What is the significance of hybridization being rare where the ranges of the common waterbuck and Defassa waterbuck overlap?
It suggests that subtle ecological or behavioral barriers have evolved to maintain separation.
The observation that hybridization is infrequent in areas where the two subspecies, the common waterbuck and the Defassa waterbuck, physically meet or overlap is a significant finding regarding speciation drivers. Even though the most obvious external distinction is the rump marking, the lack of interbreeding implies that reproductive isolation mechanisms are actively functioning. These mechanisms are likely subtle factors such as distinct behavioral patterns, mating rituals, or slight variations in localized habitat utilization that serve as effective barriers, preventing the exchange of genetic material despite the physical contiguity of their ranges. This highlights that evolutionary divergence can proceed effectively via localized adaptation, maintaining distinct forms even when sharing a fundamental ecological requirement.
