Abstract

LINZAGA-ROMAN, Blanca Estela; ANGELES-PEREZ, Gregorio; CATALAN-HEVERASTICO, Cesario  and  HERNANDEZ DE LA ROSA, Patricia. Spatial structure of Pachycereus weberi (Coult.) Backeb. In cañada del Zopilote, Guerrero. Rev. Chapingo ser. cienc. for. ambient [online]. 2011, vol.17, n.2, pp.189-198. ISSN 2007-4018.  https://doi.org/10.5154/r.rchscfa.2010.06.039.

The aim of this study was to determine the population structure of Pachycereus weberi in Cañada del Zopilote (Buzzard Canyon), Guerrero, Mexico. An observation plot of 50 x 50 m (2,500 rrP) was established and divided into quadrats of 10 x 10 m to facilitate the field survey. All P. weberi individuals with height ≥ 0.10 m were tagged, and their total height, diameter at breast height (dbh), and location by X and Y coordinates were recorded. In addition, all individuals of associated woody species with dbh ≥ 5 cm were tagged, identified and their diameter and coordinates within the plot recorded. We calculated the spatial distribution and correlation patterns of the P. weberi population divided into two developmental stages, juveniles and adults, using Ripley's index. A total of 18 species associated with P. weberi were recorded. P. weberiattained the highest Index of Relative Importance Value with 41.1 %, followed by Acacia tenciifolia with 22.6 %. P. weberi individuals with total height greater than 8.5 m and diameters from 5 to 43.8 cm were recorded. The spatial distribution pattern was clumped for individuals in both juvenile and adult development stages. The spatial correlation showed a repulsion pattern at distances of 2 to 13 m between juvenile and adult P. weberi. The diameter distribution suggests an episodic recruitment behavior, with low recruitment rates in intermediate diameter classes between juveniles and adults.

Keywords : Pachycereus weberi; Ripley's index; Index of Relative Importance Value; spatial distribution pattern; spatial correlation pattern.