4.1. Current potential distribution ranges of Kersting’s
groundnut and genetic groups
We used two approaches to model KG
distributions across agroclimatic zones of four West African countries:
a traditional species SDM using a species wide cultivated areas, and
intraspecific models based on genetic information. We found that
decomposing a species into intraspecific genetic groups increases our
understanding of potential distribution of KG, which is consistent with
results from the previous few studies
(Gotelli & Stanton-Geddes 2015;
Ikeda et al. 2016;
Marcer et al. 2016;
Oney et al. 2013). The SDMs for
Pop1 performed more accurately in estimating potential cultivation areas
of KG rather than the genetic Pop2, which showed lower prediction
accuracy. The Pop2 is found in the three agroclimatic zones of all
countries; it displays a wide distribution range like the whole-species.
Indeed, Allouche et al. (2006)
reported that the values of predictive accuracy tend to be lower when
species are more common within the distribution ranges. Our results
reinforce the view that it is necessary in SDMs evaluation, to consider
not only the use of genetic data but also the population sizes and the
cultivated ranges of each genetic unit
(Marcer et al. 2016;
Milanesi et al. 2018).