The significance of having keystone species in ecosystems lies in their disproportionately large impact on their environment relative to their abundance. These species help maintain the structure and functionality of the ecosystem. For example, predators control prey populations, while certain plants may provide essential habitat or resources for other species. Protecting keystone species is crucial because their removal can lead to significant ecological imbalances and loss of biodiversity, demonstrating their critical role in sustaining ecosystem health and stability.