20-E-0335 / DOC-6400224
13 August 2020
Tim Benseman
[FYI request #13119 email]
Dear Tim
Thank you for your Official Information Act request of 21 June 2020 for information on
possum monitoring at Oronui in the Raukumara Forest Park:
Please send all details and photos of the Raukumara RTC work where the
Oronui site recorded 65% RTC.
On 28 June 2020 you clarified your request as seeking the following information:
Who did it, when, gps data from assessor, number of traps used, spacings, was
it pre-fed, all photos taken during assessment.
On 24 July 2020 we extended your request to 14 August 2020 due to the consultation
necessary to make a decision on your request.
Possum Monitoring in Oronui
We note that you have referred to a Residual Trap Catch (RTC) result of 65% at the
Oronui site, however, we can advise that there has been no RTC work conducted at that
site. Accordingly, we have had to refuse your request under section 18(e) of the Act as
the information you seek does not exist.
Having said that, we believe that the figure you have referred to may actually reference
one of two slightly numerically similar figures. These are available here:
doc.govt.nz/our-work/monitoring-reporting/plot-level-report/.
The first figure is concerning the possum chew card monitoring on our national
monitoring programme data webpage for Oronui (site DS55). This figure is a Chew
Card Index (CCI) measurement of
0.65 for the site DS55.
Chew Card Index
Chew cards are used to estimate possum abundance. These small rectangular pieces of
plastic sheets have attractant paste pressed into internal channels. A chew card index
(CCI) is calculated by deploying up to 40 chew cards (at 20-m intervals) along four
evenly spaced 200-m transect lines (10 chew cards per line). An estimate of possum
abundance is then generated by calculating the percentage of chew card interference
(tooth impressions or scratches). For DS55, 40 chew cards were deployed along four
transect lines, see figure below for how this is deployed.
As noted, the relevant CCI result for the Oronui site DS55 is 0.65. This monitoring was
completed on 26
January 2016. DOC Tier 1 Vegetation plot has been measured twice
(2011 and 2016) but the Tier 1 animal measures have only been completed once.
The second figure is
65.7%, this is also a measure that relates to chew cards but
represents the percentage of all the sites across the country that have possums present.
This figure is presented on the page for each plot, allowing users to view the selected
plot in a national context.
You are entitled to seek an investigation and review of my decision by writing to an
Ombudsman as provided by section 28(3) of the Official Information Act.
Yours sincerely
Hilary Aikman
Director Operations Issues and Programmes
