This paper examines how the concept of a keystone species helps to sustain the stability and functionality of a grassland ecosystem via network analysis. The identified species are Bison, Prairie Dogs, and Coyotes, and the centrality measures applied to the species were degree centrality, betweenness centrality, and closeness centrality. The findings showed that the Bison and the Prairie Dogs had a high degree of centrality (4 and 3, respectively), which implied that they interacted with other species to a large extent, especially controlling the dynamics of the plants and enhancing biodiversity by feeding on herbs. Coyotes (the most betweenness central node 5) are the biggest predators in the food web that regulate the population of herbivores and ensure the balance in the ecosystem. The centrality values of Bison (0.85) and Coyotes (0.78) were close thus they were able to influence the resource allocation and energy circulation speedily and therefore played a key role in controlling the population dynamics and food web structure. Modularity analysis revealed a high level of interconnection among the functional groups of producers, herbivores, and predators, and the score of modularity was 0.75, with an important role of those species in maintaining the energy flow and the nutrient cycle. The resilience study revealed how vulnerable the ecosystem is to the disappearance of these keystone species. A 30 percent decrease in Bison numbers and a 25 percent decrease in Coyotes would cause a major disturbance in the stability of the network, as it relates to nutrient cycling and energy transfer. These results highlight the paramount role of Bison, Prairie Dogs, and Coyotes in the health and stability of grasslands. The rationale behind the conservation of such keystone species is highlighted in the current study especially with environmental issues like degradation of habitat and climate change. Conservation of these species will make grassland ecosystems sustainable and resilient in the long term.