Adaptations of whitebark pine for seed dispersal by Clark's Nutcracker

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Abstract
Whitebark pine (P. albicaulis Engelm.) has large, energy-rich, wingless seeds that are not wind dispersable, and indehiscent cones that retain their matured seeds within. Scales are easily broken off the cone axis, leaving many of the seeds exposed and held in the core of the cone. Cones are sessile on ascending limbs, and therefore conspicuous when viewed from above. These characteristics are adaptations to the foraging activities of Clark''s nutcracker (N. columbiana Wilson), which removes seeds from cones and stores them in subsoil caches, thus permitting them to germinate and become established trees. It is hypothesized that speciation of the Cembrae pines has occurred through nutcracker-mediated selection exerted on conventional white pine antecedents.