There are a lot of invasive species in Aotearoa. Aside from the infamous rats and possums, there’s everything from pine trees and deer to finches and perches, and they all pose threats to our native ecosystems. There are also species that have been brought over and naturalised but aren’t considered invasive pests, like our introduced frogs. Otago’s unique landscapes and colonial history mean that it is also home to some unique invasive species, some of which aren’t found in many other places in the country, and some of which you might not have heard of.
Wallaby
At least five species of wallaby – the smaller, cuddlier cousin of the kangaroo – have been introduced to Aotearoa from Australia, and two are now considered invasive pests. One of them, Bennett's wallabies, are mostly found in Canterbury. Their territory also encroaches parts of North Otago, although the regional council controls them in Otago to try to keep them at bay. They may be cute, but in the big numbers they are found they can destroy fences, pastures, crops, and native bush.
Threat level: 9/10
Management programme: Eradication (for Otago).
Would it be good in a pie?: Absolutely. This already exists for a reason.
Satisfaction of hitting it with your car: 4/10. Risk outweighs reward. While small enough, it could still write off your car. Bonus points if there’s a joey in the pouch, though.
Chamois
The Alpine chamois is a relative of goats, and looks like a small mountain goat. Like many invasive species, the chamois was introduced in the early 1900s, in this case near Aoraki / Mt Cook from Austria. They have since spread across the South Island, including the popular ski mountains around Queenstown. They are popular game animals, and are apparently quite tasty, but also do a lot of damage to important native alpine plants. These animals also perform the important social work of uniting conservationists and hunters over a common goal.
Threat level: 6/10
Management programme: None (hunting licences available though)
Would it be good in a pie?: Definitely. Even better than wallaby, but probably like $2 extra.
Satisfaction of hitting it with your car: 0/10. Terrifying. Horrific. Horns through the windscreen. Do not attempt. Think of the SOUND.
Banana passionfruit
To throw a plant into the mix, the banana passionfruit is native to Latin America and found in a few specific spots like the Otago Peninsula, Mt Cargill, and Quarantine Island. Banana passionfruit produce pretty pink flowers that then become (as the name hints) a unique passionfruit that is yellow and roughly banana-shaped. Despite a pleasing colour scheme and yummy fruit, these plants are vines that can climb up to 10 metres high and smother native vegetation so rallying community groups to weed them out is important in places where they threaten indigenous biodiversity. Bonus fact: passionfruit are named for the Passion of Christ, as they display a cross when sliced open.
Threat level: 6/10
Management programme: Site-led (weed control from community groups)
Would it be good in a pie?: It would be good on a pie, but they’re quite bitter and filled with crunchy seeds. Bad texture.
Satisfaction of hitting it with your car: 10/10. Like popping bubblewrap but with your car. It’s like they were made for this.
Little Owls
If you’re lucky enough to have heard ruru (morepork) calling out at night while camping, you may know that it is the only native owl we have in Aotearoa today. Around Otago however, you’re actually more likely to come face to face with a little owl. Little owls are only slightly smaller than ruru, but are plumper, paler, and have eyes that stare more deeply into your soul. Little owls prefer grasslands or abandoned buildings rather than the forests where ruru are found, and are more likely to be out and about during the day. They’re also called German owls, probably because they were introduced from Germany in the early 1900s in an (unsuccessful) attempt to control sparrows. Little owls do eat small birds, as well as lizards, frogs, and mice, but mostly feed on insects. They are not a major threat to any native species, except perhaps the Cromwell chafer beetle due to their scarcity (we’ll come back to them shortly).
Worth a special mention are the barn owls (your archetypal Hollywood owls), which have flown over to New Zealand on a number of occasions but have never formed a population; and the laughing owl, a native owl species that went extinct so recently (1914) that there are black and white photographs of this sublime bird.
Threat level: 3/10
Management programme: None
Would it be good in a pie?: I hate that this sounds delicious but let’s be honest…
Satisfaction of hitting it with your car: 1/10. Shame.
Redback spiders
If you thought the katipō was the only venomous spider in Aotearoa, let me introduce you to the redback spider. The redback spider is closely related to the native (and endangered) katipō, as both species are in the same genus of spiders; the black widows. Redback spiders, however, are smaller, faster, and deadlier; they outcompete and interbreed with katipō, posing a big threat to the natives. A relatively recent problem, they were introduced into the country in the 1980s from Australia and now thrive in New Plymouth and Central Otago.
The aforementioned Cromwell chafer beetle is a critically endangered native beetle that is only found in a 0.81km² reserve in Central Otago, and in recent years redback spiders have used rabbit holes in the reserve to build webs and hunt the chafer beetle, posing a massive threat to the population. Invasive spiders are very hard to control, but scientists have found that filling in the old rabbit holes has reduced redback numbers in the reserve – a lifeline for these special beetles.
Threat level: 9/10
Management programme: None
Cuteness: A baby playing with a knife
Would it be good in a pie?: Nooo no noonnon nonnno noon n nono noooo
Satisfaction of hitting it with your car: 0/10, they’re far too small. If they were bird-sized, I would be actively swerving into them, and this would easily be a 10. Pop!
Rook
If you think you’ve seen a crow around Otago, it was probably a rook. We don’t have any crows in NZ, but rooks come from the same family and look like a scruffier, moodier, slightly larger crow. They were introduced in the 1860s, and have been causing massive headaches for farmers ever since thanks to all the crops they destroy. They are very intelligent birds and quite social too, forming colonies of nests known as rookeries, which means any attempts to control them have to be coordinated and well thought out otherwise they just spread further. They are now more common in the North Island, but there were once thousands of rooks in Otago before eradication efforts brought the population down to less than 40 in the region as of last year. No new chicks have been reported in the region in the last six years, meaning there may no longer be a breeding population at all in Otago. Bad news for witchcraft, but great news for farmers.
Threat level: 6/10
Management programme: Eradication
Would it be good in a pie?: Yes! Like chicken, but smarter.
Satisfaction of hitting it with your car: 5/10, they should know better, but it still feels bad. The screams…
Rock snot
Didymo, also pejoratively called ‘rock snot’, is a species of phytoplankton or microalgae native to the northern hemisphere that was first detected in Southland in 2004. Since then it has spread to many rivers in Otago, Southland, and Canterbury – including Otago’s Clutha river, the largest in the country – but has successfully been excluded from the North Island thus far. When it blooms it forms large snotty mats on riverbeds that have been texturally compared to “soggy toilet paper”. And just like soggy toilet paper, it is good for nothing and can cause a lot of damage. It impacts water quality and harms native ecosystems, and can be a hazard for swimmers, hydro dams, and drinking water supplies. It can be spread from one river to another by a single drop of water, so it is a legal requirement to properly clean your clothes or gear for didymo when leaving any river, lake, or stream in the South Island.
Threat level: 8/10
Management programme: Check, Clean, Dry
Would it be good in a pie?: No. Could you market it to vegans anyway? Yes.
Satisfaction of hitting it with your car: 8/10. Fun and slidey, but you have bigger problems if you’re somehow driving on didymo.