Future directions
Understanding how plant population genetic structure is affected by life
history traits can greatly improve management strategies for populations
facing increasingly fragmented habitats due to human-accelerated global
change. Our study reveals that gene flow is generally more limited in
non-woody species pollinated by small insects, making them more
susceptible to isolation and loss of genetic diversity. Thus, in order
to preserve the largest amount of genetic diversity for species with
such traits, conservation efforts should seek to maintain numerous
subpopulations spanning a wide geographic extent. Future broad-scale
studies of FST variation could provide more even greater
insights for conservation by including population densities (Murawski &
Hamrick, 1991; Sork et al., 1999), effects of habitat fragmentation
(Aguilar, Quesada, Ashworth, Herrerias-Diego, & Lobo, 2008; Skogen et
al., 2019), and the landscape context of populations (Sork et al.,
1999).
Another avenue for future research involves linking patterns of genetic
variation at different scales. Little is known about how factors that
affect genetic patterns over fine spatial scales (i.e., within
subpopulations) extend to genetic patterns over larger spatial scales
(i.e., among subpopulations). Intuitively, species with greater
fine-scale genetic structure (Loiselle, Sork, Nason, & Graham, 1995)
should also have greater population genetic structure, but this has
rarely been tested. For example, a recent review found greater
fine-scale genetic structure in species with short-distance dispersers,
than those dispersed by birds (GelmiāCandusso et al., 2017), but it is
unclear whether this difference would extend over larger distances.
Overall, we expect that more comprehensive studies of ecological
interactions, in combination with increasing amounts of genetic data
collected at various spatial scales will continue to improve our
understanding of the factors that influence population genetic structure
in seed plants.