Abstract:
The term circa situm has been used to describe different conservation strategies within agri-
cultural landscapes. Circa situm conserves planted or remnant species in farmlands, where
natural vegetation has been modified through anthropogenic intervention. It has been pro-
posed that trees planted or retained under circa situm conditions may contribute to maintain-
ing genetic diversity, however information on the role of this strategy in preserving genetic
diversity is scarce. The aim of this study was to determine the levels of genetic diversity and
structure, and mating patterns in planted and unmanaged stands of the tropical fruit tree
Spondias purpurea L. in north western Costa Rica. In three localities, we used seven poly-
morphic microsatellite loci and genotyped 201 adults and 648 seeds from planted and wild
stands. We found no differences in genetic diversity among planted and wild stands.
Genetic structure analysis revealed that gene flow occurs among planted and wild stands
within localities. Clones were present and their diversity and evenness were both high and
similar between planted and wild stands. The number of pollen donors per progeny array
was low (Nep = 1.01) which resulted in high levels of correlated paternity (rp = 0.9). Asexual
seeds were found in 4.6% of the progeny arrays, which had multilocus genotypes that were
identical to the maternal trees. Our results show that although planted stands under circa
situm conditions can maintain similar levels of genetic diversity than wild stands, the low
number of sires and asexual seed formation could threaten the long term persistence of
populations.
