Counting keruru: can public surveys and competitions aid New Zealand conservation?

Whilst some other countries - the UK, for example - have dozens of general and specialised wildlife surveys undertaken by members of the public, New Zealand has comparatively few. Whilst this might seem odd, considering the Kiwi penchant for the great outdoors (not to mention the little matter of the endangered status of so many native species) it should be remembered that the nation has a rather small (human) population. In addition, New Zealand is no different from other developed countries, wherein environmentalists often appear at loggerheads with rural landowners, especially farmers.

Since agriculture forms a fundamental component of the New Zealand economy, any anti-farming sentiment can quickly escalate into unpleasantness, as even a cursory look at agriculture versus environmentalists news stories will confirm. Farmers are often reported as resenting what they deem as unrealistic or uninformed opinions by wildlife campaigners. But lest farmers consider this particular post being yet another piece of anti-farming propaganda, it should be noted that campaigns are usually driven by a perceived need for action in the face of government inactivity: after all, New Zealand is second only to Hawaii in the number of introduced species, many of which are in direct competition with, or predate upon, native ones.

Talking of competitions, this year's Bird of the Year contest has just been won by the cheeky, intelligent kea, the world's only alpine parrot. Run by Forest and Bird* and now in its thirteenth year, it aims to raise publicity for the plight of New Zealand's native birds and the wider environment they rely upon. With over 50,000 votes cast, this means approximately 1% of New Zealand citizens and residents entered the competition (assuming of course that non-Kiwis didn't participate).

The international level of awareness about the competition seems to be on the increase too, with the kea's victory even being reported on the website of the UK's The Guardian newspaper, albeit in an article written by a New Zealand-based journalist. The competition doesn't appear to offer anything to science, except a potential – if not unobvious - theory that the public's fondness for particular wildlife species is based upon their aesthetic qualities, with drab birds for example getting less attention than colourful ones. Then again, perhaps Forest and Bird are more interested in spreading their message rather than the results; as the old adage goes, there's no such thing as bad publicity. Indeed, the story of a Christchurch-based who tried to rig the vote in favour of the white-faced heron was reported by the BBC.

Another prominent example of the New Zealand's public involvement in environmental matters is the Annual Garden Bird survey, which began in 2007 and is run by the Government-owned Landcare Research. This more obvious example of citizen science states that the results are used to analyse population trends for both native and introduced bird species and so aid pest control programmes. However, it would be difficult to ascertain the validity of the observations, since less than 0.3% of the nation's gardens (or rather their owners) participate.

Whilst 5000 entries might be considerably more than could be achieved by other means, there are probably all sorts of details that are missed with this level of coverage. I have participated for three years now and have found that my observations do not agree with the reported trends. For example, last year's results show that the silvereye, blackbird and song thrush have declined in my area, whereas I have not noticed any such a drop-off for these birds -  and it's not as if I particularly encourage the latter two (non-native) species.

A more specific example of bio-recording was last month's Great Kereru Count, which claims to be New Zealand's biggest citizen science project. Clearly, they don't consider the Bird of the Year competition as science! Various organisations run this survey, which gained around 7000 reports this year. There are also continuous monitoring schemes, such as for monarch butterflies (which is interesting, as this is a far-from-endangered, recently self-introduced creature) whilst NatureWatch NZ allows anyone to supply a record of a plant or animal species, or indeed to request identification of one. The latter might not sound particularly necessary, but judging by how little some New Zealanders seem to know about their own environment (for example I've met Kiwis who cannot identify such common organisms as a tree weta or cabbage trees) this resource is probably essential in understanding the spread of non-native species.

With native species protection in mind, there are other, more direct, citizen science projects in the country, with everything from the Great Kiwi Morning Tea fundraiser this month to allocation of funding for predator control tools and traps – including in urban gardens - via the independent trust Predator Free New Zealand.

For an even greater level of public involvement in science and technological research, in 2015 the New Zealand Government initiated the Participatory Science Platform to aid partnerships between professionals and community groups. Three pilot projects are currently under way, with Dr Victoria Metcalf as the National Coordinator (or Queen of Curiosity as she has been nicknamed.) These projects are exciting because they involve the public from project development through to conclusion, rather than just using non-scientists as data gatherers. In addition, the ability to gain first-hand experience on real-world undertakings may even encourage children from lower decile areas to consider STEM careers. That's no bad thing.

Back to surveys. Although science communication (sci-comm) is in vogue, my own feeling is that participation is key to promoting science – the methods as well as the facts – to the wider public. Yes, some science is very difficult to understand, but there's plenty that is also easy to grasp. This includes the dangers facing species pushed to the brink of extinction by habitat loss, pollution, and introduced organisms. By actively involving entire communities, surveys and competitions can also play a part in preserving species whilst allowing a sustainable level of development.

Of course this requires a government with vision, but with New Zealand's Green Party gaining positions in the Jacinda Ardern-led coalition, perhaps the newly-formed New Zealand Government will pick up the slack after years of prevarication and inactivity. That way our grandchildren will be able to experience the cheeky kea and company for real, rather than just via old recordings. How can that fail to make sense? After all, at the lower end of the bio-recording spectrum, all it requires is for someone to make a few taps on their keyboard or smartphone. It's certainly not rocket science!

*Forest and Bird have actively lobbied the New Zealand Government in numerous cases to prevent environmental degradation via land swaps, mining and hydro-electric schemes. They have produced a volume on environmental law and a mobile app called the Best Fish Guide. All in all, they perform an immensely valuable contribution to ensure that development in New Zealand is sustainable and that the public are made aware of schemes that might impact the wider environment.

The zeal in Zealandia: revealing a lost continent

From an outsider's standpoint, geology appears to be a highly conservative science. As I have mentioned on numerous occasions, it seems astonishing that it took over four decades for Alfred Wegener's continental drift hypothesis to be formalised - via the paradigm-shifting discovery of sea floor spreading - into the theory of plate tectonics. I suppose that like evolution by natural selection, the mechanism, once stated, seems blindingly obvious in hindsight.

Regardless, the geological establishment appears to have been stubbornly opposed to the ideas of an outsider (Wegener was a meteorologist) who was unable to provide proof of an exact mechanism. This was despite the fact that the primary alternative, hypothetical submerged (but extremely convenient) land bridges, appear even more far-fetched.

Over the past few decades geophysical data has been accumulating that should generate rewrites of texts from the most basic level upwards. Namely, that the islands making up New Zealand are merely the tip of the iceberg, accounting for just six per cent of a mostly submerged 'lost' continent. Once part of the Southern Hemisphere's Gondwana, in 1995 the newly discovered continent was given the name Zealandia. Approximately five million square kilometres in size, it broke away from the Australasian region of Gondwana around 70-80 million years ago.

After a decade or two of fairly lacklustre reporting, 2017 seems to be the year in which Zealandia is taking-off in the public domain. First, the Geological Society of America published a paper in February. stating that Zealandia should be officially declared as a continent. Then in July the drill ship Joides Resolution began the two month long Expedition 371, a research trip under the International Ocean Discovery Programme (IODP). Scientists from twelve countries undertook deep sea drilling, gaining data on plate tectonics, palaeontology and climate history as well as research directly relevant to understanding the geology of the newest continent.

It is surprising then to learn that geologists first mooted the idea as early as the 1960s but that apart from some marine core samples collected in 1971, no-one undertook the necessary ocean-based research until very recently. Earth resources satellites have helped somewhat, but nothing could replace the evidence that emerged with deep drilling of the seabed. Therefore I wonder what has sparked the sudden interest in an idea that has been around for so long?

One possibility is the large amount of data that the international geological community required to prove the theory beyond doubt, coupled with the fact that this sort of research has little in the way of an obvious immediate practical benefit. It is extremely expensive to undertake deep sea drilling and few vessels are equipped for the purpose. Joides Resolution itself will be forty years old next year, having undergone several years' of refit to keep it going. Those areas of sea bed with potential oil or gas deposits may gain high-fidelity surveying, but compared to fossil fuels, fossil biota and sea bed strata research are very much at the whim of international project funding. In the case of the IODP, governments are cutting budgets on what are deemed non-essential projects, so it remains to be seen whether the intended follow-up trips will occur.

It would be disappointing if there was no further research as despite the acceptance of Zealandia, there is still a great deal of disagreement about what is known as the Oligocene Drowning. I first came across the notion of an eighth continent in the excellent 2007 book In Search of Ancient New Zealand, written by geologist / palaeontologist Hamish Campbell and natural history writer Gerard Hutching. The reason that over ninety per cent of Zealandia is underwater is due to the lack of thickness of its continental land mass - only 20-30km - making it far less buoyant than other continents.

But has this submerged percentage varied during the past eighty million years? There are some very divided opinions about this, with palaeontologists, geneticists and other disciplines taking sides with different camps of geologists. These can be roughly summarised as Moa's Ark versus the Oligocene Drowning, or to be more precise, what percentage, if any, of New Zealand's unique plants and animals are locally-derived Gondwanan survivors and how many have arrived by sea or air within the past twenty or so million years?

The arguments are many and varied, with each side claiming that the other has misinterpreted limited or inaccurate data. If Zealandia has at any time been entirely submerged, then presumably next to none of the current fauna and flora can have remained in situ since the continent broke away from Gondwana. The evidence for and against includes geology, macro- and micro-fossils, and genetic comparisons, but nothing as yet provides enough certainty for a water-tight case in either direction. In Search of Ancient New Zealand examines evidence that all Zealandia was under water around twenty-three million years ago, during the event known as the Oligocene Drowning. However, Hamish Campbell's subsequent 2014 book (co-written with Nick Mortimer) Zealandia: Our continent revealed discusses the finding of land-eroded sediments during this epoch, implying not all the continent was submerged.

It's easy to see why experts might be reticent to alter their initial stance, since in addition to the conservative nature of geology there are other non-science factors such as patriotism at stake. New Zealand's unusual biota is a key element of its national identity, so for New Zealand scientists it's pretty much a case of damage it at your own peril! In 2003 I visited the predator-free Karori Wildlife Reserve in Wellington. Six years later it was rebranded as Zealandia, deliberately referencing the eighth continent and with more than a hint of support for Moa's Ark, i.e. an unbroken chain of home-grown oddities such as the reptile tuatara and insect weta. With the nation's reliance on tourism and the use of the '100% Pure New Zealand' slogan, a lot rests on the idea of unique and long-isolated wildlife. If the flightless kakapo parrot for example turns out not to be very Kiwi after all, then who knows how the country's reputation might suffer.

What isn't well known, even within New Zealand, is that some of the best known animals and plants are very recent arrivals. In addition to the numerous species deliberately or accidentally introduced by settlers in the past two hundred years, birds such as the silvereye / waxeye (Zosterops lateralis) and Welcome swallow (Hirundo neoxena) are self-introduced, as is the monarch butterfly.

The volcanic island of Rangitoto in Auckland's Hauraki Gulf is only about six centuries old and yet - without any human intervention - has gained the largest pohutukawa forest in the world, presumably all thanks to seeds spread on the wind and by birds. Therefore it cannot be confirmed with any certainty just how long the ancestors of the current flora and fauna have survived in the locality. A number of New Zealand scientists are probably worried that some of the nation's best-loved species may have arrived relatively recently from across the Tasman; a fossil discovered in 2013 suggests that the flightless kiwi is a fairly close cousin of the Australian emu and so is descended from a bird that flew to New Zealand before settling into an ecological niche that didn't require flight.

Other paleontological evidence supports the Moa's Ark hypothesis: since 2001 work on a lake bed at St Bathans, Central Otago has produced a wide range of 16 million year-old fossils, including three bones from a mouse-sized land mammal. The diversity of the assemblage indicates that unless there was some uniquely rapid colonisation and subsequent speciation, there must have been above-water regions throughout the Oligocene. In addition, whereas the pro-underwater faction have concentrated on vertebrates, research into smaller critters such as giant land snails (which are unable to survive in salt water conditions) supports the opposite proposition.

So all in all, there is as yet no definitive proof one way or the other. What's interesting about this particular set of hypotheses is the way in which an array of disciplines are coming together to provide a more accurate picture of New Zealand's past. By working together, they also seem to be reducing the inertia that has led geology to overlook new ideas for far too long; Zealandia, your time has come!

Wondering about the wanderer: the life and times of the monarch butterfly in New Zealand

This summer has seen a proliferation of monarch butterflies in my garden. Over the past five years there's been little change in planting - except for a few additional self-seeded swan plants (a.k.a. milk weed Gomphocarpus fruticosus and similar species) - so why am I now seeing so many more Kahuku/Wanderer than previous years? This summer has seen a mixture of wet and dry weeks but not an extreme in either direction, when compared to the previous four summers in house. Is that the secret: just a balance of weather conditions; or is there more to it than that? As I pointed out in a recent post, a cluster of swan plants several street's away has seen very few monarch butterflies. Let's have a look at the details.

My experience:

Although common enough in all except the coldest regions of New Zealand, Danaus plexippus is not a native species but seemingly self-introduced at some point within the last 150 years. It's large size and colourful wing markings have led to its popularity in art and science. I've seen paintings, collages, sculptures and jewellery utilising its patterns, which contrast vividly with New Zealand's predominantly green appearance.

Swan plants, the almost sole food source, are readily available from garden centres and buying one can lead to large numbers of self-seeded plants, aiding the spread of the monarch. I've found this year that even young plants under 50cm tall have had eggs laid on them. I've also noticed that the swan plants in my back garden contain more than double the number of caterpillars than those in the front garden, despite the latter garden being much larger and having a lot more vegetation. I've even noticed that some caterpillars in the front garden disappear shortly after starting to pupate; perhaps the denser planting attracts or hides more predators?

Lifecycle:

The eggs are usually found on the underside of leaves and tend to be more conspicuous than the first instar (freshly-hatched) caterpillars. Apparently, larger caterpillars will munch through both eggs and smaller caterpillars without noticing, so it's a monarch-eat-monarch world out there! I've had to move some caterpillars when they get to a decent size in order to prevent them eating their entire plant and starving to death. Females can lay hundreds of eggs in their lifetime at a rate of up to 40 per day, so monarch care sites recommend destroying later eggs to allow the earlier individuals to survive. In general, the warmer the weather the quicker the caterpillars grown to full size before pupating. However, it has been noted that butterflies that hatch in the autumn can survive over winter, often in colonies, their lifespan extended from two months for same-summer breeders up to nine months. Unlike in their North American homeland, New Zealand monarchs do not migrate enormous distances.

Predation:

Despite absorbing toxins from milkweed, both caterpillars and butterflies are predated by a range of other animals. I've occasionally found a pair of wings on the ground, which is a good indication of predation by a South African praying mantis, Miomantis caffra. Other introduced invertebrates such as wasps will also attack monarchs. It's interesting that these predators tend to have originated in Europe, Africa and Asia yet the monarch evolved in North America; clearly, the former aren't too specialised to be able to handle alien prey. Which of course is what has happened in general to New Zealand's native birds and reptiles, with European mustelids and rodents and Australian possums finding a veritable feast amongst the kiwi and company.

Caring for monarchs:

Apart from removing caterpillars from overcrowded plants, my only other assistance is to rehang any fallen chrysalis and move the occasional pre-pupating wanderer into a wood and wire cage until they metamorphose. Although I have found one chrysalis about eight metres from the closest swan plant, a fully-grown wandering caterpillar might just prove too tempting a morsel. Otherwise I tend to leave nature to do its thing; after all, it's hardly an endangered species. Many caterpillars disappear before reaching pupation due to a combination of disease and predation and any swan plant that gets completely eaten may lead the incumbent caterpillars to starvation. Darwin was famously inspired by Thomas Malthus' An Essay on the Principle of Population, so it's great to be able to see such a theory in action in your own garden!

Public interest:

Despite being neither native nor endangered, there are various New Zealand-based citizen science projects studying them, such as by fitting wing tags for tracking purposes. Much as I am in favour of direct public engagement in science, I wonder if the effort wouldn't be better redirected towards endangered native species. As I've previously discussed, if visually attractive poster species get much of the attention, where does that leave the smaller, more drab, less conspicuous critters that may be more important?

I'm still at a loss to what has caused this summer's proliferation of monarch butterflies in my garden. There are just as many other summer species as usual, such as adult cicada and black crickets, and seemingly as many monarch predators such as praying mantises. But as I've mentioned before, perhaps what to human eyes appear similar conditions are not so to these colourful creatures. Although how much effort would be required to detail those conditions is somewhat beyond the capability of this amateur entomologist!

Backyard bonanza: collating stats for a predator-free future

I've previously discussed how a lack of understanding of statistics can cause consumers to make poor choices, so it would seem that increasing the public's understanding of them can only be a good thing. Therefore, along the lines of New Zealand's annual garden bird survey, I decided to do a bit of citizen science. My aim was to record the highest number of each fauna species seen at one time, either actually in my garden or seen from my garden. The time frame was a calendar year, so as to take into account seasonal migrations and food availability. As an aside, it might have been easier to count flora (after all, it doesn't move very fast) but with Auckland being the weediest city in the world and my floral knowledge much weaker than my recognition of fauna, I opted for the easier option of any animal that I could see without using a microscope.

A meta-analysis released this month states that almost twenty-five percent of birds on the IUCN Red List of Threatened Species are being affected by climate change. In addition, with last years' announcement to make New Zealand predator-free by 2050, such surveys might be useful for locating concentrations of introduced pest species. In a way, I'm providing a guide that anyone can follow with the minimum of effort (hint, hint). So here are my results, followed by some more information:

Class/species	Native/self-introduced	Number seen
Insecta
Ant (unknown species)	Yes	Numerous
Asian paper wasp	No	3
Black field cricket	Yes	4
Bumble bee	No	1
Bush cockroach	Yes	14
Cabbage tree moth	Yes	7
Cabbage white butterfly	No	2
Cicada	Yes	2
Click beetle	Yes	2
Common bag moth	Yes	1
Crane fly	Yes	1
European earwig	No	1
Ground beetle	Yes	2
Honey bee	No	1
Housefly	No	7
Ladybird	Yes	2
Monarch butterfly	Yes	17
Shield bug	Yes	3
South African praying mantis	No	22
Tree weta	Yes	18
Arachnida
Bird dropping spider	Yes	1
Black cobweb spider	Yes	1
Black house spider	Yes	1
Daddy long-legs	Yes	3
Jumping spider	Yes	1
Nurseryweb spider	Yes	1
Slater spider	Yes	1
White tail spider	No	1
Annelida
Earthworm	No	5
Tiger worm	No	Numerous
Hexapoda
Springtail	No	Numerous
Chilopoda
Centipede	Yes	3
Mollusca
Common garden snail	No	9
Reptilia
Rainbow skink	No	2
Aves
Australasian hawk	Yes	1
Blackbird	No	2
Black headed gull	Yes	3
Eastern rosella	No	4
Fantail	Yes	2
Goldfinch	No	3
Greenfinch	No	2
House sparrow	No	14
Myna bird	No	4
Rock pigeon	No	5
Silvereye	Yes	7
Song thrush	No	1
Spotted dove	No	1
Starling	No	4
Tui	Yes	1
Mammalia
Cat	No	2
Chicken	No	1
Dog	No	1
Hedgehog	No	1
Mouse	No	1
Rabbit	No	1

The first thing that seems obvious is just how many non-native species I observed, some deliberate introductions whilst others accidentally brought to New Zealand, but all within the past two centuries.

Now for some interesting comments about how statistics can be (mis)interpreted:

1) The method I chose to order the table by could affect how easy it is to find key points of interest. Alphabetical order is familiar but is simply a well-known form of cataloging. Therefore it can be seen as a neutral form of presentation, not emphasising any particular pattern of the results. Had I ordered by native/non-native, it might have become more apparent how many of the latter bird species there are. If I had ordered all species in one list by this method, rather than in separate classes, the pattern would have been obscured again. So simply by selecting a certain order, results can appear to support a certain notion.

2) How useful is this data if it lacks supporting information? By this, I mean factors that might affect the count: Is it a common or garden (yes, that's a pun) location or an highly unusual one? Is the locale urban or rural? What are the surroundings? How big is the garden and how much vegetation is there? Is the vegetation primarily native or non-native? I could go on like for this ages, but clearly to get a more sophisticated understanding of the causes behind the figures, this information is necessary. Even then, two locations that are almost identical to a casual observer might appear profoundly different from the vantage point of say, earthworms. I will admit to (a) having built 2 weta motels and a bug motel; and (b) feeding silvereyes in winter; and (c) having made a tui sugar water feeder that has been totally ignored. Go figure!

3) Are there any other obvious factors that could affect wildlife? How managed is the location? Are chemicals such as weedkiller used or is the garden solely organic? Again, this can have a massive effect on wildlife, such as pesticides that remove insects at the base of food webs. On the one hand, if mine is an organic garden surrounding by neighbours who spray their foliage, then it could be an island of suitability in a comparatively barren terrain. But alternatively, if most of the neighbourhood isn't fauna-friendly, how likely would my garden get visited even on the off-chance by animals that can't live in the wider area?

4) Of course there's also contingency within natural selection. For example, quite by chance some species can survive on foods not native to their ecosystem. Although stick insect numbers in New Zealand were drastically reduced thanks to DDT, gardens don't need to contain their native food plants in order to support them. In the south-west of England, three species of accidentally-introduced New Zealand stick insect have flourished for decades on the likes of roses! Also, unusual events can affect populations: in this case, the two rainbow skinks appeared several months' after laying some ready lawn so I can only assume their eggs arrived with the turf, the previous five years having seen no skinks whatsoever.

5) When it comes to surveys, timing is also important. As you might expect, most of my observations took place during the day, with the only nocturnal ventures being on clear nights when using my telescope. The moths and hedgehogs were mostly seen at night, whilst had I included birds I could hear as well as see, then a morepork would have been added to the list. Again a simple prejudice, in this case sight over sound, has skewed the statistics. The large number of mantises were not adults but nymphs all hatching from a single ootheca. As for the monarch butterflies, they were a combination of caterpillars, chrysalis and adults, having appeared in much greater numbers this year than previous, despite no additional swan plants (their only food). Interesting, a clump of twenty or so mature swan plants a few streets away hasn't yielded any monarchs in any of the three stages. Presumably, predators such as wasps are responsible.

The sheer randomness of nature is exciting, but doesn't exactly help to uncover why populations are such as they are found via small-scale studies. Oh, and further to the damage invasive species have wrought on native wildlife, you may be interested to learn that none of the mammals belonged to me, the cats and dog being owned by friends and neighbours whilst the rabbit was an escapee from a dozen houses away!

6) Finally, there's the scale prejudice. Although I have a basic microscope, I didn't include such tiny wonders as tardigrades and bdelloid rotifers, even though garden moss and leaf litter respectively has revealed these wee critters. My page of nature photographs shows this prejudice, with microscopic fauna getting their own page.

So, what can we learn from this, apart from the large number of non-native species commonly found in Auckland? Perhaps that raw data can be presented in ways to obscure patterns or suggest others, should the publisher have an agenda. Furthermore, without access to highly detailed meta data, the statistics by themselves tell only a small part of the story and as such are open to wide-ranging interpretation by the reader. Therefore the next time you read about some percentage or other, remember that even without manipulation or omission, survey data is not necessarily pure, unsullied and free of bias.