union bay natural area restoration strategy

The Union Bay Natural Area

Group 7 Final Report

ESRM 473 Restoration in North America

Introduction

The Union Bay Natural Area (UBNA) is a 73.5-acre public wildlife area and natural restoration

laboratory composed of grasslands, modest ponds, and lake shoreline that is a sanctuary for over

200 species of birds including crested cormorants, great blue herons, and eagles. Considered

Lake Washington’s second largest ‘natural’ ecosystem and one of Seattle’s largest public green

spaces (Howell et al. 2009), UBNA It is located at the east end of the University of

Washington’s campus, south of NE 45th Street and west of Laurelhurst. Currently, UBNA is

managed by the University of Washington Botanic Gardens.

History of Union Bay Natural Area

In 1916, the United States Army Corps of Engineers lowered Lake Washington to match the

water levels of Lake Union and the Puget Sound for navigation and commerce, creating a marshy

area. This marshy area was used by the City of Seattle from 1925 to 1966 as landfill (Howell et

al. 2009). When the City closed the landfill in 1966, it was capped with a thin layer of soil and

clay from a nearby construction site. In 1971, the University of Washington gained ownership of

the marsh and designated it as a Natural Area.

Description of Site

Our site was lumpy with two muddy and wet areas, was relatively bare and open, and surrounded

by grasses, patches of blackberries, and a treeline in the distance. The only vegetation was small

blackberry plants that had survived tilling and herbicide. There was little plant diversity or

vegetation that remained after we planted our own species. The soil itself appears to have a high

clay content, with poor drainage leaving pools of water on the surface of the plot in low spots. In

the winter in the PNW, the climate is wet and mild (Mediterranean climate) so there are many

overcast days that contributed to the wet soil.

Human Impacts and Disturbances

Restoration Objectives

Overall goal: Remove invasive species and reintroduce natives in order to restore the prairie area

south of Shoveler’s Pond.

● Objective 1: Removal of invasive species for the prevention of reestablishment

● Objective 2: Plot preparation for the reintroduction of native plants

● Objective 3: Plant native grassland species that will reestablish the prairie ecosystem and

suppress potential invasive species

Treatments Performed

Our team first created a plan to plant the plugs of grasses that we were given. We decided to

plant one Festuca idahoensis individual on the top of each mound, as they are adapted to

exposed, dry sites. We also placed the Festuca in some of the flat, stable areas of our site away

from the water. Because we had quite a few Deschampsia cespitosa individuals, we decided to

evenly distribute them around our plot (5 per mound, and dispersed along the rest of the site). As

those who did not survive would not be detrimental losses and we did not want to crowd the

better regions of our site. We also hoped that some would survive in the moist area, because we

were not going to risk our other species in the unfavorable conditions. The Danthonia californica

species were much smaller and more delicate than expected and came in around 7 individuals per

pot. We placed them on the slopes of the mounds because they prefer dry soils, and along the top

right corner of our site. The Elymus glaucus species were placed along the base of the mounds

and near the edge of the moist soil, as they are able to tolerate wet areas and enjoy stream edge

areas.

Next, our team decided where to plant the seeds. After stratifying in near-boiling water the night

before, the Lupinus Latifolius seeds were ready to be planted. These seeds are fairly viable, and

there were 100 seeds per packet (200 seeds total). Because lupines can tolerate a range of soils

and because we had an abundance of seeds, we planted each seed somewhat evenly around the

site except for the more moist area out of concern that they would not sprout submerged in water.

Our team shared a packet of Carex pachystachya with another group, and we received 0.25 oz,

which was still plenty of small yellow seeds. These are also good wetland colonizers, so we

planted these seeds about the entire site but more heavily around the moist area. We attempted

two planting techniques: placing into slightly depressed soil and covering lightly (on the mounds

and dryer soils), and wind scattering with the leftover seeds over moist areas. The Camassia

quamash seeds were small and black, and prefer sites that are moist and dry out over spring so

we used a similar method as the Carex species (except no wind scattering). Evenly distributed

except more heavily seeded near the moist areas.

Final Installation

The list of species of plants that our team had decided to use on our restoration site went through

several stages of revision. The plant selection included a diversity of grasses and small flowering

plants, suitable for moist grasslands. Because our site was somewhat waterlogged and close to a

permanent water source, our team decided to lean towards water tolerant species than drier

grassland species. Initially, our team decided to use: Danthonia californica, Lupinus latifolius,

Camassia quamash, Deschampsia cespitosa, Elymus glaucus, Festuca romeri, Carex inops, and

Grindelia integrifolia. However, after realizing that our site would become dryer in the summer,

we decided against Grindelia integrifolia. Also, we were able to obtain Festuca idahoensis

through the class source, instead of the Festuca romeri. Carex pachystachya was used in the

place of Carex inops. We had to reduce the number of Danthonia californica and Elymus

glaucus because the other groups had also ordered these plants, but we received an unexpected

windfall of Deschampsia Cespitosa from the class source.

Challenges and Limitations

As previously mentioned in this paper, Union Bay Natural Area was not always the open space it

is today. The site was a landfill in commission until the late sixties and subsequently capped with

clay to contain the garbage. This soil is so clay heavy that water drains very poorly and pools in

low spots throughout the site. Much of this winter has been extremely wet, and the weekend we

put our plants in the ground was no exception. This became a major driver in the way we

organized our planting actually because the middle of our plot had a few inches of standing mud

puddles. The soil was so inundated with water that it was hard to justify planting much there,

because although we picked plants that were somewhat water tolerant they would not likely

survive in a puddle of mud. The condition of our site affected almost all of our work, as

removing work and building the mounds was all made more difficult by the large pit of muck in

the middle of our plot. Also, on the topic of the limitations we would be remised not to mention

the budget constraints of this project and the availability of plants. We had to change some of the

species we had originally selected to better fit into the overall plant order we were making as a

class. Essentially the challenge we faced was to plant a palette of plants tolerant of drought in the

summertime yet tolerant of very wet soils in the wintertime. Also it was important for us to

properly prep the site and remove all the roots present so our plants had the best chance to thrive.

Project Monitoring

Final Plant Selection

Plant List

Species Number & Cost Source

Camassia quamash

Common Camas

2 packets with 100

seeds in each, $5

Inside Passage

Carex pachystachya

Thick-Head Sedge

1 ¼ pot, $14

Inside Passage

Danthonia californica

California danthonia

2 half-gallon pots, $4 UW SER

Deschampsia cespitosa

Tufted Hairgrass

6 half-gallon pots and

2 trays, $12

UW SER

Elymus glaucus

Blue Wild Rye

2 half-gallon pots and

8 3.5” pots, $46

UW SER &

Woodbrook

Festuca idahoensis

Idaho fescue

1 tray, $0 UW SER

Lupinus latifolius

Broadleaf Lupine

2 packets with 100

seeds in each, $5

Inside Passage

Plant Adaptations:

Each plant has unique adaptations that make these selections suitable for our site.

● Camassia quamash (Common Camas): Native. One of the two non-grass species on our

plot. Enjoy wet meadows that are damp in the winter and dry in the spring, just as our site

will act. Flowers bloom in the spring, which will encourage pollinators to our site. (UW

Plant Data Sheet)

● Carex pachystachya (Thick-Head Sedge): Native. These plants are excellent wetland

colonizers, and should do well in our open and damp site. Thrives in clay soil, which our

site is based on. Seeds are a good source of food for native bird species. (USDA Plant

Guide)

● Danthonia californica (California Oatgrass): Native. Occurs in Festuca dominated

grasslands, and prefers dryer soils to moist soils. These plants are stress tolerators and

survive well through droughts. (UW Plant Data Sheet)

● Deschampsia cespitosa (Beringian Hairgrass): Native. These plants prefer moist

meadow ecosystems, but are very adaptable to different climates across the northwest.

The seeds act as a food source for birds and are tall enough to provide cover for habitat.

(Burke Biology Herbarium)

● Elymus glacus (Blue Wildrye): Native. Occurs in both moist and dry meadows, and is

drought tolerant. Enjoys floodplain and stream edge habitats and acts as a good stabilizer

of soil. Seeds drop in the fall, another source of food for native animals. (UW Plant Data

Sheet)

● Festuca idahoensis (Idaho Fescue): Native. Grassland and sagebrush meadows are its

preferred habitat. Seeds are very viable and spread well to colonize new areas. Prefers

silty soils and grows well in elevated, exposed areas. (USDA Plant Guide)

● Lupinus latifolius (Broadleaf Lupine): Native. One of the two non-grass species on our

plot. These plants grow best in open forest meadows. Flowers bloom in spring, and

attract pollinators. A variety of soil types are suitable for lupine growth. (Burke Biology

Herbarium)

Before planting, our team considered what sorts of environment our plot provided and where

each species would thrive the best and where each could make the most improvements to our

site. While designing the site, we intentionally created a gradient of slope and moisture levels:

creating three mounds of high, medium, and lower heights; regions of flat and dry soil, and flat

and moist soil; and a slight slope descending from the mounds to the wet regions.