From 2009 to present, I have worked in the Whittell Forest and Wildlife Area investigating regeneration of greenleaf manzanita (Arctostaphylos patula). I have largely focused on seed production and dispersal, and I am currently focused on conditions seeds need to germinate. Greenleaf manzanita, like all manzanitas, needs fire for regeneration but their seeds are particularly sensitive to fire. My findings thus far have suggested that seed-caching rodents store manzanita seeds in the ground and when a fire occurs the soil protects them from the heat of the fire. This is a surprising discovery because we did not previously know how manzanita seeds were dispersed and the commonly observed rodent-seed mutualism has never been known to protect seeds from fires.
Manzanita fruits ripening. These fruits are ignored by birds.
Radioactively labeled manzanita seeds awaiting harvest by rodents
Chris Moore using a Geiger counter to find seeds buried by chipmunks.
A dozen greenleaf manzanita seedlings emerging in a recently-burned area.
Enclosed greenleaf manzanita shrub, testing what happens when rodents and birds cannot harvest the seeds.
Video of yellow pine chipmunk harvesting manzanita seeds
7 Cache site emptied by a rodent.
Different species of manzanitas produce larger and more fused seeds, apparently to entice rodents to harvest and store them