September 14, 2019 City of Cannon Beach Hearing

Kathleen Sayce, PO Box 91, Nahcotta WA 98637 360-665-5292 [email protected]

Brief background: As an ecologist, I have lived on this coast and studied the ecology of dune fields for several decades, from Manzanita, OR north to Point Grenville, on the southwest side of the Olympic Mountains. The beaches of Clatsop Plains and the Long Beach Peninsula are closest to me and most intensively studied. My career includes: teaching college classes on ecology and stewardship; science officer, ShoreBank Pacific; science program director, the Willapa Alliance; wetland delineations; mitigation design and monitoring; forest ecological assessments; harmful algal bloom monitoring; noxious weed ecology; and restoration design and monitoring.

Testimony, September 14, 2019—Dunes and plant diversity: Dune planting recommendations that include only one species and, too often, a species that is not native, makes it clear that recent tradition is in the lead, and not good ecological restoration practices.

Monocultures can be insidiously pleasing to the eye, think field of wheat, or green lawn, but they hide a lack of faunal habitat among those green leaves. Only the most generalist faunal species thrive in these monocultures.

I recommend that the city of Cannon Beach plant beachgrass, and then seed this area with native grass and wildflower species. Help nature decide what should grow where by bringing in species that should have been in the dunes all along.

In the decades that I have walked dunes, I have seen American dunegrass, Leymus mollis, and a dozen other native species growing among Atlantic beachgrasses on dozens of miles of dunes in Clatsop County. These are never monocultures where nature is allowed to add species back into the landscape.

These plants include: yarrow, pearly everlasting, beach tansy, yellow sand verbena, beach pea, silky beach pea, beach lupine, beach strawberry, beach carrot, sea purslane, big-head sedge, sand dune sedge, beach morning glory, black knotweed, coast bluegrass, dune goldenrod, Douglas aster, edible thistle, and more.

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There’s a theme in these common names, and yes, that theme is beaches. All of these species are adapted to summer dry, winter wet, low nutrient, salty, windy conditions. This is where they thrive.

The two species I do not recommend for public beaches are sand bur, Cardionema ramosissimum, and silver bursage, Ambrosia chamissonis: Both have spiny seed pods that easily find their way into human and canine feet.

I can provide a plant list with scientific names if you desire, and recommend that any or all of them be seeded over the newly planted dune in fall. That’s nature’s time to spread seed in this climate. [See plant list at end of this document].

None of these plants will outcompete Atlantic beachgrasses.

Adding these plants into newly shaped dunes in Cannon Beach will be like adding diverse restaurants and housing to an area that only had coffee shops and heavy industry. The animals that would normally live in the natural dune landscape will find habitats and food that allow them to flourish. The beachgrasses will still be dominant, but the other species will provide more diversity to the native animals in this area.

For more on this subject, I recommend the book Bringing Nature Home, by Prof. Douglas Tallamy. While he works in Delaware, his studies of how native plants support native animals is as pertinent here as it is on the east coast.

Monocultures may be our cultural habit, but nature does not produce monocultures. Turn the clock back and allow natural plant diversity into the dunes in Cannon Beach.

Thank you,

This presentation was truncated in spots to keep within the three minute window.

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North Oregon Coast—Dune Plants List The following native plants are adapted to foredune areas. Those on the windward side are obligates in moving sand. This is a partial list of plants that grow in dunes on the Pacific Northwest coast. Common Name Scientific Name Plant Plant Plant Windward General Leeward Yellow Sand Verbena Abronia latifolia: Nyctaginacea √

Yarrow Achillea millefolium: Asteraceae √

Pearly Everlasting Anaphalis margaritacea: Asteraceae √

Seawatch Angelica lucida: Apiaceae √

Beach Morningglory Calystegia soldanella: Convolvulaceae √

Big-head Sedge Carex macrocephala: Cyperaceae √

Sand Dune Sedge Carex pansa: Cyperaceae √

Edible Thistle Cirsium edule: Asteraceae √

Roemer’s Fescue Festuca roemeri: Poaceae √

Beach Strawberry Fragaria chiloensis: Rosaceae √

Beach Carrot, Beach Glehnia littoralis ssp. leiocarpa: √ Silvertop Apiaceae Sea Purslane Honckenya peploides: Brassicaceae √

Beach Pea Lathyrus japonicus: Fabaceae √

Silky Beach Pea Lathyrus littoralis: Fabaceae √

American Dunegrass Leymus mollis: Poacee √

Beach Lupine Lupinus littoralis: Fabaceae √

Coast Bluegrass Poa macrantha: Poaceae √

Black Knotweed Polygonum paronychia: Polygonaceae √

Dune Goldenrod Solidago simplex ssp. spathulata: √ Asteraceae Douglas Aster Symphyotrichum subspicatum: √ Asteraceae Beach Tansy, Dune Tanacetum bipinnatum: Asteraceae √ Tansy

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Addendum after morning hearing, September 14, 2019: As an ecologist, I was struck by the logic gap presented at the hearing this morning between ongoing use of hyper effective sand-trapping grasses (beachgrass species) and ongoing problems with rapid rises in dune heights in many sections of the Cannon Beach Littoral Cell.

It may be time for different methods to be deployed, to get out of the (1) dune building, (2) dune planting, and then (3) dune removal loop that Cannon Beach is stuck in at this time.

Beachgrasses are apparently too efficient at trapping sand, which inevitably results in the need for regular dune reductions in several units. Why not try something different, and see if this produces different results?

It is clear from many trials that beachgrasses form high sharply ridged dunes. Why not aim for a low, broad, round-topped dune that grows more slowly?

Beachgrasses could be planted in the leeward areas as the sand capture species of last resort, and American dunegrass planted to windward. Under this regime, sand moving onshore and into the dunes would move through the dunegrass band and pile up in the beachgrass band, where intermittent mechanical spreading of sand from the crest in the leeward area would not impact the entire dune system.

Expanding the use of plants that prefer open sand on the windward edge will help reduce the amount of sand moved by wind into the dunes, as these species often help hold sand on ‘open’ beaches, windward of vegetation lines.

A useful test of this would be to plant a few areas with only American dunegrass, to see if this grass produces a lower, broader dune that forms more slowly. If sand encroachment becomes a problem, sand fences and planting of beachgrasses can always be deployed later to recapture that sand.

If you do not test some of the assumptions embedded in the materials presented to the city, you are doomed to continue getting the same results.

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