Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Vegetation Change and Plant Demography in Permanent Plots in the Sonoran Desert

Deborah E. Goldberg and Raymond M. Turner
Ecology
Vol. 67, No. 3 (Jun., 1986), pp. 695-712
Published by: Wiley
DOI: 10.2307/1937693
Stable URL: http://www.jstor.org/stable/1937693
Page Count: 18
  • Download ($42.00)
  • Subscribe ($19.50)
  • Cite this Item
Vegetation Change and Plant Demography in Permanent Plots in the Sonoran Desert
Preview not available

Abstract

We report on vegetation changes and population dynamics during a 72-yr period within permanent plots in Sonoran Desert vegetation. A set of plots established in 1906 and supplemented in 1928 at Tumamoc Hill, near Tucson, Arizona, USA, have been mapped at irregular intervals through 1978. Data from the four 100-m^2 and one 800-m^2 plots censused most frequently (6-8 times since 1906 and 1928) are presented in detail; data from five less frequently censused plots are noted briefly. At each census all woody and succulent plants, including seedlings, were mapped by recording both stem coordinates and canopy outline. There have been no consistent, directional changes in vegetation composition in the Tumamoc Hill plots between 1906 and 1978, despite large fluctuations in absolute cover and density of most species. The relative cover of the dominants was generally similar within a given plot over the entire time sequence. Coverage of most species responded strongly to regimes of extremely wet or extremely dry years; the response of density to climatic extremes was somewhat less strong. Total cover, density,and species diversity have increased more or less continuously in many plots between 1906 and 1978. The species were divided into five groups based on several population dynamic traits. At one end of continuum are species with long maximum lifespan (often greater than the 72-yr study period), high early and long-term (50-yr) survivorship, large size at maturity, low density, erratic recruitment, and age structure skewed toward older plants. At the other end of the continuum are species with short maximum life-span, low early and long-term survivorship, small size at maturity, high density, some recruitment at most censuses, and age structures strongly skewed toward newest recruits. While some of these traits are necessarily related (e.g., long maximum life-span and high long-term survivorship), others are not (e.g., high early survivorship and erratic recruitment), and the relationships deserve further study.

Page Thumbnails

  • Thumbnail: Page 
695
    695
  • Thumbnail: Page 
696
    696
  • Thumbnail: Page 
697
    697
  • Thumbnail: Page 
698
    698
  • Thumbnail: Page 
699
    699
  • Thumbnail: Page 
700
    700
  • Thumbnail: Page 
701
    701
  • Thumbnail: Page 
702
    702
  • Thumbnail: Page 
703
    703
  • Thumbnail: Page 
704
    704
  • Thumbnail: Page 
705
    705
  • Thumbnail: Page 
706
    706
  • Thumbnail: Page 
707
    707
  • Thumbnail: Page 
708
    708
  • Thumbnail: Page 
709
    709
  • Thumbnail: Page 
710
    710
  • Thumbnail: Page 
711
    711
  • Thumbnail: Page 
712
    712