Abstract:

Noxious weeds threaten fish and wildlife habitat by contributing to increased sedimentation rates, diminishing riparian structure and function, and reducing forage quality and quantity.  Wallowa Resources’ Wallowa Canyonlands Partnership (WCP) protects the unique ecological and economic values of Hells Canyon grasslands along lower Joseph Creek, lower Grande Ronde River and Imnaha River from invasion and degradation by noxious weeds using Integrated Weed Management methods.  Objectives are to:

-Inventory and map high priority weeds,
-coordinate treatment of those weeds,
-release and monitor bio-control agents,
-educate the public as to the dangers of noxious weeds and how to deal with them,
-and restore lands to produtive plant communities after treatment.  

WCP will coordinate high priority weed treatment and restoration with all landowners and agencies throughout the program area. WCP will use other sources of funding to finance treatment activities.  

Contextual Overview:

The WCP area consists of rugged canyons and benches (attached figure 1).  These steep, semi-arid native grasslands are dynamic systems in constant flux: they are naturally subject to heavy localized rainfall, fire, flood, and constant erosion.  Their young and unstable soils (especially on southern aspects) support bunchgrass climax communities that have natural interspaces between plants.  Early settlers were attracted to the availability of bunchgrass communities for livestock forage, farmable bench lands, and forested north aspects for timber supply.  A century of intensive use left some places in poor condition and especially vulnerable to weed invasion.

Steep river banks and shallow soils make canyonland soils particularly vulnerable to erosion, and this is a major concern in the project watersheds. Noxious weeds further degrade water quality by contributing to increased sedimentation rates.  Lacey et al. (1989) found rangelands invaded by spotted knapweed had twice the soil erosion than areas uninfested.  Soil productivity is very much affected in this area even by modest erosion, as we have very shallow soils.  The rapid growth of invasive plants allows them to out-compete native vegetation (attached figure 4), resulting in the loss of functional riparian communities, loss of rooting strength and protection against erosion, decreased slope stability and increased sediment introduction into streams, as well as impacts on water quality (Donaldson, 1997).  Endangered species such as bull trout, steelhead, salmon, Spalding’s catchfly and MacFarlane's four-o'clock found in the project area are all threatened by the presence of invading weeds.  Without action to locate and rapidly treat noxious weeds, much critical habitat will be degraded.  

Seed dispersal via waterways is also a key issue facing watersheds within the proposed project.  Noxious weed managers in Northeast Oregon, Southeast Washington, and Eastern Idaho have long recognized the high potential for noxious weed invasion in the local canyonlands.  Surrounding areas such as the Whitebird area of the Salmon River and Payette County are currently battling serious yellow star thistle and rush skeletonweed infestations.  While we have been fortunate thus far to have relatively small infestations, our proximity to the aforementioned places makes us vulnerable to weed invasion.  Rivers are excellent dispersers of noxious weeds.  If we do not actively inventory and treat noxious weeds in these canyonlands, the results could be disastrous to the entire watershed.  Based on past inventory data, several sites within the project area are highest priorities, and will be the initial focus of the expenditures.  The Imnaha drainage downstream of the town of Imnaha, the lowermost portions of Joseph Creek Canyon, and Hells Canyon between Kirkwood and the confluence with the Grande Ronde are all focus areas.  Additionally, headwaters will be given restoration prioritization given that they have the greatest potential for long-distance noxious weed dispersal.  

Problems to Be Addressed:  

1) Noxious weeds go undiscovered and prosper in remote and rugged terrain.  Few people visit these regions (even fewer with weed expertise) for work or recreation, thereby allowing weed infestations to grow unnoticed.  Ground based weed inventories in the rugged terrain of the project area are time consuming and expensive and often require crossing multiple properties.

2) Noxious weed sites do not get treated consistently over time and have historically gotten away from managers.  Weed sites get lost when the people responsible for managing a weed site change, or when a community’s commitment level to weed control changes over time.  Field data gathering parameters have been varied and not specific if they were taken at all making long term monitoring impossible.

3) Weed Management efforts tend to vary at jurisdictional boundaries resulting in inconsistent and/or ineffective control.  Jurisdictional boundaries do not reflect watershed or community interrelations.  Property boundaries and jurisdictions (i.e. Oregon and Washington) have hampered past weed control efforts.  Levels of education, commitment and funding vary from place to place and community to community and landowner to landowner.  

4) Biological Control agents are used to manage large scale noxious weed infestations.  However, managers do not understand why biological control of weeds is spotty with some agents and species.  Other species do not have biocontrol agents yet.  Managers need more monitoring of biological control agents to assess an agent’s success or usefulness on a site specific basis.  Researches need more information about specific weed populations to guide research and test the efficacy of prospective new agents.  

5) Lack of public awareness and education.  Increasingly, there is a broad public interest in controlling invasive plants.  However, many people are still not aware of the problem and/or they cannot identify noxious weeds and further they need help knowing how to effectively to deal with them.  This is especially true with the increasing turnover in land ownership.

6) Some weed sites are in a degraded condition and require intensive restoration efforts to convert them to productive weed resistant perennial plant communities.  Disturbance, both anthropogenic and natural (i.e. like farming or major flooding) in the presence of noxious weed species creates an opportunity for weeds to dominate a site.  These sites need intensive restoration efforts to relieve them from weeds and foster desirable/ productive vegetation.

Project Location:  Project will focus on the Grande Ronde River, Lower Joseph Creek, and Lower Imnaha River.

Other Related Plans/Efforts:

This Project is in accordance with the following plans:

-The Grande Ronde Subbasin Plan (December 2004) identifies noxious weeds as contributors to increased sedimentation.  As a strategy for channel improvement they suggest, “Implement(ing) an integrated noxious weed management program including survey, prevention practices, education, treatment and revegetation.”

-The Imnaha Subbasin Plan (May 2004), which represents Northwest Power and Conservation Council priorities for aquatic and terrestrial species and habitats has as one of its two top priorities for terrestrial sites “reduce risk of noxious weed invasion in grassland habitat”.  

-The Wallowa County-Nez Perce Tribe Salmon Habitat Recovery Plan (August 1993) states as a priority goal to “Identify, map, and monitor noxious weeds on an ongoing basis.  Use whatever combination of herbicides, biological, and mechanical controls as necessary to control or eradicate weeds.”

-The Oregon Plan for Salmon and Watersheds (March 1997) emphasizes controlling noxious weeds that threaten range condition.  The environmental indicators for the Oregon Plan for Salmon and Watersheds use the percent of invasive species as an environmental indicator of basin condition.    

-The Wallowa County Integrated Weed Management Plan (June 2006) is focused on the context and details of weed management in this area and guides weed management for the purpose of maintaining watershed functions.

-The Grande Ronde Model Watershed Action and Operations Plan specifically list noxious weeds as a “potential water quality problem.”