Ducks Unlimited
Sunday, 21 July 2019 23:38

Planting continues at Wairio wetland

A small band of us managed to get a further 790 plants in the ground at Stages 1 and 4. This brought the total for the year to about 2500.

The water was quite high at Stage 4 so there are still some spots to be planted.

We still have 400 suitable plants at Norfolk Road Nursery and Don Bell will arrange for them to be planted when the water recedes. He will also plant about 100 Totara and
Kanuka in spot sprayed areas of Stage 2. These plants will be a modest addition to our Tree Budget. Don will also arrange to place the weed mats and install the Grotectors not yet in place.

We did not do this during the July planting due to time constraints – priority was on getting the trees in the ground.

Jim Law
 

 

Published in Issue 161
Friday, 19 July 2019 01:49

Wairio Wetland Drone Tour

 

Drone Tour of the Wairio wetlands

Watch the Drone Tour of the wetlands that was created by the Victoria University Research team 

Drone view flying over the Wairio Complex

 

Published in Wairio News
Friday, 19 July 2019 01:46

Video interview

 

DU President - Video Interview

Well-known journalist, Piers Fuller, interviews DUNZ President Ross Cottle about the history of the celebrated Wairio Wetland development

You can view the video interview here

Published in Wairio News
Thursday, 18 July 2019 22:32

Classroom in a Wetland

 

Victoria University’s classroom in a wetland!

 Five years ago, Victoria University Wellington students planted a swathe of nursery trees in the Wairio Wetland. 

This landmark wetland habitat was created in the late 1980s by Ducks Unlimited in Collaboration with the Department of Conservation (DOC).

Last week the Victoria University biodiversity team  were back.  Stephen Hartley and his team were armed with over 300 specimen trees (Kahikatea, Totara, Tawaki (or Swamp) Maire & Cabbage)- sourced thanks to a $2000 grant from DOC - to continue their comparative research into cost effective restoration processes by adding these trees as infill planting. 

The cold but enthusiastic University team were supported by members of Ducks Unlimited and DOC.

Published in Wairio News
Thursday, 04 April 2019 10:00

Wairio work

Tree protection trial
The accompanying photos show Cabbage and Totora trees planted in Grotectors (tree protectors) at Stage 2 in the Wairio Wetland. 

They were designed by Don Bell, a DU member who has been involved with the Wairio Restoration Project since its inception. These protectors are being monitored as part of the various plant survival studies being conducted by Victoria University students. It is also hoped to get students from a local secondary school involved in the monitoring process.

As the photos indicate, the plants protected seem to be doing well versus their unprotected neighbours that were similarly planted on spot sprayed sites. In addition to enhancing growth rates, the sheer visibility of the Grotector enables easy follow-up release spraying.

Based on the good results from 2013 the restoration committee decided to use these protectors for the larger plant species this year, especially Kahikatea and Totora.

Rotary support at Wairio

The South Wairarapa Rotary Club (SWRC) recently made a $1600 grant towards the restoration of the Wairio Wetland. The SWRC has contributed $14,480 in total since 2007 – they have been great supporters of this project.

It is one of the long-term environmental projects they support in the South Wairarapa. 

In addition to the cash contribution that goes towards the cost of plants (sedges, flaxes and specimen trees, the likes of Totora and Kahikatea) being used in the restoration of the Wetland Rotary members assist in the planting days. It is one way Rotary both contributes to, and participates in community activities. DU certainly appreciate the contributions.

Wet day planting at Wairio Wetland

A team of environmental enthusiasts turned up in late April for this year’s first planting at the Wairio Wetland. It was a wet day, great for the plants and not too bad for the enthusiasts but coats were definitely required! 

Planters included a great team of young women from Taratahi’s equine school who worked tirelessly in the rain. There were the usual Ducks Unlimited stalwarts and representatives from Greater Wellington Regional Council and Doc. Unfortunately, attendance by teams of students from the local primary schools had to be cancelled because of the wet weather. A GWRC team also put on a BBQ that was most popular once the allotted 650 plants were in the ground.

The planting was in a newly fenced off area of Stage 4 along the south eastern fringe of the wetland improved by the construction of a bund wall during 2013. This area has become very popular with local waterfowl with hundreds of ducks, swans and native waders taking flight when the planters arrived. In the years to come waterfowl will be able to fly into a much enhanced wetland as a result of the good work by the planters.

The next planting was July 4. Hope they had a great day.

Published in Issue 160
Tuesday, 02 April 2019 08:08

Wairio showcase for ecologists

Ecologists from around New Zealand visited the Wairio wetlands on 29 November with DU President Ross Cottle and Stephen Hartley, of Victoria University, as their tour guides.

The trip was part of the New Zealand Ecological Society’s annual conference in Wellington, and also included a visit to Pounui Lagoon and Onoke Spit, where Denise and Dougal Mackenzie were the guides.

Student Patrick Hipgrave and Dr Stephanie Tomscha spoke about their wetlands projects at the conference.

Stephen says Wairio have had good water levels for the past two years and the Raupo beds along the margins of stage 3 and 4 are maturing nicely. 

During the tours, several royal spoonbill were spotted as well as the first signs of natural regeneration of Totara and Kahikatea in the drier sections of Stage 3 under restoration plantings of manuka and kohuhu. These were planted in 2011.

The manuka and kohuhu are now more than 3 metres tall and have shaded out the ground cover of tall fescue grass to provide the microsite conditions necessary for successful establishment of totara and kahikatea seedlings

▪ For more information on Dr Tomscha’s project, visit www.victoria.ac.nz

Published in Issue 176
Tuesday, 02 April 2019 07:49

Wings over Wairio project

Victoria University master’s student Patrick Hipgrave is using drones to map wetland vegetation for his project on geographic information systems (GIS).

The project

What changes in vegetation cover over time are evident at Wairio?

To what extent is the accuracy of the image classification process improved with the addition of ancillary data?

This project investigates the use of image classification techniques to create detailed maps of wetland areas based on aerial photographs. 

The project uses an emerging set of analysis methods called ‘object-based image analysis’ to investigate the applications of remote identification techniques calibrated to detect selected native and invasive species. 

An additional objective is to compare and contrast the improvements that including ancillary data into the classification process, such as 3D digital surface models (DSMs) or near infrared imagery, may have over classifications based solely on true-colour images.

The processes being evaluated by this project may allow teams with limited budgets or time to quickly and accurately convert imagery into maps with much greater levels of details, which will improve their ability to detect and track specific plant species. 

This is especially useful in the case of wetlands undergoing restoration as they often exhibit significant changes over time, and the target species would normally be challenging to differentiate from one another in an aerial photograph.

Results to date

Though the study is ongoing, with flights every three months, the initial results would appear to confirm that a ‘true-colour only’ classification would perform poorly compared with ancillary data. The improving effects of including infrared imagery will be tested once that has been gathered. 

The classified images contain between 18 and 20 distinct classes.

Study area

The Wairio wetland was drained and converted into farmland in the 1960s.

Since 2005, it has been undergoing a managed restoration programme to return it to something approaching its natural state.

Several plantations of native plants have been established, and a weed eradication programme to control invasive species such as Bidens frondosa is in progress.  This project can assist this effort by tracking the distribution of natives and weeds.

Object-based image analysis 

Object-based image analysis works on the principle that different types of surface cover have unique properties, such as colour, texture or shape. 

For instance, weed species might be distinguished from grass as the weeds may be a different shade of green to the surrounding grass, or present a unique textural pattern owing to differently shaped leaves.

 

 The sensors being used in this project are the DJI Phantom 4 Pro Camera, to collect true colour imagery, and a Micasense RedEdge-M, a multispectral sensor for collecting near infrared imagery. The software is ArcGIS Pro 21, ENVI 5.4 and PrecisionMapper 3.32

 

 

Published in Issue 176
Sunday, 20 January 2019 03:53

Ramsar officials visit

Ramsar officials visited the Wairio wetland in March during their visit to Wellington, the host city for the Oceania preparatory meeting in the lead-up to the 13th Conference of the Parties (COP13) to be held in October 2018 in Dubai. 
 
The meeting in March was attended by eight contracting parties in the Oceania Region, an observer from Vanuatu, which is in the process of accession, and observers from international and national organisations that work on wetland-related issues. 
 
Ramsar officials said the Pre-COP meeting was an opportunity to discuss and give feedback on draft resolutions to be considered at the Ramsar COP13. It was also an opportunity to share experiences, information and 
knowledge on wetland issues common to the region and identify opportunities for cooperation, learning and improved implementation of the convention. 
 
The delegation thanked Ngati Hinewaka and Kahungunu ki Wairarapa, Greater Wellington Regional Council, Ducks Unlimited and the Department of Conservation for hosting the visit. 
 
The Convention on Wetlands of International Importance holds the unique distinction of being the first modern treaty between nations aimed at conserving natural resources.
 
The signing of the convention, now known as the Ramsar Convention, took place in 1971 at the small Iranian town of Ramsar.
 

 

Published in Issue 175
Thursday, 23 August 2018 22:09

Wairio under scrutiny

Ecological restoration of Wairio Wetland, Lake Wairarapa

The response of native wetland vegetation to eutrophication and re-vegitation management strategies.

Abstract: Aprille Gillon.

Wetlands are highly productive ecosystems that support abundant native fauna and flora and provide many essential functions and services, for example, water purification, erosion stabilisation, floodwater storage, groundwater recharge, peat accumulation and biogeochemical cycling. 
 
Despite the vast benefits wetlands provide worldwide loss and degradation still continues, mainly due to agriculture, urban development, population growth and exploitation. 

Wetland disturbance can cause altered hydrological regimes, invasive species introduction, soil and water eutrophication, habitat fragmentation  and reductions in native fauna and  flora leading to an overall reduced functionality. 
 
Ecological restoration is an active practice commonly undertaken in degraded wetlands to re-establish ecosystem functioning, and most commonly includes revegetation, reconstruction of hydrology, weed control, pest management, and native species reintroductions. 

Wairio Wetland on the eastern shores of Lake Wairarapa forms a part of Wairarapa-Moana, the largest wetland complex in the lower North Island. Historically Wairio was an abundant kahikatea swamp forest, with a diverse range of waterfowl, waders and freshwater fish. However, the wetland was adversely affected by a draining scheme during the 1960s and 1970s, the construction of Parera Road, and the invasion of willow trees planted for erosion control. 

Draining of the wetland, division from nearby lagoons and ponds, nitrogen and phosphorus build-up in waterways and exotic weed invasion all contributed to the poor state of the wetland. In 2005, Ducks Unlimited (DU) in conjunction with the Department of Conservation (DOC) and members of the local community formed the Wairio Wetland
Restoration Committee to manage and restore the wetland to its presettlement state.
 
Restoration undertaken at the site have included native tree planting, earthworks, weed control, pest management and fencing sections of the site to exclude cattle, have met with mixed success. 

This thesis reports on two studies undertaken at Wairio Wetland with aims to inform future restoration efforts. 
 
There had been a proposal to divert nutrient rich water from Matthews lagoon into Wairio Wetland to increase filtration and improve 
the water quality of Lake Wairarapa. The outcomes of the effects of nutrient loading on established plant communities remain unknown. Therefore, the first study conducted between December 2012 and May 2013 in  Stage 2 of the wetland, examined the effects of fertiliser addition on biomass, structure and diversity of a wetland plant community. 
 
Different levels of phosphate and nitrate fertiliser were applied to 50 plots (4m2) of vegetation at the site with percent cover and the average height of respective species recorded every four to five weeks. Results showed the addition of phosphorous and/or nitrogen had neither a positive nor negative effect on the plant community at Wairio with no significant changes in the 15 species recorded at the site. These results contrast other studies that have reported increases in biomass, reductions in biodiversity and common/introduced species out competing rare/native species. 

The short duration of the experiment and summer drought conditions may have obscured the above-ground visual responses of the plant community to nutrient addition: therefore, further continuation of this experiment is advised. Variable survival rates of previous plantings, and uncertainty about the most cost-effective practice under current site conditions, provided the impetus for this study.

Therefore the second study, conducted between July 2011 and January 2014 in Stage 3 of the wetland, further investigates the effects of various management treatments on establishment of native woody vegetation.

Note: Both the experiments described in the above thesis are on-going. Stephen Hartley who is Deputy Director for the Victoria University Centre for Biodiversity and Restoration Ecology and is a Senior Lecturer in Conservation and Ecology, will continue to monitor the growth of trees in Stage 3, and a Belgian intern student will re-survey the nutrient enrichment plots in Stage 2.

To view Aprille Gillon’s full thesis go to:-
http://researcharchive.vuw.ac
handle/10063/3648
The study involved monitoring 2368 planted trees of eight native wetland tree/shrub species, including: Cordyline australis, Dacrycarpus dacridioides, Olearia virgata, Podocarpus totara, Coprosma robusta, Coprosma propinqua, Leptospermum scoparium, and Pittosporum tenuifolium. The trees were subjected to various planting treatments, including the excavation or retention of topsoil, presence or absence of weed mats and presence or absence of nurse trees with spacing of 0.75m or 1.5m. Survival and growth of each tree was measured every six months over the 30 month experimental period. 

Results showed that interspecific competition and hydrology appeared to be the main processes influencing the establishment of native plantings at Wairio Wetland, with plant mortality greatest in the first year after planting. Water logging, in particular, was detrimental to establishment of all species at the site except D. dacridioides. Topsoil excavation and the planting of nurse trees at 1.5m spacing was the most effective management treatment combination promoting survival of plantings at Wairio. 

However, the success of management treatments varied greatly between species at the site and had different impacts on plant growth. Topsoil excavation was beneficial to survival of D. dacridioides and C. robusta but detrimental to growth of C. australis, O. virgata, C. propinqua, Ptenuifolium and L. scoparium. 

The concurrent planting of nurse trees with focal trees was beneficial to the survival of D. dacridioides, growth of P. totara, and survival and growth of C. australis. The planting of nurse trees further apart at 1.5m compared to 0.75m had a positive effect on the survival of C. propinqua and P. tenuifolium, and survival and growth of L. scoparium. Weed mats were beneficial to survival of O. virgata and growth of L. scoparium but detrimental to growth of D. dacridioides. These management treatments can be used in future revegetation efforts at Wairio Wetland and potentially in other wetland restoration projects throughout New Zealand.
 

 

Published in Issue 162
Monday, 19 March 2018 07:22

Boggy Pond April rounds

Last April, I was able to complete the servicing round down at Boggy Pond, Mathews and the Wairio Restoration Block. The total predators trapped there for the month was :
 
1 cat, 5 ferrets, 1 weasel, 9 rats, 29 hedgehogs, 6 mice and 1 hawk.
 
While there I GPS’d another eight potential trapping sites on the new bund wall that was recently created.
 
A Timms trap was missing from the trap site by the Bridge to No Where and a Timms/ DOC 250 was missing past the second bridge  leading to the Viewing Hide. I suspect these  have been stolen as they were there when I serviced the gear in February. These missing traps will be replaced after duck shooting season. I am wary that more may disappear during that time with the influx of hunters to the area.
 
Steve Playle.
 
 

 

Published in Issue 164
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