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Elusive Bittern
Elusive Bittern caught on camera at Wairio Wetland
Jessica Wagner is a student at Victoria University of Wellington, researching rat response to scent and acoustic stimuli in the Wairio wetland. The intended outcome of Jessica's research is to determine what stimuli are most attractive to rats in order to improve trapping efforts, and ultimately, to protect rare birds such as the Bittern and wetlands in general.
Jessica was a recipient of one of the wetland care scholarships.
"I was recently going through my footage and noticed that one of my cameras has recorded a video of a Bittern on the 4th of December! I thought that you and others at Ducks Unlimited NZ may be interested in this so I have attached the video below. Feel free to share with anyone else who may be interested" (Jessica) .
Research scholarships aid restoration
Research scholarships aid restoration of native wetlands
Thanks to Wetland Care Research Scholarships funded by Ducks Unlimited, our student researchers are finding the best ways to recreate a haven for waterfowl.
Wetlands in Aotearoa New Zealand are precious natural resources viewed as taonga by Māori, which provide a habitat for fish and birds.
Even in purely financial terms, wetlands are valuable for their role in filtering nutrients from water, absorbing carbon, and controlling erosion and flooding.
Sadly, they are now in crisis. With over 90% of our wetlands lost over the past 100 years, many plants and animals are struggling for survival, including the elusive matuku (Australasian bittern) and pūweto (spotless crake).
Purple Loosestrife - pretty enemy
Help spot purple enemy at Lake Wairarapa
2022 Wairarapa Moana annual spring matuku and spotless crake survey
First recorded booming within the DU Wairio wetland
The spring 2022 survey report compiled by Shane Cotter, a contractor engaged by GWRC.
John Cheyne of Wetlands Works led annual spring surveys for Australasian bittern (matuku, Botaurus poiciloptilus) and spotless crake (pūweto, Zapornia tabuensis) at selected wetlands within Wairarapa Moana between 2012 and 2021. In 2022, John passed this responsibility to me. I conducted the annual spring (October-November) 2022 survey using the same methodology as in previous years so continued comparisons could be made of the annual results.
This year’s survey focused on the core wetlands (Boggy Pond, Matthew’s Lagoon and Wairio wetland) and the northern wetlands (Barton’s Lagoon, Tauherenikau delta, Simmond’s Lagoon, JK Donald Block). Only booming male matuku are surveyed because females are much less vocal and therefore very difficult to detect and monitor. This booming call is associated with males attempting to attract females for breeding. Pūweto were also surveyed at Boggy Pond and Matthew’s Lagoon.
In the 2022 survey, 11 booming male matuku were located at the core wetlands and 12 in the northern wetlands. This is an increase in previous years and a record number at both locations. At the core wetlands, numbers have remained relatively stable at 8-9 birds since 2014 while at the northern wetlands, annual numbers of male matuku has varied between 3-9 birds. Overall, the combined number of booming male matuku at the core and northern wetlands has steadily increased from 10 in 2016, to 16 in 2018, to 18 in 2020, and now 23 birds in 2022. In addition to the 23 male matuku heard booming during the 2022 survey, three other birds were seen, one in Matthew’s Lagoon near Boggy Pond and two in Wairio wetland.
At Boggy Pond, nine pūweto were located, the most in Boggy Pond since 2018 and significantly up on the single individual in 2021. At Matthew’s Lagoon, none were recorded during the kayak survey which has been a regular result there since 2014. While undertaking the matuku survey, four other pūweto were heard calling independently, not in response to playback calls. Two were calling in Matthew’s Lagoon close to each other while at two locations within Wairio wetland, one individual was heard calling. I believe there are more pūweto present than recorded during the pūweto surveys. They have just moved to different areas of the wetland complex outside the pūweto survey routes seeking more suitable habitat.
On-going predator trapping with the regular servicing of traps is essential as several predators were seen dead in traps within days of the traps being serviced and rebaited with fresh bait by the trapping contractor at the core wetlands. These included a weasel and several rats. All traps observed were well set up and maintained, and had good vegetation clearance.
Follow the 'read more' link to view the survey report.
Wetland Care first scholarship award
Restored wetlands on private farms deliver ecosystem services and increase diversity, with varied results, a recent study has found.
Shannon Bentley, a master’s student at Victoria University and the first recipient of a Wetland Care Scholarship funded by Ducks Unlimited NZ, is studying how wetland restoration on farms changes plant, soil, and microbial characteristics.
In 2018-2019, as a part of the research group, Wetlands for People and Place, she sampled 18 privately restored wetlands and paired unrestored wetlands on farms in the Wairarapa.
For her master’s thesis, she analysed the wetland plant communities, soil physiochemical characteristics, and soil microbial communities to understand how they change with restoration. She found that wetland restoration on private property shifts plant, soil, and microbial characteristics towards desirable remnant wetland conditions. She also showed that the outcomes of wetland restoration varied within and between wetlands.
She ‘lived life to the full’
Diana (Diny) Dermer, a long-time DUNZ member and wife of Director John Dermer, passed away, aged 75, at her home on March 1.
Diny played an active part in running their farm at Cheltenham, 15 kilometres north of Feilding, before the couple retired to Palmerston North in 2019.
She was born in Pahiatua, as her parents, Kit and Dombey Beetham, farmed at a little place called Pori, near Makuri, a small village about 30 kilometres east of Pahiatua.
John said: “She went to the Makuri School when she was seven because her parents reckoned she was too small at five (she always described herself as a little runt), and there she learnt very little, she thought.
“They moved to a farm near Waipukurau with a lovely old homestead and a climate that meant you didn’t need a raincoat on the horse’s saddle all the time. (Farm bikes were still in the future).
“Her mum died of breast cancer when Diny was 21. Her parents had sent her off to England at the time, but her mum’s death had a huge effect on her. “We met when we were 15, again when we were 21 and she somehow didn’t get married till I turned up again nine years later,” John said.
She worked as a waitress at Expo 70 in Japan and talked about that experience a lot. She also worked at the British High Commission and remembered sleeping under the desk after a boozy lunch. Sometimes waking up to see the boss’s shoes very close,
John said. “We got married in 1975 and I dragged her back to Waipiko, our little farm near Cheltenham, where we did all sorts of things, including having two daughters. “Diny loved the vege garden, her bantam hens and Pekin ducks, plus all sorts of other plants. She was a natural partner when we started to plant out Waipiko and develop the wetlands.
“She spent lots of time with a spade in her hands helping with actual planting. We had many discussions about what to plant and where.
“Both of us learnt a hell of a lot from our membership of New Zealand Farm Forestry Association, and all the areas – in the North and South Island – we visited as a result of this.
“She always seemed to manage a fruit tree or two into our plantings and as a result, I could pick an apple or a plum while cruising round the farm.”
Camping and tramping were other loves. She completed many of the South Island’s major tramps – the Milford, which she reckoned was the best, and the Abel Tasman, Kepler and Heaphy tracks. Diny was always a friendly face at DU’s conferences. Tributes to Diny spoke of her joie de vivre, laugh and honesty, and described her as a special person who was a lot of fun.
“Diny was such a vibrant and outgoing lady who lived life to the full,” one tribute said.
“She was always full of energy, bright and cheerful and never afraid to say what she thought!! Her warm character and zest for life will be sadly missed by many,” said another.
Diny is survived by John and their daughters Ana and Kate and four grandchildren.
Wetland restoration under the microscope
Restored wetlands on private farms deliver ecosystem services and increase diversity, with varied results, a recent study has found. Shannon Bentley, a master’s student at Victoria University and the first recipient of a Wetland Care Scholarship funded by Ducks Unlimited NZ, is studying how wetland restoration on farms changes plant, soil, and microbial characteristics. In 2018-2019, as a part of the research group, Wetlands for People and Place, she sampled 18 privately restored wetlands and paired unrestored wetlands on farms in the Wairarapa.
For her master’s thesis, she analysed the wetland plant communities, soil physiochemical characteristics, and soil microbial communities to understand how they change with restoration. She found that wetland restoration on private property shifts plant, soil, and microbial characteristics towards desirable remnant wetland conditions. She also showed that the outcomes of wetland restoration varied within and between wetlands.
More than 40 per cent of New Zealand is held in private ownership, and private property holds huge potential for wetland restoration, containing 259,000km of stream length (Daigneault, Eppink, & Lee, 2017). Additionally, wetland degradation is extensive in lowland environments which are primarily in private ownership.
The outcomes of wetland restoration undertaken by landowners’ own prerogatives are poorly tracked. Private restoration is driven by personal preferences and finances, so the extent and form of restoration are varied. For example, the 18 wetlands sampled in Shannon’s study were restored in many different contexts and using many different techniques.
Wetlands differed in time since initial restoration (6 months to 42 years ago), size (0.4ha to 33.7ha), upstream watershed area (4ha to 2,263ha), dominant plant community (woody v herbaceous), and the number of restoration techniques used (2 to 8).Wetland restoration is beneficial for a number of reasons, but particularly for regaining wetland ecosystem services and increasing native biodiversity. Ecosystem services are ecological processes and functions that have beneficial outcomes for humans.
Compared with all other ecosystems, wetlands produce the highest levels of ecosystem services per unit area. This high production of ecosystem services is due to wetlands’ unique biology and geology resulting from their position at the interface of water and land. Wetlands are particularly effective at producing the ecosystem services of water purification, flood abatement and climate regulation through carbon sequestration.
Shannon found that with restoration, soils regained wetland traits, providing more ecosystem services. The restored soils had higher carbon content, lower bulk density, and lower plant-available phosphorous. Increased soil carbon content shows the carbon sequestration potential of soil expands with restoration.
Additionally, reduced plant-available phosphorous indicates restored wetlands can take up phosphorous and improve downstream water quality.
And finally, with increased carbon and reduced bulk density, water moves through the wetland soils slower to reduce peak flood heights.
Shannon found wetland soil microbes increased in biomass and fungal dominance after restoration. These changes, in part, explained the increase in capacity for wetlands to deliver ecosystem services.
Soil microbes are responsible for decomposition and nutrient cycling. A greater mass of microbes means restored wetlands have more capacity for biogeochemical cycling and decomposition, which can accelerate processes such as carbon burial, as
seen with the increased carbon in restored wetland soils compared with unrestored soils.
The presence of arbuscular mycorrhizal fungi (AMF) also increased after restoration. AMF help plants survive and reduce phosphorous in soils, thus contributing to cleaner waterways.
Each restored wetland showed a lot of variability of soil and microbial responses within and across wetlands. Because wetlands are found along a hydrological gradient between saturated soils and drier, upland soils, the microbial and soil properties differed according to the landscape position.
Soils close to the water’s edge, as a result of being saturated, had more carbon, microbial biomass, and more fungal biomass, and were less dense. By examining the plant communities, Shannon found that, after restoration, plant diversity increased within the plot and across the landscape. This means that with restoration, habitat heterogeneity increases, a beneficial outcome that increases ecosystem stability and the number of ecosystem services produced.
Additionally, she found that wetland soils and plant and microbial communities showed different levels of recovery that were not consistent with the length of time that they had been restored.
Some projects’ soil and microbial characteristics recovered faster than others. The main difference between fast and slower-recovery wetlands was the hydrological regime.
Restoration projects that occurred on isolated hydrological systems such as depressional, rainwater-fed wetlands took far longer to re-establish remnant wetland conditions. Projects undertaken on flowing hydrological systems such as springs and streams underwent successional processes faster to establish wetland conditions that have a higher production of ecosystem services.
The study has shown that restoring wetlands on private farms increases the ecosystem’s ability to simultaneously produce multiple different ecosystem services and support more biodiversity.
As food production demands continue to rise simultaneously as land becomes more scarce, agricultural systems are becoming more industrialised and intensive. This is placing pressure on natural ecosystems, as seen by reduced water quality, native habitat, and changing landscapes from carbon sinks to sources.
There is increasing recognition that we need mixed agroecosystems so food production does not compromise other ecosystem services.
Wetland restoration is gaining significant traction as a solution to issues surrounding water quality, climate regulation, flooding, and loss of native habitat, and this study has shown that private restoration is effective tool to do just this.
Shannon concludes her report by saying: “I would like to thank all the landowners that generously allowed us to sample their wetlands; each site we visited was so beautiful and unique.
“I thank Ducks Unlimited for the funding that allowed me to do this research. I also thank the Holdsworth Foundation, the Sir Hugh Kawharu Foundation, Wairarapa Moana Trust, and Victoria University for the financial support I have received.
“Finally, I would like to thank my supervisors Dr Julie Deslippe and Dr Stephanie Tomscha for their guidance and help in producing this research.”
Leading predators up the garden path
Mammalian predators rely primarily on smell as their main cue, enabling them to detect food from a distance. Smell is usually a reliable strategy for food location.
As part of long-running research into the behaviour of introduced mammalian predators in New Zealand and Australia, researchers from Manaaki Whenua – Landcare Research and the University of Sydney asked whether it might be possible to manipulate predator behaviour by using misinformation. Could we use unrewarded prey odour cues to fool predators, and make them ignore real prey cues? If we could make predators less efficient at hunting, might we also make them miss real prey?
Over two nesting seasons, the researchers tested the response of cats, ferrets and hedgehogs to false odour cues at nesting sites for three shorebird species – the banded dotterel, wrybill and South Island pied oystercatcher. These native bird species nest on the ground on braided rivers in Canterbury and are highly vulnerable to predators. The researchers made odorous pastes from bird carcasses and feathers – and tested whether repeated exposure to these odours would affect the predators’ behaviours.
They set out the pastes at 300 to 400 points across nesting sites before the birds arrived to nest, and also during the nesting season. Predators’ behaviour was then compared to that at testing sites without paste.
Camera traps were used to monitor predators’ interest in the paste, and to monitor the survival of nests with and without odour paste.
In the second nesting season, the paste/ no-paste sites were swapped to increase the reliability of the results. All three types of predator were attracted by the paste odours, but ferrets and cats, in particular, quickly lost interest when there were no prey associated with the scent cues.
Thus, when the birds arrived to nest, the predators had already altered their behaviour by ignoring bird odour, including that of the real birds.
The effects on nest survival were striking for all three bird species: compared with non-treated sites, odour treatments resulted in a 1.7-fold increase in chick production over 25 to 35 days and doubled or tripled the odds of successful hatching.
For banded dotterel, the researchers estimate that this intervention could result in a 127 per cent increase in the population size in 25 years of annual odour treatment.
The method is best suited to small areas of vulnerable biodiversity where lethal control methods are difficult to implement.
Lead researcher Dr Grant Norbury of Manaaki Whenua – Landcare Research worked with colleagues at the University of Sydney, Dr Catherine Price and Prof Peter Banks, who developed the idea.
Dr Norbury says that this field experiment provides clear evidence of altering predators’ perceptions of prey availability on a landscape scale, and “could significantly reduce predation rates and produce population-level benefits for vulnerable prey species at ecologically relevant scales, without any direct interference with animals”.
Photos: Grant Norbury
Spectacular Rakatu
With international travel off the agenda for now, it may be time to check out some of New Zealand’s public-access wetlands.
One such gem can be found on the Southern Scenic Highway between Manapouri and Tuatapere.
If you are heading south from Manapouri, take a right after the sign for Rakatu Wetlands and at the end of a 1km gravel road, there’s a car park with information boards.
There are four main walks, from 15 minutes long to two to three hours. It’s a spectacular setting with Fiordland National Park as its western backdrop, and no less impressive are the flush toilets up the track to the lookout. Complete with toilet paper and soap, they are an unexpected bonus to visitors expecting the usual pongy long drop.
The 270-hectare wetland complex was created for the benefit of fish and waterfowl as well as protected bird species to mitigate and remedy the adverse effects of the Manapouri Hydroelectric Power Scheme.
It is administered by the Waiau Fisheries and Wildlife Habitat Enhancement Trust.
Rare carnivorous plant found
A seldom-seen carnivorous species has been found during a survey of rare plants at Waikato’s Whangamarino Wetland.
It’s been more than a decade since threatened plants have been surveyed at Whangamarino Wetland, with the last survey in 2009.
Waikato District biodiversity rangers Lizzie Sharp and Kerry Jones, and plant expert Britta Deichmann waded into the boggy wetland for 12 days between September 2020 and April this year.
“We were particularly excited when we found Utricularia australis or yellow bladderwort, an aquatic carnivorous plant,” Lizzie Sharp said.
“We had several ID books out and a lively debate about whether it was yellow bladderwort or the invasive weed Utricularia gibba or humped bladderwort.”
The difference between the two plant species is the number of divisions in the
leaves, and closer inspection revealed it was yellow bladderwort, which is known only in the North Island.
“Yellow bladderwort was found at one site in the 2009 survey, and prior to that, at 11 sites based on historic data.
“By 2009, 10 of those sites had been infested with humped bladderwort, and as more than 10 years have passed since that survey, we expected the worst ...”
The bog in the Whangamarino Wetland is treacherous so visits by the public are discouraged. There are no tracks into the swamp, but people are permitted on the Maramarua and Whangamarino rivers and Reao Stream.
For more information about Whangamarino Wetland and its biodiversity, visit: www.doc.govt.nz/our-work/freshwater-restoration.