Start Date
2-11-2019 11:20 AM
End Date
2-11-2019 11:30 AM
Abstract
A major responsibility of Multnomah County Drainage District #1 (MCDD) is to manage drainage and maintain water conveyance within 45 miles of ditches, sloughs, and streams in the Portland Area. In 2014 MCDD staff observed an increasing abundance of noxious weeds, which resulted in additional resources allocated to the removal of plant material. The increasing abundance of noxious weeds conflicts with MCDD’s responsibility of maintaining conveyance. With assistance from Mosaic Ecology LLC, annual exploratory surveys were initiated in 2016 within the Middle and Upper Columbia Slough sub-watersheds to assess the current distribution of noxious weeds and provide recommendations for management. In 2018, 14 of the 41 target weeds were found to be present within the survey area. Of the five primary targets, Myriophyllum spicatum was the most abundant species within both sub-watersheds. Myriophyllum aquaticum was not present in the Upper Slough, but is highly abundant within the Middle Slough, west of I-205. Manual control of M. aquaticum in 2016 and 2017 successfully removed isolated populations from the mainstem, east of I-205. Short-term control recommendations include containment of existing aquatic noxious weeds while applying Early Detection and Rapid Response (EDRR) strategies to new populations. The primary long-term control recommendation is to increase canopy cover and enhance riparian buffers along the mainstem and side channels of the Columbia Slough to reduce sunlight to macrophytes. Emphasis would be placed on establishing woody species on the southern banks of waterways. Developing long-term partnerships with local government, business, and non-profit stakeholders will be critical to the success of long-term goals.
Subjects
Habitat restoration, Land/watershed management, Plant ecology
Persistent Identifier
https://archives.pdx.edu/ds/psu/33798
Rights
© Copyright the author(s)
IN COPYRIGHT:
http://rightsstatements.org/vocab/InC/1.0/
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
DISCLAIMER:
The purpose of this statement is to help the public understand how this Item may be used. When there is a (non-standard) License or contract that governs re-use of the associated Item, this statement only summarizes the effects of some of its terms. It is not a License, and should not be used to license your Work. To license your own Work, use a License offered at https://creativecommons.org/
Exploratory noxious weed survey of the Middle and Upper Columbia Slough Watersheds
A major responsibility of Multnomah County Drainage District #1 (MCDD) is to manage drainage and maintain water conveyance within 45 miles of ditches, sloughs, and streams in the Portland Area. In 2014 MCDD staff observed an increasing abundance of noxious weeds, which resulted in additional resources allocated to the removal of plant material. The increasing abundance of noxious weeds conflicts with MCDD’s responsibility of maintaining conveyance. With assistance from Mosaic Ecology LLC, annual exploratory surveys were initiated in 2016 within the Middle and Upper Columbia Slough sub-watersheds to assess the current distribution of noxious weeds and provide recommendations for management. In 2018, 14 of the 41 target weeds were found to be present within the survey area. Of the five primary targets, Myriophyllum spicatum was the most abundant species within both sub-watersheds. Myriophyllum aquaticum was not present in the Upper Slough, but is highly abundant within the Middle Slough, west of I-205. Manual control of M. aquaticum in 2016 and 2017 successfully removed isolated populations from the mainstem, east of I-205. Short-term control recommendations include containment of existing aquatic noxious weeds while applying Early Detection and Rapid Response (EDRR) strategies to new populations. The primary long-term control recommendation is to increase canopy cover and enhance riparian buffers along the mainstem and side channels of the Columbia Slough to reduce sunlight to macrophytes. Emphasis would be placed on establishing woody species on the southern banks of waterways. Developing long-term partnerships with local government, business, and non-profit stakeholders will be critical to the success of long-term goals.