury Sandstone, which is followed upwards ultimately by the thick, shale-dominated Wianamatta Group. It isn’t an abrupt change but usually a transition, via several metres of alternating sandstones and shales called the Mittagong Formation. The quartz-rich sandstones of the Mittagong resemble finer-grained versions of the Hawkesbury Sandstone and they are interleaved with dark grey to black shales, siltstones and laminites.

Originally named Passage Beds by JF Lovering in 1954, the current name was adopted from a selected type locality, the Gib (Mt Gibraltar) railway tunnel at Mittagong, where the formation is 15 m thick. Elsewhere it is almost invariably less than 10 m and can locally be absent altogether. Exploratory drilling for the Epping to Chatswood railway tunnel at Macquarie Park, for example, encountered only a 2 to 5 m thickness of it.

The variability is in part due to the nature of the dwindling flood plain and braided river system which deposited the Hawkesbury Sandstone. This vast system eventually lost its strength and became a plain of scattered sandbanks, swamps and lagoons. Clays settled in the latter but were periodically overwhelmed by sand brought by late floods leading to a sandstone/shale alternation of very variable thickness.

For such a thin unit the Mittagong Formation has a disproportionate effect on vegetation because it usually creates a broad bench at the top of the Hawkesbury Sandstone’s steep rocky dropoffs and cliff lines. This leads to the retention of soils and can even collect downwash from overlying Ashfield Shale if present. Such level surfaces can also attract deep weathering and laterite formation.

Like the shale lenses in the Hawkesbury, Mittagong Formation forms richer soils than the sandstone but stonier, more lateritic and less fertile than those of the overlying Ashfield Shale. These yellowish soils are typically classified as belonging to the Lucas Heights soil landscape, highlighting similarities in the bedrock between Mittagong Formation and Hawkesbury Sandstone with its shale lenses in the Lucas Heights area.

Plant communities hosted by Mittagong Formation are diverse and usually gradational to those of adjoining shale or sandstone, often falling within the broad envelope of Shale Sandstone Transition Forest with either a sandstone bias or a shale leaning depending on setting. In other sites the communities may be more tightly defined in terms such as Sydney Turpentine Ironbark Forest, Turpentine Ironbark Forest, or where strongly lateritised, Duffys Forest. They tend to have one thing in common, they are mostly legally defined as threatened, mainly because they survive in narrow, disjointed enclaves isolated by land clearing.

Is it Possible to View the Mittagong Formation?

Not as easily as you might think, and only in artificial cuttings – natural exposures are virtually unknown!

You can look at its type locality at the south-west end of the Gib Tunnel at Mittagong but only by telephoto lens through a security fence (see photo at the top of this page). It's also visible in cuttings along the M31 nearby, but at 110 km/h it's a case of ‘don't blink or you'll miss it’. The best locality is probably the road cutting of the Picton railway overbridge (see photo) though you'll have to park down the road and walk back in if you want to see it hands on.

In our own local area there are a number of rather poor and vulnerable artificial exposures, like the M2 cutting under the Barclay Road over-bridge at North Rocks. But this is currently being plastered in concrete by the North Connex guys and will soon largely disappear. The embankment of the Abbott Road eastbound feed-in lane to the M2 is good too but you can't stop there, nor can you for the south-west embankment of the M2 north-west of the Lane Cove Road interchange at Macquarie Park.

As for natural outcrops, when you stroll around in bushland on the flat ground above Hawkesbury Sandstone dropoffs you may see abundant shards of lateritised shale and siltstone in the soil, but unless you stumble on an erosion gully or creek line you'll be lucky to see anything more.

Sheldon Forest

Sheldon Forest is a pretty good start. Wander down past the scout hall to the sweeping apron of tall Blackbutt forest and you'll be descending from Ashfield Shale onto Mittagong Formation. As the track descends further towards the Hawkesbury Sandstone dropoff there is a marked increase in Turpentines, Sydney Red Gums and many shrubs of sandstone affinity such as banksias. But you don't have to return very far back uphill before shale species like the pea-flowered groundcover Tick Trefoils Desmodium rhytidophyllum and D. varians reappear.

Auluba Reserve

At roughly 3.5 ha, this is probably the largest area of Mittagong Formation bushland in the Lane Cove catchment. It's primarily Blackbutt forest very like lower Sheldon but several other tree species are present, notably Sydney Red Gum, Red Bloodwood and Red Mahogany, and both White and Narrow-leaved Stringybarks are present though these are rare, scattered and sometimes in poor condition. The shrub flora is rich and includes the critically endangered Julian's Hibbertia, H. spanantha. The Sydney region has a greater diversity of hibbertias than any other similar-sized region of Australia and H. spanantha will very likely not be the last new species to be discovered.

North Epping Oval Bushland

This sits above the sandstone on the opposite side of the Lane Cove Valley across from South Turramurra. It's a small area with a very diverse tree community, including Sydney Red Gum, Red Bloodwood, Narrow-leaved Stringybark, Sydney Peppermint, Blackbutt, Turpentine and Christmas Bush. The shrub Laurel Geebung Persoonia laurina, uncommon in the Lane Cove catchment, is quite common here.

Fred Cateson Reserve, Castle Hill

Located at the junction of Showground Road and Gilbert Road, this is a classic locality to walk from shale cap down across the Mittagong Formation and see key plant species. The lower parts of the reserve are Hawkesbury Sandstone but the crest of the rise bordering Gilbert Road carries shale and transitional flora, notably with trees like Grey Gum, White and Thin-leaved Stringybarks, Grey, Broad-leaved and Narrow-leaved Ironbarks, Red Mahoganies and Forest Red Gums. As you descend towards the sandstone, Red Bloodwoods and Black She-oaks assert their presence.

Fagan Park – Carrs Bush, Galston

A stones throw north of Galston, this popular area of grassy park, lakes and bushland straddles the sandstone–shale transition zone, though how much is Mittagong Formation and how much Ashfield Shale is hard to deduce on the ground. The bushland fringe along Arcadia Road is certainly on shale and you can find good specimens of White Stringybark, White Mahogany and Grey Ironbark. This changes north-eastwards, and if you enter the park from Carrs Road you will first see the odd White Mahogany and Grey ironbark but you will immediately enter an area of pure Turpentine forest, almost certainly hosted by Mittagong Formation soils.

This is the third in a series of articles by John Martyn on Sydney’s geology.