Road Kill

There are two more dead deer lying along the road that ends just a few miles from town.  One is a doe, probably pregnant, the other a young buck just out of rut.  Someone has stopped and sawn off the antlers of the buck but both carcasses remain in the ditch, apparently inaccessible to scavengers.  They are hardly visible from a car, and possible to overlook even from a bicycle, as the cold weather has prevented the usual tell-tale smell.

We think of roads as opportunities for our own rapid movement and convenience, if we think about them at all, not the ribbons of death that wind through the home ranges or migration routes of many animals.  Stand at a rest stop along a busy interstate and see how many seconds pass in which there are breaks in traffic from one side of the highway across all lanes to the other side.  Not surprisingly, research has shown that roads can be major obstacles to animal movement.

How much roads cut off movement depends on not only the traffic load but the animals themselves.  Some animals such as urban gray squirrels seem almost oblivious to the traffic despite the risk and frequent near-misses.  There are video clips of urban wildlife using crossroads and even apparently waiting for lights to change before they cross.  They include deer, gray squirrels, coyotes, and Japanese crows.  The crows, of course, can easily fly over the traffic, but it seems that some of them have figured out that if they drop nuts into the crosswalks, cars will run over them, and the cracked nuts can be retrieved when the light changes.  These animals have adapted to live in the new world we've created for them.

But the vast majority haven't adapted.  Desert bighorn sheep populations are already showing reduced genetic diversity in just four decades after interstate highways threaded among them, raising the risks of extinction for the now-isolated populations.  Cougars avoided two-lane paved roads although dirt roads did not deter them.  Both wolves and elk in the Canadian Rockies avoided roads and trails in national parks as their traffic increased, but elk were less repelled and actually used the areas near moderately busy trails as predator-free zones because the wolves appeared more sensitive to the disturbance.  There are gradients in responses, and consequences.

At the other end of the spectrum, freshwater turtles don't seem to recognize the danger.  Turtles moving between two wetlands in Florida were willing to attempt to clamber over a barrier made of plastic netting to cross the busy highway separating the wetlands; nearly all those that succeeded were killed.  Populations of turtles near roads have a sex ratio skewed towards males relative to populations away from roads. More dead  female turtles are found on roads than males because the females are driven to leave the safety of water to find nesting sites.

The biggest issue may not be just the body counts, as staggering as they may be (upwards of 350 million wildlife deaths per year in the United States).  The worst thing about road kill may be what it reveals about our own fundamental thoughtlessness.  We are the one species that seems able to contemplate killing in an abstract way, evaluating the moral and ethical consequences of taking another's life.  The vast majority of us would not describe ourselves as careless killers, and would claim to avoid causing senseless death when possible.  Then we get into our cars.

The speed limit on the road with the dead deer is fifty miles an hour.  Every branch of this winding road ends a few miles farther into the hills, serving an exurban bedroom-community development.  People claim to like living in the country because they enjoy nature, but nature had better not get in the way of easy access to town.  Of course, very few wildlife-vehicle collisions occur on purpose; after all, people are often also victims of severe injuries or death when large animals like moose are involved.  But nearly all animals that are hit die.

When animals die of natural causes besides predation, they tend to die in places where scavengers can get to them, so that the occasion of death is also an occasion for the continuation of other life.  One of the elements of roadkill is its wastefulness, because the traffic may prevent scavengers from at least cleaning up after our carelessness.  Worse, other animals may be attracted to the bounty then also die in traffic.  This is only one aspect of the particularly repugnant facets of road kill.  Another facet is its anonymity, with neither killer or victim aware of the other.  It is the ultimate in thoughtless take.

The vast majority of victims are not ever seen before being hit, especially if they are low to the ground and cryptic, like snakes, lizards, or salamanders.  It is easy to ignore the carnage if you never see it, easy to believe that you don't contribute to it, easy not to think about it at all.  What if we did think about it?  What if seeing a dead animal, even a snake or a slug, required a moment of reflection and grief?  We would have to slow down enough to see the corpses.  If we slowed down, there would be far fewer of them.  That would be one benefit.  The process of acknowledging the losses might have a far greater benefit, that of helping us recognize our own place in the scheme of life, the first critical step to salvaging our planetary home.

Tale of Two Skinks

There are two edges to the sword of change that is slicing through so much of the biological skin of our planet.  The first is the staggering loss of biological diversity, adding up one of the great waves of extinction in Earth's history.  Along the trailing edge, ecosystems and the species that evolved in them are under increasing pressure from species new to the system.  We pay a lot of attention to the problem of extinction, but much less to invasion, even though it can and does contribute to the former.  It is perhaps a bit easier to rally to save a charismatic species such as a panda rather than organize to fight the diffuse threat posed by signal crayfish or purple loosestrife or kudzu.  However, scientists have started asking why some species become so destructively overabundant even though close relatives may be on an endangered list. 

Behavior alone won't dictate success.  Species that establish in new places also tend to be introduced over and over,  increasing the odds that eventually, a few individuals will survive the initial colonization event.  This in turn may be dictated by who lives where the most common transport routes start.  However, individual behavior seems to play a larger role than we expected.

Kudzu consuming a barn in North Carolina. Photo: NASA

If you want to successfully colonize a distant planet, you might consider taking a close look at how this works right here at home.  First, you've got to get yourself on some kind of transport vehicle, whether in the gut of another animal or the hold of a trading vessel or cargo plane headed elsewhere.  Realize you're probably not a welcome passenger, so you've got to be discreet.  You have to survive the journey, which means somehow finding or maintaining conditions in which you can live, with enough water, warmth and energy to avoid death.  Once you arrive, you need to sneak out of the way lest you be caught in the act and exterminated.  Very few stowaways make it this far, but the journey isn't over yet.  You need to find appropriate food, water, and shelter in these new, unknown surroundings.  Eventually, you need to reproduce successfully, which means you need to find, recognize, and successfully interact with a mate.  Next, your children must also raise children.  The resulting little community must avoid being found and eradicated, and finally, new colonists must leave and establish more communities before the invasion can be considered a success.

The odds, in short, are heavily stacked against you.  However, even if animals don't get help (in the form of deliberate introductions by people, such as starlings in North America, cane toads in Hawaii and Australia, or possums in New Zealand), some species still manage to pull it off.  We've just started to think about how animal behavior influences the risk of successful invasion.

Delicate skink. Photo: Peter Robinson, Museum Victoria, Australia

The delicate skink, Lampropholis delicata, and its cousin the garden skink (Lampropholis guichenoti), illustrate the point.  The delicate skink is native to eastern Australia, but has managed to colonize New Zealand, Hawaii, and Lord Howe Island.  The closely related garden skink, however, has stayed home even though it is quite similiar to its more adventurous cousin in many ways.  The two skinks are similar in size, have similar diets, and similar life histories.  Both species live together in urban areas in Australia, close to transport hubs such as major shipping ports and airports.  Both are common, and occur at high densities, suggesting no lack of individuals available for export.  What, then, is different?

Although both skinks like to explore new environments, the delicate skink was far more willing to move through a tube when it couldn't see the exit, enter a small black box in the test cage, and walk up a graveled ramp to reach a heat lamp suspended above the cage floor.  A greater willingness to explore, then hide, may explain a good part of why delicate skinks are called plague skinks while garden skinks have been at worst temporary tourists who never established outside their native range.  The opportunity to become a problem appears to be the same, but the behavior of the animals influences who takes advantage of that opportunity.

Garden skink.  Photo: Peter Robinson, Museum Victoria, Australia.

Not all delicate skinks successfully found the elevated basking site; animals, after all, are individuals.  Other research found that individual mosquitofish vary in their tendency to strike out for new horizons.  Interestingly, fish that chose to disperse also seemed less tolerant of other mosquito fish, and these personality traits were consistent in individuals over the study.  There may need to be a range of personalities and behavioral tendencies to support a successful invasion from start to establishment. 

We don't often think of the individuality of wild animals, or how much that might matter to the survival of a species.  If we were better at recognizing the individuality of non-domesticated animals, how might that change our view of them?



Sources
Chapple, D.G., S. M Simmonds, and B.B.M. Wong. 2012. Can behavioral and personality traits influence the success of unintentional species introductions? Trends in Ecology and Evolution 27:57-64.


Chapple, D.G., S. M. Simmonds, and B.B.M. Wong. 2011. Know when to run, know when to hide: can behavioral differences explain the divergent invasion success of two sympatric lizards? Ecology and Evolution 1:278-289.


Colautti, R.I., I.A. Grigorovich, and H.J. MacIsaac. 2006. Propagule pressure: a null model for biological invasions. Biological Invasions 8:1023-1037.


Cote, J., S. Fogarty, K. Weinersmith, T. Brodin, and A. Sih. 2010. Personality traits and dispersal tendency in the invasive mosquitofish (Gambusia affinis). Proceedings of the Royal Society B 277: 1571-1579.

Driloleirus macelfreshi lives!

This week marked the third anniversary of a significant scientific discovery made by my dogs.  We were out on a walk on a messy afternoon marked by mud, driving rain, and wind, courtesy of a Pacific winter storm.  Young dogs still need their walks, and so do their owners.  I can't really say quite how it happened, other than as I bent down to discharge my responsibility as a dog walker after my old dog had finished her business, I glanced back and saw the young one standing with a long pinkish stringy thing hanging from his jaws.  He looked quite pleased with himself, and was an instant away from flinging up his head and consuming his prize.  I witnessed this in the split second between discovery and annihilation. And somehow I knew that he absolutely must not be allowed to eat this thing, not for any risk to himself, but because of what it was. 

I leaped at him, howling at him to drop it, which is absolutely not how you are supposed to train a six-month old pup to surrender highly desired objects.  Fortunately for science, he was so shocked at my behavior he did drop it, and in his moment of indecision I swooped on his find and scooped it into a spare plastic bag.  The dog was utterly unimpressed at my inexusable theft of what he regarded as rightfully his.  There are times when I wonder whether he still remembers this.

At that time, however, we went home, and I laid the dog's find out on the counter.  It was an earthworm, and it measured four feet four inches long.  It was flabby, pale pinkish-gray, impossibly thin, and quite dead.  It was also the first specimen of the Oregon giant earthworm, Driloleirus macelfreshi, to be documented in twenty-seven years.  We know very little about this species, other than it seems to be endemic to the wooded bottomlands of the Willamette Valley.  It had been pretty much assumed to be extinct.

There are many little pieces to this discovery, each of which made that sudden, instinctive recognition on my part possible.  Over a decade ago, I had the great fortune to meet two of the last earthworm taxonomists in the world, Dorothy McKey-Fender and her son, Bill Fender.  This in itself was a culmination of improbable circumstances, but the crux was a workshop, conducted by Dorothy who was then in her eighties, on how to identify native earthworms.  The workshop was followed by a search for native worms in 2000.

Bill Fender and Dorothy McKey-Fender with a specimen of Driloeirus macelfreshi in their laboratory in 2000.  Photo: D. K. Rosenberg

I know a little about earthworms, as much probably as any average gardener or curious naturalist knows.  Native worms have been largely replaced by exotic species, and most of the worms we see as we go about our daily lives are descendants of recent immigrants to this continent as most of us are.  Ecologically speaking, we do not even know what we've lost, because the native worm fauna has been very poorly studied and described.  We do know that different families of worms behave differently, and affect nutrient turnover and soil humus in different ways.  We do not understand all the implications, although they include reducing the humus layer, which is itself a vital habitat for many organisms, and allowing exotic weeds to establish on the surface of soil no longer protected by that deep blanket.  For the most part, though, we just don't know what we've broken or what pieces remain somewhat intact.

There are earthworms out there, native worms, very different from the nightcrawlers we all immediately identify as the ultimate worm.  Even more amazing, there happens to be a gigantic native worm called the Oregon giant earthworm, Driloleirus macelfreshi.  Dorothy McKey-Fender herself had studied most of the specimens that have ever been collected- a scant few dozen in all.  They were far too rare to allow the workshop participants to examine, but Dorothy moved around the lab room set up with dissecting scopes and trays filled with other worms pinned to the black wax, delighted to share some of the knowledge accumulated over a lifetime.  Her love and respect for these animals was palpable, and her excitement contagious.  I've been more aware of worms since then, for their own sake, not just for what they do.

So there we were, in a wet riparian forest at the tail end of a storm dumping heavy rains, swelling the Willamette River until it licked and curled at the bases of the cottonwood trees along its banks.  A party of several people and several dogs ahead of us had walked right by the corpse of the giant worm lying on a bed of fallen leaves, not far from the floodwater's edge.  I would not have noticed it either, if my young dog hadn't loved to eat dead things.  But at least in that instant of seeing it, I was open to the existence of giant native worms.  Without that, the discovery would not have been possible, even if I had still looked straight at my dog in that instant before he snatched and swallowed.

Looking for another giant worm- the last one was right around here somewhere...

The worm is now among those in the McKey-Fender collection, although a small segment of the tail sits in a vial on my desk for possible genetic analysis.  More importantly, we know we can still look along the rivers and woods and hope for more than we recently dared hope for, that one of the unique forms of life on this planet may still be with us.  If we can be open to those possibilities, I hope we can also be open to more creative visions of how to live more gently and equitably among all of our fellow species.

Leaves in Grass

Our neighbors have gone south for the winter, seeking climates where it does not rain six days out of seven.  They leave by Halloween each year, before the rains have really set in, and return when spring is still early enough that wet cold days are the norm even as the Indian plum sends out graceful arcs of cream-colored flowers.

I've been thinking about communities lately, both ecological and human.  We take it as a given that the natural world is made up of many interconnected pieces, so that no single organism stands by itself.  For some reason, we have a much harder time accepting this view of our own communities, even though it is every bit as true.  This matters, as how we manage the coming enormous upheaval on a planet in rapid climatic transition will depend on how we see each other, and our relationship to both the rest of humanity and to the larger biological community of which we are an indivisible part.

The leaves have fallen in the neighbors' garden, thick enough to smother the grass if they remain there until spring.  I took the dogs and a rake and wheelbarrow and went to work, sweeping up the remnants of last summer's photosynthesis and depositing them in the garden plot.  Leaves are extraordinary.  They do all the work of taking sunlight, which in itself is simply energy, and transforming that energy into actual food- both for the plants, and for nearly all the rest of the non-plant life forms on the planet.  It is a very cool trick.  An even more amazing part of the trick is to shed the biomass when it becomes more of a liability than an asset, first salvaging the good stuff before letting the depleted leaf fall free.  The rest of us get a blaze of colorful glory before the curtain falls and winter takes the stage.

We have an understanding with these neighbors.  In the summer, they allow us to pasture our ewes and lambs on their five-acre pasture, and keep an eye on the water trough.  They've helped us build fences, taught us how to deliver lambs that are too tangled to come out on their own, and loaned us innumerable tools.  They've shared vegetables, gardening knowledge, tips on livestock care, small gifts, and great stories.  They are the sort of neighbors most people only know of through a culture of yesterday. 

In return, we help as we can, share lamb and blueberries and fresh bread, and keep an eye on their place when they go away for the winter.  I rake leaves and I can never quite believe that the summer is really gone, our neighbors are gone, and now there is the winter to be gotten through before we look down the hill and see their lights shining, breaking the darkness with a friendly light that says the neighborhood is as it should be.  The leaves have got to be gathered up first, and given a chance to move through the next stage of the cycle.

Shed leaves are a major component of soil humus, providing food and shelter for all manner of soil organisms.  I leave a fair number of scattered leaves as I rake, so they will provide fodder for the earthworms and enrich the soil that in turn supports the tree.  They'll be long gone by spring, and they are scattered enough so they will not impact the grass.  I use a bamboo rake and a wheelbarrow, because they get the job done while leaving me with the peaceful late fall afternoon, broken by the happy huffing of my dog in hot pursuit of his tennis ball, which I throw between sweeps of the rake, the calls of small flocks of juncos and chickadees, and once the sound of a tree falling in the woods by the creek.  It was wet and windy the day before, and the cycle of renewal incorporates more than just leaves.

I finish before dark, but not before the cold of evening flows in along the creekbed next to the garden, and the sheep start looking expectantly for some alfalfa pellets in their feeder.  Properly done, the afternoon's work will nourish both the human community and the wild one, with no loss to either.  Surely we can find a way forward that truly honors that which we value most.

Newts

One of the reasons I love living in western Oregon is that winter brings another season of life rather than a frozen dead spell, when most organisms either flee or hibernate until spring.  A few mammals and birds tough it out where winter brings snow and ice, but the woods are pretty quiet besides the sound of bare branches scraping in the wind.

Here, the tree branches are free of leaves now thanks to some Pacific storms ranting across the coastal mountains.  The branches aren't bare, however.  The forest is turning a new shade of green, one with delicate pale-gray hues, as the lichens unfurl on every small branch and twig of the oaks and maples.  Thick rugs of newly revived liverworts and mosses embrace the trunks and larger branches.  The snakes and lizards have disappeared, but the rough-skinned newts are out, marching along on their rubbery legs as they begin to move toward their breeding pools.

Photo by Miguel Viera, Flickr Creative Commons

The rough-skinned newts, Taricha granulosa, appear when late fall finally eases the harsh seasonal drought with the misty rain.  The newts are both numerous and active during daylight, unlike any of their kin.  They are encountered more often than they are noticed, judging by the number of flattened corpses on the road leading to the forest gate, and sadly, even in the woods where vehicular traffic is replaced by bicycles and walkers.  It isn't always adaptive to look like a somewhat rotten stick when viewed from above.

Rough-skinned newts tend to freeze in place if startled, although they can move along at a good clip if they decide they need to.  They are patient, and will stand motionless in mid-stride for many minutes if disturbed.  Their second line of defense is to curl in a distinctive ring, head thrown back, tail arched toward their throats, exposing their undersides in bright warning.  This dance to avoid being eaten is called the unken reflex, and it is shared among salamanders, toads, and frogs who defend themselves using chemical warfare as a last resort.

Unken reflex.  Photo by Ap2il, Flickr Creative Commons.

In the case of the newt, the bright orange color is backed up by tetrodotoxin, a potent neurotoxin, one shared with the blue-ringed octopus, a few toads, and some fish, most famously the puffer fish.  The Japanese serve a dish called fugu, which ideally offers the adventurous diner tingling lips but if not expertly prepared, leaves the victim paralyzed then dead through respiratory failure.  The Seattle Audubon Society's book Amphibians of the Pacific Northwest(1) reports that people have died from eating newts in the genus Taricha, although they do not reveal the circumstances.

How exactly such a diverse group of organisms have hit upon the same defense strategy is still unclear, although some researchers have suggested that symbiotic relationships with bacteria who synthesize the tetrodotoxin may explain the pattern(2).  Not everyone agrees, however, that this is how the newts acquire their chemical weaponry(3).  All stages of the newt are toxic, and mothers seem to pass on the poison to their eggs.(4)  Individual newts have variable levels of the toxin(5); presumably it is biochemically expensive to manufacture, and you might get by with a less stringent defense if your enemies expect all members of your species are equally bad for the digestion.  The predators, however, are on to the game.  Common garter snakes (Thamnophis sirtalis) have immunity to the poison(6), although they may become toxic themselves from the tetrodotoxin that builds up in their livers after eating several newts(7).  Larval dragonflies will snack on larval newts, and seem able to discriminate the palatable individuals from those best left alone(8).  Ultimately, any strategy is a gamble, and staying alive means playing the odds.

The chemical-defense strategy may not be the best option in this new world dominated by humans.  Cars do not notice unken reflexes, nor do fast-moving bicycles respond to poison.  Newts can live a long time if they avoid tetrodotoxin-resistant snakes and savvy dragonflies.  Like many long-lived species, they reproduce slowly, with few offspring reaching adulthood.  Their populations are poorly equipped to lose many members to novel death traps.  When I find a newt on a road or a popular path, I promptly give it a lift to the other side, hoping it will keep moving away from the ribbon of danger it cannot hope to comprehend. 

In December, we'll begin looking in the drainage ditches and small ponds in our area, hoping to see the graceful, slow dance of the swimming newts as they gather to mate, then lay eggs long before the first buds appear on the trees.

References (for the terminally curious)
(1).Jones, L.L.C., W.P. Leonard, and D.H. Olson, editors.  2005.  Amphibians of the Pacific Northwest.  Seattle Audubon Society, Seattle, WA.
(2). Chau, R., J.A. Kalaitzis, and B.A. Neilan. 2011. On the origins and biosynthesis of tetrodotoxin. Aquatic Toxicology 21(3):131-141.
(3). Lehman, E.M., E.D. Brodie, and E.D. Brodie. 2004. No evidence for an endosymbiotic bacterial origin of the tetrodotoxin in the newt Taricha granulosa. Toxicon 44(3):243-249.
(4). Lehman, E.M. 2005. Tetrodotoxin as a maternally-endowed defense against egg predation in the rough-skinned newt, Taricha granulosa.  Integrative and Comparative Biology 45(6):1032.
(5). Hanifin, C.T., M. Yotsu-Yamashita, T. Yasumoto, E.D. Brodie, and E.D. Brodie.  1999. Toxicity of dangerous prey: variation of tetrodotoxin levels witin and among populations of the newt Taricha granulosa. Journal of Chemical Ecology 25(9):2161-2175.
(6). Brodie, E.D. III, and E.D. Brodie, Jr. 1990. Tetrodotoxin resistance in garter snakes: an evolutionary response of predators to dangerous prey. Evolution 44:651-659.
(7). Williams, B.L., E.D. Brodie, and E.D. Brodie. 2004. A resistant predator and its toxic prey: persistence of newt toxin leads to poisonous (not venemous) snakes. Journal of Chemical Ecology 30(10):1901-1919.
(8).  Gall, B.G., A.N. Stokes, S.S. French, E.A. Schlepphorst, E.D. Brodie, and E.D. Brodie.  2011.  Tetrodotoxin levels in larval and metamorphosed newts (Taricha granulosa) and palatability to predatory dragonflies.  Toxicon 57(7-8):978-983.

Live Burial

There are still some glorious sunny afternoons as October draws down, but the warmth of the sun is noticeably less than just a few weeks ago.  The turkey vultures have wobbled south on their wise wings, leaving the red-tailed hawks and the chickadees in charge.

In the ground, along with the seeds the chickadees miss, the hatchling turtles are waiting.  They've been out  of their eggs for as much as two months now, paddling free of the one shell they'll shed in this life, to voluntarily wait in the womb of earth their mother shaped until spring brings them a second birth.

Western pond turtles lay their eggs in summer, coming out of the water in long evenings or short nights to find the right dimple in the soil, with the right texture, to dig a flask-shaped hole.  Into this vessel they pour a half-dozen or so fragile eggs.  The mother turtle tamps a plug of earth into the vessel's neck, and then abandons the chamber and its developing contents to fate.  Motherhood as we think of it is not a turtle's strongest suit.

The development of the embryos inside the eggs unfolds to the warmth of the earth surrounding them.  Even the mix of males and females that emerges from the nest is set by the sun, as solar radiation heating the earth triggers cascades of biochemical reactions during a few critical days of development.  In that short time, the power of the distant sun determines each turtle's future role in the propagation of the species.  The eggs will hatch twelve to seventeen weeks after laying.

Sometimes the newly hatched turtles will leave their sanctuary  before winter, but most often they remain inside unless flooding or some other catastrophe forces an evacuation.  Instead, they shelter in place, encircling each other on tiptoe, heads pointing up, and waiting as the short winter days spin past.  They wait, while water percolates through their sometime shelter, and frost makes iron of the earth around them.  Their tissues may freeze, and some of them die from the cold.  The rest of them stand still, embracing both living and dead in the darkness.

What does a turtle think, in the blank black cold, unmoving?  Where are the lines between death and life and consciousness, through the long night?  The gift of golden yolk their mother gave them must sustain their metabolic fires until the little turtles finally venture forth from cold bleak safety.  What is it like for them, to feel the warmth of the sun directly for the very first time, when they are already almost a year old?

Even then, they wait and do not eat.  Newly minted pond turtles in western Oregon may not venture toward water until mid-May, although they emerge as early as March.  The size of quarters, the hatchlings are cheap snacks for herons or raccoons or wandering mink, and they take shelter in either the narrow hole that protected them all winter, or they move a few scant feet away and use moss or leaves as frail shields against large appetites.

They don't make the abrupt journey to water's edge for another two months.  Maybe they are waiting for the spring sun to chase the last of winter from the pond water, so it is warm enough for a little turtle to digest food and grow without having to rely too much on the deadly risky business of basking.  We do not understand much about this.  Once the young turtles grown enough to escape the mouths of many of their enemies, they'll join their bigger kin on logs or rocks.  That may happen next summer, or the year after.  Until then, they will shelter in mats of floating algae, bits of pond weed with eyes.  Next winter, they'll choose a living burial either in muck at the bottom of some pond or in the leaf litter and soil on the forest floor, but they may get up and move around on good days.  They’ll take with them the memory of the sun, felt and seen, rather than only its echo in yolk.  

I think of this, as I toss the last of the season's apple windfalls over the fence for the sheep, as the sun swings lower and the old year shuts down.  I think of how the earth shelters both our past in the bodies and bones of our ancestors, and the substance of our future.  Pond turtles are only one more expression of that understanding, and we owe them thanks for that.



Hope in a White Plastic Box

Among all the bad news about the environment, you don't hear so much about the success stories.  There really are some, and they are very useful not only in what we can learn from them, but also for the hope they can inspire.  Hope is a great motivator for human behavior, probably far greater than we typically realize.  It also generally makes us feel better, and although that observation could naturally lead to a discussion of how we may be hard wired to respond to hope, to a kind of innate optimism, I'd rather discuss a specific event for now.

The subject: Oregon spotted frogs, Rana pretiosa.  These animals might not seem a likely source of hope.  They're a candidate species for listing under the Endangered Species Act.  Candidate species are those that the U. S. Fish and Wildlife Service has determined to be worthy of listing, but the agency just hasn't quite got around to getting the paperwork all done.  There's no regulatory muscle behind the designation.  It just formally states that Oregon spotted frogs might be in some pretty serious trouble.  Unfortunately, it is a common story especially for a species of amphibian.

Oregon spotted frog, Rana pretiosa.  Photograph by Dan Rosenberg.

All is not gloom and doom, however.  A group of people, including biologists with the Washington (state) Department of Fish and Wildlife, NorthwesTrek Wildlife Park, the Woodland Park Zoo, the Oregon Zoo, and other organizations has been working to reintroduce populations of frogs into areas where they've been driven out.  It is a complex process, involving a several-year-long evaluation of site hydrology, presence of exotic species like bullfrogs, and potential for disease.  It isn't easy to find sites that pass muster for biological reasons, and the candidate sites are also subject to more human considerations, such as land ownership and other land uses.

Then there's the issue of where you get your frogs.  The animals released on October 6 were collected as egg masses from two sites whose populations were robust enough to handle some baby-snatching.  Egg masses from both sites were then distributed to the zoos and other organizations who reared the frogs. 

This is an even more formidable task than finding a place to release any frogs you might raise.  A suitable wetland doesn't look all that spectacular, but it provides the right water temperatures, nutrition, and shelter to turn an egg into a frog.  Mimicking that is actually very, very difficult.  Every species is different.  Will  Oregon spotted frogs thrive on one of the pre-formulated tadpole chows (yes, there are such things), or some new recipe?  Are conditions optimal for proper development?  How do you clean the rearing pens without accidentally throwing out the babies with the tank water?  When you're dealing with a rare species, failure to raise healthy young individuals really isn't an option.

Thankfully, much of the needed husbandry has been worked out, and the project collaborators brought over a thousand young frogs for release into the site.  Frogs were first introduced several years ago, but each year the population is augmented to ensure it gets established and begins to grow on its own.  Although it wasn't the first time, the people involved clearly viewed the release as sweet reward for the arduous care they'd given the thousands of eggs, tadpoles, and little frogs over the last seven months.

Rana pretiosa just before release.  Photo by J. A. Gervais

Plastic containers were lugged down to the muddy shoreline, lids removed, and the young frogs burst out like popcorn.  Some animals dove right down, seeking shelter.  Others hit the water and bounced right back onto the land, and a few even leaped for the containers.  I had to wonder what passes through the mind of a frog at a moment like this.  "This water is COLD!"  "Where's the frog chow?"  "Whoa!  This isn't what I signed up for, where's that plastic box?" 

More serious questions include how exactly an animal raised in a tank is going to know how to find wild food and life-saving shelter, recognize danger in time to escape, and learn to deal with an environment staggeringly more complex and changeable than the conditions it has experienced since hatching.  Incredibly, a large proportion of young frogs seem to figure it out.  I was told that the six-week survival rate is actually quite high.  Not the sort of release strategy that would work for an animal that depends on parental guidance to learn how to survive, but frogs don't look after their young, and they seem to start life with all they fundamentally need to know already programmed into their neurons.  Frogs are much easier to deal with than, say, condors or elephants.  Humans may have invented formal schools, but plenty of other species believe in education.  Not frogs, fortunately, which simplifies things like reintroductions.

Releasing 300 young frogs into the wild.  Photo by J. A. Gervais

It was all over at each release site in a matter of minutes, at least from our perspective.  We plodded back through the muck, put the now-empty containers back into vehicles, and went our separate ways. 

Back in the pond, the new arrivals were dealing with amphibian-centered immigration issues, determining who will get what space with access to which resources.  They were learning how to navigate a new world much bigger than a rearing tank, and populated with river otters, herons, kingfishers, and raccoons.  The long-term payoff that justifies all the work will be the number of egg masses that these animals will eventually lay, and the persistence of this population of the species.  The short-term payoff may be equally significant to the humans involved, a rush of hope, of empowerment, a sense that the situation hasn't completely gotten away from us after all.  There is a chance we can still fix some of the things we've broken. 

There's a trick to this hiding thing.  Newly released R. pretiosa not quite "getting it".  Photo by J. A. Gervais

It's a brave new world we must face, one full of unimaginable threats.  Recognizing our vulnerability is a crucial first step to survival.  Hope will be equally necessary to motivate us to move forward into the future with strong hearts and open hands, oriented to find solutions to save what we love.  It is good to know that redemption can be found in something as simple as a white plastic box.