Final answer:
When grasses and small plants die and decay, they contribute to the accumulation of soil organic matter, promoting litter decomposition and nutrient cycling, which affects the community's vegetation structure and composition.
Step-by-step explanation:
As grasses and other small plants die and decay, they contribute to the building of soil organic matter in that community. This process is crucial for litter decomposition and nutrient cycling, which in turn affects the structure and composition of vegetation. Grasses and forbs decompose and return nutrients to the soil, creating an environment supportive of other plant species and eventually leading to a mature climax community. This cycle is an integral part of the ecosystem, enabling a dynamic equilibrium where organisms grow, die, and contribute to the soil, which supports new life.