Nature Watch: Life in the Slow Lane

About the author: Steve Ellis is a naturalist and Land Trust member who enjoys sharing his love of the natural world. His blog series, “Nature Watch,” will appear each month in “Habitchat,” chronicling native plants and wildlife you can expect to see during that particular time of year. We thank Steve for sharing his passion, illustrating the importance of island conservation.

Overview

The pace of life in March quickens as nature shakes off the winter doldrums. This is true for all local habitats except one.

I think of the forest floor as the slow lane on nature’s highway. Plants growing in this protected zone proceed at a leisurely pace, blooming later and for longer periods of time compared to their counterpoints in other, more open habitats. While salmonberry and red-flowering currant race to bloom in March, salal and evergreen huckleberry can afford to wait.

Animal life follows the same patient pattern as the plants. Birds in the treetops flit quickly from branch to branch and from twig to twig while sparrows, wrens and other ground-dwellers pick their way slowly among the sword fern fronds and salal stems. They only fly quickly when confronted by an opening such as a forest trail, not wanting to be exposed to predation.

Mammal life beneath the trees also behaves in a more sedentary way. Douglas squirrels and Townsend’s chipmunks race up and down the tree trunks but slow to a crawl in the lowest tangles. Voles and deer mice only scamper quickly when exposed in an opening in the “jungle.” The woody stems of salal are to the deer mouse what the challenge of a dense willow or alder grove is to humans.

Vagrant shrews move endlessly but not at a breathtaking speed. I’ve gotten down on all fours to follow one that was tracking down invertebrates. Even with my human clumsiness, I’m able to keep up with a shrew. Incidentally, crawling close to the forest floor gives you the perspective of a shrew or vole.

Most of the invertebrates living on the forest’s ground floor navigate slowly through life. These include pill bugs, beetles, millipedes, slugs and snails. Their movements are slow, which means their predators don’t have to race at top speed. Most spiders and other invertebrates wait for their victims to come to them. Ensatinas (small terrestrial salamanders) and northwestern salamanders leisurely patrol this habitat, looking for prey.

The slowness of the salamanders and other such predators found in the forest contrasts sharply with those found in the open. Coyotes employ quick pounces, and nothing rivals the speed of a diving Peregrine Falcon that is intent on capturing a shorebird.

Trees and their understory of shrubs and ferns shelter the forest floor from most stormy weather. This stable environment allows the local fauna to creep, crawl and inch their way through life.

Should you go into the woods, leave your running shoes at home and prepare to amble in the slow lane.

Narrow-collared snail-eating beetle by Martha Ellis.

Fauna: Narrow-collared snail-eating beetle (Scaphinotus angusticollis)

A remarkable predator haunts the dark forest floor. Snail-eating beetles prowl through the leaf litter, stalking their slow-moving prey.

Narrow-collared snail-eating beetles are nearly an inch in length. Their elliptically-shaped carapace – the hardened protective cover on the back – is black or deep maroon. They have very long legs and an extended, narrow head.

Prey for these beetles includes slugs, spiders, invertebrate eggs and, of course, snails. Their elongated heads allow them to access the meat of a snail despite its shell. The head shape also precludes sticky snail mucus from fouling their bodies. Long legs allow the beetles to clamber around and over vegetation and debris as they hunt.

Snail-eating beetles are eaten by American Robins, Swainson’s Thrushes, Spotted Towhees and other birds that poke around the leaf litter.  Ensatinas and northwestern salamanders also prey on them.

Finding a snail-eating beetle can be a bit of a challenge, as they prefer to be active at night. During the daylight hours they tend to hide under fallen wood. While I have seen them occasionally during the day, your best chance for a sighting is at night. Wet mixed or deciduous forests are the beetles’ preferred habitat. They have a sweet tooth and sometimes will come to fallen fruit.

Narrow-collared beetles are unable to fly and as a consequence are vulnerable to habitat fragmentation. It is fortunate that some Land Trust preserves along with our State Parks provide refuges for them. The beetles play an integral role in the slow lane.

Twinflower by Martha Ellis.

Flora: Twinflower  (Linnea borealis)

The delicate twinflower may be the only forest floor shrub that is in a hurry.

Twinflower is a low evergreen shrub that grows from above-ground runners called stolons. Thin Y-shaped stems rise to support pinkish or whitish trumpet-shaped flowers. A fragrant aroma reminiscent of honey exudes from the two flowers located on the arms of each Y.

At least two twinflower shrubs are required for cross-pollination purposes. The blooming period is short, 7 to 10 days, unlike the blossoms of salal and other shrubs that last for weeks.

Several species of hoverflies and small bees are attracted to the flowers and thus perform pollination. I’ve seen bumblebees weighing down the thin stems as they attempt to access the nectar.

Dry nutlets succeed the pollinated flowers. These nutlets cling to the fur and feathers of passing mammals and birds, which inadvertently help to spread the plants. Most twinflower growth is from the stolons, which extend up to one foot a year under the right conditions. When a stolon touches bare earth, it sends roots into the soil, helping to anchor the shrub in place.

Deer, rabbits, snails and slugs eat the stems and leaves of twinflower.

Blooming begins by late April. Look for the nodding trumpets and shiny leaves of twinflower in mossy forests. Any forest without a closed canopy can shelter twinflower, though it does best in deciduous woods.

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