Demography and genetics suggest metapopulation dynamics of breeding colonies in the Patagonian Kelp Gull, Larus dominicanus

AMANDA LYONS; NORA LISNIZER; PABLO YORIO; PABLO GARCÍA BORBOROGLU; JUAN BOUZAT; JOSEPH SCHALK

Baltimore, MD, USA

Congreso; SCB's International Congress for Conservation Biology (ICCB); 2013

Society for Conservation Biology

Demographic data from Kelp Gulls in Patagonia, Argentina, revealed an increase in the overall abundance of the species. However, individual colonies differed significantly in size and have variable growth rates. Demographic modeling showed that the growth of rapidly increasing colonies cannot be explained solely by within-colony recruitment, suggesting that migration from other colonies is significant. We compared the genetic structure of four Kelp Gull colonies located along a coastline of ~1,000 km, each representing regions with different demographic trends. DNA analysis of intron sequences from the myelin proteolipid protein gene revealed similar intra-colony levels of sequence diversity. Analysis of molecular variance indicated some genetic structuring, with ~4% of the observed variation being explained by differences among colonies. Genetic structuring was mainly driven by the Punta Tombo colony being differentiated from La Pastosa and Vernaci, two colonies located within regions with the highest growth rates. Genotype diversity showed increased levels of heterozygosity in Punta Tombo and decreased heterozygosity in La Pastosa and Vernaci. Decreased heterozygosities and the presence of unique haplotypes could be indicative of more recent colonizations and subsequent drift of rare haplotypes within these colonies. Our results suggest that proper conservation strategies for the Kelp Gull should take into account the metapopulation dynamics of this species.