Advisor

Keith Hadley

Date of Award

1-2006

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Geography

Department

Geography

Physical Description

1 online resource (2, x, 136 pages)

Subjects

Roadkill -- Oregon -- Clackamas County, Deer -- Oregon -- Clackamas County, Traffic accidents -- Oregon -- Clackamas County, Wildlife management -- Oregon -- Clackamas County

Abstract

Road-kill of wildlife is common on Portland, Oregon's suburban fringe where development has increased road densities and traffic volume in rural areas. I identify the spatial and temporal patterns of black-tailed deer (Odocoileus hemionus columbianus) deer-vehicle accidents (DVA) at the suburban/rural interface of developing northwest Clackamas County using deer carcass pickup reports for county maintained roads for 1997-2004 and Oregon Department of Transportation deer-vehicle accident reports for 1996-2004. No black-tailed deer DVA models exist in the literature.

DVA increased 121% from 1997 to 1999 followed by a 26% decline by 2004. The initial DVA increase appears related to population growth and development into rural areas, an increase in the average daily vehicle-trip distance, and deer immigration from public lands. The subsequent decline appears related to DVA-induced decreases in deer populations, year-around hunting permits, growing predator populations, and fawning habitat loss.

Temporal OVA patterns for black-tailed deer show a minor peak in June-July and a major peak in October-November. Forty-two percent of DVA occur during the rut/hunt months of September, October, and November. This pattern corresponds to the black-tail's annual cycle and resembles patterns reported for white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus columbianus). Weekly DVA increased from a low on Sunday to a high on Friday and Saturday. DVA showed two daily peaks at 0500-0700 and 1800-2200, corresponding to dawn and dusk when deer activity is highest.

I identified 19 DVA hotspots with 16-27 DVA using CrimeStat III statistical clustering software. Hotspots occurring in rut/hunt months were separate from hotspots occurring in nonrut/nonhunt months. Similar to white-tailed and mule deer, black-tailed DVA hotspots commonly occurred where roads intersect or parallel water features, large forest blocks, and other areas of cover, or separate food sources from cover. Sixty-five percent of DVA occurred outside of hotspots with ≥ 10 DVA.

Deer-vehicle accidents have important ecological and economic costs and are frequent on northwest Clackamas County roads. Additional research supported by multi-agency carcass pickup repo1ting and the acquisition of precise DV A locations using a Global Positioning System (GPS) is needed to better identify wildlife movement corridors.

Description

If you are the rightful copyright holder of this dissertation or thesis and wish to have it removed from the Open Access Collection, please submit a request to pdxscholar@pdx.edu and include clear identification of the work, preferably with URL

Persistent Identifier

https://archives.pdx.edu/ds/psu/28746

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