Ecological Archives E091-146-A1
نویسندگان
چکیده
Appendix A: Details on methods of spatial pattern analysis. The pair-correlation function g(r) is based on the distances between all pairs of points of a given point pattern. The estimator used for the pair correlation function is shown in equation A1. In essence, the univariate quantity λg(r) gives the expected density of neighbours in a ring of radius r and ring-width of dr around an “average” point of the pattern, where λ is the intensity of the pattern (i.e., number of points of the pattern divided by the area of the study plot). The pair-correlation function isolates specific distance classes which makes it especially suitable for exploratory data analysis (Wiegand and Moloney 2004, Perry et al. 2006, Illian et al. 2008). The bivariate paircorrelation function for patterns comprising two types of points [i.e., dead (1) and surviving plants (2)] follows naturally; the bivariate quantity λ2g12(r) gives the expected density of type 2 neighbours in a ring of radius r (and ring-width dr) around an “average” type 1 individual, where λ2 is the intensity of the pattern of type 2 points.
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