Scientific Questions Simmer Over Koala Plot Data

A long-running issue relating to the reliability of vegetation data is causing major tensions in North Hawks Nest. Planners, landowners and even scientists are now in dispute over the location of missing plots of feed trees in an undeveloped area of core koala habitat.


3 concerned scientists, Graeme Wells, Anthony Stimson, and Steve Philips say that despite recent thorough searches, utilising GPS, local records and modern technology, they are unable to replicate the data-sets underpinning most koala plots in the southern end of Mungo Brush Rd, North Hawks Nest – including 9 plots recorded by Eco-Pro between 1996 and 1998. Given the length of time since these surveys, is this a reasonable assessment?

No, this is not a reasonable assessment. I am of the opinion that the premise that a replication can be done at all is flawed. Given that these plots are over 15 years old and the environment is constantly changing it would be virtually impossible for anyone to replicate the data sets today.

According to all 3 concerned scientists, other plot locations they’ve searched consistently contain different mixes of tree species, and trees of different height and diameter to what was recorded in the work of Eco-Pro, Wildthing Environmental Consultants and Robert Payne Ecological Surveys. What is your scientific opinion on this broad issue – that the 1990’s vegetation surveys can’t be replicated across much of North Hawks Nest – and to what degree are the current scientists erring?

My opinion on the fact that the 1990’s vegetation surveys cannot be replicated is that this is unsurprising considering:

  1. This type of data was never meant to be replicated 15 years later. If it were, the original plots would have been permanently marked with star pickets to allow future identification of the same site, allowing a fair comparison. What in fact occurred was an indicative sampling of the landscape to identify the presence or absence of koalas. The land subject of my report was approximately 440 hectares or 4.4 million square metres. Each plot was 1600 square metres or 0.04% of the land in total. The report was designed to provide a snap shot of the local koala population at that time, not to identify individual trees.

  2. The tree height and diameter recorded in my report was roughly estimated in the field as a reference only. The key observation when assessing koala occupation was the presence of koala scats (droppings) at the base of these trees. Given that the tree heights and diameters in my report were an estimate, it is unsurprising that recent “exact” recordings fail to match closely with an estimate from 15 years ago.

  3. The natural environment is in a constant state of change and an expectation that data is capable of being reproduced in the same form 15 years later is flawed.

Steve Philips, has told 7.30 “that the plots at the southern end cannot be reproduced no matter how generous and/or forgiving I choose to be with their placement”. The scientists have tested the methodology used by all consultants, and despite making allowances for different mapping technologies, all describe great difficulty locating plot centres against the diagnostic evidence contained in survey data. In your view, how scientifically accurate was the methodology used by Eco-Pro in North Hawks Nest, in terms of enabling the accurate reproduction and replication of findings forfuture fieldwork and monitoring?

See above.

Can you describe the methodology used by Eco-Pro in its surveys in 1996 – 1998 –was GPS used – and/or how were the plots identified, and data/location ID recorded? GPS was not used. The location of plots was roughly estimated using a 1:25000 topographic map (with a 1mm error on the map equalling a 25m error on the ground) recorded directly onto a topographic map. In your scientific opinion, to what extent is the 1990 methodology different to current practices – and what deficiencies might exist in the original data?

Scientists employ a wide range of methodologies in investigating our environment. Technology has contributed greatly to environmental science over the past 15 years, including allowing more accurate identification of locations through the use of GPS. In saying that, I am of the opinion that the methodology employed in the original report is aided very little by technology or advancements in scientific practices generally, because indicative sampling with a focus on actual koala presence remains one of the most reliable methodologies available today.

One specific example raised by all scientists relates to your work on Lots 107 and 108 (the two southern most plots), where a large number of Angophora Costata trees appear to be recorded in the data-set. 7.30 understands the opinion of all scientists is that the Angophora trees recorded are not present in the field, and likely never were present on those two specific lots. How do you respond to this scientific opinion?

It is assumed by the phrase “all scientists” you are in fact referring to Graeme Wells, Anthony Stimson, and Steve Philips. I have not been provided with any factual basis for their opinion that the Angophora costata trees were “likely never present”. I observed Angophora costata trees in the area. My observations are consistent with the two other scientists who prepared reports around the same time. I understand that clearing was conducted on lots 107 and 108 in or around 2001 in accordance with Council Records. In light of my observations at the relevant time, the observations of my peers around the same time period, clearing of the land in the interim and the constantly changing nature of every environment and without the benefit of knowing what factual basis the other scientists rely on to come to this opinion, I consider that opinion to be erroneous.

The 3 concerned scientists have all noted that many of these data-sets have recorded scratch marks and scats – visible markers of koala activity – on specific trees in specific plots. They have commented, that if these trees can’t be identified in the field today, then the utility of the data-sets may be questionable as historic records for future scientific, and planning activity. To what extent does Eco-Pro stand by the accurate placement of scats and scratch marks in its published work?

As discussed above GPS technology has enabled more accurate location of significant sites in a range of environmental science areas. It is fair to say that identifying specific trees in specific plots with corresponding information about the presence of scratch marks and scats would result in better data for consideration. The fact that there now exists more detailed and / or actuate data collection processes does not vitiate the usefulness of historical records of data collected using substantially the same process, being the actual observation of scratch marks and scats.

How do you respond to the reasoning, provided to 7.30 from Graeme Wells and Anthony Stimson, that some of the area east of Mungo Brush road might not be a core breeding and feeding area – that it’s possibly a secondary or even marginal habitat?

I have not been on the site since 1997 so it is difficult for me to comment. I note that Steve Phillips identified the presence of koalas the eastern side of Mungo Brush Road in 2001 as part of a Commission of Inquiry into this matter and that part of this land was identified as Core Koala Habitat.

7.30 has interview Glenn Handford from local council for comment on these issues, and the previous Public Inquiry held. Does Eco-Pro have any new advice for Great Lakes Council on the current scientific issues raised?

Great Lakes Council have a dedicated team of professional ecologists who both work for the Council or consult with them. Considering I have not worked on the site for about 15 years, these other scientists are far more aware of the issues regarding the area in question than I am and would provide more up-to-date advice to Council.


3 concerned scientists, Graeme Wells, Anthony Stimson, and Steve Philips say that despite recent thorough searches, utilising GPS, local records and modern technology, they are unable to replicate many data-sets underpinning core koala habitat findings in the southern end of Mungo Brush Rd, North Hawks Nest. This review has included surveys carried out by firms Eco-Pro, Wildthing Environmental Consultants and Robert Payne Ecological Surveys. Graeme Wells, and Anthony Stimson, have concerns that they have been unable to replicate 7 plots carried out by Wildthing in 1998 on “Portion 25/ DP 753166”, and two 1997 plots on lot 106 and 107. They have suggested to 7.30 that flaws might exist in the original fieldwork. To what degree might there be errors in the data set – and what deficiencies might exist in the original data?

From review of the 1997 and 1998 Wildthing investigations mentioned above there is little to suggest that errors are present in the recording of data within the plots. In both instances the plot surveys were undertaken in accordance with the AKF Habitat Atlas methodology, which was the accepted best practice methodology at the time, by two highly competent and qualified ecologists with a good working knowledge of Koala populations in the region. As I am unaware of the methodology employed by Wells and Stimson to verify Wildthing’s results or the results of any documented Koala habitat survey they have conducted I cannot see their rationale for declaring the presence of flaws or errors in Wildthing’s results.

Can you describe the methodology used by Wildthing in its surveys in 1996 – 1998 – was GPS used – and/or how were the plots identified, and data/location ID recorded?

The 1997 Koala plots on Lots 106 and 108 were located within the Blackbutt Open Forest vegetation community, in a location roughly equidistant from Mungo Brush Road and the eastern end of this community in order to reduce the impacts from any edge effects and to provide a representative sample of this community. These plots were conducted to the same methodology as EcoPro’s earlier plot in Lot 107 in order to allow consistent analysis of this vegetation community across all three lots.

The 1998 Koala plots on Portion 25 were investigated by way of thirteen plots on a 100m grid within the area of Open Forest dominated by Blackbutt and Swamp Mahogany in the east of the site. Each 40m x 40m plot was subdivided into 20m x 20m sub-plots, in which scat searches were undertaken in accordance with the AKF methodology. Where these assessments returned greater than 30% of trees with scats in a sub-plot, subsequent spot assessments were undertaken around this sub-plot. As the two north-easternmost initial plots returned this high activity level, it is presumably the seven subsequent plots around these two points which are being referred to above by Wells et al.

Wildthing did not have access to reliable hand-held GPS at the time of the investigations on site and therefore the location of the plots had to be derived as well as possible by calculations of distance and bearing from known waypoints such as roads, site boundaries, etc. This information was then represented on maps showing these features by hand, as was the most practical method before the widespread accessibility of accurate GPS and vector mapping platforms (which are the norm today).

How responsible was Wildthing’s selection of methodology, in view of producing data-sets that able to be verified, replicated in the field, and used for future monitoring and scientific work?

The methodology employed by Wildthing was consistent with industry best practice at the time, and was chosen in a way that would be compatible with other work in the area conducted under the AKF methodology. The AKF Spot Assessment Technique was most recently updated in 2009 and still forms the basis of similar assessments conducted by Wildthing. As for the future usefulness of the plot surveys, if hypothetically the plots were to be conducted again in the precise locations of the previous plots and no scats or scratches were found, this would still not negate the validity of the 1997 and 1998 results. The simple fact of past recorded Koala presence within these plots and the lack of significant change to the habitat on the sites means that there is a likelihood of Koalas resuming use or continuing intermittent use of this habitat. Since the plot survey was not intended to identify Koala abundance or density the historical record of activity levels they represent would therefore be useful in a comparative future study.

How confident now is Wildthing that it could locate and replicate its 1990’s plots in the field?

On the basis of the mapping Wildthing undertook at the time it is reasonable to expect that we would be able to locate the mapped position of the original plots to within approximately 20m of their position. If GPS were available at the time of the 1997 and 1998 surveys the probability of finding these sites would be improved, however even with the better accuracy of hand-held GPS today the chance of finding the precise location of the plots would be remote, as the error margin of the original record would be compounded by the error margin of a current attempt to locate the plots. It is highly likely that most if not all physical markers of the plot locations on site would be either destroyed or highly obscured by now.

There would, however, be little to gain in attempting to precisely ‘locate and replicate’ the earlier plots. Over the intervening 15-16 years the trees would have grown and shed branches and bark. Some trees would have likely died and some others would have matured. Therefore since there has been little alteration to the basic character of the habitat, a plot survey following the same methodology in the same habitat in as close proximity as possible to the mapped plot locations would provide an equally representative result as a plot in the precise same location.

How do you respond to the reasoning, provided to 7.30 from Graeme Wells and Anthony Stimson, that based on their recent survey verification and scientific opinion, some of the area east of Mungo Brush road might not be a core breeding and feeding area – that its possibly a secondary or even marginal habitat?

It was Wildthing’s conclusion in 1997 that Lots 106-108 did not constitute ‘Core Koala Habitat’ under SEPP 44, nor did this area as a whole satisfy the Australian Koala Foundation criteria for ‘State Breeding Aggregate’, and that blanket exclusion of the Open Forest habitat on Lots 106-108 from consideration for potential future development areas on the basis of Core Koala Habitat was not justified. However the results of the ecological review and investigations at the time indicated that the Open Forest and Closed Scrub habitats are likely to be valuable to native species. Whether a development on site would be able to proceed and in what form would still be dependent on the results of flora and fauna investigations and threatened species assessment necessary as part of the zoning and Development Application process.


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