Biodiversity & Conservation

, Volume 11, Issue 12, pp 2117–2141

A stratified approach for modeling the distribution of a threatened ant species in the Swiss National Park

Authors

  • R. Maggini
    • Institute of EcologyUniversity of Lausanne
    • Palais de RumineMuseum of Zoology
  • A. Guisan
    • Institute of EcologyUniversity of Lausanne
    • Swiss Center for Faunal Cartography (CSCF)
  • D. Cherix
    • Institute of EcologyUniversity of Lausanne
    • Palais de RumineMuseum of Zoology
Article

DOI: 10.1023/A:1021338510860

Cite this article as:
Maggini, R., Guisan, A. & Cherix, D. Biodiversity and Conservation (2002) 11: 2117. doi:10.1023/A:1021338510860

Abstract

We present models predicting the potential distribution of a threatened ant species, Formica exsecta Nyl., in the Swiss National Park (SNP). Data to fit the models have been collected according to a random-stratified design with an equal number of replicates per stratum. The basic aim of such a sampling strategy is to allow the formal testing of biological hypotheses about those factors most likely to account for the distribution of the modeled species. The stratifying factors used in this study were: vegetation, slope angle and slope aspect, the latter two being used as surrogates of solar radiation, considered one of the basic requirements of F. exsecta. Results show that, although the basic stratifying predictors account for more than 50% of the deviance, the incorporation of additional non-spatially explicit predictors into the model, as measured in the field, allows for an increased model performance (up to nearly 75%). However, this was not corroborated by permutation tests. Implementation on a national scale was made for one model only, due to the difficulty of obtaining similar predictors on this scale. The resulting map on the national scale suggests that the species might once have had a broader distribution in Switzerland. Reasons for its particular abundance within the SNP might possibly be related to habitat fragmentation and vegetation transformation outside the SNP boundaries.

Formica exsecta Nyl.Generalized linear modelsModelingPotential distribution mapsRandom-stratified samplingSwiss National Park

Copyright information

© Kluwer Academic Publishers 2002