Tuesday, August 29, 2017

Longfin Eel. Enjoy them. Don’t destroy them

We have Longfin Eel in our Mangaiti Stream. This photo is of one up the headwaters at the Gordonton Road end that the local children regularly feed.
Longfin Eels are in the "at risk - declining" threatened status. They are the larger of our two eels. The other being the smaller and more common Shortfin Eel. The Longfin has a very interesting life cycle. They are endemic to New Zealand and grow in our rivers, streams and fresh water lakes to a good old age (can be 80 years). They are probably the biggest eel in the world. Slow growing and sometimes some females can reach 2 metres long and weigh up to 40kg.
On reaching their breeding size, the eels migrate to the sea. The details of the lifecycle are not clear. They swim for up to five or six months to tropical Pacific waters, possibly near Tonga, where they spawn and die. The eggs hatch into leaf-shaped larvae that float back to New Zealand on ocean currents.
Arriving in astounding numbers in spring, the larvae transform into slender, transparent “glass” eels. The glass eels soon turn into grey-brown elvers (young eels) and begin migrating upstream. And so the cycle repeats.

Mangaiti Gully Management plan

This management plan has been compiled by Mangaiti Gully Restoration Trust (MGRT) and covers the whole 30 hectares of gully. Its aim is to get everyone onto the same page; MGRT, gully neighbours, HCC, WRC and anyone else that may have an input into restoring Mangaiti Gully’s native biodiversity.
It covers flora (plants) and fauna (animals) management, threats and suggested ways of managing them, along with building infrastructure, education and social benefits among other things. If anyone would like a copy you are welcome to email your request to  gullyrestoration@gmail.com
(Unfortunately we are unable to attached a pdf file to this blog site)

Rat eradication programme

This has gained good momentum with 60 bait stations installed which are being serviced by 15 enthusiastic community service agents. These are the people that live on the gully edge and have been trained to service the bait stations and record that information into the TrapNZ website.
After six years since it conception this is a really interesting time for this project. On our page of TrapNZ all the information we require is being recorded to monitor the success or otherwise of the programme. After going through the next seasonal rat breeding cycle we will know by June / July next year whether we are going to achieve our objective of clearing out all breeding resident rats.
Click on the map to enlarge

A measure of the Fauna’s health

The health of the native fauna in any restoration project is the final piece of the jigsaw.  We really need to be able to measure how things are going. In the bush this is usually done by doing regular bird counts. However we run into difficulty in an urban situation where birds (Tui) can fly from one gully system to another with relative ease. To overcome this the Trust is developing a way of measuring the Tree Weta not just by the numbers present but by the size (length and weight). The Weta is predated on by both rats and possums (as well as Morepork) so we feel this would be a good indicator species for measuring fauna health. We have started to put up specially designed Weta homes for the project with the aim of having twenty or more spread throughout the gully system.

A book review

The Unburnt Egg
More stories of a museum curator

By Brian Gill
ISBN 978-1-927249-29-1
This first edition was published in 2016 by Awa Press

Brian Gill was curator of birds and other land vertebrates at Auckland War Memorial Museum for over thirty years. In his book “The unburnt Egg” he brings a dusty museum’s storeroom, its scientists and its creatures within the museum’s collection back to life in a most entertaining and informative way. Each chapter leads you off on another adventure around New Zealand or the Pacific; each story another chapter.
Even though it is a book of short stories, it is written in such a way that after completing a chapter you are eager to progress to the next, much like a good novel.
I thoroughly enjoyed reading this book and highly recommend it to anyone that has an interest in natural history.

Saturday, May 27, 2017

Lacebarks do the trick

Silk cover over the Puriri Moth Caterpillar hole
Mangaiti Gully Restoration Trust is an innovative, progressive Trust that is pushing conventional boundaries in urban restoration.  This means enhancing the environment within the gully system to take the negative pressure off the native fauna (birds, invertebrates, reptiles and fish) which urbanisation invariable brings.

Selective and targeted planting is one way to achieve this. An example is the Puriri Moth. An impressive native moth that is the largest native in NZ with a wing span of 150mm. Their caterpillar bore into the trunks of Grey Willow and Privet when native species are absent. If these are removed during weed clearing our native moth is also removed. To manage this, extensive planting of a native substitutes like Lace Bark is being done. This winter 62 Lace barks that we grew from seed have been planted in the latest cleared area. These grow relatively fast giving good early canopy cover which helps to shade out sun loving weeds.

Adult Puriri Moth

Red and Yellow Admiral Butterflies

Red Admiral
Progress is being made to reintroduce Red Admiral butter flies to the gully. We have propagated a number the nettle plants that they require for breeding. We are fencing off an out-of-the way area for the nettle and there will be signage on the fence to warning people that touching the plants will cause an unpleasant irritation.

Yellow Admiral
We have identified a river bank on the Hauraki plans that has nettle and Red Admirable butterflies. This will be the source of stock once our nettle plants are established. Yellow admirals are already present in the gully so we are looking forward for their population to increase.