A practical approach to the study of spatial structure in simple cases of heterogeneous vegetation

• Published in: Journal of vegetation science 2001-02, Vol.12 (1), p.99-108
• Main Authors: Pélissier, Raphaël, Goreaud, François
• Format: Article
• Language: English
• Subjects: Biodiversity and Ecology; Coniferous forests; Contour lines; Ecological competition; Environmental Sciences; Forest ecology; Frequency distribution; Local density function; Plant ecology; Point pattern; Ripley's K-function; Second-order local neighbour density function; Spatial points; Trees; Tropical rain forests; Vegetation structure
• ISSN: 1100-9233; 1654-1103
• DOI: 10.1111/j.1654-1103.2001.tb02621.x

Spatial heterogeneity is a characteristic of most natural ecosystems which is difficult to handle analytically, particularly in the absence of knowledge about the exogenous factors responsible for this heterogeneity. While classical methods for analysis of spatial point patterns usually require the hypothesis of homogeneity, we present a practical approach for partitioning heterogeneous vegetation plots into homogeneous subplots in simple cases of heterogeneity without drastically reducing the data. It is based on the detection of endogenous variations of the pattern using local density and second-order local neighbour density functions that allow delineation of irregularly shaped subplots that could be considered as internally homogeneous. Spatial statistics, such as Ripley's K-function adapted to analyse plots of irregular shape, can then be computed for each of the homogeneous subplots. Two applications to forest ecological field data demonstrate that the method, addressed to ecologists, can avoid misinterpretations of the spatial structure of heterogeneous vegetation stands.