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March updates: kikuyu grass, ferns and cats

Kia ora koutou,

Well, hasn’t the world been tipped upside down lately??

Luckily for those living rurally, business can continue pretty much as usual, with some small hands home from school maybe even lightening the workload.

Researchers from both universities and Crown Research Institutes (e.g. AgResearch) have moved to working at home for the next month. This has been a huge a rapid transition for some, but it does mean that we’re still all on deck and available via email, phone, zoom etc.

Living Laboratories


The effects of the 19/20 summer drought
Pourewa site in Sept 2019 (top) vs Feb 2020 (bottom)

While the drought in the North Island made/is making life hard for a lot of people (animals and plants), one silver lining is that we were able to get some great data from our parched Pourewa site.

The aim of the project is finding out how best to grow back native forest, so it’s good to know how newly planted saplings cope in dry conditions.

Project manager Jeff Silby says it’s interesting the trees that performed the best were the ones planted last but into loose topsoil – the result of drainage being installed. But there was something else that really grabbed his attention.

“There appears to be higher survival rates of saplings that are surrounded by kikuyu grass,” Jeff says.

Kikuyu is an exotic grass that will often smother young trees, so it needs to be managed well in restoration plantings. However, it’s fairly drought tolerant and in this case might be protecting the soil from water loss.

“So in dry conditions kikuyu grass might act as a nurse species for the young natives! We hope to collect some data on this in the future. On the drone maps you can see where the kikuyu is, because it’s still green. Maybe we need to plant kikuyu everywhere? We will see what the data tell us first.” - Jeff Silby

We have also planted small areas of native ferns, which will hopefully spread out into the surrounding pasture and overtake exotic weeds.

This will then provide shade and shelter for native trees to germinate and outgrow the ferns. Once the native trees provide enough shade to the understory the ferns will die and the area will transition to native forest.

We have trialled three fern species: rarauhe/bracken fern (Pteridium esculentum), matata/ring fern (Paesia scaberula) and pigfern (Hypolepis ambigua).

Dr Cate Macinnis-Ng and volunteers from the University of Auckland have been measuring stomal conductance of leaves, which indicates water use and can indicate a plants ability to survive dry conditions.

We also measured soil moisture levels across the 2019 planted area. Around 12cm below the surface the moisture was very low, but fortunately there was a little more moisture at the level of the deeper roots.

During March we were also recording tree height data and were planning on doing some soil samples, but this has had to be postponed given the current lockdown.

You can go on a virtual tour of the Pourewa site with Jeff and learn about all the sampling we’re doing in this video.

Te Muri

Site #2: Te Muri
Site #2: Te Muri

We’re also extremely excited to be able to announce Te Muri as our second Living Labs site.

This site is 4.2ha of Auckland Council owned farmland, on which we aim to plant around 14,000 native trees.

The main goal of this site will be finding out the effect of changing tree spacing/density. Given the huge cost that can be involved in reforesting large areas of land, how few trees can you get away with planting? Further apart means a lower initial cost, but too far apart and the cost of weed maintenance will surpass the savings you initially made.

This site is still in the planning stages but we’ll keep you updated as we make progress (once we all come out of lockdown!).

Other News

AgResearch have now completed the reports for our original three study farms and are in the process of reviewing them. Yes, things can take a long time in research!

Our initial funders, the BioHeritage National Science Challenge, have also completed their scoping process to map out how they should invest the next five years of funding they received from MBIE.

One of the investments is called “A BioHeritage Scorecard for Aotearoa” which aims to create sector-specific ways of measuring how biodiversity is tracking, in a way that can be compared across the country.

Another is called “Diverse, successful and practical pathways to ecosystem regeneration” which aims to learn from existing restoration projects (both successes and failures) to figure out what works best, and then communicate those tools and methodologies to communities.

Both investments are in the initial ‘paperwork’ phases but we’re keeping an eye on how they progress and we have been specifically named by both teams as being in a good place to be involved.

In case you missed it, our PhD student Cathy Nottingham was recently profiled in the BioHeritage Challenge newsletter.

Over the next few years she will be investigating how feral cats use vegetation on farms and what this means for our native wildlife. You can read the full article here.

While we’re not too sure how things will progress over the next few months, at least this time in lockdown gives us plenty of opportunities to catch up on those ‘rainy day’ jobs, and of course spend some quality time with whānau.

We’ll look forward to getting in touch again once everything is on the mend.

Kia haumaru (stay safe),

The Farming & Nature Conservation team:

Hannah Buckley, David Norton, Brad Case, Margaret Stanley, Valance Smith, Stacey Bryan, Tarn Gillman, Adam Forbes, Jeff Silby, Estelle Dominati, Margaret Brown, Fleur Maseyk, Bruce Small and Roxanne Henwood.

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