Patterns of natal dispersal and genetic structure of Atlantic Puffins (Fratercula arctica) in Atlantic Canada

Abstract

Dispersal is a complex, individual process with consequences for genetic structure, population dynamics, and the persistence of populations. In this thesis, I investigate patterns of natal dispersal and population structure of Atlantic Puffins (Fratercula arctica, hereafter ‘puffin’) using observational and genetic data. First, I assess sex-biased dispersal, focusing on individuals that hatched on Machias Seal Island and dispersed to four breeding colonies in the Gulf of Maine. I determined that there is not a sex-bias in dispersal, although females that fledged later were more likely to disperse. Second, I investigate how diet and breeding success information gathered during prospecting influences puffin dispersal decisions for puffins hatched on five breeding colonies in the Bay of Fundy and Gulf of Maine. I found that puffins were more likely to disperse when conditions on islands they prospected were better compared to conditions on their hatch island. Finally, I evaluate the genetic diversity and structure of puffins breeding in the Gulf of Maine, Gulf of Saint Lawrence, and Newfoundland and Labrador shelf regions of Atlantic Canada using double digest restriction-site associated DNA sequencing (ddRADseq). I found that puffins breeding on Machias Seal Island were genetically distinct from puffins breeding in Newfoundland and Québec and did not find evidence of inbreeding at any colony. Overall, my thesis shows that gene flow from larger northern breeding colonies into the Bay of Fundy and Gulf of Maine region is limited, and that dispersal within the metapopulation is affected by the quality of puffin breeding colonies. This work supports managing the Gulf of Maine and Bay of Fundy puffin metapopulation separately and highlights the importance of understanding context-dependent dispersal amid rapid environmental change.