Analysis of spatial heterogeneity of the weed community in a manilagrass lawn using power-law

Spatial heterogeneity is a fundamental index for describing lawn weed communities. The spatial distribution characteristics of weeds in a manilagrass (Zoysia matrella) lawn in Guangzhou of South China were evaluated using a power-law model. Twenty-seven weed species were found in the lawn. Centella asiatica, Fimbristylis dichotoma, Lindernia crustacea, Phyllanthus urinaria, Sacciolepis indica, Desmodium microphyllum and Viola inconspicua were the most abundant species, their occurrence frequencies varied from 10.0% to 54.0%. The rest of them were relatively sparse and the occurrence frequencies were below 10.0%. Some species such as Eclipta prostrate, Fimbristylis schoenoides, Palhinhaea cernua and Centella asiatica had high heterogeneities. On the other hand, the species such as Lygodium japonicum, Emilia sonchifolia, Digitaria sanguinalis, Hedyotis corymbosa, Pogonatherum crinitum, Scoparia dulcis, Cynodon dactylon, Pouzolzia zeylanica, Urena lobata and Eragrostis tenella demonstrated the mostly random patterns. The data fit the model well with estimates given at the levels of heterogeneity for not only single species but also the community as a whole. The frequency of occurrence and the spatial heterogeneity of individual species in a unit area can be easily determined using the power-law method. The power-law method is helpful for the studying lawn weed communities, especially where there are large numbers of weeds.