Arctic hares: Unsuspected long-distance travelers of the Far North

Abstract

Long-distance movements undertaken by animals are among the most fascinating biological phenomena on Earth. They include dispersal to reach new breeding sites, predictable migrations, and various forms of resource-based nomadism. About 12% of vertebrate species undertake large-scale migrations, but because the costs of terrestrial locomotion are high, only 1% of terrestrial mammals are known to migrate. Yet even on land, the distances traveled can be spectacular. Over the last decade, the sustained rise of animal tracking has uncovered unsuspected long-distance movements in several terrestrial mammals. This is the case of the Arctic hare (Lepus arcticus), whose study on Ellesmere Island revealed the longest distance travelled ever documented in a lagomorph, revealing unprecedented mobility capabilities for this order of mammal. More importantly, our observation has important implications for movement ecology and opens new avenues for understanding the functioning of the polar desert, one of the biomes most exposed to global warming.

Full text

Arctic hares: Unsuspected long-distance travelers of the Far North
Émilie Desjardins1 (emilie.desjardins@uqar.ca), Sandra Lai1, Jacob Caron Carrier1, Charline Couchoux1, François Vézina1, Andrew Tam2, Nathan Koutroulides2& Dominique Berteaux1
1 Université du Québec à Rimouski, Quebec Centre for Biodiversity Science & Centre for Northern Studies, Rimouski (QC)
2 Department of National Defence, Astra (ON)
Alert
Lagomorphs (pikas, rabbits, and hares) are small to medium-sized herbivores that occupy diverse
habitats across all continents except Antarctica. They are considered sedentary, and movement is
usually limited to natal dispersal, performed over distances that are short (< 1 km to 35 km).
In the High Arctic, migrations of Arctic hares (Lepus arcticus) have long been suggested, but the
possibility of large-scale movements is often dismissed based on limited mobility capacities of
lagomorphs.
➀Context ➁Methods
Of the 25 collared hares, 20 underwent a
directional fall movement and settled around Lake
Hazen, covering minimum distances of 113-388 km.
Among them, a female named BBYY (Blue/Blue on
left ear and Yellow/Yellow on right ear) traveled the
longest distance ever documented in a lagomorph,
revealing unprecedented mobility capabilities for
this order of mammal!
From her Alert departure to her settlement near
Lake Hazen, she traveled:
388 km over
49 days
Average of
8 km/day
Maximum of
31 km/day
➂Results
Objective: Elucidate the movement ecology of understudied Arctic hares at the northeastern
tip of Ellesmere Island (Nunavut, Canada).
These preliminary results highlight that important natural history surprises may still emerge in familiar
but understudied mammals, generating questions spanning various topics in ecological research:
Arctic hare ecology
The exceptional fall movement of these Arctic hares opens new research avenues about locomotion
capacities, annual movement patterns (migration or nomadism), and social behavior of Arctic hares, as they
may be migrating in groups.
Ecosystem ecology
Animal movements shape food-web dynamics and community structure. Arctic hares may translocate seeds
and pollen, compete with other herbivores, and have several predators such as Arctic wolves, that are
themselves mobile. Determining key processes (e.g., nutrient cycling, herbivory, predation) transferred along
with Arctic hare movements is thus essential to better understand their impact on ecosystem functioning.
Movement ecology
Long-distance movements are favored in highly seasonal, poor, or stochastic environments. The Lake Hazen
area is a thermal polar oasis presenting a milder microclimate and a higher plant productivity than the
surrounding polar desert. The polar desert areas like Alert may, however, have less predators. Exploiting such
heterogeneity in the landscape may benefit Arctic hares, leading to a migratory or nomadic strategy.
Conservation biology
Human modifications of landscapes and climate have already severely reduced the extent of animal
movements worldwide. Recognizing the large scale at which movement occurs in Arctic hares calls for
effective conservation of a mobile species living in one of the biomes most exposed to climate warming.
➃Implications
60°
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120°90°60°
17 Sep 2019
18 June 2019
29 Nov 2019
01 Oct 2019
17 Oct 2019
N
S
W E
100 km500
At Alert (82°30'N, 62°20'W), in summer 2019,
25 Arctic hares were ear tagged and equipped with
Argos satellite collars.
Argos collars provided one location per day, based on
the smallest location error.
Greenland
Ellesmere
Island