GENETIC VARIABILITY BETWEEN BREEDING AND NON-BREEDING POPULATIONS OF THE BLACK SKIMMER (Rynchops niger intercedens) IN SOUTHERN SOUTH AMERICA: FIRST INSIGHTS ON POPULATION CONNECTIVITY

MARIANO Y JELICICH, ROCÍO; MADRID, ENRIQUE; DEL FRESNO, PAMELA; FAVERO, MARCO

Cusco

Congreso; IX Congreso de Ornitología Neotropica; 2011

Sociedad de Ornitologia Neotropical

The Black Skimmer (Rynchops niger) is a neotropical bird widely distributed in SouthAmerica. In Argentina, anecdotal reports from small colonies of R. niger intercedens on thebreeding grounds next to rivers, contrasts with the high numbers registered in nonbreedinggrounds on the southeastern coast of Argentina (up to 10,000 non-breeders inMar Chiquita Coastal Lagoon). Even though differences in breeding phenologies occurbetween colonies in Brasil and Argentina, the observed contrast in bird abundances raisesthe question of the existence of a non-breeding mixture of birds proceeding from coloniesdistributed throughout major South American hydrological basins. In this study weanalyzed the molecular polymorphisms between skimmers? populations from Brasil andArgentina. Significant genetic differentiation was detected between sampling sitesproviding evidence that South American populations of the black skimmer are notcompletely panmictic. Moreover, results suggest the existence of two genetic groups, oneformed by the Brasilian population and another including Argentinean sites. Higher geneticdiversity was observed in Mar Chiquita population, which is consistent with the hypothesisthat this site is a converging wintering area for multiple skimmers groups. Based on themolecular analysis presented here, we suggest that populations from Brasil and Argentinashould be managed separately until further information about the connectivity between these areas is found. Ongoing studies including additional colonies will reinforce theseresults. Mar Chiquita should be consider a key wintering /stopover area where severalpopulations of skimmers seems to be converging, being a critical and important site for theconservation and management of this species.