Vegetatio

, Volume 69, Issue 1, pp 79–87

Ecological amplitudes of plant species and the internal consistency of Ellenberg's indicator values for moisture

  • Cajo J. F. Ter Braak
  • Niek J. M. Gremmen
Article

DOI: 10.1007/BF00038689

Cite this article as:
Ter Braak, C.J.F. & Gremmen, N.J.M. Vegetatio (1987) 69: 79. doi:10.1007/BF00038689

Abstract

Two methods for estimating ecological amplitudes of species with respect to Ellenberg's moisture scale are discussed, one based on weighted averaging and the other on maximum likelihood. Both methods are applied to phytosociological data from the province of Noord-Brabant (The Netherlands), and estimate the range of occurrence of species to be about 4–6 units on the moisture scale. Due to the implicit nature of Ellenberg's definition of moisture, it is impossible to improve the indicator values in a statistically sound way on the basis of floristic data only. The internal consistency of the Ellenberg indicator values is checked by using Gaussian logit regression. For 45 out of the 240 species studied the indicator value is inconsistent with those of the other species. The same method is used to estimate the optima and amplitudes of species considered moisture-indifferent and of some species not mentioned by Ellenberg. Some of these ‘indifferent’ species show a remarkably narrow amplitude.

It is concluded that the Ellenberg indicator values for moisture form a reasonably consistent system.

Keywords

AmplitudeGaussian logit curveIndicator valueLogit regressionMaximum likelihoodOptimumToleranceUnimodal response curveWeighted averaging

Copyright information

© Dr W. Junk Publishers 1987

Authors and Affiliations

  • Cajo J. F. Ter Braak
    • 1
  • Niek J. M. Gremmen
    • 2
  1. 1.TNO Institute of Applied Computer ScienceWageningenThe Netherlands
  2. 2.Research Institute for Nature ManagementLeersumThe Netherlands