Abstract
Plant-Plant competitive interactions have been reported to be among the forces that shape plant community structure. We studied the effects of varying the density of Cynodon dactylon on the growth and development of the invasive plant species Tagetes minuta and Gutenbergia cordifolia in pot and field plot experiments following a completely randomized design. Increasing densities of C. dactylon strongly reduced T. minuta and G. cordifolia growth and development, leaf total chlorophyll and increased leaf anthocyanin of both invasive species. These detrimental effects may have contributed to poorer T. minuta and G. cordifolia performance under C. dactylon densities of more than 8 individuals per pot/plot compared to those in pots/plots without C. dactylon. This study suggests that C. dactylon can be successfully used to manage the two invasive plants, thus, improving forage production and biomass in affected rangelands.