Giant kōkopu. Photo: Andy H

icks

Welcome to the September edition of the Bog Paper.

Read the results of the April freshwater survey of some of the ponds and bog tarns in the Waituna catchment, learn about a macrophyte on the floor of Waituna Lagoon, meet the team and find out what the difference is between AK, CIW and Living Water.

Freshwater kōura

What’s lurking in our bog tarns?By Emily Funnell, Technical Advisor - Aquatic and Reporting Unit

Earlier this year the Department carried out a freshwater survey of some of the ponds and bog tarns in the Waituna catchment.

We have always known that giant kōkopu, kōura and other species can be found lurking in these waterways, but we have never known how

extensive the use of these habitats is. So in April we had a peek in a number of ponds all around the catchment, many on public conservation estate but also a few on private land. (Thanks for your assistance!)

I would like to be able to say that we found these waterways teeming with fish, but unfortunately only a couple of sites fitted this description. Giant kōkopu and other freshwater species were largely absent from most of the catchment except for the Munroe Dam and the tarns on the strip of land on the southern

side of the lagoon. These sites had more giants than we could shake a stick at and with a good range of sizes. The tarns around Carran Creek and

those to the west of Waituna Creek were all devoid of freshwater fish. This indicates that we may have

been overestimating the use of these habitats by fish, with fewer populations than we

thought.

So what is the value of this information? We now know where

the secure populations of giant kōkopu are in the catchment so we can carry out more focussed investigations and management. The beauty of these sites is that there are few threats to them in their isolated locations. With little habitat change we anticipate that these populations will be around

for a long time. 

Awarua Wetland | September 2014BOG PAPERConservation for prosperity – Tiakina te taiao, kia puawai

AK, CIW and Living Water – What is the difference?Over the past year you have probably heard DOC staff use lots of letters when talking about the wetlands. We have AK and CIW, and now Living Water has come along. What do they stand for?

AK stands for Arawai Kākāriki. It is a wetland restoration programme run by DOC on 16,000 ha of your public conservation land in the Awarua–Waituna Wetlands, stretching from Tiwai Peninsula to Fortrose and inland to the Southern Scenic Route. Nationally, Arawai Kākāriki works alongside local communities to restore three of New Zealand’s most important wetlands.

So what is ruppia?

Ruppia is a macrophyte. It is a green, salt tolerant aquatic plant that grows on the floor of Waituna Lagoon like a meadow of long wavy seagrass. It is essential for a healthy lagoon and is the life support system for the Waituna Lagoon.

Just like grass, its roots hold the sediment together and its leaves use up nutrients, create oxygen and provide a home for fish and aquatic invertebrates to live. It is even a meal for some fish and wildlife.

Without ruppia the water quality declines, animal numbers decrease and the lagoon could become dominated by algae. Put simply: healthy ruppia = healthy lagoon = healthy fish and mahinga kai.

What’s up?

DOC has just received the latest annual monitoring report from NIWA, which describes the health of the ruppia beds in Waituna lagoon.

This year’s results recorded the lowest number of sites with ruppia and a

reduction of overall cover of ruppia since annual monitoring began in 2009. One of the species, Ruppia megacarpa, was found at only one of the 48 monitoring sites. Nuisance algal species that cause algal blooms and could smother ruppia plants were also recorded in the lagoon during the monitoring.

Why should we be worried?

“Waituna used to have extensive beds of macrophytes, dominated by Ruppia megacarpa, Ruppia polycarpa and Myriophyllum triphyllum (water milfoil) back in the 1960s. In 2007, ruppia beds covered 66% of the lagoon and were a nuisance to boaters,” says Emily Funnell, DOC’s Technical Advisor – Aquatic and Reporting Unit.

“We know that ruppia is very sensitive to water levels, salty conditions during spring germination, nutrient loads (nitrogen and phosphorous) and water clarity. Even though some overseas species of ruppia are marine species, ours are freshwater and estuarine species that

By Sarah Thorne, Project Manager Awarua Wetlands

It sounds like a bad joke. What is green, stringy and lurks at the bottom of Waituna Lagoon? The answer is ruppia. Or it should be. But right now the future is not looking very green for this aquatic plant.

Ruppia – Who cares?

are ‘tolerant’ of salty conditions but not salt lovers,” explains Emily.

When the lagoon is open, ruppia beds are lost either through drying out or possibly through wave damage. The lagoon has now been open for two consecutive growth seasons, so the ruppia beds have had little opportunity to germinate and grow and are now looking pretty unhealthy.

We don’t know how resilient the system is to these effects and whether the ruppia beds will recover under the ‘optimal conditions’ of a closed lagoon mouth and high water levels.

Next steps

DOC is committed to working with locals and the Waituna Partners and working groups to help create the best conditions possible for ruppia in the Waituna Lagoon. The latest monitoring results suggest that the lagoon is still in a vulnerable state with low growths of ruppia.

Arawai Kākāriki is hoping the lagoon will stay closed over the coming spring and summer months to give

ruppia the best chance to successfully germinate, reproduce and grow, anticipating that under ideal conditions (high water levels and low salinity) ruppia will flourish in the lagoon again.

A full copy of this report Macrophyte monitoring in Waituna Lagoon –Summer 2014 is available on the

DOC website doc.govt.nz/arawai-kakariki-research-monitoring.

Ruppia research

Next year the Arawai Kākāriki wetlands restoration programme will seek funding to monitor ruppia levels throughout the year as well as carrying out a seed bank study. 

Hang on a second – so you say it is a salt tolerant plant and it is often referred to as a ‘seagrass’ but yet it can’t handle the salty conditions in the lagoon when it is open to the sea? The term seagrass is used to refer to a number of plant families that are largely found in marine environments. Our Ruppia species are not part of these families but some overseas species of ruppia are marine species, which is where the confusion comes from. R. polycarpa and R. megacarpa are freshwater and estuarine species that are only tolerant of salty conditions as opposed to being salt lovers. This gives them a competitive edge over other aquatic species such as water milfoil which dies rapidly in saline conditions.

CIW is the Community Investment in Water Programme and is now known as Living Water. This is the Fonterra and DOC partnership which focuses on five sites nationally over ten years. Living Water works with local communities, dairy farmers, iwi and other stakeholders to improve sensitive water catchments. Our vision locally is to work with the local community to continue to enhance the health of Waituna catchment and the lagoon, to create healthy, functioning farms and wetlands living side by side now and in the future.

These programmes complement each other: Arawai Kākāriki on public conservation land and Living Water on private land. Both programmes are about working with local communities and agencies and sharing what they discover across New Zealand, and together will contribute over $750,000 into the Awarua–Waituna area this year alone! 

Published by: Department of Conservation, Murihiku/Invercargill Office PO Box 743, Invercargill 9840

September 2014

We want your ideas!In the next couple of months Arawai Kākāriki and Living Water intend to write 5-year plans for the Waituna Wetlands and its catchment, outlining what we want to achieve and how. We are going to team up and would love to talk to you and get your local views. Please let us know how you want to be involved, or if you have any ideas.

Contact usFor further information on any of these articles, or if you have a story or photos or ideas you would like to share, please contact:

Sarah Thorne Department of Conservation

Phone: (03) 211 2488  

Email: slthorne@doc.govt.nz

Local eyes and earsWe are incredibly lucky that we don’t have high numbers of large animal pests in our wetlands and it’s important that we keep it this way. If you see a wild pig or goat please let us know immediately by phoning 03 211 2400.

Meet the team

Sarah in a snapshot! I’m your Arawai Kākāriki Project Manager, and I look after the public conservation land down at Waituna. Please feel free to call me if you want to talk about your wetland or anything going on in it. I have a big smile and don’t bite! When I am not at work, I am wrangling three small kids, a Keith and a variety of animals at our wee farm at Tussock Creek.

Hi I’m John McCarroll, partnerships ranger and project lead for the Living Water partnership for DOC. I work with Nic and the team on getting things underway in Waituna and I’m really excited to be a part of this programme. When I’m not being nagged by Nicola and Sarah, I play football and spend time with my lovely wife and two wee girls at home.

Nicola Toki: I’m the Fonterra South Island Project Manager for the Living Water (DOC and Fonterra) partnership. I’m a born and bred Southlander, so it’s awesome to spend lots of time down here working on ways to improve water quality and biodiversity in the Waituna Catchment (and it means I get to see my nanas!). When I’m not down south, I live in Waipara in North Canterbury with the Bloke, our boy Hunter, two dogs and the chooks.