Transfer processes drive population dynamics of kelp gull colonies in Patagonia: implications for management strategies

Abstract

The dispersal of individuals among breeding sites is considered to be one of the key processes in seabird population dynamics. The kelp gull (Larus dominicanus) is the most abundant gull in coastal Argentina, although its population dynamics in the region remains poorly understood. This article aims to address aspects of kelp gull demography along a wide coastal sector (~1800 km) in northern Patagonia to improve our understanding of population changes and contribute to the design of management strategies and monitoring programmes. Modelled scenarios suggest that annual increases of 10-20% are high for the species, and 29% of 62 evaluated colonies presented growth rates within this high reference range. Transfer processes among colonies (e.g. source-sink) contributed to the growth of at least six kelp gull colonies. These processes have been instrumental in the growth of small, and in some cases recently established colonies, which had generally higher growth rates and were found near large and long-established colonies. These are the first studies of kelp gull demography on the coasts of Argentina aimed at understanding the population dynamics of this species in a metapopulation context.