How meso-scale pollen dispersal and its gene flow shape gene conservation decisions

Abstract

Pine pollen dispersal has been well-studied over a century due to its ubiquity, robust shape and unusual longevity; this knowledge can be brought to bear on forest population genetics applications and gene conservation programs for pines and other high-latitude wind-pollinated species. Dispersal models are shifting towards meso-scale transport processes so I assert here that this shift in transport scale is important to population genetics assumptions inherent to gene conservation decision-making. Support comes from the following: (1) aerodynamic properties for pollen is more akin to spores than seeds. (2) Gradient-free dispersal is typical of pollen transported at meso-scale distances. (3) Importance of vertically uplifted pollen on meso-scale transport has been overlooked and its interaction with atmospheric processes is not yet understood. (4) A fraction of pine pollen retains its capacity for germination and seed fertilization after meso-scale transport. These findings raise the question of whether forest fragmentation aligns with genetics theory of small populations; this question shapes ex situ and in situ collections. The shift to meso-scale transport of pine pollen can re-shape forest gene conservation decision-making about ex situ and in situ collection strategies.