New Zealand is truly a paradise – near zero pollution, wide stunning vistas of soaring mountains, crystal aquamarine waters, glittering glaciers and a wide diversity of flora and fauna.  In the spirit of transparency I do need to tell you about some bad dudes that are the focus of an all out war by the Kiwi’s to eradicate them so that the above scene will be around for future generations.

I have written in previous posts about the many invasive animal and plant species that were brought to New Zealand by human settlers.  These have wreaked havoc on the  country’s natural balance.  Sadly, many endemic species have been decimated  due to these intruders.  Pests such as possums, rats and stoats compete with many birds for food and habitat. They also eat the eggs and young and attack the adults.  These invasive mammals that have been brought to New Zealand may look cute and fuzzy but they are a menace:

All photos in this post come from the New Zealand Department of Conservation:








Insects such as foreign wasps consume massive amounts of honeydew which is an important food for native birds, bats, endemic insects and lizards. They have been known to attack and eat baby birds and other  insects.   They also terrify tourists and locals alike and their stings are painful.  Their numbers are astounding. In some beech forests there are  an estimated 12 nests, or 10,000  wasps, per 2.5 acres.  Here is a scary fact from New Zealand’s  Department of Conservation:

The total combined body-weight of wasps in these forest areas is higher than the weight of all native birds, stoats and rodents, put together.


German wasp



My readers are well aware of my intense fear of flying insects so you can imagine my relief at  NOT running into these wasps.  However I admit I was quite queasy writing about them and posting these photos, but chalked it up to a facing my fears moment.

The tiny Argentine ant is one of the world’s most invasive and problematic ant species. They are very aggressive and do bite people, although they are not poisonous. Various colonies can combine into super colonies, reaching extraordinary numbers.  With these statistics any native insect and even bigger creatures are in major trouble if a super colony attacks.

Argentine ant.


The  pest of this post’s title is one that topped my repugnance meter.  Firstly, the name:  Rock Snot.  What the @#$%^?

Rock snot, or its official name Didymo is a type of single-cell brown algae called a diatom. It forms  thick mats on river bottoms and shorelines and can smother bottom dwelling organisms which then affect fish  and so on up the food tree. It has been around for thousands of years but it only arrived in New Zealand about 18 years ago.  Since  the individual diatom is microscopic it can  spread easily – even through a droplet of water. Massive quantities of these diatoms encase themselves in a protective silica jell = rock snot.

We did not run into any rock snot during our visit and that was due in part to the very tough rules New Zealand has put into place to prevent its contamination and spread.  For example, when we hiked through the Milford Track we had to remove our shoes before entering a mid-point lodge.  Similarly, when we took a boat across Lake Te Anau to the Glowworm Caves, we had to step through a disinfectant upon arrival and before leaving for the mainland.

Given Kiwi’s belief in a clean non-toxic environment, the above is an example of the main methods being employed to prevent spreading – as noted in the below suggestions from a New Zealand environmental website:

Check: Before leaving the river, remove all obvious clumps of algae and look for hidden clumps. Leave them at the site. If you find clumps later don’t wash them down the drain, treat them with the approved methods below, dry them and put them in a rubbish bin.

Clean: Soak and scrub all items for at least one minute in either hot (60°C) water, a 2% solution of household bleach or a 5% solution of salt, antiseptic hand cleaner or dishwashing detergent.

Dry: If cleaning is not practical (e.g. livestock, pets), after the item is completely dry wait an additional 48 hours before contact or use in any other waterway.

There does not seem at present to be any effective means of killing the snot without adversely affecting the environment – a scary notion since the Didymo is now present all over the world.

This is rock snot:





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