UI001
Analysis of riparian vegetation loss in Hillsboro, Oregon City and Portland, Oregon from 1990-2008

CREATOR(S): Vivek Shandas

PRINCIPAL INVESTIGATOR(S): Vivek Shandas

ORIGINATOR(S): Vivek Shandas

DATA SET CONTACT PERSON: Ted Hart

MOST RECENT METADATA REVIEW DATE:

16 Feb 2013

KEYWORDS:

aerial imagery, change detection, riparian ecosystems, trees, vegetation

PURPOSE:

Investigate the performance of local development policies that protect riparian vegetation in three cities in the Portland, OR metropolitan area. Analyze the extent of vegetation loss along stream corridors between the years 1990 – 2008, to determine whether management strategies correlate with different on-the-ground losses of riparian vegetation and clarify the dynamics of riparian vegetation loss on the ground and with respect to management issues to better equip urban resource managers and policy makers in all urbanizing areas to craft effective policies for the future. The project focuses on three main questions: 1) What has been the extent of vegetation loss along stream corridors during the recent wave of development?; 2) Have different local management approaches resulted in varied rates or patterns of loss?; and 3) What are the major, particularly anthropogenic, causes of vegetation loss?.

METHODS:

Experimental Design - UI001:

Description: Vegetation patch edge determination followed methods from Schuft et al. (1999), and was based on a separation distance of at least 5 m (approximating the crown width of a mature woody tree/large shrub). A consistent viewing scale of 1:1500 was maintained while digitizing. The 1990 photographs were gray scale at 0.30 m resolution; the 1997 photographs were color at 1.22 m resolution; the 2002 photographs were color at 0.30 m resolution. The 1997 photographs (x and y coordinates), previously orthorectified by Metro, and USGS digital elevation maps (z coordinates) were used as a basis to orthorectify the 1990 and 2002 photos using ERDAS Imagine software. For each photo, at least 12 ground control points were used and the total root mean square error was maintained below 1.0.

Citation: Schuft, M. J., Moser, T. J., Wigington, P. J., Stevens, D. L., McAllister, L. S., Chapman, S. S. & Ernst, T. L. (1999) Development of landscape metrics for characterizing riparian-stream networks, Photogrammetric Engineering & Remote Sensing, 65, pp. 1157 – 1167.

Quality Assurance - UI001:

Description: Quality assurance steps included: (a) cross-correlation of alignment of streamline locations provided by Metro with USGS quadrangle maps and Metro contour maps; (b) snapping streamlines to city lines when streams formed jurisdictional boundaries; (c) truncating shadows from photos where determination was possible; (d) field checks and corrections made accordingly for several dozen features that were ambiguous at viewing scale; and (e) cross-checking digitizing interpretations for a randomized 10% of the total stream length, between two observers, with a resulting error 53%. In addition, 1997 and 2002 changes were interpreted while referring directly to 1990 digitized vegetation polygons to minimize interpretation error among years. Further information on image analysis, GIS and QA/QC methods were provided in Yeakley et al. (2006).

Citation: Yeakley, J.A., Ozawa, C.P., and Hook, A.M. 2006. Changes in Vegetated Riparian Buffers in Response to Development in Three Oregon Cities, pp 296-302 In: Aguirre-Bravo, C., Pellicane, Patrick J., Burns, Denver P., and Draggan, Sidney, Eds. 2006. Monitoring Science and Technology Symposium: Unifying Knowledge for Sustainability in the Western Hemisphere. 2004 September 20-24; Denver, CO. Proceedings RMRS-P-42CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 990 p.

SITE DESCRIPTION:

Riparian vegetation has been analyzed along all permanent stream corridors, utilizing buffers that range from 7.5-200 meters on both sides of the stream for the cities of Hillsboro (Washington County), Oregon City (Clackamas County) and Portland (Multnomah County). In 2002, streamside lengths of Hillsboro, Oregon City and Portland were approximately 65 km, 32 km and 454 km, respectively. The City of Hillsboro stretches over 57 km, Oregon City includes more than 21 km, and the City of Portland covers more than 347 km.

TAXONOMIC SYSTEM:

None

GEOGRAPHIC EXTENT:

Research sites include the three cities of Hillsboro, Oregon City and Portland, Oregon.

MEASUREMENT FREQUENCY:

Irregular, on average every 5-6 years

PROGRESS DESCRIPTION:

Complete

UPDATE FREQUENCY DESCRIPTION:

asNeeded

CURRENTNESS REFERENCE:

Observed

RELATED MATERIAL:

Metro (2002) Regional Land Information System (RLIS) data. Available at http://www.metro-region.org Ozawa, C.P. and Yeakley, J.A. 2007. Performance of Management Strategies in the Protection of Riparian Vegetation in Three Oregon Cities. Journal of Environmental Planning and Management 50: 803-822. Schuft, M. J., Moser, T. J., Wigington, P. J., Stevens, D. L., McAllister, L. S., Chapman, S. S. & Ernst, T. L. (1999) Development of landscape metrics for characterizing riparian-stream networks, Photogrammetric Engineering & Remote Sensing, 65, pp. 1157 – 1167. Yeakley, J.A., Ozawa, C.P., and Hook, A.M. 2006. Changes in Vegetated Riparian Buffers in Response to Development in Three Oregon Cities, pp 296-302 In: Aguirre-Bravo, C., Pellicane, Patrick J., Burns, Denver P., and Draggan, Sidney, Eds. 2006. Monitoring Science and Technology Symposium: Unifying Knowledge for Sustainability in the Western Hemisphere. 2004 September 20-24; Denver, CO. Proceedings RMRS-P-42CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 990 p.