An Individual-Based Model of the Population Dynamics of the Arctic Fox (Vulpes lagopus semenovi) on Mednyi Island, Commander Islands, North Pacific

Phenotypic integration and modularity influence morphological disparity and evolvability. However, studies addressing how morphological integration and modularity change for long periods of genetic isolation are scarce. Here, we investigate patterns of phenotypic integration and modularity in the skull of phenotypically and genetically distinct populations of the Artic fox ( Vulpes lagopus ) from the Commander Islands of the Aleutian belt (i.e. Bering and Mednyi) that were isolated ca 10 000 years by ice-free waters of the Bering sea. We use three-dimensional geometric morphometrics to quantify the strength of modularity and integration from inter-individual variation (static) and from fluctuating asymmetry (random developmental variation) in both island populations compared to the mainland population (i.e. Chukotka) and we investigated how changes in morphological integration and modularity affect disparity and the directionality of trait divergence. Our results indicate a decrease in morphological integration concomitant to an increase in disparity at a developmental level, from mainland to the smallest and farthest population of Mednyi. However, phenotypic integration is higher in both island populations accompanied by a reduction in disparity compared to the population of mainland at a static level. This higher integration may have favoured morphological adaptive changes towards specific feeding behaviours related to the extreme environmental settings of islands. Our study demonstrates how shifts in phenotypic integration and modularity can facilitate phenotypic evolvability at the intraspecific level that may lead to lineage divergence at macroevolutioanry scales.

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Low vulnerability of Arctic fox dens to climate change-related geohazards on Bylot Island, Nunavut

Arctic Science ◽

10.1139/as-2019-0007 ◽

2021 ◽

Author(s):

Florence Lapierre Poulin ◽

Daniel Fortier ◽

Dominique Berteaux

Keyword(s):

Climate Change ◽

Vulnerability Index ◽

The Arctic ◽

Arctic Fox ◽

Mass Movements ◽

Vulpes Lagopus ◽

Cold Temperatures ◽

Major Threat ◽

Bylot Island ◽

Permafrost Regions

Climate change increases the risk of severe alterations to essential wildlife habitats. The Arctic fox (Vulpes lagopus) uses dens as shelters against cold temperatures and predators. These dens, needed for successful reproduction, are generally dug into the active layer on top of permafrost and reused across multiple generations. We assessed the vulnerability of Arctic fox dens to the increasing frequency of geohazards (thaw settlement, mass movements, thermal erosion) that is arising from climate change. On Bylot Island (Nunavut, Canada) we developed, and calculated from field observations, a qualitative vulnerability index to geohazards for Arctic fox dens. Of the 106 dens studied, 14% were classified as highly vulnerable while 17% and 69% had a moderate and low vulnerability. Vulnerability was not related to the probability of use for reproduction. While climate change will likely impact Arctic fox reproductive dens, such impact is not a major threat to foxes of Bylot Island. Our research provides first insights into the climate-related geohazards potentially affecting Arctic fox ecology in the next decades. The developed method is flexible and could be applied to other locations or other species that complete their life cycle in permafrost regions.

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