Imagine

We were trying to herd the sheep into their small three-sided shelter one evening recently, so we could worm the ewes and trim hooves.  It always amazes me how good animals are at reading human body language; they often seem to know what we're up to before we even know ourselves.  Somehow, when the order of business switches from feeding them to moving them around, the sheep recognize it instantly, and they are not always on board with the agenda. They weren't on board this time, behaving as if we were driving them into a dragon's den.

Part of the problem is that sheep really don't like going from bright light into a dark space where they can't see well.  Individually, they enter this shelter on their own all the time, but being pushed as a group made a significant difference in their willingness to enter when we were pressuring them.  Time and again we almost got the lead ewe through the wooden gate, and at the last second she dodged aside, the younger ewes and the lambs quickly following her lead to the far end of the field.  This went on until the light softened with the setting sun, reducing the contrast of the dark interior of the shed.  The old ewe finally decided that it wasn't so frightening in there after all, and led the flock inside.

Photo: J. A. Gervais

Taking the risk of going forward isn't always easy, even if you're a human.

We're facing an unprecedented global environmental crisis because we've modified the atmospheric chemistry enough to begin raising global temperature.  The science behind this fact is well established; the devil is, as usual, in the details.  We don't know precisely at what point increasing carbon dioxide concentrations may begin to force positive feedback loops, whereby the rate of warming is increased still faster.  We do know that this could happen when the frozen methane hydrates in the high-latitude ocean sediments and in the tundra's permafrost begin to melt, releasing large volumes of methane.  Methane is a potent greenhouse gas.

We know that even the deep ocean is warming rapidly.  We don't understand how exactly that will alter ocean currents, or how quickly warmer water will begin releasing the frozen methane in marine sediments, or breaking the ice dams that have stabilized some of the world's largest ice sheets by slowing their entry into the seas. We don't know at what point melting ice sheets will reach a point of no return, where nothing we do could stop the enormous volume of glacial water from pouring into the oceans.  We know from the paleoclimate record that sea level has risen in the past as much as a meter in a quarter century.  We just don't quite understand the exact conditions that would be needed to trigger an event like that again.

But we can guess that we may be getting close.

These are enormous facts, dark facts, rooted in a past most of us cannot imagine and extending into a future that we cannot see, even though that future may be only a few decades away.  Facts fail to resonate with most of us, leaving them in the realm of simply facts, hard-edged, immutable, and seemingly irrelevant to the impulses and instincts that drive most of our behavior.  What does it take to make these inert facts part of our living consciousness?

I wonder if part of the problem is that we don't run forward into the utter unknown very well.  For the vast majority of our evolutionary history, not launching off into the abyss was probably very wise; you take those sorts of risks only when going back or staying where you are is absolutely untenable.  Pushed hard enough, the unknown ahead is less horrific than what you know is behind you, and then you jump.  The trick is recognizing when you are truly at the point of jumping or being pushed, that instant between having some mastery over your fate and losing any hope of control.

 Photo: Jeff Gervais

We may actually be at one of those tipping points, where we could manage to make our planet's climate very difficult for human civilization to persist, at least as we've known it for the last few centuries.  Are we able to perceive that we may have no choice but to accept the fact that the way of life we know now cannot continue, and we can choose, or not choose, to consciously guide its transformation?

Beyond any other species that has ever existed on Earth, we have the capacity to imagine future states and plan out the actions needed to achieve them.  I wonder if our apparent inertia in the face of an increasingly dire body of scientific evidence isn't rooted in two paradoxes.  The first is that although we are intelligent enough to create civilizations that ultimately threaten our own life-support systems, and even to realize it, we seem unable to emotionally grasp and process the enormity of the danger we collectively face.  Rational choice requires emotional roots.  Can an incipient catastrophe carry sufficient emotional weight, or do we have to live through it first?

The second paradox lies in the fact that despite our technological prowess and extraordinary cultural and social diversity as a species, we  appear unable to imagine any other world, any other set of human societies, than the ones we currently know.  So we are caught, unable to emotionally respond to the danger that our current position threatens, and unable to imagine a future different from the present, one that is worth risking the unknown to achieve.  Both block proactive planning and execution of those plans.

Imagine first the world you would like to live in, or the one you would like to bequeath to those who follow you.  What things and beings, tangible or intangible, would this world have in it?  If you listed them all out, how many of them deal with the roots of survival and of happiness, versus the trappings of our civilized lives that bring as much stress or ambivalence as they do real value?  What aspects of our society are most necessary to achieve those core needs?  If no one steps forward to lead us all, how can each of us fill that leadership void, in our own communities, in our own individual way?  How will we break the impasse, and will we manage to get in front of the wave of changes we've unleashed, or allow it to utterly overwhelm us?

Photo: Jeff Gervais

Reciprocal Flows

There has been a traditional divide between the worlds of water and dry land in ecology and management, one that has greatly impeded our understanding of the linkages between the two, and long prevented us from realizing, once again, that the artificial divisions we place upon our perception of the world in an attempt to make it easier for us to understand or manage are just that- artificial.  I realized this more fully when I first began to work with the land we owned along the creek north of town.  At first it seemed straightforward enough.  There was creek, and there was upland, and there was only a narrow ragged remnant of forest running along the banks.

It is a fairly short creek, only a few miles from headwaters to its confluence with a small river.  The source is on the major ridge to the north of us.  From there, the creek cuts quickly downslope until it reaches the valley floor not far upstream from us.  The creek slows down a bit there, taking the time to begin to meander, and it supports a nice riparian woodland of bigleaf maple, pacific ninebark and Indian plum, and wildflowers such as delphinium and trillium.  By this point, the creek is big enough to throw a good temper tantrum during a winter storm, and of maintaining a base flow during the summer drought.  Both are important not only to the life of the creek, but to the life of the forest as well.

The riparian zone upstream. Photo: J. A. Gervais

The water doesn't just come from the channel coming down from the north.  There are numerous seeps along this section of the valley, places where suddenly sedges bristle up, where you can sink a tractor up to its axle before you can blink (we've done that).  Fencepost holes sometimes filled with groundwater within minutes, making us rethink the placement of fence lines.  This water is coming from the ridges that run to the west and east, traveling below the surface for perhaps a kilometer or more before bubbling back up into daylight. Some of it likely comes up right in the creek bed.  This is known as hyporheic flow.  It means there's more to the creek than the channel, and that wearing mud boots is generally a good idea even in the meadow.

I've been slowly bridging the divide in my formal education, reading more about just how much a mix of upland and aquatic worlds a riparian zone really is. Large woody debris slows the flow of water, allows sediments to settle, and provides pools.  There isn’t any large wood in our section of creek, because there haven’t been large trees to provide it for many years, and it probably was dragged out if it had fallen in.  There isn’t much of a floodplain here anymore either, because the creek has cut a channel too deep to climb out of in all but the worst floods.  The end result is a truncated system, created from historical misuse.  The floods this past January, however, began to pile up debris and created side channels, the first signs of returning complexity in our section of creek.  Maybe we're getting somewhere, reestablishing the connections between aquatic and terrestrial, past and present.

 Creek bed after the floods rearranged it.  Photo: J. A. Gervais

This patch of land has been farmed for decades.  The last people who lived here rescued abused horses, and fenced in a broad wedge that included the creek.  The horses, over a dozen of them, trampled the banks and stripped the trees, until only a thin, wavering line of vegetation remained.  When the horses left, invasive blackberry thickets grew to over ten feet in height, choking out any hope for new native trees and shrubs.  But this creek has been designated a possible salmon stream, and landowners along the length of it have been encouraged to restore the riparian forest that once graced the length of its banks.

The forests along waterways support the life in the water, which in turns provides resources to the life on land.  Hatches of aquatic insects such as mayflies don’t just feed the fish, but they also support the birds and bats and spiders living along the banks.  In turn, terrestrial insects and plant matter falling into streams and rivers provide major sources of nutrients and energy to the aquatic community.  In fact, one study suggested that nearly half of the annual diet of rainbow trout was made of insects that fell into the stream.  The terrestrial insects are strongly affected by the vegetation along the waterway.  If we wanted to see salmon return, we needed to plant trees.  I had just plunged across the terrestrial/aquatic divide.

 Future ash swale, four years after planting.  Photo: J. A. Gervais

We mowed down the blackberry and with a good number of friends, planted over a thousand native trees and shrubs into the two acres along our section of creek.  Things are looking up.  The planted trees and shrubs have done pretty well, especially the willow.  Even more encouraging, a number of tough volunteers have sprung up from the areas once smothered by blackberry.  We’ve found banana slugs and rough-skinned newts on our property.  We’ve heard frogs in the seeps along its banks and seen fish and invertebrates in the water.  We’re not back to the conditions that existed a hundred and fifty years ago, but they're probably better now than in any point during the past three quarters of a century.  We hope the trend continues beyond our ownership.

Although you can’t stand in the same river twice, the continuum of history and geography shapes the water flowing around your legs.  There is still old farm junk caught in the creek bed, sheets of sediment twisting and crumpling against the bits of rooted rusting iron.  The fence line is new, barely five years built.  When we put the fence in, it was set far enough back that there was easy safe distance from the wire to water.  The creek has looped toward the fence since then, maybe wanting to add more metal debris to its collection.  The creek already reclaimed the lower pasture corner during that violent storm last January, jumping out of its bed and sweeping an arm across the grass, depositing silt from the high ridge.  Remember what's happened before, what came and went, where proud accomplishments failed.

 The tenuous boundaries between terrestrial and aquatic systems. Photo: J. A. Gervais

What we do on the banks of a river affects what happens between those banks, but it’s all pretty temporary in the lifespan of moving water.  In the end, erosion will wear down the divides.


Resources:

• Baxter, C. V., K. D. Fausch, and W. C. Saunders. 2005. Tangled webs: reciprocal flows of invertebrate prey link streams and riparian zones. Freshwater Biology 50:201-220.

• Gregory, S.V., F. J. Swanson, W. A. McKee, and K. W. Cummins. 1991. An ecosystem perspective of riparian zones. Bioscience 41(8):540-551.

• Iwata, T., S. Nakano, and M. Murakami. 2003. Stream meanders increase insectivorous bird abundance in riparian deciduous forests. Ecography 26:325-337.

• Kawaguchi, Y. and S. Nakano. 2001. Contribution of terrestrial invertebrates to the annual resource budget for salmonids in forst and grassland reaches of a headwater stream. Freshwater Biology 46:303-316.

• Kawaguchi, Y., Y. Taniguchi, and S. Nakano. 2003. Terrestrial invertebrate inputs determine the local abundance of stream fishes in a forested stream. Ecology 84(3):701-708.

• Laeser, S. R., C. V. Baxter, and K. D. Fausch. 2005. Riparian vegetation loss, stream channelization, and web-weaving spiders in northern Japan.  Ecological Research 20:646-651.

• Nakano, S., and M. Muraami. 2001. Reciprocal subsidies: dynamic interdependence between terrestrial and aquatic food webs. Proceedings of the National Academy of Sciences 98(1):166-170.