Spatial structural analysis of species associations in mixed Montpellier maple (Acer monspessulanum L.) stands of Zagros woodlands (Case study: Firooz Abad, Fars province)

Interspecific interaction of tree species is an important process in establishing spatial structure of species associations in ecosystems with low species diversity. This study was aimed to investigate the interspecific interactions of Montpellier maple (Acer monspessulanum L.) and two accompanying species (i.e., Amygdalus scoparia and Astragalus gossypinus) in a site close to Firooz Abad, Fars province. A 200 m × 200 m sample plot was selected in a part of the site. The spatial locations of 629 individuals were measured together with their tree species, height and crown area. In addition to bivariate g(r), M(r) and P(r) were applied to explore more details about interspecific species interactions. The results showed that A. monspessulanum had the highest density, mean height and crown area compared to other species. The results indicated negative interspecific interactions of tree species, which was decreased with increasing distance. Negative interactions were observed between A. monspessulanum with A. scoparia and A. monspessulanum with A. gossypinus up to spatial scale of 3 m and 10 m, respectively. Moreover, A. monspessulanum and two other species showed repulsion up to 7 m distance. In general, it was concluded that A. monspessulanum showed negative interspecific interactions with A. scoparia and A. gossypinus in the study area. This might be caused by environmental heterogeneity and resource limitation. Furthermore, M(r) and P(r) explored more details about type and spatial scale of negative interspecific interactions of A. monspessulanum with two other species.