Blog by Georgia Thomson-Laing (Cawthron Institute)
Coming out of winter and into spring, I was more than looking forward to getting out into the field for my fifth Lakes380 sampling campaign, this time up in the Hawke’s Bay Region. After a quick flight with Susie and Maïlys from Nelson to Wellington, we met up with the rest of the team (Riki, Andrew and Marcus) at GNS Institute in Avalon, all packed up and ready to hit the road. With two Utes, plus two trailers in tow, we drove several hours north to stay overnight in Waipukurau.
The next day we got underway early with a quick drive down the road to Lake Hatuma. It was a beautiful morning to sample our first lake, sunny, no wind and the lake was calm and glassy. Lake Hatuma was surrounded by pasturelands with haphazard fences disappearing into the water and edged with abundant willows with evidence of stock grazing up to the lake. Many birds were present on the lake, most notably black swans and even a few herons.
For efficiency, we employed the relatively recent one boat system for collecting both cores and water quality samples. Five of us hopped on Kea and paddled out to find the deepest spot. It soon became apparent, with oars rowing both mud and water that this lake was very shallow, and our target depocenter was in fact a grand 0.5 m. Apparently in the previous summer the majority of Lake Hatuma had dried up completely and it was possible to walk across the lake bed, albeit a little spongy! Although having been on several field trips before, this was my first experience collecting water quality samples from the coring boat. With leg room a hot commodity, Maïlys and myself successfully teamed together, dodging the occasional core barrel to collect our water quality samples.
One lake down, we drove four hours further north – our destination was Tiniroto Lakes area, just southwest of Gisborne. Arriving to our accommodation in picturesque farmland, the last day of August felt unseasonable warm with the spring lambs already out and about. This scene set the tone for the rest of the trips – the days were primarily sunny, warm, and dotted with an abundance of new-born spring animals and extensive rolling farm hills.
We spent the next two days sampling five of the Tiniroto lakes. This started with my first three-lake sampling day that consisted of lakes Karangata, Kaikiore and Kaikereru. It was great that Tania Gerrard (from GNS) was able to join us in the field for this day. Thankfully, the lakes were situated close together, so we managed to finish at a relatively leisurely time in the early evening. This was despite some challenging bumpy on-farm driving adventures and dodging a multitude of lambs, calves, and baby goats. We definitely did not get a little stuck in a muddy patch and there were of course no relieved sighs when some skilful driving got us back on track! The lakes themselves were relatively shallow (ranged from 3 – 13 m), surrounded by plentiful raupo and sporting healthy populations of introduced birds, notably swans and paradise ducks. Maimai’s were present, hidden in plain sight around all these lakes. In addition to farmland, these lakes were situated by Hackfalls Arboretum so there were a diverse range of exotic trees on the banks of all the lakes.
The third lake of the day, Lake Kaikereru, was the first visibly green lake of the trip. Aptly named, a couple of kereru flew across the lake mid-sampling. Fish and game access to this lake was possibly responsible for the almost precariously perched toilet on the lakeside (see photo).
With the sunny weather holding, the next day we sampled lakes Waihau and Rotokaha, the two remaining lakes in Tiniroto. These were both shallow, lakes in a similar farming landscape.
Personally, the highlight of this day was finding Kākahi. Firstly, on our drive out of the Tiniroto Lakes area, we stopped at Kangaroa River with some impressive limestone cliffs and found Kākahi in the shallow sandy river sediment. This was the first time I had seen Kākahi in a river! Then, in Lake Rotokaha, during a paddle around the lake’s periphery, Susie and myself discovered a beautiful Kākahi (see photo) in the sand.
Following our day’s sampling and a brief stop at the Tiniroto Tavern, we set out for Napier. Our sunny streak was finally broken when we arrived in the pouring rain to unpack and clean gear. I can assuredly say that taking an extra five minutes to put on all of my wet weather gear would have been prudent (and my wet gumboots agree!).
We started the Napier/Hastings part of the campaign with a change of plans due to the night of heavy rain. After scoping out some farm lakes in Te Awanga and deciding the wet grass and clay was too slippery, we changed tack and headed farther south to Horseshoe Lake. The lake had an interesting history as it used to be a horseshoe shape with a peninsula but has since been dammed and become a ring lake due to the raised water level. Nestled in the middle of sheep and beef farmland, it was fenced off from stock with obvious native planting in riparian margins and an awesome Ecolodge on its edge. Battling substantial wind for the first time this trip, we sampled.
Afterwards, we visited with interested local farmers, Rachel and Greg, who told us some interesting lake history amongst their three dogs and cat at their lovely homestead. Apparently the one white swan on the lake was an old female that had outlived her mate and been solitarily living on the lake for the past decade or so! We gratefully sourced some diesel from them (our rental Ute was uncomfortably low on fuel) and drove back to Napier.
Day six dawned a chilly but sunny day with a fresh dumping of snow from the night before. We headed towards the white tipped Kaweka ranges to sample two lakes at their base. These lakes were the most picturesque of the trip, situated at around 600 m altitude and fringed with natives adjacent to extensive pine forestry. Access to the first Kaweka lake was from a forestry road. Access to the second lake required a bit more imagination, determination, heavy lifting and ultimately the creation of a path through 50 m of shrubby bush. But both lakes were beautiful and clear, and it was my first coring day of the trip. I helped to pound in and pull two respectable sediment cores!
Our sampling concluded on day seven. We returned to the two farm lakes in Te Awanga. A warm and dry day, the paddocks were dried out and we successfully sampled two relatively small farm lakes. Then it was time to clean, core cut the 11 lakes from the week and pack up. We hit the road early the next day, with a five-hour drive to finish the week. It was awesome to spend the week with such a fun and hardworking team (see below photo plus Susie who is the photographer) and to visit a part of New Zealand that I have not previously explored. Another successful sampling campaign completed!