Well, that's annoying. This blog got hacked. I'm still trying to figure out how it happened. For now I've changed the site password and turned off the custom theme and all plugins. Hopefully I'll have things back to usual soon once I know it's fully cleaned.
In September I wrote of my surprise at finding the first Chilean glory creeper I had seen in Christchurch. It's a fast growing, well dispersing, aggressive vine similar in many ways to the infamous weed Old Man's Beard. Unlike Old Man's Beard, Chilean glory creeper is just at the beginning of trying to get established. It's an incipient weed and already it's a nationally unwanted organism that is banned from sale, propagation, and distribution by the National Pest Plant Accord. It was also the Environment Canterbury weed of the month of July 2008. As a weed to watch out for, it's already won all the awards.
I was gobsmacked to find a patch of the plant today at Lincoln University, and just 10 m off a path that I walk just about every week. To my knowledge the species has never been recorded from Lincoln (and I've looked for records in all the usual places like the NZ Virtual Herbarium).
It was growing in a shaded part of the garden under an old Corsican pine, east of the Commerce building. I wouldn't have noticed it if it hadn't been flowering, but I recognised it immediately as soon as I saw its bright yellow and orange tubular flowers. It must have been here for more than a year though as, on looking closer, I found at least two adults with tuber roots and at least 15 juveniles including young seedlings. I expect it arrived last year, somehow, and the young I found are the next generation. The adults were flowering and had developing immature seed pods. I found it just in time.
I've pulled out or uprooted everything I could find but it's likely that some of it has survived. I'll keep an eye on it. At least this patch won't seed this year.
The bigger question is where it came from. It produces large amounts of wind-dispersed seeds so the parent of this patch could be quite a distance away.
For me this underscores the big challenge for surveillance of incipient weeds. Weeds are easiest to stop early in their invasion, but that requires that we find those populations early in their establishment. I must have walked near this plant 50 times in the past year and not noticed it. That I've recently found at my son's school and now where I work makes it likely that there are a lot more Chilean glory creepers out there creeping their way into Christchurch.
Please keep a look out for this species right now, while it's in flower, and if you think you might have found one please post a photo of it on NatureWatch NZ. How many other surprises are out there quietly establishing in the out of the way places just over your shoulder?
The strong El Niño westerly winds this month have brought Australian painted ladies (Vanessa kershawi) to Christchurch. I'd never seen these butterflies before (and I count every butterfly I see). Yet, this month I've seen two of them.
New Zealand's environment has changed hugely since human arrival, especially in the drier lowlands. This has made a lot of open grassland and scrubland habitat better suited to Australian species than New Zealand's endemic forest specialists. Because of this, there's been a constant trickle of Australian native species finding their way across the Tasman Sea and establishing in New Zealand. Among NZ birds, the recent Australian arrivals include the silvereye, spur-winged plover, black swan, welcome swallow, and probably the pukeko.
The warmer conditions and stronger westerly winds predicted from global warming must be likely to accelerate this trend. It's likely only a matter of time before vagrant Australian species arrive in enough numbers at the right places and times to permanently establish. One of these is likely the Australian painted lady butterfly. It's a not uncommon vagrant in New Zealand, especially in the west, often blown across the Tasman in strong winds. To-date, there are no records of it surviving a New Zealand winter here, but that may only be a matter of time and rising greenhouse gases.
Back in 1968, entomologist Eric Pritchard observed an Australian painted lady laying eggs on what he called Japanese cudweed (a Gnaphalium sp.) in St. Heliers Bay, Auckland. He carefully collected the leaves with the eggs, and they hatched into caterpillars. He successfully fed them on Japanese cudweed. Four successfully made it through to pupae and emerged as butterflies 46–49 days after the eggs were laid. Eric concluded at the time that "Although Vanessa kershawi has found suitable host plants in Auckland it does not yet seem to persist here." He reported his findings in the journal NZ Entomologist.
I expect to see more painted ladies in years ahead..
Here's another addition to my growing list of discoveries of garden plants beginning to establish in the wild in Christchurch: white corydalis, Pseudofumaria alba (previously known as Corydalis ochroleuca). Last month I found my first Chilean glory creeper in Christchurch. Last year it was the South African plant, Nemesia floribunda and the Peruvian lily, Alstroemeria aurea. These contribute to the ongoing creep of garden plants out into wild New Zealand. Some will become only minor components of wild plant communities. Others will become invasive weeds. Forecasting which will do what is still very difficult. It makes sense to stop anything with weedy tendencies while it's easy to do so.
I found the Pseudofumaria alba wild and thriving along the side of the stream that runs along the eastern boundary of St. Albans School (my 7-year old son and I were exploring while my wife was playing soccer on one of the adjacent fields). This is the first patch of this plant I've ever seen and it took me a while to figure out what it was. It was growing in partial shade spreading along the weedy bank above the narrow channelised stream.
I've since discovered on the NZ Virtual Herbarium that this species has previously been collected wild in Auckland, first in 2002, in Taranaki first in 2005, and somewhere in/near Christchurch in 2005 and 2006 (the Virtual Herbarium fudges all of its coordinates so I can't tell exactly where they were). There are a couple of other older specimens in the Allan Herbarium but I can't tell from the online information whether or not they were wild and from where they were collected.
Not much is known about this species. It is native to rocky woodlands of southern and eastern Europe (according to missouribotanicalgarden.org), and has naturalised (gone wild) in parts of western Europe (e.g., Sweden). Several garden sites emphasise its propensity to self-seed (like finegardening.com, davesgarden.com, and missouribotanicalgarden.org). User coriaceous on davesgarden.com writes that "It can sometimes self-sow excessively, but the seedlings aren't difficult to control."
The fact sheet at davesgarden.com also notes that parts of the plant are poisonous if ingested. A related species, Corydalis caseana, was found to cause "serious losses of sheep" in parts of California where it had gone wild. Corydalis generally are poisonous to cats.
So, it's a poisonous European woodland species that readily self-seeds and is now establishing in parts of New Zealand. It's also is in the poppy family (Papaveraceae) and we have no native plants in the poppy family. Pseudofumaria alba is therefore unlikely to become a host plant for many native insect herbivores and fungi and so play a limited role in food webs and have a competitive advantage over native plants.
Do we want another poisonous plant wild in our cities? If in doubt, pull it out!
Even the worst weeds begin as a small scattering of wild plants here and there in a landscape. It can take decades to centuries for them to gradually build up in numbers until they're dominating habitats and frustrating people. It's with that in mind that I'm always on the lookout for wild exotic plants that I've not seen before. On Monday, I added another to my list for Christchurch: the Chilean glory creeper (Eccremocarpus scaber). My list also includes the first Canterbury record of the South African plant, Nemesia floribunda, already a widespread weed around Dunedin (and which I wrote about here), and the Peruvian lily, Alstroemeria aurea (which I wrote about here).
Chilean glory creeper is a rapidly growing vine that is listed on New Zealand's National Plant Pest Accord, the list of the worst weeds that are banned from sale and distribution. It's a weed that we don't want to become widespread. Weedbusters NZ, the government's weed website, has a useful weed information sheet for the species.
I saw my first wild Chilean glory creeper in Christchurch on Monday, growing in a wooded corner of Cashmere Primary School, where my son goes to school. It was about to flower. I posted an observation with photos on NatureWatch NZ, took a sample for my herbarium, and alerted the city council botanist Trevor Partridge. And next time I'm at the school I'll dig it out. It most likely came from a nearby garden so I'll be keeping a close eye out for more.
Consistent with the early stages of an invasion, there have been a scattering of recent records of this species in the wider area in the past decade or so. The last time I saw this species was on a roadside between Little River and Cooptown on Banks Peninsula (see this NatureWatch NZ observation). That patch has since been controlled. The NZ Plant Conservation Network's plant distribution database contains two local records from the DOC Plant Database, one from Governors Bay in 2002 and one from Barnett Park in Redcliffs in 2006, both likely removed by now. The NZ Virtual Herbarium has two 2005 records from Christchurch collected by botanists Bill Sykes and Arthur Healy (the exact locations are obscured on that site so I'd have to request them or visit the Allan Herbarium to learn where exactly these were). Botanist Murray Dawson tells me that there might still be some at the end of the Governors Bay coastal walk in Lyttelton Harbour.
Weed populations are at their weakest at this early stage in their invasion. If new incursions continue to be reported and controlled, it should be possible to keep the lid on new weeds. That's a big "if" though as it hinges on there being enough botanically curious or knowledgeable people about in the area reporting new plants as they find them. If you see an unusual new plant wild in your neighbourhood, please don't be shy about posting a photo of it on NatureWatch NZ.
One of the rare plants in Christchurch is Leptinella nana. I got to see it in flower this month in the Port Hills, and I also saw it in September with Christchurch botanist Melissa Hutchison, when it was still not yet in flower bud. Colin Meurk commented on one of my NatureWatch NZ observations that this is "reputedly the smallest 'sunflower' in the world". As you'll see from the photo below next to a 20 cent coin, it's a tiny plant.
The species is listed as "Threatened - Nationally Critical" in the 2012 conservation assessment of NZ plants. The species is only known from one site in the North Island and two sites in the South Island. One of the South Island sites is in Marlborough and the other is on Mt. Pleasant in the Christchurch Port Hills. See the NZPCN fact sheet for more details.
Leptinella nana is found growing in places along the track side up on the damp and shaded south side of Mount Pleasant. In these areas, it appears to be dependent on disturbance to maintain suitable open areas for it to grow without getting overrun by taller competitors like rank grass. Where it's present, it's doing well and is quite common.
Why this species is so rare, both nationally and in the Port Hills, is not clear. It's a very small plant, and easily overtopped by taller, fast growing herbaceous plants. There are an enormous number of naturalised plants (weeds) that now fall into this category. The NZPCN fact sheet note that slugs can be an issue for these plants in cultivation. That could also be the case in the wild, although I didn't see any obvious signs of herbivory up on Mount Pleasant when I visited. It would be well worth some careful study, especially on how weeds and trackside disturbance are affecting its success..
Monarch butterflies have got to be New Zealanders' favourite Lepidoptera. Aside from the cabbage white butterfly, which are unwanted pests of our cabbages and broccoli, monarchs are easily the most abundant butterfly in Christchurch. They are also entirely dependent on all of the swan plants and other milkweeds that people plant in their gardens for the monarch caterpillars to eat. While swan plants have gone wild in Northland, in Christchurch there's not a single wild plant species that monarch caterpillars can develop on. That's a remarkable amount of community effort to collectively farm this pretty North American butterfly.
This Kiwi devotion to the monarch is well illustrated by a stylish mural in Christchurch that I discovered recently by artist Ira Mitchell-Kirk. On it, there are four panels, showing a tui (native bird) on a lowland flax (native plant), a fantail (native bird) on a kowhai (native plant), a Mount Cook buttercup (native plant), and, ... wait, what? A monarch (North American butterfly) on a generic leaf (most likely the North American swan plant). It's odd to see a monarch on a mural celebrating natural New Zealand. As pretty as they are, a monarch is as much a natural part of New Zealand as a cow.
Central Christchurch mural by Ira Mitchell-Kirk. Spot the odd species out.
It would be nice if a NZ native butterfly of moth could reach the same level of public recognition as the monarch has achieved. New Zealand is a land of some remarkably pretty moths, most of which can be found in NZ cities. They deserve to be well known and celebrated in New Zealand. At the moment, most don't even have common names. As my small step towards this, I offer a few of my favourite moth species that I managed to photograph this year.
While stoats and possums are well entrenched in the public eye as enemies of New Zealand's native biodiversity, public opinion remains largely positive for hedgehogs. Hedgehogs remain widely regarded as cute garden residents that eat slugs in people's vegetable gardens. Some people still put food and milk out for hedgehogs. I even found a popular group set up to rescue sick, orphaned, and injured hedgehogs.
Nevertheless, in terms of impacts of native wildlife, hedgehogs are right up there with stoats, possums, and rats. They eat just about anything they can catch, including insects, frogs, lizards, birds eggs, and even adult chickens. Hedgehogs are now wild in all sorts of native habitats, even subalpine grasslands. Wildlife scientists and conservationists are unanimous that hedgehogs and native wildlife don't mix well. This has been nicely summarised in newspaper articles here, here, and here. For a more scholarly take on the same topic, here's a scientific article by Landcare Research ecologists Chris Jones and Grant Norbury quantifying the diet of hedgehogs in a NZ dryland, including native skinks and rare beetles.
All this was well illustrated for me on our Christmas camping trip to Okains Bay on Banks Peninsula. At the campground's kitchen-toilet block, the lights remain on all night, which attracts in all sorts of local insects. And one hedgehog had set itself up there to eat whatever it could catch.
It turns out that it didn't like huhu beetle antennae (the rest of the huhu was suitably appetising). Huhu beetles (Prionoplus reticularis) are New Zealand's largest beetle, and are still common thanks to their liking for plantation pine trees. In the morning the deck was littered with huhu beetle antennae. I went around the building picking up all the antennae I could find. The one toilet block hedgehog had eaten at least 27 beetles that night. It undoubtedly ate a great many other insects too, like the big moths attracted to the lights, but it ate those whole.
In areas where hedgehogs are common, they are clearly important predators for small creatures the live on or near the ground..
Here's a pretty wild flower that popped up in our garden this year, in Cashmere, Christchurch. It's also spreading through the northeastern corner of Cracroft Reserve, adjacent to our house. I uploaded a photo of it to NatureWatch NZ and learned that it was Peruvian lily, Alstroemeria aurea. It's a lily with orange striped flowers.
According to Flora III, it was first collected wild in NZ back in 1945 when Arthur Healy found it on an Upper Hutt, roadside. It has since been recorded wild in almost every region of New Zealand. Flora III, published in 1980, regarded it as "rare on roadsides and waste land."
I expect that's still the case as I have not seen it anywhere else in the neighbourhood, and certainly not anywhere visible from the street down Dyers Pass Road, Hackthorne Road, and Macmillan Ave (which I bike and run along frequently). The NZ Virtual Herbarium lists two collections from Canterbury, both collected by Bill Sykes from Christchurch in February 1990, and another under its synonym, Alstroemeria aurantiaca , by Peter Heenan in December 2006.
That makes it a recent addition to Canterbury's naturalised flora and puts it early in its invasion. Perhaps it will always remain rare, but we've no way of knowing that for sure. It pays to be cautious with new plant naturalisations. I pulled it out from our garden and cut the flowers off the plants in the reserve so they wouldn't seed.
(The flowers didn't go to waste though. They looked glorious in a vase in our kitchen. I'm not completely immune to the gaudy charms of colourful exotic plants. Plus one went in my plant press for the herbarium.).
Here are some miniature pink mountain ranges on eucalyptus tree leaves that I found in Christchurch this week, by the Blenheim Road roundabout, on my bike ride to work. After some work on the internet looking through NZ's many eucalyptus herbivores, I figured out that they're caused by an Australian gall wasp called Nambouria xanthops. It has been suggested on NatureWatch NZ that the host tree here is Eucalyptus viminalis.
Nambouria xanthops was first found in New Zealand in October 1999 in Auckland. It was unknown to science at the time and was formally described from the New Zealand material in 2002 by NZ wasp expert Jo Berry and NZ forest entomologist Toni Withers. According to Forest Research's Forest Health News (no. 129, May 2003), it had been recorded from about 10 species of Eucalyptus in NZ.
NatureWatch NZ users have documented Nambouria xanthops in Auckland, Wellington, and now Christchurch. I cannot easily tell whether this is the first record from Christchurch since most NZ insect collections are still not available online.
I have sampled one leaf and have it in a vial on my office desk in the hope of rearing some adult wasps from the galls.