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Delta Ponds Revegetation Project

by Charlene Simpson, Island Lakes Condominium resident

Visitors and residents who drive Goodpasture Island Road or walk the trails at Delta Ponds Park see thousands of what look like sticks in the ground surrounded by plastic cages. What’s happening? The plugs are willows and other native riparian trees; the cages protect the green wood from active beaver and nutria. One of the goals of the Delta Ponds restoration project is to replace invasive, non-native vegetation with native vegetation.

Delta Ponds revegetation project
Delta Ponds revegetation project

Eugene Parks and Open Space staff began removing invasive species in the fall of 2004. Vast quantities of blackberry, English ivy, and Scots broom were grubbed out.  Specialists in emergent and aquatic weed control were contracted to remove yellow flag iris, and purple loose strife (Holts, 2010).  All of these “trouble makers” are Oregon Department of Agriculture state listed noxious weeds.  This dubious distinction is bestowed to a plant that is deemed “injurious to public health, agriculture, recreation, wildlife, or any public or private property” (ODA Plant Division, Noxious Weed Program website).

Blackberry removal  C. Simpson
Blackberry removal C. Simpson

One of the most tenacious plant invaders is Himalayan blackberry.  Grubbing out non-native blackberries that have grown to impenetrable thickets is a tough, backbreaking job.  Main plants have large, deep, woody root balls that sprout at the nodes.  Control of re-sprouts and new seedlings is an ongoing process that can take years.  Natural Areas Restoration Supervisor Trevor Taylor (2012) informs us that in recent years herbicides have been added to the toolbox as manual efforts alone were not adequate.

Revegetation followed several rounds of invasive species removal.  75,000 genetically local trees, shrubs, sedges and rushes were planted between 2006 and 2011 (Holts, 2011).  Species were selected for their adaptability to specific habitats found at the site:

1) wetland transition, 2) riparian, and 3) upland.  Planting was timed for maximum germination and survival.  Some supplemental irrigation was required during summer months.

City’s Alton Baker Native Plant Nursery
Alton Baker Native Plant Nursery (courtesy of City Parks & Open Space Division)

Herbaceous species were introduced for ground cover from seed collected locally and grown out in the City’s Alton Baker Native Plant Nursery (Delta Ponds, 2004) and from seed purchased from a private contractor who grows seed from genetically local sources (Taylor, 2012).

A wide diversity of plants and wildlife will benefit from this project.  Specially targeted species include juvenile Chinook salmon, Western pond turtles, neotropical song birds, and native riparian plant communities.  A benefit to Goodpasture Island residents and visitors will be enhanced recreational and educational opportunities.

References:

Delta Ponds Restoration and Recreation Project. September, 2004.  City of Eugene Parks and Open Space Division.

Holts, Lauri. Spring 2010. “Federal Stimulus Dollars and New Bridge Connection Improve Delta Ponds Natural Area.”  Eugene Outdoors.  City of Eugene Parks and Open Space Division.

Holts, Lauri. September 2011. Delta Ponds Floodplain Restoration Project Summary. City of Eugene Parks and Open Space Division.

Integrated Resource Management website: 

Oregon Department of Agriculture, Plant Division, Noxious Weed Program website:

Taylor, Trevor.March 28, 2012.  Personal communication.

Wold, Eric. Spring 2010.  “Seeking External Grant Funding for Eugene’s Parks and Natural Areas.”  Eugene Outdoors. City of Eugene Parks and Open Space Division.