From:
Harry Caley
To:
Jane Andrews
Subject:
FW: Auckland query - Glyphosphate willow spraying - effect on wildlife
Date:
Monday, 19 January 2026 8:25:01 am
Attachments:
image001.jpg
Kia ora Jane,
Here are some thoughts from one of our Biorangers who works at Whangamarino.
Hope this helps
From: Lizzie Sharp <[email address]>
Sent: Wednesday, 14 January 2026 11:21 am
To: Harry Caley <[email address]>; Gary Boyd <[email address]>
Cc: Suliana Teasdale <[email address]>; Kate McAlpine <[email address]>
Subject: RE: Auckland query - Glyphosphate willow spraying - effect on wildlife
Kia ora koutou
I have been aerially spraying willow at Whangamarino, and there is a lot to consider for sure.
There are lots of options for monitoring, but it’s a balance of undertaking operational work or
researching and monitoring on a small budget.
My priority for willow control is to open up matuku-huurepo habitat (feeding and breeding), and to
prevent encroachment into the peat bogs. I try hard not to bite off more than I can chew so that
we don’t have bigger issues to chase the following year with successional weeds.
Within my control and budget are to wait until the end of January so that matuku have a chance of
fledging and getting mobile (same for other wetland species), but aerial willow control needs to
happen before the willow drop their leaves which starts in week 1 or 2 of Feb in Waikato. It’s a
short timeframe but do-able. I also consider what vegetation types are underneath the willow so
that I can use a method and chemical to bring back the desired species as fast as possible. I
found a matuku-huurepo foraging, and a nest near by, under a dead willow canopy one year after
spraying which to me is a good sign.
If there are sedges and rushes underneath, I sometimes use MET, though this now has a lot of
NES conditions to meet. I am seeing natives regrowing at site after a couple of years though.
There are very few studies on the effect of glyphosate on aquatic animals in NZ, but one by Wech
et al. 2018 suggest that it’s unlikely to affect negatively, especially when you account for the
ecosystem benefit of removing willow.
Mudfish have been known to utilise willow root systems when the desired natives are not
present, you could monitor populations before and after, though it may take several years for
effects to be seen.
Happy to talk further
Ngaa mihi
Lizzie
From: Harry Caley <[email address]>
Sent: Tuesday, 13 January 2026 9:02 am
To: Gary Boyd <[email address]>; Lizzie Sharp <[email address]>
Cc: Suliana Teasdale <[email address]>; Kate McAlpine <[email address]>
Subject: FW: Auckland query - Glyphosphate willow spraying - effect on wildlife
Kia ora korua,
My familiarity with glyphosphate spraying is limited but I am aware of several events where this
takes place, and I am sure there are many more. I have been browsing our literature for known
effects on wildlife but have only found papers relating to invertebrates or native flora.
I figured it best I reach out to some people in the Department who may have experience in this
space!
Could you please point me in the right direction to some resources about spraying in wetlands.
Were there considerations for wetland birds and what were they if so?
Ngā mihi nui,
Harry
H. Caley
Science Advisor – Wetland Birds
Fauna Science Advice
Te Papa Atawhai/Department of Conservation
M: +64 027 3571554
Christchurch Office | Ōtautahi
Level 3 161 Cashel St | Private Bag 4715 | Christchurch 8140
Mon
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Fri
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From: Jane Andrews <
[email address]>
Sent: Tuesday, 13 January 2026 8:33 am
To: Harry Caley <[email address]>
Subject: RE: Auckland query
Kia ora Harry,
I’m following up on my email I sent last year regarding an urgent query about glyphosate spraying
of willows. Although some time has passed since I emailed the query is still urgent. Do you have
any time today or tomorrow for a quick chat?
Many thanks
Jane
Jane Andrews|Team Manager Ecological Advice
Environmental Services
Te Kaunihera o Tāmaki Makaurau | Auckland Council
Level 19, Te Wharau o Tāmaki - Auckland House, 135 Albert Street.
Visit our website:
www.aucklandcouncil.govt.nz
From: Jane Andrews
Sent: Tuesday, 16 December 2025 5:13 pm
To: [email address]
Subject: Auckland query
Kia ora Harry,
My colleague Sabine has passed on your details. I have an urgent query regarding impacts of
drone spraying (glyphosate) on wetland birds. Are you around tomorrow for a quick teams or
phone call?
Kind regards
Jane
Jane Andrews|Team Manager Ecological Advice
Environmental Services
Te Kaunihera o Tāmaki Makaurau | Auckland Council
Level 19, Te Wharau o Tāmaki - Auckland House, 135 Albert Street.
Visit our website:
www.aucklandcouncil.govt.nz
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