Thursday, February 12, 2009

Tangled banks

Charles Darwin began the final paragraph of On the Origin of Species by Means of Natural Selection with this vivid imagery:
It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us.
The bank of vegetation along our shore - in what an ecologist would call the riparian zone - is a tangle of fern, sumac, grape, dogwood, gentian and a dozen sedges and grasses. Rooted in muck in the parallel littoral zone is a similarly rich tangle of pondweeds, water lilies, milfoils, bladderwort and eelgrass.

There's a lot to say about the riparian and littoral zones of Stony Lake: their vital functions, their diversity, their degradation and their preservation. One could focus on a single wetland species and consider aspects of its form, distribution, life history and origin in an intellectually robust manner made possible by Darwin. All of these are complex and important subjects which merit thorough exploration.

But for today it's enough just to momentarily reflect on the stretch of shoreline we've come to know well with a modest appreciation of some forms most beautiful and most wonderful.

A number of most beautiful forms flourish within these tangles. Song Sparrows and Northern Yellowthroats nest discretely in the thickets. Eastern Phoebes stuff their chicks with freshly emerged damselflies gleaned from the stems of the rushes. Just below the water line, thick mats of vegetation provide spawning substrate and nursery habitat for many fishes. By early summer, teeming schools of fry can be seen warming themselves at the surface. Some birds follow the fish.

A little deeper in the bay, down a narrow channel through the cattails, the loons nest. Only hours after the young hatch, the family swims out into the main body of the lake to a sheltered nursery area among some small rocky islands. Other fish eaters - mergansers, kingfishers, bitterns, herons and ospreys - nest elsewhere on the lake but forage along our shoreline. Big fish come to feed on the small fish. With the myriad forms comes a tangle of sounds - splashing, squawking, buzzing, trilling, screeching, drumming, warbling, hooting, chipping, rasping, cooing, peeping and croaking, lots of croaking.

Yet this is more than a sumptuous feast for our eyes and ears. Darwin's great insight - that of our shared ancestry - makes it personal and profound. He shattered the arrogant myth of a separate creation and freed us to find community and communion in all living things. That seems pretty wonderful.

Thanks and happy birthday Charles Darwin.

Some people don't like their banks tangled. Here's a disentangled bank.

Related and recent:

Rick Salutin's Valentine for Mr. Darwin (Globe and Mail - 13-02-09)

Verlyn Klinkenborg's
Grasping the Depth of Time as a First Step in Understanding Evolution (New York Times - 23-08-05)

Blog for Darwin

Darwin Online

A Shoreline Primer from Fisheries and Oceans Canada.


Tony Wildish said...

I'll take the tangled bank anyday! I love the photos, and the way you piece them together in the post. It makes me want to go there and see for myself.

Anonymous said...

What great photos throughout this site! And great story telling too. Lots of birds in common with us in BC. Have you seen the E-Fauna BC site ( It has a bird photo gallery.

T and S said...

I came to your blog from Larry's I and the bird post.

WOW...You have some amazing wildlife life images in your blogs. I enjoyed browsing through your archives...Thomas