Long-term satellite tracking reveals patterns of long-distance dispersal in juvenile and adult Arctic foxes (Vulpes lagopus)

Abstract

Long-distance dispersal plays a key role in species distribution and persistence. However, its movement metrics and ecological implications may differ whether it is undertaken by juveniles (natal dispersal) or adults (breeding dispersal). We investigated the influence of life stage on long-distance dispersal in the Arctic fox, an important tundra predator. We fitted 170 individuals with satellite collars during a 13-year study on Bylot Island (Nunavut, Canada), and analysed the tracks of 10 juveniles and 27 adults engaging in long-distance dispersal across the Canadian High Arctic. This behaviour was much more common than expected, especially in juveniles (62.5%, adults: 19.4%). Emigration of juveniles occurred mainly at the end of summer while departure of adults was not synchronized. Juveniles travelled for longer periods and over longer cumulative distances than adults, but spent similar proportions of their time travelling on sea ice versus land. Successful immigration occurred mostly in late spring and was similar for juveniles and adults (30% versus 37%). Our results reveal how life stage influences key aspects of long-distance dispersal in a highly mobile canid. This new knowledge is critical to understand the circumpolar genetic structure of the species, and how Arctic foxes can spread zoonoses across vast geographical areas.

Keywords: breeding dispersal; canid; movement ecology; natal dispersal; sea ice; tundra.

Figure 1.

Fate of 170 Arctic foxes equipped with Argos Platform Terminal Transmitters on Bylot Island (Nunavut, Canada) in 2007–2019 and tracked from 2007–2021. Long-distance dispersal was defined as a movement with no permanent return reaching ≥80 km away from the boundary of the initial territorial buffer where they resided when captured. Unique ID and individual fate of all individuals are reported in the electronic supplementary material, table S2.

Figure 2.

Long-distance dispersal paths of juveniles (a1; n = 10) and adults (b; n = 27) from Bylot Island between 2007 and 2021. Paths of interrupted natal dispersal (n = 4) and short-distance natal dispersal (n = 2) are presented in the inset map (a2). Dots at the end of the paths indicate successful dispersal with immigration (white) or tracking ending during transience by collar failure (gray) or fox death (black). a1 mostly shows Baffin Island, a2 mostly shows Bylot Island (located at the northern tip of Baffin), and B mostly shows the Canadian Arctic Archipelago, located between mainland Canada and Greenland.

Figure 3.

Timing of emigration (light gray) in juvenile (a; n = 10) and adult (b; n = 27) Arctic foxes and timing of immigration (dark gray) in juvenile (c; n = 3) and adult (d; n = 10) Arctic foxes undertaking long-distance dispersal after being equipped with Argos Platform Terminal Transmitters on Bylot Island (Nunavut, Canada) in 2007–2019.

Figure 4.

Initial and final bearings for complete and incomplete long-distance dispersal (LDD) undertaken by juvenile (initial: a, final: c, n = 10) and adult (initial: b, final: d, n = 27) Arctic foxes tracked from Bylot Island (Nunavut, Canada) in 2007–2019.