COLUMN| Webs of life are ever-changing in local parks

Migrant warblers are moving through Juanita Bay Park. Black-headed grosbeaks, Bullock’s oriole, Common yellowthroats,

Migrant warblers are moving through Juanita Bay Park. Black-headed grosbeaks, Bullock’s oriole, Common yellowthroats, and yellow warblers are setting up housekeeping. The serviceberry bloomed and faded in a week, but yellow iris and yellow buttercups are adding color to the myriad of leafing out greens.

In Watershed Park, local Boy Scouts have built “turnpikes” (permeable walkways of gravel over stone within a wood frame) over several muddy low spots on the big loop trail. Pacific Madrone, bigleaf maple, mountain ash, bitter cherry, trailing blackberry, fringecup, and large-leaved avens are blooming along the trails.

Webs of life

The Seattle Times recently (May 18) highlighted a regional example of interconnection, reporting on an ongoing study by a scientist with Skagit River System Cooperative. His study shows that beaver in a specific scrub-shrub wetland niche of the estuary are major facilitators of salmon fry survival. The beaver’s primary building material in this habitat is sweetgale or Pacific bayberry (scientific name Myrica gale). Beaver dams in these ecosystems create excellent rearing habitat for Chinook salmon. The ponds’ detritus load supports large numbers of invertebrates that young fish of several species feed on.

The depth of the ponds, engineered by the beavers to allow them to swim even at low tide, thwarts the great blue herons who feed, in part, on young fish. The density of the sweetgale shrub habitat also deprives herons of landing spaces for shore feeding. Sweetgale’s habitat relies on floated, downed nurse logs from the uplands to create their required high tide habitat with the correct water regime (balance of wet and dry). This is a wonderful regional example of how nature enmeshes life in mutually interacting networks. I expect further study to establish additional interactions and mutual services within this ecological niche.

As I read the article, I visualize the beaver pond in Juanita Bay. It is mostly surrounded by reed canary grass (Phalaris arundinacea), a non-native hybrid grass classified as an invasive weed in Washington. Its tendency to form a monoculture and crowd out native vegetation is easily observable here. Our pond has very few willows and red-twigged dogwood to shade it, and is fished regularly by herons, some fish eating ducks, and our otters. The park restoration plan calls for experimental plots to determine how to successfully remove reed canary grass from this park. Successful removal of this particular invasive plant, it turns out, is very site specific. More interconnections to be discovered!

Green Calendar

Sit, Sip & Stroll: From 11 a.m. to noon, Thursdays. Discussion followed by a guided stroll along Mercer Slough’s trails. Free, no pre-registration. Meet in the Douglas Fir Community Room of the visitors’ center, 1625 118th Ave SE. Visit

Eastside Audubon general membership meeting: Begins at 7 p.m. May 28. Program: Martyn Steward: Recording Bird Songs and how Birds Produce Song.

Northlake Unitarian Universalist Church, 308 Fourth Ave. South (at State Street), Kirkland.

Seattle Tilth Edible Plant Sale: Runs from 9 a.m. to 2 p.m. May 30 at Issaquah’s Pickering Barn. Note: the Issaquah Saturday Farmer’s Market runs concurrently at this location. Additional parking: pass barn, and take first left, then left again into parking lot.

Saturday May 30, 2009, 9-a2.. Friends of Kiwanis Park workparty. Bring water bottle and tools such as clippers, shovels, gloves. Wear closed-toe shoes. Adults, teens, families. Youth under age 14 must be accompanied by an adult for the duration of the event. Youths ages 14-17 need a signed waiver form or a parent/guardian present at sign-in.

SEELC class: The class on fish stocks and fish harvesting runs from 7-8:30 p.m. June 2 at Bastyr University. Adults. Free, pre-registration required. Visit

SEELC class: Class on geology and soils for children 8 years and older runs from 4-6 p.m. June 2 at St. Edwards Park. Free, pre-registration required. Visit

Janice Johnson is a Juanita resident, a volunteer ranger at Juanita Bay Park, and also active in other environmental and musical groups.