Genetic structure of Pinus parviflora on Mt. Fuji in relation to the hoarding behavior of the Japanese nutcracker

Pinus parviflora (Japanese white pine) is distributed along a wide range of altitudes between 1100 and 2500 m above sea level (asl) on the northwestern slope of Mt. Fuji in Japan. The seeds of P. parviflora are presumed to be dispersed from the mountainous area to the timberline by the Japanese nutcracker (Nucifraga caryocatactes var. japonica). We aimed to clarify the effect of the nutcracker on the genetic diversity and structures of P. parviflora populations on Mt. Fuji. Leaf samples were collected from eight populations at altitudes between 1100 and 2500 m asl. Using 11 microsatellite markers, we investigated the genetic diversity and structures of P. parviflora populations on Mt. Fuji. The average expected heterozygosity (HE), allelic richness (Ar), and inbreeding coefficients (FIS) of the P. parviflora populations on Mt. Fuji were 0.66, 1.66, and 0.14, respectively, suggesting a lower genetic diversity in comparison with those of P. parviflora populations in other regions of Japan. The genetic structure of the population at the lowest altitude of 1100 m was significantly different from that of the other populations. However, certain individuals in the populations at higher altitudes (2300–2500 m asl) were likely derived from populations at lower altitudes (1100–1500 m asl), probably because of the hoarding behavior of the nutcracker. Our results indicate that seeds carried from low altitudes by nutcrackers have become established at the timberline and have contributed to expanding the distribution and maintaining the genetic diversity of P. parviflora on Mt. Fuji. Seed dispersal affects the potential rates of recruitment, invasion, and range expansion in plant populations and consequently the probability of population persistence (Ouborg et al. 1999, Nathan and Muller‐Landau 2000, Neuschulz et al. 2017). Dispersal also affects the rates of gene flow, thereby influencing the genetic structure within and among populations (Ouborg et al. 1999, Nathan and Muller‐Landau 2000, Richardson et al. 2002a). Therefore, the seed dispersal process is an essential process in the dynamics and evolution of plant populations. A number of studies have determined the distances and patterns of seed dispersal by animals and have discussed the effects of dispersal on plant distribution and populations (Tomback 1982, Vander Wall 1990, Ouden et al. 2002, Traveset et al. 2014, Neuschulz et al. 2017). However, few studies have focused on post‐dispersal processes and their consequences, namely the recruitment and dynamics of plant populations and their genetic structures