What factor contributes to higher algal species richness in the presence of certain consumer species?

Higher algal species richness in the presence of certain consumer species can be attributed to intermediate predator densities. This concept is grounded in the "intermediate disturbance hypothesis," which suggests that moderate levels of predation or disturbance can foster biodiversity. In ecosystems, the presence of consumers at intermediate densities prevents any single algal species from dominating due to overgrazing. This allows multiple algal species to coexist, as those that are less palatable or grow more slowly can escape intense predation while still being present in the community. Thus, the diversity of algal species increases as these consumer species maintain a balance, enabling a variety of algal species to thrive.