CONICET | Buscador de Institutos y Recursos Humanos

Wood stork, Mycteria Americana (Linnaeus 1758), is a key bioindicator ofenvironmental changes and an effective target for conservation-directed monitoring inwetlands where it inhabits and reproduces. We investigated past and contemporarylevels of genetic diversity, genetic differentiation and demographic processes in woodstork populations from two major wetlands in Brazil, using nine microsatellite loci and a237-bp fragment of mtDNA. Amapá populations (northern region) showed slightlyhigher levels of genetic diversity than Pantanal populations (central-western region) andboth populations had a low number of effective breeders. Assignment tests, F-statistics,AMOVA and Bayesian clustering analyses suggested ongoing gene flow among colonieswithin regions, but significant differentiation between regions. Bayesian coalescentanalyses based on both markers indicated that the northern population exchangedmigrants with unsampled populations, and that the central-western population wasfounded by individuals from the north. Mitochondrial estimates revealed that the timingof population divergence broadly overlapped the Last Glacial Maximum (LGM; ~20,000YBP) and that the central-western population expanded more recently. The resultssupport that the coastal wetlands in northern Brazil remained stable enough to shelterlarge wood stork populations during the LGM, and that the storks colonized freshwaterwetlands in the central-western region following deglacial warming. Conservationpolicies should consider Amapá and Pantanal wood stork populations as geneticallydifferentiated units and priority should be given to Amapá populations which representthe source gene pool. Continuous genetic monitoring of wood storks could help detectsigns of demographic trends that could reflect alterations or degradation in wetlands