Community Partner

USDA Forest Service

First Advisor

Catherine E. de Rivera

Date of Award

Spring 2010

Document Type

Project

Degree Name

Master of Environmental Management (MEM)

Department

Environmental Science and Management

Language

English

Subjects

Oregon silverspot butterfly -- Mortality -- Oregon, Oregon silverspot butterfly -- Habitat -- Oregon, Wildlife habitat improvement, Wildlife recovery -- Oregon, Express highways -- Environmental aspects, Endangered species -- Oregon, Conservation biology

DOI

10.15760/mem.23

Abstract

The Oregon Silverspot Butterfly (OSB), Speyeria zerene hippolyta, is federally listed as "threatened." It historically inhabited coastal regions of Washington, Oregon, and California (USFWS 2001). OSB populations only remain at five sites, four of which are in Oregon; one remaining population is in California, and none exist in Washington state as they have been extirpated (BFCI 2009; USFWS 2001). The site selected for this study was Rock Creek-Big Creek, adjacent to the Siuslaw National Forest. At this site OSB habitat is bisected by Highway 101; butterflies are observed to use both sides of the highway throughout their life cycle. It is suspected that vehicles on Highway 101, through collisions and their turbulence, present a substantial threat to OSBs at this site. This suspicion, however, has not yet been quantified and is only minimally evaluated in this paper.

Effective mitigation techniques have rarely been developed and tested for small or flying organisms. Mitigation for one species may not work effectively for others. Moreover, due to expense and scale, it is prohibitive to test multiple mitigation options sequentially. Therefore, we explored whether gathering targeted ecological data would help prioritize mitigation options for a threatened species, the Oregon silverspot butterfly. We studied OSB ecology in order to evaluate the likely success of mitigation options before funding was pursued for implementing or directly testing any of them.

In this research, we considered four potential management options that seemed most likely to be effective based on available information, including barrier installation; earthen berm removal and other actions to reduce the attractiveness of the road relative to the surrounding habitat; environmentally triggered, flashing speed-reduction-sign installation; and vegetation manipulation. Again, because these management scenarios are not yet in play, we could not directly test them. Rather, we gathered data on the behavioral ecology of OSBs and the environmental conditions of the road compared to surrounding habitat to determine which mitigation measures would have the greatest potential for effectiveness. To inform mitigation options we examined six questions about environmental conditions across habitats or microhabitats and how these correlated with OSB presence.

Rights

In Copyright. URI: 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).

Comments

A project report submitted in partial fulfillment of the requirements for the degree of Master of Environmental Management.

Persistent Identifier

http://archives.pdx.edu/ds/psu/15769

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