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Alien plant species threat assessment and management prioritization for Sequoia-Kings Canyon and Yosemite National Parks

Open-File Report 2002-170

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Executive Summary

This document reports the results of alien species surveys at Sequoia-Kings Canyon and Yosemite national parks. It includes the findings of a comprehensive literature review of the biology and ecology of all alien plant species found during these surveys and the ranking of those species for prioritizing management and control programs. Surveys primarily targeted areas of human disturbance, such as campgrounds, corrals, developments, roads, trails and pastures. Alien species richness was compared across elevational gradients within the parks. To compare and contrast species composition among sites, an exploratory cluster analysis of the sites included in the speciesrichness- by-elevation figures was conducted using ordination techniques. All alien species discovered during the directed surveys were grouped into one of four management priority categories based on their attributes, potential impacts, and geographical extent. Category 1 species are aliens that are currently restricted to a relatively small number of sites in each park and have either been shown to greatly affect native vegetation or have a high probability of causing serious impacts. Category 2 species are restricted to a relatively small number of sites and are ones that generally have a lesser effect on native vegetation. Category 3 species are broadly distributed in the parks, are apparently increasing their ranges within the parks, and are those that have been shown to have a great impact on native vegetation. Category 4 species are those that were detected by the surveys but not assigned to one of the three ranked categories and are considered low priority.

Suggested Citation

Gerlach, J.D., Jr., P. Moore, B. Johnson, G. Roy, P. Whitmarsh, D.M. Lubin, D.M. Graber, S. Haultain, A. Pfaff, and J.E. Keeley. 2003. Alien Plant Species Threat Assessment and Management Prioritization for Sequoia-Kings Canyon and Yosemite National Parks. USGS Open-File Report 02-170.

ISSN: 2331-1258 (online)

Table of Contents

  • Executive Summary
  • Acknowledgements
  • Preface
  • Part I
  • Part II
  • Part III
  • Part IV
  • Part V
  • Appendixes A–H

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Alien plant species threat assessment and management prioritization for Sequoia-Kings Canyon and Yosemite National Parks
Series title:
Open-File Report
Series number:
2002-170
Year Published:
2002
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Western Ecological Research Center
Description:
ix, 149 p.