The myth of plant species saturation

  1. Thomas J. Stohlgren1,*,
  2. David T. Barnett2,
  3. Catherine S. Jarnevich1,
  4. Curtis Flather3,
  5. John Kartesz4

Article first published online: 31 JAN 2008

DOI: 10.1111/j.1461-0248.2008.01153.x

Issue

Ecology Letters

Ecology Letters

Volume 11, Issue 4, pages 313–322, April 2008

Additional Information

How to Cite

Stohlgren, T. J., Barnett, D. T., Jarnevich, C. S., Flather, C. and Kartesz, J. (2008), The myth of plant species saturation. Ecology Letters, 11: 313–322. doi: 10.1111/j.1461-0248.2008.01153.x

Author Information

  1. 1

    National Institute of Invasive Species Science, U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO 80526, USA

  2. 2

    Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, USA

  3. 3

    USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO 80526, USA

  4. 4

    Biota of North American Program, Chapel Hill, NC 27516, USA

* *E-mail: tom_stohlgren@usgs.gov

Publication History

  1. Issue published online: 31 JAN 2008
  2. Article first published online: 31 JAN 2008
  3. Editor, Nicholas Gotelli Manuscript received 12 October 2007 First decision made 9 November 2007 Manuscript accepted 20 November 2007

SEARCH

SEARCH BY CITATION

ARTICLE TOOLS

View Full Article (HTML) Get PDF (368K)

Keywords:

  • Biotic resistance;
  • competitive exclusion;
  • habitat heterogeneity;
  • invasion;
  • plant diversity;
  • saturation;
  • species richness

Abstract

Plant species assemblages, communities or regional floras might be termed ‘saturated’ when additional immigrant species are unsuccessful at establishing due to competitive exclusion or other inter-specific interactions, or when the immigration of species is off-set by extirpation of species. This is clearly not the case for state, regional or national floras in the USA where colonization (i.e. invasion by exotic species) exceeds extirpation by roughly a 24 to 1 margin. We report an alarming temporal trend in plant invasions in the Pacific Northwest over the past 100 years whereby counties highest in native species richness appear increasingly invaded over time. Despite the possibility of some increased awareness and reporting of native and exotic plant species in recent decades, historical records show a significant, consistent long-term increase in exotic species (number and frequency) at county, state and regional scales in the Pacific Northwest. Here, as in other regions of the country, colonization rates by exotic species are high and extirpation rates are negligible. The rates of species accumulation in space in multi-scale vegetation plots may provide some clues to the mechanisms of the invasion process from local to national scales.

View Full Article (HTML) Get PDF (368K)