Presentation Title

Elk Rock Cliff: Vegetation Surveys on a Vertical Cliff Face

Start Date

5-2-2018 11:10 AM

End Date

5-2-2018 11:20 AM

Abstract

At river mile of the Willamette River, Portland Parks and Recreation (PPR) manages a 3.3 acre (1.3 ha), 300ft tall basalt cliff, the unique phytogeology of which historically attracted botanists from around the region. Of the 106 plant taxa reported historically from Elk Rock Cliff, 29 are (locally) rare, 3 species (Delphinium leucophaeum, Bolandra oregana, Sullivantia oregana) have state and federal status and 18 taxa have no recent records from our area. This is likely due to the difficulty of accessing the cliff and the fact that no one had attempted a thorough survey of the cliff face. In 2017, PPR, in partnership with the Bureau of Environmental Services, developed a method of using high resolution photography and GIS technology to undertake a comprehensive botanic survey of Elk Rock Cliff. A series of 122 individual photographs were taken of the cliff in March and again in May to capture both leaf off and peak bloom times of rare plant species. Examining individual photographs and comparing them to real time examination of the cliff face with spotting scopes and binoculars allowed ecologists to identify dozens of species of invasive and native plants across the cliff. GIS technology was used to resolve the fact that the cliff face varies in all three dimensions to determine canopy cover for each species. The results of this survey will allow the City to prioritize and implement restoration tasks to preserve and protect the rare species that still exist on Elk Rock Cliff.

Subjects

Habitat assessment, Land/watershed management, Plant ecology

Persistent Identifier

https://archives.pdx.edu/ds/psu/25623

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Feb 5th, 11:10 AM Feb 5th, 11:20 AM

Elk Rock Cliff: Vegetation Surveys on a Vertical Cliff Face

At river mile of the Willamette River, Portland Parks and Recreation (PPR) manages a 3.3 acre (1.3 ha), 300ft tall basalt cliff, the unique phytogeology of which historically attracted botanists from around the region. Of the 106 plant taxa reported historically from Elk Rock Cliff, 29 are (locally) rare, 3 species (Delphinium leucophaeum, Bolandra oregana, Sullivantia oregana) have state and federal status and 18 taxa have no recent records from our area. This is likely due to the difficulty of accessing the cliff and the fact that no one had attempted a thorough survey of the cliff face. In 2017, PPR, in partnership with the Bureau of Environmental Services, developed a method of using high resolution photography and GIS technology to undertake a comprehensive botanic survey of Elk Rock Cliff. A series of 122 individual photographs were taken of the cliff in March and again in May to capture both leaf off and peak bloom times of rare plant species. Examining individual photographs and comparing them to real time examination of the cliff face with spotting scopes and binoculars allowed ecologists to identify dozens of species of invasive and native plants across the cliff. GIS technology was used to resolve the fact that the cliff face varies in all three dimensions to determine canopy cover for each species. The results of this survey will allow the City to prioritize and implement restoration tasks to preserve and protect the rare species that still exist on Elk Rock Cliff.