Archives For Wetlands

Informative new signs at the Manawatu Estuary are teaching visitors about the bird species that rely on this internationally significant wetland habitat.

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DOC Ranger Jane Hughes explores and measures the secretive world of the Whangamarino Wetland.

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Wetlands are New Zealand’s shy places, so you need patience to photograph them well. DOC’s Des Williams explains…

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Twice a year Stella McQueen arrives in her campervan at Whangamarino Wetland to count fernbirds/mātātāa and spotless crake/pūweto for four hours every dawn and dusk.

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It seems everything has its day. Today is Crepe Day, World Play Your Ukulele Day, Groundhog Day and… World Wetlands Day!

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By Emily Funnell, Technical Advisor – Aquatic and Reporting Unit

Earlier this year we carried out a survey in some of the ponds and bog tarns in Southland’s Waituna catchment.

This work was undertaken as part of DOC’s Arawai Kakariki wetland restoration programme in the Awarua-Waituna Wetlands.

Waituna wetlands sign. Photo: itravelNZ | CC BY 2.0.

Waituna Wetlands

We have always known that giant kōkopu, kōura/freshwater crayfish and other species can be found lurking in in the tarns and ponds, but we have never known how extensive their habitat was.

Freshwater crayfish/kōura.

Freshwater crayfish/kōura

In April we had a peek in a number of ponds all around the catchment, many on public conservation land, but also a few on private land.

Surveying for freshwater fish at Munroe Dam.

Surveying in the Munroe Dam

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. Photo: Andy Hicks.

Giant kōkopu in the Waituna catchment

Giant kōkopu and other freshwater species were largely absent from most of the catchment ponds, except at the Munroe Dam and in the tarns on the southern side of the lagoon. These two sites had more giant kōkopu than we could shake a stick at, and with a good range of sizes.

Giant kōkopu. Photo: Andy Hicks.

Giant kōkopu

Unfortunately, the ponds and 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.

Network of bog tarns at Waituna Lagoon.

Network of bog tarns at Waituna Lagoon

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.

Cicada. Photo: Andy Hicks.

Cicada at Waituna

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.

Most freshwater zooplankton are too small to see with the naked eye.

To bring these amazing animal-like organisms to your attention, we’ve put a 1.02 mm cladoceran (water flea) under the microscope for our photo of the week.

A 1.02 mm female Cladoceran (Water Flea). Photo copyright: Ian Gardiner. All rights reserved. Used with permission.

This beautiful, incredibly complex creature was caught on film by photographer and citizen scientist, Ian Gardiner, who kindly allowed us to share his photo.

Zooplankton are a vital component of freshwater food webs. The smallest zooplankton are eaten by the larger zooplankton which, in turn, are eaten by small fish, aquatic insects and so on.

Herbivorous zooplankton graze on phytoplankton or algae and help maintain the natural balance of algae.

“It has long been an axiom of mine that the little things are infinitely the most important.” ― Arthur Conan Doyle, The Memoirs of Sherlock Holmes

Photo: Cladoceran (Water Flea) | By Ian Gardiner | © All rights reserved