Meandering in the meadows

musings about seed dispersal

One fine day in late September—in between other days of slatting rain and wind, Parks and Rec hikers headed up the ridge behind Cropley Lake. It was a good day for that hike. However, I was feeling considerably less ambitious, so I chose another way to spend the lovely day. Oh, I started at Eaglecrest, all right, as did the main group, but I elected to meander about the mid-elevation meadows with a friend.

The first treat was a migrating red-tailed hawk soaring over the ridges, calling to another one half a mile away. This bird had very dark plumage, as is common in western populations, but the red tail was clearly evident.

That was a good start to our little explorations. We soon found another prize: a stand of alpine blueberries, which (maybe along with the other low-bush species) beat the tall-bush species for flavor. We browsed for a while and then figured out the best situations in which to look for more. Sure enough, the good ones were definitely concentrated in certain kinds of places (a secret, of course), so naturally we searched them out and browsed some more. Very satisfactory! We could have harvested a good bucketful, if we hadn’t eaten so many.

As we cruised around, we also encountered several stands of the high-bush blueberries, both the ‘early’ one and the ‘alaskan’ one, with good crops of berries still on the bushes. So all those folks who fussed about a poor berry crop maybe just did not go far enough.

We found the seed heads of leatherleaf saxifrage, with seed still in the capsules. I’m ashamed to say that I’d never looked closely at these before, but we did so now. And that led to a discussion of the various means by which seeds disperse from the parent plants. Here’s a quick synopsis with selected local examples:

Colorful berries are usually sweet (and a few are rich in oils), and both color and content are adaptations to attract vertebrate consumers that eat the fruit and pass the seeds through the digestive tract. The seeds survive gut passage and often germinate in a handy little pile of manure. If a bear is the consumer, the manure pile is quite sizable and competition among the hundreds of germinated seeds is fierce. When an urban human is the consumer, however, the usual dispersal pathway generally fails. I have seen animals eating all of our local kinds of berries except bunchberry (a.k.a. dwarf dogwood), which seems to remain in place until the berries just fall off (unless a mouse has opened the fruit and eaten the seed).

bear-scat-viburnum-David
After a meal of Viburnum. Photo by David Bergeson

We’ve all seen the seeds of fireweed, cottonwood, and willow floating through the air on their fluffy, white ‘parachutes’. Lots of other plants disperse their offspring in similar fashion: goldenrod, aster, dandelions, to name a few. Still other plants put little wings on their seeds: all of our conifers, for example, and maples and alders. Both wings and parachutes are adaptations for wind dispersal.

The seed pods of lupine open explosively on warm, dry days, scattering the seeds. You can hear the pitter-patter of falling seeds if you listen for it. The dwarf mistletoe that parasitizes hemlock trees also disperses its seeds explosively. And the plant known as jewelweed or touch-me-not vigorously pops open its seed pods at the slightest touch.

Some plants make seeds with hooks that latch onto fur (or socks) and get carried some distance from the parent plant. Examples include bedstraw, avens, and some grasses. And plants that grow in water sometimes have flotation devices (but how do pond lilies and buckbean seeds get from one muskeg pond to another??).

There are many plants, however, whose seeds have no evident adaptation for dispersal; leatherleaf saxifrage is one such, and shooting stars, wild iris, and chocolate lily fit this category. In some cases, the stem that supports the seed capsule is moderately tall, and seeds may simply get shaken out at a short distance from the parent. In other cases, the entire plant may be eaten by a large animal and the seeds passed through the digestive tract. A few plants, such as the swamp gentian, put their seeds in splash-cups to await a raindrop that will wash them out. But in many cases, we are just left to wonder how the seeds get to new sites for establishment.

I have not mentioned a means of seed dispersal that occurs in other North American forests, namely dispersal by ants. The seeds of these plants have an oil body at one end of the seed; the ants collect and eat the oil body, and then dump the seed in their midden. Very neat! But, alas, I don’t know of any ant dispersed plants around here, and there may not be any, given our paucity of ants.

However, for many local species I do not know the most likely means of seed dispersal. Folks often go on walks to survey the variety of wild flowers that bloom earlier in the year, so why not try a walk to survey the variety of seed capsules and likely dispersal mechanisms?

Autumn bits and pieces

alpine colors, tasty berries, and treats for bird-watchers

I’m inclined to think of fall as ‘dud’ season here. The birds are no longer nesting and few are singing; the forest is silent. Although we have our gorgeous, golden cottonwoods and sometimes some bright yellow willows, we don’t have the dramatic and spectacular show of fall foliage that the Midwest and New England enjoy. The days are getting shorter and shorter. And then there usually is the rain…

However, September brings us a number of good things too. Highbush ‘cranberry’ bushes had a bumper crop again this year, and soon the pungent aroma of cranberry ketchup-making will fill my kitchen. Their pink and red leaves brighten the forest understory. Devil’s club leaves make a fine yellow background for the bright red fruits. Brilliant scarlet dwarf dogwood berries dot the ground. In the muskegs, the leaves of shooting stars are bright yellow spears of light on a darker backing.

But the best color is in the alpine zone. The sedges and avens make a golden-brown backdrop for swathes of deer cabbage, whose leaves run the gamut of color from yellow through orange and red to purple. Dwarf dogwood is here, too, its leaves ranging from summer green to autumn crimson. Low-growing blueberry bushes make a purple-leaved carpet topped with a heavy crop of blue berries. Close up or from a distance, this is a color treat.

The blueberry crops on the ridges are rich pickings this year. With ‘berry rakes’, it is possible for two people to gather over twenty-five pounds in an hour, and leave the patch still loaded with berries for later foragers.

There are two species of low-bush blueberries that grow up on the ridges (and in bogs). One has leaves with smooth edges; the other has somewhat darker leaves with very tiny teeth along the edge. The blossom-end of the berry is slightly different: the one on the toothy-leaved species looks like a small bulls-eye. Once you train your eyes, the two species are readily distinguishable. And, at least for some of us, it is worth making the distinction—berries of the toothy-leaved species (Vaccinium caespitosum) taste better (although the difference may dwindle if the berries are cooked).

In late September, the upper meadows still feature a few late flowers: an occasional purple monkshood, sturdy little clumps of the blue gentian, and lavender daisy-like flowers of fleabane. On the way up to Granite Basin, we even found a thriving stand of miners’ lettuce in full flower, well past its usual blooming season.

Despite the paucity of bird song, there are a few treats for bird-watchers. Hawks migrate south along the ridges—Gold Ridge is a great place to see a variety of species, sometimes in considerable numbers. On a recent trip up to Naked Man Lake on Douglas, we spotted a lone female northern harrier coursing over the meadows and a sharp-shinned hawk dashing into a grove of trees. Flocks of pipits and lapland longspurs flit overhead in open habitats. In Granite Basin, we watched a flock of twenty-five or thirty ptarmigan fly up-valley and disappear behind the ridges. And occasionally, a soft, winter song of a dipper can be heard along the streams, or a song sparrow may trill from a shoreline thicket.

Townsends-Solitaire-by-Bob-Armstrong
Townsend’s solitaire. Photo by Bob Armstrong

On the upper slopes of Ben Stewart, we saw a pair of Townsend’s solitaires, presumably on their way south. This long-tailed thrush is a rather rare bird around here; it is more common in the open forests of the Interior. It typically nests on the ground on open slopes, cutbanks, and even cliffs, often tucking the nest under an overhanging rock, log, or tuft of vegetation. Summer foods include all kinds of insects and other invertebrates. But in winter, in montane woodlands down south, it commonly feeds on juniper berries. This food resource is so important that each bird defends a territory around clumps of juniper trees, to help ensure its winter food supply. Other fruits may be eaten, especially if juniper berries are scarce.

 

Even though it signals the onset of dark days, snow shovels, and slippery streets, I rather enjoy watching the termination dust gradually increase on the peaks. At first it’s just a beautiful powdered-sugar dusting on the highest crags. It may disappear for a spell, but the inevitable accumulation is imminent.