Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, Annual Report 2005

Abstract

Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, 2004iii AbstractThe restoration of wetland salmon habitat in the 235-km tidal portion of the Columbia River is accelerating and is anticipated to improve habitat quality through hydrological reconnection of existing and restored habitats. Currently, multiple groups are implementing a variety of restoration strategies. However, the region lacks a standardized means of evaluating the effectiveness of individual projects and methods for assessing estuary-wide cumulative effects. This project is establishing a framework for such evaluations. A priority has been to develop a protocol manual for minimum monitoring of physical and biological metrics, intended to standardize data collection critical for analyzing changes following restoration actions. The draft manual included with this report is a practical technical guide for the design and implementation of restoration monitoring from Bonneville Dam to the river mouth. Additionally, the project's literature review and synthesis identified ways that effects can accumulate (e.g., cross-boundary effects, compounding effects) as well as analytical tools (e.g., models, matrices) for assessing them. Restoration project managers on the estuary began using the draft manual in 2005, and their feedback will be incorporated as the manual is finalized for wider distribution. Field studies are being implemented to test the protocols and to evaluate additional potential indicators for detecting a signal in the estuarine system (e.g., organic matter production, sedimentation, food webs, biodiversity, salmon habitat usage, and allometry.) Baseline data were collected in 2005 on two restoration sites and two associated reference sites. The sites represent two habitat types of the estuary -brackish marsh and freshwater swampthat have sustained substantial losses in area and that may play important roles for salmonids. Baseline data collected included vegetation and elevation surveys, above-and below-ground biomass, water depth and temperature, nutrient flux, fish species composition, and channel geometry. This data will be reported and evaluated in the 2005 Annual Report, which will include a new version of the protocol manual revised based on 2005 field work. Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, 2004 iv Evaluating Cumulative Ecosystem Response to Restoration Projects in the Columbia River Estuary, 2004 v PrefaceThis report is a deliverable for the 2004 study. As such, it includes all of our work products for the 2004 study year. Future annual reports will be prepared for the remaining study years 2005 through 2009. In this report we introduce the research problem (Chapter 1), review the literature (Chapter 2), summarize CRE habitat use by juvenile salmon (Chapter 3), describe a conceptual model for the CRE ecosystem (Chapter 4), develop standard monitoring protocols for CRE restoration projects (Chapter 5), and provide recommendati...

A Levels-of-Evidence Approach for Assessing Cumulative Ecosystem Response to Estuary and River Restoration Programs

“…Because such an approach has not been tested in this way, we undertook a multiyear study to apply the levels-of-evidence approach to evaluate the effects of restoration actions on the LCRE (Diefenderfer et al , 2007. The chief merit of a levels-of-evidence approach for this application lies in the construction of an inferential case for the occurrence of cause-and-effect in a complex ecosystem, an argument made robust through its basis in multiple causal criteria.…”

Evaluating Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2008

“…Soon after dike breaching and culvert installation, the muted tidal signals on channels inside the dikes were replaced by tidal dynamics comparable to the reference site (Diefenderfer et al 2006). However, the frequency of inundation and area-time inundation index remained much different on adjacent restoration and reference sites.…”

“…And, most importantly, a levels-of-evidence approach (Downes et al 2002) to evaluate cumulative effects was proposed. During 2005, Diefenderfer et al (2006 developed hypotheses regarding the effects of hydrologicalreconnection restoration methods, refined the selection of measurable metrics, tested restoration effectiveness monitoring protocols, continued to develop a sampling design supporting an estuary-wide 1 Effectiveness monitoring involves activities designed and undertaken to assess how well a particular restoration project performs relative to reference site(s). 2 Validation monitoring involves activities directed at testing cause-and-effect relationships between management activities and monitoring indicators (Busch and Trexler 2003).…”