The Paths Most Traveled

4/18/24 – Making room for migrations

snapping turtle unwilling to be hurried / author photo

Hello everyone:

This essay marks three full years of writing the Field Guide. I started on Earth Day, 2021. Since then, it’s been 157 weeks, a lot of very late nights, and a deliberately uncounted number of hours. (Sometimes it’s best not to know one’s hourly wage.) As I reflect back on these three years of writing and my dedication to it, I’ll step out of my comfort zone and express my hope that those of you who are loyal free subscribers might be encouraged to make the leap to a paid subscription.

My writing here matters to me, and I’d like it to become the center of my working life. If it matters to you, and if the price is affordable, I’d be honored to have you on my list of paid supporters. To that end, then, for a short time I’m offering a 20% discount on a paid annual subscription. If that’s still not affordable, please don’t give it a second thought. I still believe in keeping the work available to all subscribers, because the conversation is too important.

To my paid subscribers, especially the incredibly generous Founders, thank you. You help keep the work free for those who cannot afford it. I’ll continue to do all I can in the months and years ahead to earn your support.

In this anniversary moment, I’m also curious what ideas any of you – original subscribers or new arrivals – might have for improving the Field Guide. Reading the essays for your listening pleasure? (I started but got sidetracked.) Separating the curated Anthropocene news into a separate email? Creating more of an online community in conversation about the ideas my work explores? Please let me know in the comments or reach out directly by responding to this email.

Finally, to mark the first two Field Guide anniversaries, I created an index to all my topics, great and small, for readers to better explore all I’ve written about. Anyone interested in that again this year?

As always, please remember to scroll past the end of the essay to read some curated Anthropocene news.

Now on to this week’s writing:

I talk here often of the “fabric of life.” It’s a metaphor meant to portray the density, diversity, and interconnectedness of the living world, and it’s a reminder to see ourselves honestly as a thread in the fabric rather than delusionally as the weaver. Even as our Anthropocene actions slash through the fabric, we are still being told by the makers of knives that the living world is an object rather than our family. And so my frequent use of the fabric metaphor is also an invitation to shift our thinking from egocentric to ecocentric.

I am fond of the fabric image, but like most metaphors it has limitations. Fabric is thin, to begin with, which makes it hard to fit in all that wriggles between magma and the magnetosphere. Worse, it’s static. Life is always on the move, whether physically through space or genetically through time.

And it is that constant movement I’m thinking about this week.

Life is as deep and as restless as the sea. (Not a surprise, really, since this is an ocean planet.) I’m reminded of this as spring migrations are well underway here in northeast North America. Tree swallows are zooming and squabbling over the nest box colonies I’ve established in a few places. We suddenly have a pine warbler and a rose-breasted grosbeak at the feeder, and on Monday I heard the first haunting notes of a hermit thrush as I ambled off-trail through a pine/spruce/hemlock forest. On Sunday, I shepherded a large, sleepy, grumpy snapping turtle as she crossed a busy road. And Heather, my mother, and I spent a late rainy night last week doing Big Night work, counting and protecting frogs and salamanders as they migrated across the pavement en route to breeding and egg-laying in vernal pools and other wetlands.

spotted salamander on its damp migration / author photo

The public conversation about migration usually focuses on the epic scale: the vast herds of wildebeest or caribou, the vast distances of Arctic terns and gray whales. But those are the migrations that inspire the human eye and mind. I think they trigger the collective memory of our own restless globe-spanning irruptions over the last million years, while also reminding us of our more recent relentless colonial expansions. But we marvel at these long journeys as individual accomplishments rather than the miraculous swaying of energy through astonishingly complex systems. Worse, as we grow more distant from the living world, we see these movements as rare and strange while forgetting that they have been ubiquitous and normal since long before humans spread out from Africa.

Everyone is in motion. Migrations happen at every scale and in every environment. From dragonflies and snakes to salmon and tuna, and from warblers and hummingbirds to ants and salamanders, life hums its tunes while ambling down endless paths. Spiders and their gossamer sails, eels and their mysterious origins, swifts and their alien airborne lives: It may be wiser to think of migrations as extensions of ordinary busy life rather than exceptions to it. Even the thoughtful and imaginative – and essential – explorations by fungal mycelia and slime molds look like journeys to me, even if they are journeys in which each organism is in many places at once.

The greatest migration is vertical, and it’s made by the smallest of organisms: “It’s by far the biggest movement of any animals on the planet, and it happens every day, all over the ocean,” as reported in National Geographic. Zooplankton, in their hidden lives beyond and below our own, support all life on Earth as they move to the surface from the depths every night – from as deep as 3000 feet – retreating as sunrise approaches. The scale of the migration is mindboggling. Trillions of tiny animals with an estimated mass of 10 billion tons make nightly journeys far greater than any human marathon. And the effort is incredible, as this excellent Scientific American article explains: “For a quarter-inch fish larva, making a one-way vertical trip of 1,000 feet is the equivalent of a human swimming more than 50 miles – in just an hour or so.”

Other large species, like octopus and a variety of deep-dwelling fish, follow the zooplankton up and down, adding to the migration.

Known as diel vertical migration, this is much of the oceans’ biomass moving in their own tidal surge upward as darkness arrives and downward as light returns. These animals (both microscopic and macroscopic) move comfortably through an incredible range of temperature and pressure, and we’re only realizing now how subtle their movements are. As Scientific American notes, zooplankton a thousand feet deep, where only 0.012% of sunlight filters through, respond to prolonged cloud cover. Some species in high polar latitudes will realign their migration to lunar cycles when the sun is absent in winter months.

And, amazingly, it’s not just the zooplankton. Phytoplankton, the tiny plants that provide half of all the oxygen you and I breathe, are what zooplankton feed on, and they’ve been observed making their own vertical migrations, slower but just as sure, to reach nutrients and/or avoid predators. Our long-held assumptions about both types of plankton, that they merely float with the currents, have been upended. Even the name – plankton come from the Greek for “wanderer” or “drifter” – is inaccurate.

Again and again we find that we haven’t been paying enough attention to how life moves, and to why it matters.

microplankton / credit: courtesy of David Liittschwager, CC BY-SA 4.0

Back on land, the first State of the World’s Migratory Species report came out in February. It found, unsurprisingly, that many threatened and endangered migratory species are closer to extinction than ever. Overexploitation and destruction/fragmentation of habitat are driving the losses. PBS and NPR both had good articles on this.

Our numbers – growing at a billion every 11 or 12 years – are interfering with the numbers of other plants and animals, certainly, but it’s more than that. It’s how we live, taking from everything and everywhere, unaware somehow that migratory species need safe passage along their entire journeys. These are not point-to-point trips; they’re threads that cannot be cut. Remove food sources for monarch butterflies, grassland birds, or salmon parr, and their journey is over. Build dams that stop shad and eels, and their journey is over. Provide toxic mining ponds for snow geese, and their journey is over. Drive heedless on rainy spring nights along frog-dotted roads, and their journey is over.

You’ve probably heard the stories of passenger pigeons in county-sized flocks darkening eastern and central North American skies for hours or even days at a time? With a population of 3 to 5 billion in the 19^th century, these birds moved trainloads of nutrients around the continent, eating and being eaten at a scale that shaped innumerable ecosystems. Driven to extinction by the dawn of the 20^th century (though someone is trying to revive them), they made up a significant portion of North American birds when European colonists first arrived. I’m not sure what that total number was, but it was reduced to about 10 billion by 1970, and we’ve lost 3 billion more since then. For those of you in this part of the world, imagine what the skies and forests would look like if we hadn’t wiped out so many moving parts of the fabric.

Why have we ended and stunted so many of life’s ancient paths, even those as broad and deep as the passenger pigeons? In part, it’s because we’ve been so careless about the ones we’ve built for ourselves. Our ships crisscrossing the oceans are too noisy and too polluting, our fences are too numerous and too unforgiving, and our roads are, quite frankly, a metastatic cancer upon the land.

Our roads, fences, dams, farms, power lines, and other industrial/urban development now lay across the continents in a pattern so dense that it might as well be a mesh of barbed wired pressing down upon the living world. Roads are the most egregious, by far, and have spawned their own field of science – road ecology – created to understand all the impacts of our transportation system on other species. (In researching this piece, I also found a call to develop the science of “fence ecology” in an Anthropocene article on the genetic and health losses in populations of wildebeests who could no longer migrate through a world of fences.)

Those of you who’ve been with me from the beginning will recall the three-part series I did on road ecology in October of 2021. I plan on republishing it sometime, with updates, especially once I read the book I’m most excited about this year: Crossings: How Road Ecology is Shaping the Future of Our Planet, by Ben Goldfarb. (Goldfarb wrote the excellent Eager, all about the miraculous qualities of beavers in restoring climate- and biodiversity-resilient landscapes. I highly recommend it.) It is hard to fathom, but roads cause more harm to wildlife populations than any other factor.

a gorgeous gray fox by the roadside / author photo

40 million miles of roads scar the continents. A million animals die every day on American roads alone. Roads isolate wildlife populations, reducing their genetic diversity. Roads alter, disrupt, or simply end migrations that have existed for time immemorial, whether for antelope and elephants traversing large landscapes or for salmon, shad, or alewives stopped by culverts that allow no passage. Road noise diminishes communication essential for breeding and territorial claims. Here’s how Ben Goldfarb introduces it in a well-written piece for High Country News:

The essential insight of road ecology is this: Roads warp the earth in every way and at every scale, from the polluted soils that line their shoulders to the skies they besmog. They taint rivers, invite poachers, tweak genes. They manipulate life’s fundamental processes: pollination, scavenging, sex, death.

Among all the road’s ecological disasters, though, the most vexing may be noise pollution — the hiss of tires, the grumble of engines, the gasp of air brakes, the blare of horns. Noise bleeds into its surroundings, a toxic plume that drifts from its source like sewage. Unlike roadkill, it billows beyond pavement; unlike the severance of deer migrations, it has no obvious remedy. More than 80% of the United States lies within a kilometer (approximately 0.6 of a mile) of a road, a distance at which cars project 20 decibels and trucks and motorcycles around 40, the equivalent of a humming fridge.

All of which begs the question: What journeys are we on, really? Where are we going and why? If this is an evolutionary migration toward the superior destiny of mankind, blah blah blah, we can’t afford to pay the ethical and biological toll. I suppose an argument can be made that, despite the plastics, SUVs, and data centers we’re still animals focused on breeding, rearing young, feeding and housing ourselves. But I think we all know, on some level, that the future being constructed for us just gets weirder, less relevant, and more harmful to the world that future is parasitizing.

Maybe it’s just me, but have you ever been in a long line of cars, in the midst of a demoralizing landscape (take your pick: suburban, urban, industrial, rural) and felt that the unfolding civilizational fabric is meaningless and wrong? That we’ve made, and are on, the wrong path? Or, when arriving home, that scrolling online feels like walking through a clearcut of bleeding stumps? That the journey we’re on, such as it is, is interfering with countless others?

I’m assuming that these are rhetorical questions for most of you, since you willingly navigated here to something called The Field Guide to the Anthropocene.

These feelings are reinforced as we live amid news, every day, that our disregard for the living world has radically accelerated the global extinction rate and heated the atmosphere and oceans enough to threaten or disrupt all migrations, great and small. Whatever happens to the nightly journeys of plankton, rest assured, will happen to us too.

But the good news, of course, is that this reality, and those feelings, can be as temporary as we want them to be. A U-turn tomorrow will not fix things, but knowing we’re doing the right thing will change the journey. The living world is still so lush, so indomitable, and so long-lived that should the atmosphere and oceans cool, should the road noise and highway murder

be reduced, and should the fences and dams come down, the world would return to more fully weaving itself through itself, repairing the fabric, as it has always done.

Some of this good work is already being done, from the rapid build-out of renewable energy to the replacement of culverts with living streams under roadways. As I note below, the Biden administration just put conservation on the same footing as resource extraction in leasing U.S. public lands. Everywhere we look, scientists and activists are racing to slow or reverse the losses in populations of birds and amphibians and whales and every other threatened animal and plant species. We’re still wielding far more knives than needles and thread, but we know what to do. We just need to be convinced of the need to do it.

Which brings me, finally, to Earth Day. On Monday the 22^nd, we mark the 54^th anniversary of the original movement, which still stands as the single largest public protest in U.S. history. In 1970, 20 million people – nearly 10% of the U. S. population – marched in the streets. It made sense for politicians and corporations to pay attention, which in turn led to the Clean Air and Clean Water Acts, and to the creation of the EPA. That’s a pretty good reminder of what happens when enough of us align our path with those paths that have been traveled forever.

Thanks for sticking with me.

In other Anthropocene news:

Don’t throw away your eclipse glasses. Check out this information page from Astronomers Without Borders, which directs you to regional collection hubs where the glasses will be processed and eventually donated to countries where eclipses will occur next.

Excellent news for conserving public lands: From the Post, the Biden administration (via Sec. Deb Haaland’s Dept. of Interior) has announced a new rule governing the auctioning off of leases for land controlled by the Bureau of Land Management. BLM has always prioritized resource extraction for mining, oil and gas drilling, and grazing, but now, as the Post says, the agency will give equal consideration “to entities with plans to restore or conserve public lands” under what will be called “restoration leases” and “mitigation leases.” This affects a tenth of all the land in the U.S. Haaland announced the new rule, saying

Today’s final rule helps restore balance to our public lands as we continue using the best-available science to restore habitats, guide strategic and responsible development, and sustain our public lands for generations to come.

From Reasons to be Cheerful, an excellent article on the science of ecoacoustics and how it’s helping to restore coral reefs. The oceans are not quiet places, and sound plays a key role in communication and navigation. Researchers have long known that playing the sounds of a healthy reef in a unhealthy one will accelerate the return of coral, fish, and other species. As one researcher explained,

the global data indicates there is a better future ahead. You might say that coral reefs are the first ecosystems we could lose… but that then makes them the first ecosystems we could save, and if we can save coral reefs, we can save anything.

Also from Reasons to Be Cheerful, an incredible long-term restoration of salt marsh and other coastal habitat is happening south of San Francisco. It’s a 50-year plan for 15,000 acres. Over 3000 acres have been restored so far. Many organizations are working together to build vital habitat, learning as they go and providing a model for other large restoration projects.

From Oceanography, a very long, very thorough, and quite readable explainer on the fate of the Atlantic Meridional Overturning Circulation (AMOC), which moves warm water north along the surface of the Atlantic Ocean and south along the ocean floor. Much of the world’s weather is stabilized by the AMOC. A warming atmosphere has already slowed the current down, and the rapid melting of Greenland ice may stop it altogether, affecting much of life on Earth. My own piece, Running AMOC, framed the story, but this article is a real education.

From the Post, a “heat pump petting zoo,” really a tech fair, introducing visitors to all sorts of new, wise, helpful energy-saving tech, from heat pump water heaters to e-bikes and more.

From The Conversation, why e-bikes and electric mopeds are doing far more for cutting emissions than electric cars. They’re a better solution for many of the short trips we make in our big, heavy, often unnecessary cars and trucks.

From Anthropocene, making cows more climate-friendly by reducing their methane output. It’s worth asking whether we should be tweaking this problem or reimagining it altogether, but the article lays out the tweaking options, while still conscious of the bigger question: “But are such high-tech innovations a helpful step towards meeting our climate goals, or just a bandaid for our continued consumption of environmentally destructive beef and cheese?”

Also from Anthropocene, a large landmark study by 58 researchers studying 2655 farms in 11 countries found that, across the board, diversification techniques (i.e. moving away from monoculture) improved environmental and social benefits, like increased biodiversity and improved crop yields. As one study co-author put it, “This is evidence that this can actually work — we can imagine agricultural systems that are more diverse and serve people and nature at the same time.”

From Wired, an explanation of the paradoxical warming of Earth’s surface temperatures as we reduce greenhouse gas emissions. As emissions drop, so does aerosol production. And aerosols, like clouds, help cool the planet. But they also infiltrate lungs and kill people.

From Axios, the newest round of coral bleaching across the globe, as unprecedented ocean temperatures soar above normal, is “a warning, not a death sentence.” Not yet, at least. This is a short, informative explainer, well worth your time.

From Bill McKibben, a wise and wry write-up on the trillions of dollars that will be lost in the global economy because of the heat that’s already baked into the system. If you’re not yet subscribing to his climate newsletter, The Crucial Years, and you want clear-headed perspective on what good activism looks like, you should. Here’s a sample, in which he outlines how we got here:

There are a couple of things to say here.

One, some of you may remember the famous Limits to Growth report from the early 1970s. It predicted that without serious efforts to change our demands on the planet, economic growth would begin to suffer right about now. We thought about it as a society and then, with the election of Ronald Reagan, rejected it; we are now harvesting that bitter fruit. If we don’t act now then our children may wish they still had bitter fruit to harvest.

Two, capitalism—which regularly acts homicidally—is acting truly suicidally. Having been warned for years now, it resists every effort to rein in its excesses. As Exxon’s CEO helpfully explained earlier this year, it’s not that you couldn’t make good money from renewable energy—you just couldn’t make ‘above average returns’ because sunshine is free. So instead we’ll tank the world, and with it the world economy (which is a subset of the first, not the other way round).