Data from: Utility of island populations in reintroduction programs—relationships between Arabian gazelles (Gazella arabica) from the Farasan Archipelago and endangered mainland populations

Understanding local adaptation and population differentiation is vital to
the success of reintroduction initiatives. Like other mammals living on
islands, Arabian gazelles (G. arabica) show reduced body size on the
Farasan archipelago, which we corroborated in this study through
morphometric analyses of skulls. In light of the steep population decline
on the Arabian Peninsula—but stable population development on the
archipelago—we tested the potential suitability of Farasan gazelles as a
source for reintroductions on the mainland. We, therefore, investigated
genetic differentiation between Farasan and mainland populations using
eleven nuclear microsatellite loci and detected a distinct genetic cluster
exclusively present on the archipelago, which we inferred to be separated
from the mainland cluster for less than 2,000 years. About 30% of sampled
individuals from Farasan Islands showed assignment to a mainland cluster
with signs of ongoing introgression. Analyses using the
Isolation-with-Migration model confirmed recent (probably human-induced)
bidirectional exchange of gazelles between mainland and island
populations. Hence, the surprisingly uniform island dwarfism most likely
reflects phenotypic plasticity, i.e., altered morphology as a direct
consequence of harsh environmental conditions and resource limitation on
the archipelago. Should a further decline of Arabian gazelles on the
mainland necessitate restocking in the future, Farasan gazelles may thus
become an additional source for captive breeding programs.