Quadrat covariance analysis and the scales of interspecific association during primary succession

. Three term covariance analysis is used to investigate interspecific association at a range of spatial scales, using both density and presence/absence data to evaluate the strength of species interactions. This procedure also investigates the relationship between the spatial patterns of species. These methods are applied to the vegetation on a series of glacial moraines near Mt. Robson, British Columbia, Canada, in order to test whether the plants of different species and their patterns become more independent and more random during succession. Another hypothesis tested is that if a species exerts a positive influence on others by increasing soil nutrients, this effect decreases with surface age. The vegetation analysed supports both these hypotheses to the extent that most species pairs have maximum covariance intensity on medium aged surfaces. The covariance-blocksize graphs derived from density data and from presence/absence data were qualitatively similar in their trends; however, the results are sufficiently different to suggest that the relationships among species can be subtle, affecting density rather than presence. The results also show that the affect of scale on species associations is more complex than simple models predict.

[1]  P. Greig-Smith,et al.  QUANTITATIVE PLANT ECOLOGY , 1959 .

[2]  Lonnie W. Aarssen,et al.  Vegetation dynamics and neighbour associations in pasture-community evolution. , 1985 .

[3]  D. Macisaac,et al.  New methods for the analysis of spatial pattern in vegetation , 1989 .

[4]  K. Kershaw,et al.  Association and Co-Variance Analysis of Plant Communities , 1961 .

[5]  G. A. Yarranton,et al.  Spatial dynamics of a primary succession: nucleation , 1974 .

[6]  M. B. Usher,et al.  Analysis of Pattern in Real and Artificial Plant Populations , 1975 .

[7]  P. Greig-Smith,et al.  The Use of Random and Contiguous Quadrats in the Study of the Structure of Plant Communities , 1952 .

[8]  M. Hill,et al.  The Intensity of Spatial Pattern in Plant Communities , 1973 .

[9]  D. J. Blundon,et al.  Quadrat variance analysis and pattern development during primary succession , 1990 .

[10]  K. Kershaw,et al.  An Investigation of the Structure of a Grassland Community: II. The Pattern of Dactylis Glomerata, Lolium Perenne and Trifolium Repens: III. Discussion and Conclusions , 1959 .

[11]  K. Kershaw.  PATTERN IN VEGETATION AND ITS CAUSALITY , 1963 .

[12]  M. B. Usher.  Pattern in the simple moss-turf communities of the Sub-Antarctic and Maritime Antarctic , 1983 .

[13]  Flora of Alberta. , 1960 .

[14]  M. Wade,et al.  THE DETECTION OF SMALL-SCALE PATTERNS IN VEGETATION , 1979 .

[15]  K. Kershaw,et al.  Quantitative and Dynamic Ecology. , 1965 .

[16]  P. Greig-Smith,et al.  Data on Pattern within Plant Communities: I. The Analysis of Pattern , 1961 .

[17]  T. L. Esslinger,et al.  A sixth checklist of the lichen-forming, lichenicolous, and allied fungi of the continental United States and Canada , 1987 .