Posted by Helen Armstrong

During my career as a primary school teacher I have helped many students plant in excess of a thousand native trees and shrubs in and around our school. And never in that time have I ever wondered about tree physiology-until now.

At present I am part of a group of teachers participating in a Science Teaching Leadership Programme [STLP] administered by the Royal Society Te Apārangi. The programme has two specific phases. The first phase involves teachers taking paid leave from their school for two terms to engage in a programme of learning that involves them working in a host organisation for approximately 15 weeks, alongside scientific staff, to get an appreciation of the Nature of Science. The Nature of Science is the over-arching theme of the New Zealand Curriculum which all schools teach science through. The second phase of the programme involves the teacher working alongside school management and their teaching colleagues to improve the quality of science learning across the school or science department.

I am being hosted by Dr Cate Macinnis-Ng and the School of Biological Sciences. She and her team of PhD and Masters students are working on projects which are looking at how environmental changes, such as drought, affects kauri and other native trees such as tanekaha.

I am enjoying discovering how and when a tree uses such things as sugar, water and carbon and how these are transported around a tree. Before being part of this research I thought I had a fairly good grasp on how a tree or plant breaths. Turns out there is so much more I didn’t know, but thanks to Cate and her team who have given me the opportunity to be involved in their research, I am learning so much more than I could ever learn by reading articles or watching YouTube clips.

Being part of an ongoing research project has really opened my eyes as to what scientific research involves. In the media you see and read about all the amazing work and breakthroughs scientists have made all around the world. But what you don’t see is the hours of work, determination and set- backs that go into discovering something new- be it a cure for the common cold or how trees react under changing conditions.

I am excited to use what I have learned in my placement back at my school and channel the natural curiosity of our students into as many different curriculum areas as possible, enabling them to have a deeper understanding of science. Some of the projects I have been involved in whilst on my placement can be modified to be used in a classroom so the children will be even more able to benefit from the experience I have had.

I am willing, able and very keen to learn as much as I can whilst on my placement which will end in late June 2018, so if you need an extra pair of hands for fieldwork, experiments, presentations or are involved in anything that you think I might find interesting, please feel free to contact me.

helena@easttamaki.school.nz

Posted by Ben Cranston

On the morning of 20 March 2018, a crew of University of Auckland researchers, professional arborists, and volunteers set out for Huapai Scientific Reserve in the northern Waitākere range with a few objectives in mind: most notably, to collect 24-hr transpiration and leaf water potential values for kauri (Agathis australis). We were equipped for an overnight stay in the forest and spirits were high. Climbing, gear-and-sample running, eating, and sleeping shifts were divided up between participants and the plan was laid out…

The first day was mostly meant to familiarize new climbers with the protocol as well as replace some older, ailing equipment in the canopy. In effect, we ended up using day 1 to ease into an appropriate mindset for the overnight campaign which was to begin early on the second day. In addition, we were able to snag a bit of press and drone footage of the science going on at Huapai which was very cool!

I also was able to obtain a great vantage point of the throughfall exclusion shelters which were recently installed at the site. In this frame, it is slightly discernible that soil under the tarps is staying dry relative to outside. Preliminary results from sapflow measurements are showing no clear distinction between droughted and non-droughted trees, but that should hopefully change over the course of the year(s) owing to these tarps.. stay tuned.

Our resident arborist, Freddie Hjelm, had his enthusiasm for New Zealand forests on full display throughout the whole trip. On behalf of everyone in the Macinnis-Ng lab, I offer our sincerest appreciation to him and the rest of The Living Tree Company crew for helping us stay safe and problem-solve when the going got tough!

Apart from a trove of data (currently being processed), over the course of the collection period we were all treated to views like these. Climbing up the stems of my study trees  revealed a cathedral among the canopy not to soon be forgotten.

It was a lot of work from a lot of people but we made it to the next day. The volunteers did an amazing job hanging in there well into the night and I can only hope that the experience was worth the toil.

 

Ben Cranston is a PhD student at The University of Auckland. His project is part of the Kauri Drought Experiment under the supervision of Cate Macinnis-Ng.

 

By Zach Carter

Isolation and area are important quantities in island biogeography because they help estimate species richness on isolated natural communities. Geographically small and isolated communities are often hotspots of considerable endemism because immigration  occurs at a low frequency, thereby allowing time for cladogenesis to occur. I have recently been interested in quantifying isolation because its application could extend beyond that of determining how species came in to being. Just as immigration is thought to be less extensive on islands that are isolated, so too should be the immigration of terrestrial mammalian pests. I have theorised that highly isolated islands hosting invasive pests are, therefore, good candidates for cost-effective eradication programmes.

While area is a concrete measure of geographic size, isolation has taken on a contrived definition since its scientific inception. In order to define this term, I compiled many of the most popular metrics describing isolation and reduced them using Principal Components Analysis (PCA). In doing so I could parsimoniously extract the most important information and graph isolation visually to better understand its inter-workings. The metrics I am using include: the shortest distance to the New Zealand mainland, the longest over-water distance from the mainland, the proportion of land surrounding each island within a target organisms maximum swimming distance (1km, 3km, and 5km, known as landscape-scale isolation), the summed distance to the nearest four life supporting islands (any landmass greater than 5ha in size), The path from the mainland that requires the least amount of energy expenditure (known as a least-cost path), and the amount of land covered with the least-cost path.  An example of one metric, the least cost path, is provided below with a Grey Group Island off the coast of Great Barrier Island.

I conducted this analysis on (almost) every offshore New Zealand island at least one hectare in size. While very early in the analysis, the PCA determined that three components are necessary to describe isolation. A preliminary output featuring two principal components is provided below.

As can be seen via the red circle, islands that have already been eradicated of invasive mammal pests tend to cluster largely in the 3rd quantile. If the 3rd principal component is plotted, the clustering in a 3-dimensional space is even more apparent (though difficult to see with a photo). This indicates to me that many of the islands already free of invasive mammals exhibit many similarities from an isolation standpoint. With this mentality, islands within the red circle that have not been eradicated may be good option in the near future. This research is preliminary, though, and will require more analysis!