It takes a special kind of obsession to do fieldwork

I wrote a few weeks ago about the start of the field season. I have been back up to the field site a couple of times since then mostly for basic surveying and laying out the plots that will stay in place for the next few years.

This week things got serious, though. Our orchids of interest, Cypripedium arietinum (ram's head orchid, fr: Cypripède tête-de-bélier), are finally blooming! This year they're blooming rather later than usual, as I have informal records going back several years showing the orchid flowering by May 17th -- they didn't start this year until May 22nd.

Here's what these little beauties look like:

C. arietinum

These little guys are gorgeous up close, but actually not very showy (at least to the human eye) -- they are very small, generally somewhere between 10 and 25cm tall at the flower (around a handspan off the ground) and the labellum (white and purple-veined petal-looking portion of the flower) is only about 1-1.5cm tall from lip to point, around 1cm wide, and only 1-1.5cm from front to back -- similar in size to the tip of an index finger. Moreover, their sepals (the brownish-red petal-like things sticking up, or out to the sides) are brownish and earlier in flowering development they lean down over the labellum, disguising it from view from above. This position of the sepal over the labellum can be seen in a photo in one of my previous blog posts, here. These factors come together to make C. arietinum a subtle, hard-to-spot little orchid.

C. arietinum flower

One rather interesting aspect of orchid pollination biology is the production of pollinia. Basically, instead of presenting pollen in loose grains that are removed and delivered in small numbers by pollinators, orchids (and a few other plants, e.g. milkweeds) produce their pollen in two big sticky masses called pollinia (singular pollinium) -- a pollinator either leaves with a big blob of sticky pollen, or without any pollen at all. Similarly, a flower receives pollen in big sticky masses. There are a couple of advantages to this kind of system: paternal success per pollinator visit is improved, because if a flower gets an opportunity to sire seed (i.e. its pollinium is transported to another flower), it gets to sire a lot of seed all at once because there are enough pollen grains in the pollinium to fertilize most/all of the available ovules; maternal success per pollinator visit is also improved, for similar reasons to the above. Of course, there's a loss of genetic diversity in offspring, as under these conditions all seeds from the same flower are full-siblings (same paternal and maternal parent), whereas if pollen grains were carried individually or in small numbers many of the resulting seeds would be half-siblings (same maternal parent, but different male parents).

I actually took some photos that show the pollinia of C. arietinum, so let's take a look:

C. arietinum pollinium -- look at the top of the labellum, where we have a fleshy structure below the dorsal (top) sepal -- if you look closely, under that structure (which is composed of filaments and pistil, fused), we see a round yellow blob -- that's the pollinum!

So why would it be better to increase reproductive success per pollinator visit at the expense of genetic diversity of the offspring? Current thought is that it's related to the plant being deceptive (or rather, to the plant receiving very few floral visitors because it's deceptive). I've talked about floral deception before, but in a nutshell the flower lures pollinators in by signalling that it offers a reward (nectar), but once the pollinator arrives it discovers that it's been had, that there's no nectar reward at all. Being food deceptive allows a flower to reduce its investment of energy in pollinator attraction (it doesn't have to make nectar, which is costly), but being food deceptive also means that the flower gets a lot fewer visits, because the pollinators learn that this flower is a liar and not worth visiting.

It's a pretty liar, though, eh? C. arietinum looking into the labellum

Regardless of the delay in their flowering time this year, now that the orchids are blooming the intensive fieldwork starts. We set out several days this week to tag all of the flowering individuals (we're already up over 200 individual orchids), measure a suite of their characteristics, measure soil pH and moisture for each of them, take down canopy closure and other plot characteristics, and note the size of the flowering community around each individual. This is an enormous amount of work, as you might have guessed. And there are still at least 100 orchids left to go!

One of the best things about fieldwork, which I touched on briefly in my last post, is that making close observations out in the field can lead to new questions and new discoveries. For example, yesterday during my fieldwork I noticed something very odd and cool. It won't come as a complete surprise to my blog readers, as I have talked about mutations twice before. This time, no fasciation, but instead I found five two-flowered individuals in this species that generally only has one flower per stalk. Individuals producing more than one flower on the same stalk naturally have been documented in quite a few orchids, especially Cypripedium spp.; however, there are a number of possible reasons for the multiple flowers: stress-related growth malfunction? soil contamination growth malfunction? natural genetic mutation? natural morphological variation? When it comes right down to it, we don't currently know the cause.

Of these two-flowered individuals, there seemed to be two broad 'types'. The first is a two-flowered individual wherein the upper flower is right-side-up and the lower flower is upside-down. There were three of this type in one of our study plots. Here are some pictures:

C. arietinum two-flowered individual. The upper flower is on the right, and the lower on the left.

One visible consequence of the orientation of the second (lower) flower is that the bottoms of the labellums of the two flowers press together and result in some distortion of the shape of the labellum -- for all three of this type of two-flowered individual in the plot, the lower flower's labellum was compressed such that the point at the bottom (oriented upward in this flower) was folded back instead of deployed (flower on the left in the above photo), while the upper flower's labellum had its point deployed (flower on the left in the photo below).

C. arietinum two-flowered individual, from the other side -- the upper flower is on the left and the lower on the right

 As you may have guessed, the second type of two-flowered individual I saw yesterday during my fieldwork was on in which both the first and second flowers were oriented correctly.

C. arietinum 2-flowered individual with both flowers correctly oriented

Though there's no interference between the two flowers in their growth like with the two-flowered individual above, I did notice that this individual also had some weird sepals on the upper flower -- notably, the dorsal sepal is oddly tilted off to the side (you can't really see it in the photo below, for example), and on that side where the dorsal sepal is the lateral sepals are actually entirely missing, so it's short a pair of lateral sepals and the dorsal sepal is positioned oddly. Because of my low sample size (only two flowers), I have no idea if this weird sepal situation is related at all to the double flowers. The lower flower, though smaller than the upper, appears well-formed.

C. arietinum two-flowered individual showing the flowers up close

I am still mulling over what kind of work we might be able to do with these unusual individuals. We will be limited by our very low sample size, but I live in hope -- maybe there will be more that we haven't spotted yet, as there are quite a few plots left to go! In the meantime, they're a curiosity worth documenting. Maybe this natural history find will turn into an ecological one in future!

I suppose I've had a good ramble through the orchid patch now and will get back to the title of this post, which is ostensibly the main point here. These lovely pictures don't convey one aspect of the season: blackflies! It is peak blackfly season, so it's absolutely brutal out there. We are all wearing bug hats and tucking our pants into our socks, our shirts into our pants, binding our cuffs with rubber bands, wearing gloves, and just about bathing in DEET because the blackflies are ravenous and exceptionally numerous. It takes a special sort of obsession to put up with them for ten hours a day!

I shared this video last year, but it's particularly apropos at the moment. Here's some delightful Canadiana about blackflies, sung by Wade Hemsworth and the McGarrigle Sisters and with animation by the national film board:

Natural history and ecology go together like flowers and pollinators

I've only very recently returned from Victoria, where I attended CSEE2017 and gave a talk. CSEE2017 was fantastic, but I will save my commentary thereupon for another post. I'm only mentioning my visit to Victoria now because I went to the Butchart Gardens while there. To be perfectly honest, these days as a plant ecologist I often get grumpy visiting ornamental gardens, as they generally have few or no native plants, usually have virtually no pollinators to watch, and just lack ecological interest. Certainly I found the gardens beautiful, and if I were a horticulture aficionado I might have found more to interest my curiosity while there, but what actually caught my attention was this:

Tulip showing stem fasciation and an abnormal number of flowers.

Fasciation: an abnormal condition of growth tissues, wherein in the meristem (area of actively dividing, growing, and differentiating cells), rather than having its normal domed/round shape, is elongated in one dimension, resulting in thick, wide organs and distorted growth. For a more detailed discussion of fasciation, I invite you to read my previous blog post on the topic (linked below).

I have talked about fasciation before, in context of a rather awesome monster thistle that displayed multiple levels of fasciation plus homeosis (substitution of one organ for another), so that was an individual with a lot of issues. But this fasciated  tulip is rather intriguing to me because it exhibits only stem fasciation, with no other visible abnormalities. The photo below shows the fasciated stem clearly.

Fasciated tulip stem

Now, the fasciation of just the stem is interesting to me because it is specifically accompanied by a subsequent splitting of the fasciated stem and the production of multiple otherwise normal flowers, as seen in the first photo and even the one below, where there are two tulips rather too close to one another, but they are not fused (i.e. they grew on separate meristems) and they seem to be anatomically normal. You may have noticed that the photo below is a different plant -- at the gardens I saw three cases of this kind of stem fasciation in tulips with an abnormally large number of otherwise anatomically normal flowers.

Fasciated tulip again

Since I saw it three times, it may well have been more common than that at the garden. Possibly this is a heritable fasciation (i.e. fasciation resulting from a genetic mutation); the probability of this option depends a bit on how the garden acquires and maintains their tulip population -- if they breed their own tulips, then it is possible that these fasciated individuals are actually related to each other, which increases the probability of this being a heritable genetic mutation.

Fasciated tulip!

However, as with the thistle, there are other reasonable possibilities, among them the possibility that the fasciation has an environmental cause (e.g. a pesticide or fertilizer applied to all the tulips), or that it results from a bacterial or fungal pathogen transmitted through the garden by gardening activities like watering and weeding.

My friend and travelling companion, Kayleigh, also found a case of fasciation in Bellis perennis (english daisy) in Victoria. First, here's a normal one:

Bellis perennis normal specimen -- photo taken by K.G. Nielson and used with permission

And our weird mutant showing floral fasciation (this is what is not seen in the tulips above; with them, the stem is fasciated but the flowers normal; with this one, the stem is normal but the flower is fasciated):

Bellis perennis fasciated individual -- photo taken by K.G. Nielson and used with permission

So you might be wondering when I'm going to get to the point. The point is this: an ecologist should also be a natural historian! There was an interesting opinion piece recently published about the importance ecologists place on natural history (the largely observational study of organisms, particularly their traits, their interactions with their environment, and their history), and how ill-equipped many young ecologists feel to teach natural history.

This story resonates with me, because I adore natural history but make no pretensions to having great skill or knowledge in the area; I am largely self-taught on this subject. I run this blog partly to share the beauty and wonder and amazing scientific appeal of nature, and partly to remind myself to root my ideas firmly in the reality (read: natural history) of the organisms and communities I study.

I believe that natural history is where it all begins: a couple of ecologists on a walk notice a bunch of fasciated plants, and this spurs all sorts of wonderful lines of inquiry about how the fasciation comes about, how the condition might spread in a population, the particular mechanisms of function, the possible associations between assorted fasciation types, etc etc etc.

Darwin is a particularly notable example of beginning ecology with natural history: his work starts with incisive observation and proceeds from there into testable hypotheses and experiments.

When it comes down to it, everything we do as ecologists starts in with natural history.

I don't have enough experience or expertise to weigh in on whether natural history training is lacking in many universities as suggested in the article I linked. I can't even say whether my own lack of extensive natural history training is due to my own neglect of my options, or due to an absence of options available to me. But at the personal heart of it, I'm an ecologist because it allows me to blend my deep and abiding love of natural history with the elegance, logic, and rigour of the scientific approach. I'm sure I'm not alone.

The best ecological questions and hypotheses happen because ecologists are also natural historians.

Besides, it's better for our health to get outside and wander around once in a while with our eyes wide open.

From Lab to Field to Lab Again

I'm back from the field! Now that I'm not living in a tent, I may have a bit more time to share some photos and information about the things I saw over the summer.

Me at my fieldwork site with my experimental plants about two weeks ago; this posed shot is rather relaxed for my fieldwork, but the real work is rather sweaty & prickly, and consequently makes a bad photo, so this is what you get

I have been thinking, in the few days since my return from a gruelling (and wonderful!) summer of fieldwork, about the nature of the scientific endeavour. I thought it would be fun today to write a bit about how science happens.

.........

We scientists would like to believe that the first impulse to science is in an observation or an idea. I disagree with this; I think science begins with obsession.

Nerds like me, willing to accept ludicrously long work hours and an income well below the poverty line, out of sheer obsession with their area of research, are the beginning of the research process.

When you expose such a personality to the body of human knowledge in their area of obsession, research is conceived. Through the eyes of the obsessive researcher, every piece of knowledge emphasizes the existence of gaps. And researchers feel compelled to fill them.

("Obsession," declares my husband in a tone which carries an undercurrent of 'duh', "What else could drive somebody to create a fully mobile bull thistle garden, 350 strong, and take it for walkies all summer long?" He's right, of course; my obsession with my research is what inspired me to do it, and what kept me going through all the digging and hauling.)

So about this time last year, I was just embarking on the amazing adventure that is an M.Sc. I read, I taught, I wrote, I drafted, I erased (I erased more than I have ever erased in my life!!!), I rewrote, I redrafted, and of course, I obsessed. Eventually, I produced a design that passed muster with my supervisor and thesis committee (a collection of more senior researchers, generally bona fide ones unlike we 'apprentice' M.Sc. students).

This is the point at which field ecological research takes a turn for the practical. I called, drove, e-mailed, talked, and otherwise explored for the express purpose of getting together the field site, field equipment, and experimental plants that I needed to take my idea from the whiteboard into the field.

Fieldwork itself, though dispassionately described in a few stark paragraphs in the methods section of a research paper, is a distinctly visceral affair. Clean lines on quadruled paper become muddy tracks through scrub brush, and neat numbers are toiled out in days sweating under a blazing sun.

Solitary bee eating salt off of my sweaty skin

The pollinators whose behaviour was my primary research interest, in my plans mere marks on a page, became companions and hitch hikers, inhabiting space not just in my mind but around and even on my body.

And I, obsessive scientist that I am, stood there and let them crawl over me. I observed them, interfering as little as I could, and watching closely as they unfolded their mysterious existences before me.

The road at my field site, no longer a line on a page but a hot, dusty path

I took these pollinators, real, physical creatures, and I transformed them once more into marks on a page. Data. The greatest treasure of the researcher.

At the end of my field season, when all my precious experimental plants had ceased to flower and I had collected all of the data that I could, I packed the pollinators and the plants up into ink on paper in my bags with my field gear and I carted them back to the lab and the dusty road dissolved into pixels of data behind me. Over the coming months the data will take shape again, not as physical things but as beautiful ideas, as lines and curves and points filling theoretical spaces.

Eventually, I will write this all up as a tidy, dispassionate research paper and I will be proud of it. And I will remember the depths, both mental and physical, that lurk beneath those few clean words on white paper.

Is Scilla siberica invasive?

I've noticed the crocuses, daffodils, and even some early tulips blooming in the neighbourhood gardens this week. But the most eye-catching flower out right now is Scilla siberica (siberian squill).

S. siberica

Scilla siberica is an introduced species, native to Russia, which was introduced here as an ornamental plant. It is attractive and easy to cultivate, as it spreads widely with very little encouragement or care needed. This species is a member of the Asparagaceae (asparagus family).

A friend of mine asked me a question this week that has no easy answer: Is S. siberica an invasive species? There are now some places in the United States where S. siberica is certainly listed as an invasive species [1], though there also appears to be some debate about this listing. At present S. siberica is not found on Canadian invasive species lists [2].

S. siberica

Disagreement about whether or not to list a species as 'invasive' arises from the difficulty of determining what precisely an 'invasive' species is, and the philosophical and moral debate about what we should do about it. In ecological terms, in order to qualify as invasive, a species must be (a) outside of its native range and (b) spreading to the detriment of native species. The first criterion is easy enough to judge, provided there is a historical record or some other straightforward evidence of the species' native status. The second criterion is much harder. It takes a lot of research to establish that (a) native populations are suffering and (b) the suffering is caused by the introduced species.

For example, in some places S. siberica is forming high-density populations in sites which have been previously occupied by native spring ephemerals (eg Trillium spp, Sanguinaria canadensis, etc). These native spring ephemerals are showing drops in population density and other metrics of health.

Knowing these two facts does not establish a causal link; because we're dealing with an open system, it's not so easy to tease apart potential causes of observed effects. Maybe the native spring ephemerals are suffering because of deer predation, or habitat disturbance, climate change, insect predation, fungal infection, or any number of other potential causes -- and more likely several causes including competition from the introduced species. It will take time effort to determine what, precisely, is the cause of the documented decline.

S. siberica flower - note the blue anthers and central stripe along the petals; I certainly can't dispute the aesthetic appeal of this species

And this is where we get to the non-scientific aspect of this whole issue: deciding at what level of proof we should take action. Listing a plant as an invasive species is not just a scientific statement: it's a policy decision, too. So we have to consider the policy; while scientific standards of proof shouldn't be overly impacted by practical concerns, practicality is central to policy decisions and will affect how evidence is assessed.

On the one hand, we don't want to take action without understanding the causes. This could lead to wasted or misdirected efforts, or unintended harm. But by the time we meet the scientific standards for proof, it may be too late to take any useful action. We must find ways to balance the need for good evidence with the unfortunate reality of haste, financial limitations, and culture.

All species which meet the scientific criteria for invasiveness are invasive in both senses (as this is the stricter definition), but some species which do not yet meet the scientific criteria may still qualify as invasive for the purposes of policy-making. The degree of proof to qualify for policy-oriented 'invasiveness' is in principle less strict. Exactly where we draw the line is currently unclear, and may always have to be decided on a case-by-case basis (this is never an attractive option politically; nobody likes to hear the answer "it depends" when we talk about rules, policy, and enforcement).

I believe that this issue will eventually have to be settled politically, as part of a much broader public discussion about what we, as a society, will do to address environmental issues.

So: Is S. siberica an invasive species?

Yes. And no. And we don't all agree what to do about it.

Naturalized S. siberica population in a public park in Montreal