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.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Population Variability of Sparrows in Space and Time

John L. Curnutt, Stuart L. Pimm and Brian A. Maurer
Oikos
Vol. 76, No. 1 (May, 1996), pp. 131-144
Published by: Wiley on behalf of Nordic Society Oikos
DOI: 10.2307/3545755
Stable URL: http://www.jstor.org/stable/3545755
Page Count: 14
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Population Variability of Sparrows in Space and Time
Preview not available

Abstract

The abundance of a species through time and across space, and the variability of that abundance, determines the species' persistence within its geographic range. We investigated the relationship between abundance and variability of nine species of grassland sparrows to uncover their population dynamics across their ranges. Sparrow populations consist of centrally located sites of high abundance with relatively low variability surrounded by sites of low abundance with relatively high variability. These sites are distributed across space such that variability decreases and abundance increases with increasing distance from the edge of a species' geographic range. Population numbers as a whole become increasingly variable over time, but only a portion of the total population heavily influences this increase in variability. For all but one species variability accrued in the areas of highest abundance. Thus, for these sparrows, the edge of the range is sparsely populated and variable, but not increasingly so. We suggest that the spatial and temporal behavior of grassland sparrow populations exhibit a "source and sink" dynamic where the core of the range 'feeds' the less productive peripheral areas. Conservation of species that exhibit this dynamic would depend on preservation and management of highly productive core areas.

Page Thumbnails

  • Thumbnail: Page 
131
    131
  • Thumbnail: Page 
132
    132
  • Thumbnail: Page 
133
    133
  • Thumbnail: Page 
134
    134
  • Thumbnail: Page 
135
    135
  • Thumbnail: Page 
136
    136
  • Thumbnail: Page 
137
    137
  • Thumbnail: Page 
138
    138
  • Thumbnail: Page 
139
    139
  • Thumbnail: Page 
140
    140
  • Thumbnail: Page 
141
    141
  • Thumbnail: Page 
142
    142
  • Thumbnail: Page 
143
    143
  • Thumbnail: Page 
144
    144