2023 Volume 39 Issue 3 Pages 59-74
This study clarified the biomass characteristics and spatial pattern for each species in weed communities. Using our methods for surveying/analyzing plant communities that have been developed by us over the past 20 years, we studied spatiotemporal changes in the biomass of the summer annual weed community in a dry field left fallow for many years. We cultivated the field in mid-May in 2006, 2008, and 2009 and set 7 to ten 1 m2 Squares, each subdivided into 100 0.01 m2 Divisions, and then left them untreated. Plant individuals of naturally germinated weed species in each Division in each Square was successively clipped for every around 20 days from June to November, and then each year, for the frequency distribution of total biomass and that of each species per Division fit of the gamma distribution was applied. Depending on results of the good fit, the use of a generalized linear regression model was applied to express the growth processes of community biomass. Based on the parameter p of gamma distribution, we determined the spatial heterogeneity of the total biomass and each species at each survey stage. The dissimilarity level in species composition, measured using biomass, increased gradually from the juvenile stage to the maximum biomass stage. Subsequently, the dissimilarity remained stable and high until October/November. Finally, we discussed the importance of biomass measurements including spatial heterogeneity in vegetation.
