What is the evolutionary consequence of the waterbuck's fixed social structure around geographically fixed water resources?

It validates a viable long-term strategy for males based on defending resource-rich territory.

The social organization of waterbucks, particularly the territorial system adopted by males, is directly linked to the predictability of their primary resource: permanent water. Because water sources are geographically fixed landmarks, defending a stable territory surrounding such a vital resource becomes a profitable long-term strategy for males seeking reproductive success by attracting females who also require guaranteed proximity to water. If the environment were characterized by extended droughts forcing mass migration, this territorial system would collapse, favoring flexibility seen in other bovids. The persistence of the territorial structure proves that, throughout much of their evolutionary history, localized water availability has been reliable enough to reward this high-investment defense strategy.