EFFECTS OF AVIAN SEED DISPERSAL ON THE GENETIC STRUCTURE OF WHITEBARK PINE POPULATIONS.

We used allozyme analysis to examine family structure, the spatial patterning of related individuals, in two populations of whitebark pine (Pinus albicaulis), a subalpine conifer that commonly displays a multistem form. The individual stems within clumps are genetically distinct individuals, having arisen from separate seeds. Individuals within a clump are genetically more similar than individuals in different clumps, but individuals in neighboring clumps do not appear to be more similar than individuals in distant clumps. This family structure appears to be a direct result of the seed-caching behavior of Clark's nutcrackers (Nucifraga columbiana), the primary dispersal agent for whitebark pine seeds.