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Tuesday, September 27, 2011

How many scientists does it take to change a light bulb?

Q: How many scientists does it take to change a light bulb?
A: They won't change it.  It's not their problem.

I noted something in the news a few weeks ago.  Presidential candidate Michelle Bachmann made a statement about the potential side effects of a vaccine for cervical cancer.  The response from the medical and public health communities was swift: the statement had no supporting evidence behind it.  Vaccines may carry some risks and cost money, but they save lives.  The benefits clearly outweigh the risks in most cases (although not all doctors agree whether teenage girls should get the vaccine for various reasons).  The rebuke got plenty of coverage, and the misinformation was effectively countered.

Contrast that with the blatantly false statement by Texas governor Rick Perry recently, that global warming is a hoax.  I heard it repeated over and over on the radio news briefs, with no countering view presented whatsoever.  Maybe some of that stems from the media's own reticence to acknowledge that there really isn't any debate at all in the world of science over the reality of human-induced climate change.  But no news outlet I follow, not even the "liberal" ones, reported on any response at all from the scientific community.  It's possible I missed it.  It's also possible that there was an outcry, but the media didn't report it.  Unfortunately, there is abundant evidence that the media tend to overplay any climate change deniers' claims compared to the overwhelming scientific consensus on the issue.  However, I really don't think that's what happened either, and an example of what makes me feel that way can be found in Hawaii in early November.

The Wildlife Society, the venerable professional society for wildlife ecologists and natural resource managers, is holding its annual meeting on the Big Island of Hawaii.  On their conference web site, the Society states that of all states, Hawaii "spotlights the most-pressing challenges that natural resource managers and conservationists face today—including the rapid spread of invasive species and the impacts of a changing climate."


The plight of the polar bear is probably the most widely publicized outcomes of global climate change.  Photo by Kathy Crane, NOAA Arctic Research Program.

 
Conference attendees won't be out solving those problems on the ground, they'll be attending paper sessions, networking, discussing the various topics of particular focus, and going on field trips.  The vast majority of them are going to have to fly to get there.  That adds up to a tremendous blast of carbon into the atmosphere, another blow to the goal of stabilizing emissions to try to limit the damage already underway.  That won't do much to help the highly endangered native Hawaiian ecosystems. The Wildlife Society meeting in Hawaii doesn't have a session on climate change. Presumably that will be discussed on the side.

Does The Wildlife Society really take climate science seriously?  One has to wonder.  Maybe this is why politicians and other leaders in our society go unchallenged far too often when they make blatantly ignorant statements about climate change.

Yellowstone fire. Photo by NOAA.

Unfortunately, this blind behavior isn't limited to wildlife biologists.  Virtually all of the scientific societies dealing with the biological sciences and even conservation biology hold national meetings and encourage their membership to attend.  Sometimes you can view presentations after the fact on the website, but no society to my knowledge allows members to attend remotely, or to view presentations in real time through skype, webinars, or other streaming technology.  Even the National Science Foundation expects the panelists charged with reviewing grant proposals for funding to fly in for a three-day meeting.  I found this out when I was invited to participate on a review panel.  When I asked if I could attend remotely, because the climate change science is very clear regarding the danger of carbon emissions, my email went unanswered.  Apparently not.

Individuals often do little better.  Most of us have changed our light bulbs, carry reusable grocery bags and coffee mugs, and occasionally carpool or use alternative transportation.  Very few of us have even begun to think about how we need to change the fundamental way we've begun to do business in the last few decades.  When I bring up climate change to another scientist, most often the answer is a shrug and a comment that the public is stupid, politicians are stupid, or we can't do anything about it anyway.  In short, it isn't our problem, we just do the science.

For people who profess to care about ecology and conservation, this is a travesty.  All of us need to recognize that we can either start planning how we are willing to be inconvenienced to limit the damage already in the works, or have far greater inconveniences forced on us without choice.  Not going to scientific meetings or networking in person is inconvenient.  There is a potential cost to a person's career.  But climate change and the horrendous damage that will follow from increased violence of storms, droughts, fires, and the fundamental chemical changes in the ocean and atmosphere will be far worse.

Wreckage of Hurricane Irene. Photo by Christopher Mardoff, FEMA

If we scientists, trained to evaluate evidence and respond accordingly, are unwilling or unable to take climate change seriously enough to alter how we do business, why should the reporter, the member of the general public, or the politician?

First, we have to own the problem, and be willing to recognize that we, too, are responsible both for the problem and its solution.  That is the necessary first step to being able to tackle the serious misinformation being presented by our society's leaders.  Changing a light bulb or restructuring a scientific society's annual meeting to encourage remote attendance won't save the planet all by themselves.  But if you walk your talk, people notice.  And when you also feel strongly enough about your science to call out those who would twist it to their own ends, people are much more likely to take you seriously. 

The Hawaiian honey creepers are counting on us.

'I'iwi, Vestiaria coccinea.  Photo by Jack Jeffry

Monday, September 12, 2011

Food Web

Buying a bag of dog food isn’t a big deal, if you’ve got a dog and a budget that allows you to look after your friend without making harsh choices about who’s going to get to eat in your household this week.  From the sales figures, most pet owners don’t have that misfortune, pet product sales being one of the most recession-proof industries in the last few years.  The figures aren’t all about dog food, either.  They include all the accessories you can possibly imagine, and unless you’re a dog owner, quite a few that you possibly can’t.  For many of us, our dogs are a major focus of our discretionary spending.

I never thought much about dog food until my young dog threw us a curve ball with his first grand mal seizure in the middle of a long night last winter.  After tests, our vet concluded that Raven has idiopathic epilepsy. At least he’s just a dog, as much as we love him, and not another human being.  For one thing, he only falls over from a height of two feet, not far enough to risk serious injury, and his thick fur helps pad the impact.  His life will not suddenly become much more difficult because he can’t drive a car, and he seems unburdened by the knowledge that he could unpredictably suffer another episode, something human epileptics must accept.  He’s still the same happy-go-lucky sweet goofball he’s always been, most of the time.  But each seizure is still a scary mess, and not something anyone would care to deal with if they don’t have to. 


I did some research, quickly learning that there is no consensus on how to best manage this condition other than with medication, which often doesn’t work.  Among the many tips unsubstantiated by any scientific research was the suggestion that feeding a high-protein diet without preservatives might alleveiate the seizures.  Diet changes had reportedly helped reduce seizures in children.  The lack of consensus in managing this disease may stem from the fact that lots of malfunctions in the brain lead to seizures; not knowing the exact cause, some cautious experimentation seemed in order.

This led to a trip to the local high-quality pet store.  I faced an entire wall of dog kibble, nothing compared to what I’d face at PetsMart but enough to be overwhelming.  After squinting at a half-dozen ingredients labels printed in size-three font, I sought the help of one of the store personnel, who in my experience have been pretty knowledgeable about what they sell.  I explained what I needed to an earnest young woman wearing round wire-rim glasses.

She pointed me to a bag of kibble that not only contained the requisite high protein content and no preservatives, it was made with regional meats including salmon, wild boar, and bison.  It cost $80 for a 30-pound bag.  They’re human-grade ingredients, the young woman at the store told me proudly.  Your dog will love it, she said. 

I’m sure he would.

We choose to share our lives with animals, and the benefits can be legion.  Part of the compact we make in return for their love is food, water and shelter.  Dogs happen to be carnivores, and although it is possible to feed a generalist carnivore like the domestic dog a diet made up of protein that is not meat-based, it is not easy and mostly not recommended.  My dog may eat more meat in a month than I have in my entire adult life. 

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I struggled to explain that even without the sticker shock, I couldn’t feed my dog this food in a world that is rapidly becoming ever more crowded with people, with fewer resources to go around.  A lot of pet food is made from the scraps that those of us who can afford to be picky would prefer not to eat; in any case, the industrial food system pretty much renders them inedible to people and marginally edible for pets.  Feeding a dog is not necessarily synonymous with starving a person.  A bag of dog food doesn’t represent much against world hunger in any real sense.  Reformulating the entire company’s line of dog food into something not only human grade but human palatable wouldn’t make much of a dent.  However, even very small acts can build to major consequences.  And something within me balked at feeding my dog the flesh of a fish swimming against extinction in much of the Pacific Northwest.

Let the fish stay wild in the rivers.  I don’t like my dog eating the waste from the slaughterhouse floor and a staggering list of preservatives whose chemical names I can barely pronounce, but there has to be a middle ground, somewhere.  There has to be a way to restore some sanity to a world where the affordable food may not be safe or nutritious, and the safe food is the prerogative mostly of the obsessed or the wealthy.  Unfortunately the problem isn’t just limited to pet food, or pet ownership.

That led to a second dilemma for me, as I had to ask myself how much of my income I was willing to spend on my dog, and therefore not on helping other people.  The bills associated with owning my dog have soared, with twice-daily medications, regular blood tests, a somewhat less fancy but high-quality kibble, and other expenses.  There’s less money to donate to the food bank, the animal shelter, or to conservation.


Raven is not aware of issues of social justice, let alone concerned about them.  That’s not why we invite dogs into our households.  They’re there to give love, make us laugh, and maybe to offer us the opportunity to express the best parts of ourselves now and then.  These needs fall right behind the basic need of being fed.  Hopefully the people around us meet these needs, but it doesn’t always work that way, and many of us just find great joy in our relationships with our animals.  Those relationships are clearly worth a great deal, but how do we balance the choices with the obligations we hold to each other, let alone the other beings on this planet?

How will we navigate a world where increasing scarcity may force even more choices between who eats and who does not, where the shortages are not just political?  What exactly should go into a bag of dog food?

Wednesday, August 31, 2011

Manipulative Bounty

It is late summer in western Oregon, meaning the wild blackberries are just ripening, dangling tantalizingly between the wicked thorns of canes that can arch up over fifteen feet in the air.  The canes form thickets impenetrable to animals larger than rabbits.  Come and get it- just don't forget your machete and a willingness to make a small blood sacrifice.


We don't give plants much credit for intelligence, at least not as we typically define it, but the dark, sweet fruit is all about making up for the one thing plants sorely lack once they've put down their roots: mobility on a time scale relevant to getting your kids out from underfoot.  Trouble is, if you dump your offspring right around your knees, you're liable to kill them by outcompeting them, for space, water, and especially light. You are also a magnet for seed predators, waiting for the bounty to fall.  So, somehow, plants have to get their seeds away from them.

Some plants have gone the engineering route, and over time natural selection has outfitted them with pods that burst open, giving their seeds the equivalent of a blast from a cannon, or lightweight parachutes to help them drift away.  These plants don't ask for help from another living organism.  Some plants produce seeds that float to new locations, like coconuts.  Other plants have done some modified engineering, covering their seeds with sticky coatings or grapple hooks to catch a ride on any passing animal.  They are the freeloaders, getting a lift on the sly and offering no compensation for the service.

Jewelweed, Impatiens capsensis, has exploding pods, earning it a second name, touch-me-not.  Photo by Catherine Khalar

But plants with fruits definitely do ask for help from organisms that are capable of quick movement.  They pay a fee up front, and hope the agent delivers the goods as planned.  In short, fruits are a biological bribe.

The intended agents are those animals whose guts digest the fruit but leave the seeds unharmed.  The time it takes to process the meal helps guarantee a final deposit away from the parent plant, protecting the seeds both from infanticide and from the usual buildup of seed-eating insects or fungi that prey on the fruit that drops to the ground from the parent plant.  Think of an untended feral apple tree.

Some plants have evolved to rely primarily on birds to disperse their seeds.  Bird fruits are typically fairly small so they can be swallowed whole, and are often black, blue, or red and placed out on the ends of slender branches.  Other fruits appeal more to mammals, with big green or pale yellow fruits, often with an odor.  Many other plants outfit their seeds with small fleshy bodies called eliasomes, that appeal to ants.  The ants take both the seed and the eliasome back to their nests, where the elaisomes are consumed and the seeds are discarded, often in a safe underground spot perfect for germination.  Even fish eat fruit.

The fruits of salal, Gautheria shallon.  Photo by J. A. Gervais
Some fruits are simply weird, such as the osage orange.  If you've never seen one, it is a fruit the size of a softball and about as appetizing.  You need a hammer to crack one open.  The Missouri Department of Conservation considers the fruits hazardous and advises wearing hard hats in their vicinity.  In her engaging book The Ghosts of Evolution, author Connie Barlow makes a compelling case that such fruits actually are anachronisms, whose main seed dispersers were now-extinct large mammals and possibly even dinosaurs.  These fruits now "disperse" by crashing to the ground and possibly rolling away a little, sometimes helped along by flowing water.  Seed dispersal isn't an exact match of goods for services.

There are plenty of cheats, too, animals or other organisms that take the payment without delivering the goods.  My goats eat blackberries with gusto, but no seed will survive the ghastly conditions of their rumens.  Fungi readily infest fruit, and usually also destroy the seeds.  I've found that banana slugs eat fruit, but they damage a percentage of the seeds they eat, taking a higher payment than planned for their services.  The plant has to offer enough fruit to ensure that some of it falls into the right mouths- the first step, but only the first step, in the chain of events that will ultimately lead to a new plant that will someday produce its own seed.

Animal delivery may also come with a secondary benefit.  Tapirs in South America use latrines, small areas of communal relief.  Along with the rest of the waste, they deposit the seeds of the palm, Maximiliana maripa. Over time, these turn into stands of fruit-producing trees.  Tapir poop, too, seems to discourage the beetles that eat the seeds.  Ant garbage dumps are excellent germination sites for many plants.  Bear poop contains thousands of seeds which later germinate in the clumps of calling cards the bears leave behind.

Black bear fattening up on blueberries, Sol Duc wilderness, Olympic National Park. Photo: J. A. Gervais

Hot peppers are my favorite example of botanical craftiness.  Hot peppers get their kick from a compounds called capsaicinoids, which includes capsaicin.  The capsaicin triggers a specific receptor in mammals that is infamous for its response.  It is used in many different cuisines around the world, and also mace (something to think about when contemplating how spicy-hot you want your meal).  Turns out that peppers use birds as seed dispersers.  Birds can't taste capsaicinoids because they don't have the receptors- no tear-gas effect for them.  The compounds do, however, affect how quickly the birds' guts process the meal, shaping the rain of seeds over the landscape, and preventing a huge pile of seeds  from being deposited all in one place.  When that happens, most of them die from the competition.  The capsaicinoids also protect the fruit from attack by fungi, which would destroy the seeds.

The blackberries that are so common locally involve another twist.  They are an exotic species, Rubus armeniacus, originally from the Himalayas.  In open areas with plenty of sun, they can overgrow small buildings, abandoned cars, and nearly any other plant.  They also produce prodigious quantities of very tasty fruit, which feed nearly every wildlife species in the area judging by the bright purple bird droppings deposited on the car and mammal scat along trails in the woods.  Those seeds really get around.  The plant is a pernicious challenge to people trying to restore meadows, pastures, or stream forests. 

The blackberry thickets provide shelter and food to small mammals, birds, and reptiles in the forgotten wastelands that have been badly disturbed, but never rehabilitated or fully claimed by people.  At least the thickets are a good fortress against free-roaming cats, and offer a terrific late-summer energy boost to birds about to migrate.  They also provide us with an abundant supply of local fruit for the freezer, and blackberry jam in midwinter is one of the finest wild gifts we receive from the woods and fields around us.

Blackberry thicket overgrowing a roadside.  Local bunnies taunt the dogs from under this natural razor wire. 
Photo: J. A. Gervais

Tuesday, August 9, 2011

Unintended Consequences

She kicked hard, flailing her sturdy legs madly, just missing my restraining hands.  She didn't have much of a range of motion because of her shell, but that didn't stop her from trying, stretching her neck around to snap at my fingers.  Once her hind leg kicked my wrist, and I was startled by how strong she was.  I had a good grip, however, and what happened next was my decision, not hers.

The turtle in my hands was a red-eared slider.  Like me, she was a native of the eastern half of the country.  I had come west a quarter-century ago, seeking broader horizons, while she had arrived here thanks to the pet trade. Whether she had once been released by a well-meaning but misguided pet owner who no longer wanted her, or had been born wild herself, I couldn't tell.

Red-eared slider, Trachemys scripta, basking in non-native waters.

It's against the law in many states to release non-native pets, and red-eared sliders are not even legally sold in Oregon in the first place.  But they're here, and they have found Oregon's waters to be enough like home to settle down and raise large families.  We don't really know all the potential consequences of this, although there is evidence that the native turtles don't do well once they're forced to share their space with this new arrival. 

My scientific permits specify that I cannot release any non-native turtles if I catch them.  This is meant to help remove the invaders, and give the native species a better chance of survival.  It isn't about just the individuals, or even individual species, but the sum of all the plants and animals, and the unique communities they form.  These communities can affect how water flows, how frequently and severe wild fires will burn, and whether soil will be swept away before the wind.  These processes are of fundamental importance to our well-being, if not our very survival.

I hold another set of permits, this set from the university.  These specify how I must handle individual animals in order to reduce any pain or suffering.  I have stated exactly how I'll keep any sliders I catch, and for how long, before delivering them to the state veterinarian for what amounts to their execution.  Under those conditions, the Institutional Animal Care and Use Committee gave me permission to proceed.  This set of permits is not at all concerned about ecological processes, but it is deeply concerned with the welfare of individuals.

There are very good reasons for both permits.

Turtle trap with red-eared slider inside.

Personally, I happen to really like animals.  I happily share my house with two dogs and a geriatric cat and there would be more if it didn't mean serious strife with my husband.  We raise sheep and goats, and the fact we slaughter our own meat makes us acutely aware that living beings are individuals, each with their own perspective and purpose.  I do not take killing lightly.

As a professional, I am only too aware to how careless introductions have changed everything from the composition of trees in the forests in much of the country to the soil dynamics beneath my feet.  I don't know if red-eared sliders will end up being the biological equivalents of neutron bombs in Oregon's aquatic systems, although they will have impacts.  I suspect probably not, although other invasive species may deserve the comparison.  However, I am not a policy maker, and it is not my call.  The law, and my permits, are clear.

Yet it is amazing how the ancient instructions for life have adapted these turtles to an utterly new place, one dominated by humans.  Sliders are doing fine here, and may do better still as the Pacific Northwest climate shifts to warmer and drier weather.  At some point, we may need to choose based on what can exist in the future, rather than what existed in the past.  The changes we're bringing about on our planet are so great that asking these questions is no longer only the business of theoreticians.  What do we want our future world to look like, given our past actions, and the choices we now have?

That is the big picture.  The small picture is me, holding this turtle, next to a drainage ditch near the airport, on a cool overcast windy day.



It isn't the turtle's fault.  She was only following the instincts that have carried her kind forward for millions of years before she swam into the trap baited with overripe sardines.  I personally didn't bring her here.  All that matters now, however, is that I have caught her, and what happens next is solely my decision.

I do what I must, based on what I know and what I have agreed to do, and she goes in a plastic bin filled with an inch of ditch water.  I wish her a quick and painless death as I look out over the landscape she won't see again.  I lug the sloshing bin to the truck.  It is a good deal heavier than a five-pound turtle, a gallon or so of water, and the container.  I am also weighed down with the ethical costs of undoing what never should have been done in the first place.

Thursday, July 28, 2011

How Science Works

National Public Radio ran a brief story on Friday, July 22, about an article in the prestigious journal Science.  It was originally published in 2010, and claimed that the likelihood that someone lives to be 100 years old could be predicted with 77% accuracy based on 150 genetic markers.  The study was subsequently retracted last week.  The authors had apparently realized there were mistakes made in how the data were collected.  The error was not caught during the peer-review process.

What, you might ask, is the peer-review process?

The final, critical step in research is publishing the results in a scientific journal to add this small piece of knowledge to the collective whole.  The researcher writes up the paper and submits it to a journal, whose editor decides whether the paper fits the journal and is good enough to be worth further review.  If the manuscript passes first muster, it gets sent out to two or three people who are thought to be competent in the subject area, scientific peers of the manuscript's author.  These people are asked to review the paper and decide whether the methods are defensible, the conclusions reasonable, and the overall manuscript worthy of publication.  The editor makes the final decision based on the reviewers' recommendations and the editor's own review.

NPR zeroed in on the fact that this paper had come under criticism for its methods, and they interviewed one person in the field who felt the paper's flaws should have earned it a double thumbs down during the review process.  They didn't interview the original reviewers or the editor who originally decided the paper should be published.  NPR also didn't tell their listeners that a small percentage of papers in the scientific literature are retracted every year, as flaws in experimental design or data analysis are discovered that negate the results. 

Even scientists make mistakes.

The major story here was missed entirely: the system works, more or less, which is about as good as any other human endeavor.  Science is an iterative process, and although redoing someone else's work never earns the accolades that the original work received, the repeated testing is crucial.  This often gets overlooked, as Science (the journal, not the discipline) and other top-ranked publications vie to publish the most cutting-edge, and therefore the least-tested, results.  This tendency inevitably leads to the occasional retraction.

Science (the discipline, not the journal) advances as people come up with ideas, and then disprove them or fail to do so.  Bad ideas may arise from mistakes in data collection, data analysis, or simply from lack of sufficient knowledge to describe a system or pinpoint an underlying process.  The crucial part is not that someone got it wrong, but that the mistake was found and ultimately corrected, thus advancing what we know.

An example can be found in the early efforts to describe the structure of an atom.  This is a pretty weird idea, one that currently involves mostly empty space, a tiny and impossibly dense nucleus, and electrons whizzing around in set orbits of very specific shapes, moving so quickly they are equally likely at any point in time to be anywhere within this orbital shell.  It is such a weird idea that chemists resort to ball and stick models to describe structures made up of multiple atoms even though we know that is not at all what an atom or molecule actually looks like. 
P orbitals, or where one series of electrons in an atom exist. 

Ball and stick model of the sugar glucose.  Image from NASA.

This wasn't always the accepted view.  The physicist J.J. Thomson suggested based on his early experiments that the atom was more like a plum pudding, with the plums representing the electrons that were embedded in the atom.  A decade later, physicists had to admit that this idea was wrong based on work conducted both by Thomson himself and by Ernest Rutherford, who had been Thomson's student.  It seems rather silly in hindsight, but Thompson's early experimental data supported his pudding model.  It provided crucial insight along the way even though it wound up in the "bad idea" heap in the end.  Thomson, incidentally, won the Nobel Prize in 1906 and Rutherford won it in 1908, both for their work on describing the structure of the atom.  In short, they got it right more than they got it wrong.


Plum pudding, which we know now is not at all like an atom.
Photo by Jules:stonesoup, flickr creative commons

Science, the discipline not the journal, is all about looking for patterns and determining the processes that create them.  An occasional misstep along the way should be expected.  No idea or study should be accepted with full confidence until it is corroborated by other researchers conducting other tests.  In hindsight, it is always possible to say that someone should have known better.  That isn't terribly useful, however. 

As our grasp of science and use of technology grow ever more complex, it is even more important to understand how the process of gaining that knowledge actually works.  The terminus of a glacier is a broken, dangerous mess of calving chunks of ice and stone that continually fall as the ice moves.  The anarchy at the front fails to reflect the cohesion of the massive river of ice that flows inexorably behind.  We should focus as much of our attention on the mass of knowledge behind the advancing front if we are interested in trying to use what we know to our best advantage.

Our survival is going to depend on it.

Johns Hopkins glacier face, Alaska Photo: USGS

Tuesday, July 12, 2011

Life in a Sandwich Board

Imagine living in a sandwich board.  Not one you could remove, like an advertisement people parade at busy intersections, but one that is made of your own bones and will be with you for your entire life.  No bending to touch your toes.  In fact, forget about touching your toes.  Forget about curling up, sitting down, even rolling over.  You can't breathe by expanding your rib cage, instead you have to pump air into your lungs using the muscles in your throat.  Now imagine that you need to swim around in order to survive.

Red-eared slider, Trachemys scripta. Photo: J. A. Gervais

This improbable body plan is actually a pretty ancient idea, because turtles have been using it, without major changes, since the Triassic.  In other words, over 200 million years.  Good ideas simply don't go out of style, and this good idea has endured ice ages, drifting continents, the disappearance of the dinosaurs, the appearance of mammals, and the arrival of the ape with the big brain and opposable thumbs.

The shell is an extraordinary piece of biological architecture.  Formed from the ribs and the spine, it incorporates the the carapace, or top shell, the plastron, or lower shell, and the bridge, the plates that hold the two together. The hips and shoulder blades are encompassed inside the rib cage.  Ultimately, nearly half a turtle's mass is bone.
Red-eared slider, Trachemys scripta.  Photo: J. A. Gervais

Life inside the shell has its advantages, in that you carry your fortress with you.  Although the shell offers some protection, determined otters and other predators have been known to pry legs or the tail free and gnaw them off.  There are no fast getaways, and if the fortress is breached, there isn't much that the turtle can do about it.

There are other drawbacks.  Reproduction is challenging, to say the least, when both participants are dancing in suits of their own unremovable armor.  The distinctly domed carapace of the female makes things more difficult, as does the fact that most female turtles are larger than the males.  The male turtles' plastrons are slightly dished, and their front claws are extra long, to help them hang on to get the deed done.  It's an awkward affair, but one that has worked well enough for a long time.

The shell has to grow with the turtle.  Each bony plate must grow in synchrony to keep the shell in its proper shape.  Turtles lay eggs, and unlike birds, they form a clutch and lay it all at once.  All those eggs have to fit in there somewhere, which is why females have taller, more domed carapaces than males.  Too big a shell wastes energy, both in its growth and in the effort needed to haul it around.  Too small, and turtles cannot gain weight to form their eggs, carry them til laying, or get fat to survive the winter- not to mention draw deep enough inside to be safe from their more nimble, agile enemies.

Turtle shells have worked so well they've not only been around for millions of years but turtles and tortoises also occupy all continents except Antarctica, in habitats ranging from the deep ocean to deserts.  They can survive in some pretty degraded environments, appearing to be much more robust than many other vertebrates to pollution, reduced water quality, and other challenges thrown at them in recent times. 


This pond supported turtles...  Photo: J. A. Gervais

However, the ape with the big brain and opposable thumbs may be too much for them, as wetlands disappear and turtles fall victim to roadways, over harvesting, the pet trade, and other human activities.  With a little care, however, at least a few may survive for another few million years, moving through time in that same cautious, patient manner that has served them so well for so long.

Sunday, June 26, 2011

Delphinium

I first noticed that they had all vanished along the creek bed near the road the first day of summer.  Farther up in the shadier parts of the forest, a few still linger, but their wrinkled, faded appearance suggests that they, too, will soon disappear.  Below the last faded flowers, fat pods are forming, swelling with the seeds of a spectacular display in the future.  The Delphinium flowers of the western Oregon woods belong to spring, however, and their season is now over.

I begin watching for Delphinium long before the buds have even formed.  The leaves begin pushing up in February, a welcome sign of spring after a long, dark, wet winter.  By April, the plants are beginning to form their buds, and the first flowers appear at the end of the month. 

Photo: J. A. Gervais

The flowers are a brilliant deep bluish-purple, a color so intense one friend remarked that it makes your teeth hurt.  They seem to glow, and I can only imagine what visual signal they send to bees and other insects that can see in the ultraviolet spectrum.  That incredible blue colors not only some of the petals but also the sepals, which form the star-like form of this flower and the long trailing spur that give this flower its common name, larkspur.  The true petals are small and held tight in the flower’s center.  The topmost petal arcs white in color, a bright flash in a field of midnight blue.

The genus Delphinium is large, with several hundred species currently recognized.  Individual plants growing in different places vary dramatically in size and form, and Delphinium species can hybridize with one another.  Keying them out often involves digging them up and studying their roots.  I’m pretty sure that the larkspurs growing along the shady creek banks in the forest above me are Delphinium trollifolium, but I haven’t dug one up to fully key it out.  I don’t need to know so much that I’m willing to murder a plant that each spring gives me such a marvelous gift.


Photo: J. A. Gervais

Hummingbirds, bees, and butterflies visit Delphinium flowers for their nectar.  The plants however contain an alkaloid compound that is highly toxic; although some insects use it as a host plant for their larvae, Delphinium has frequently been responsible for livestock poisoning.  Presumably, wild grazers learn to leave it alone.  So it grows locally in dense stands of stunning color, heralding in the growing season even when overcast and wet weather in western Oregon continues.  It may be raining, but there is still cause for celebration.

The flowers remind me of dark velvet stars, each with a comet’s tail trailing behind it as it leans out from the stem.  Or they might be little people, arms and legs outstretched in a joyous leap.  Flowers are structures evolved with the sole purpose of ensuring cross-pollination and the production of viable seeds.  Delphinium burst forth each spring to mark the renewal that arises only from the loss of those that came before.

Photo: J. A. Gervais