Hoban and Schlarbaum (2014) made a valuable contribution with their quantitative analyses explicitly incorporating population structure in determining genetically representative ex situ sample sizes. They have confirmed and extended by simulation modeling much of what has been common practice, but based primarily on population genetic theory and qualitative judgment. However, we disagree with a basic premise of the paper – i.e., “…common protocols for ex situ collections do not consider population structure” (pg. 90), perhaps because Hoban and Schlarbaum (2014) are unaware of literature that has been influential in rare plant conservation practice (e.g., Falk and Holsinger, 1991, Touchell et al., 1997 and Guerrant et al., 2004 and references therein). Here we argue that previous collection guidelines explicitly incorporated population structure at least qualitatively and that other factors also influence sampling decisions.
Available at: http://works.bepress.com/edward_guerrant/8/