Species’ geographic ranges and distributional limits: pattern analysis and statistical issues


  • M.-J. Fortin,

  • T. H. Keitt,

  • B. A. Maurer,

  • M. L. Taper,

  • Dawn M. Kaufman,

  • T. M. Blackburn

M.-J. Fortin, Dept of Zoology, Univ. of Toronto, Toronto, Ontario, Canada M5S 3G5 (mjfortin@zoo.utoronto.ca). – T. H. Keitt, Integrative Biology, Univ. of Texas, Austin, TX 78712, USA. – B. A. Maurer, Dept of Fisheries and Wildlife, Michigan State Univ., East Lansing, MI 48823, USA. – M. L. Taper, Dept of Ecology, Montana State Univ., Bozeman, MT 59717, USA. – D. M. Kaufman, Division of Biology, Kansas State Univ., Manhattan, KS 66506-4901, USA. – T. M. Blackburn, School of Biosciences, The Univ. of Birmingham, Edgbaston, Birmingham, UK B15 2TT.


With the increasing concern about species conservation, a need exists for quantitaive characterization of species’ geographic range and their borders. In this paper, we survey tools appropriate for the quantification of static spatial patterns related to geographical ranges and their borders. We then build on these static methods to consider the problem of changes in geographic range through time. Methods discussed are illustrated using lark sparrow data from the North American Breeding Bird Survey. While there is no such thing as the “best” or “only” method to analyze species geographical range and border, we show that a series of methods can be used in sequence to provide complementary and useful quantitative information for species occupancy of range. Indeed, the location of species’ borders estimated at different times can be compared to identify locations where species expand or go locally extinct. The ability to delineate accurately species’ ranges will be useful to conservation biologists, managers and ecologists.