Climatic variability as a driver of spring moult phenology in a population of arctic foxes in Norway
(2021) BIOM02 20202Degree Projects in Biology
- Abstract
- Arctic environments are subject to high seasonal variability. For the species inhabiting these latitudes, adaptation to both harsh winters and milder summers is necessary. Among the few mammals capable of sustaining such variable circannual conditions, the arctic fox (Vulpes lagopus) shows remarkable morphological and physiological traits that enable individuals to remain in the Fennoscandian tundra year-round. One of its most striking adaptations is perhaps through its seasonal change of coat, where foxes moult from a dense, pale winter pelage to a shorter, darker summer coat. In addition to the thermoregulatory role of the moult, this seasonally dichromatic coat provides an efficient camouflage in a landscape where snow is present only... (More)
- Arctic environments are subject to high seasonal variability. For the species inhabiting these latitudes, adaptation to both harsh winters and milder summers is necessary. Among the few mammals capable of sustaining such variable circannual conditions, the arctic fox (Vulpes lagopus) shows remarkable morphological and physiological traits that enable individuals to remain in the Fennoscandian tundra year-round. One of its most striking adaptations is perhaps through its seasonal change of coat, where foxes moult from a dense, pale winter pelage to a shorter, darker summer coat. In addition to the thermoregulatory role of the moult, this seasonally dichromatic coat provides an efficient camouflage in a landscape where snow is present only part of the year. With the rise of climate change, larger species have expanded their distributional ranges northward, imposing new pressures on the relatively small arctic fox from intraguild predation and competition. In this context, adequate timing of moulting is critical, while reduced snow cover duration and extent is expected to increase the frequency of mismatches of a white winter coat on a snowless background. In this study, I investigated the possibility of arctic foxes to adapt to changing inter-annual environmental conditions, by looking at plasticity in their spring moult phenology. The study was conducted in one of today’s largest inland subpopulation of arctic foxes, where the two main morphs, white and blue, co-occur. Using images obtained from remote wildlife camera traps, I characterized the moult progression of 176 individual arctic foxes, from initiation (start date) to completion (end date), over the period 2011-2018. Interannual climatic conditions over this period varied considerably, including both particularly warm and particularly cold years, and governed the timing and rate of the spring moult. Snow cover duration was found to be the strongest driver of the phenology of moulting, with foxes losing fur earlier and at a faster rate with decreasing numbers of days with snow on the ground. Temperature was another predictor, complementary to snow cover, and a shift towards later moulting under colder conditions was recorded. Lastly, white foxes were found to moult earlier than blue individuals only in warm years with particularly short snow cover durations. These results suggest that arctic foxes are capable of matching local environmental conditions through plasticity in their spring moulting phenology, potentially offsetting some of the detrimental consequences of climate change-induced stressors on the species. (Less)
- Popular Abstract
- The arctic’s best turncoats
Species living in the arctic experience highly variable conditions from one season to the other and need to adapt to both harsh winters and milder summers. Among the few animals capable of living year-round at these high latitudes, the arctic fox (Vulpes lagopus) displays specific strategies that allow individuals to tolerate the coldest temperatures. One of its most efficient adaptations is perhaps its seasonal change of coat, a phenomenon known as moulting, where the animal’s fur transitions from a short summer coat to a longer, denser winter pelage. With an increase of fur thickness by 140% in winter, arctic fox’s pelt is the warmest of any arctic animal. The function of the moult is however not limited to... (More) - The arctic’s best turncoats
Species living in the arctic experience highly variable conditions from one season to the other and need to adapt to both harsh winters and milder summers. Among the few animals capable of living year-round at these high latitudes, the arctic fox (Vulpes lagopus) displays specific strategies that allow individuals to tolerate the coldest temperatures. One of its most efficient adaptations is perhaps its seasonal change of coat, a phenomenon known as moulting, where the animal’s fur transitions from a short summer coat to a longer, denser winter pelage. With an increase of fur thickness by 140% in winter, arctic fox’s pelt is the warmest of any arctic animal. The function of the moult is however not limited to regulating body temperature, it also provides an efficient camouflage against the landscapes of the tundra. Indeed, seasonal coats are typically pale (often white) during the snow-covered winter months and significantly darker (often brown) in summer.
With the rise of climate change, special attention has been given to the arctic, where global warming operates at a faster pace. Milder temperatures and subsequent reduced snow give a new face to these particularly vulnerable regions. Animals that thrive in these habitats need to keep up with the rapid change, and as global warming progresses, new threats appeared for the arctic fox. Larger species such as the red fox expanded their range northward and now overlap with arctic fox’s territory, bringing with them the threat of predation and competition for resources. In this context, adequate background matching is essential, whereas mismatch is expected to increase in frequency as snow decreases in amount and extent.
This study investigates the capability of arctic foxes to modulate their winter-to-summer moult, in order to best fit changes in climatic conditions. To achieve this, pictures from wildlife camera traps located on feeding stations near active den sites were collected over the period 2011-2018, where climatic conditions varied substantially from one year to another. Based on these pictures, the date of several moult progression stages (from 100% to 0% winter fur) was recorded for 176 individuals within one of today’s largest populations of arctic foxes in Norway, where both white and blue morph arctic foxes co-occur.
Arctic foxes lose their fur earlier and at a faster rate in cold, snowy years. The start and duration of fur change is mainly governed by the number of days with continuous snow on the ground, and temperature has some complementary influence. For instance, in 2015, where the average duration of snow on the ground was 49 days longer than in 2011, arctic foxes at the study site completed their full moult on average 39 days later. Additionally, foxes of the white morph moult earlier than blue ones on particularly warm years, with no difference observed otherwise. These findings suggest that arctic foxes adapt the timing of their moult to match environmental conditions, which could reduce some of the pressures imposed by climate change. Understanding the resilience capability of threatened species such as the arctic fox is critical to provide context for conservation action planning. Flexibility in the moult timing in response to climatic variables should be investigated further to determine whether the phenomenon occurs at a larger scale.
Master’s Degree Project in Biology, Conservation Biology 30 credits 2021
Department of Biology, Lund University
Advisors: Craig Jackson and Ola Olsson
The Norwegian Institute for Nature Research and the Biodiversity Unit of the Department of Biology (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9041667
- author
- Laporte-Devylder, Lucie
- supervisor
- organization
- course
- BIOM02 20202
- year
- 2021
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9041667
- date added to LUP
- 2021-03-11 11:36:26
- date last changed
- 2021-03-11 11:36:26
@misc{9041667,
abstract = {{Arctic environments are subject to high seasonal variability. For the species inhabiting these latitudes, adaptation to both harsh winters and milder summers is necessary. Among the few mammals capable of sustaining such variable circannual conditions, the arctic fox (Vulpes lagopus) shows remarkable morphological and physiological traits that enable individuals to remain in the Fennoscandian tundra year-round. One of its most striking adaptations is perhaps through its seasonal change of coat, where foxes moult from a dense, pale winter pelage to a shorter, darker summer coat. In addition to the thermoregulatory role of the moult, this seasonally dichromatic coat provides an efficient camouflage in a landscape where snow is present only part of the year. With the rise of climate change, larger species have expanded their distributional ranges northward, imposing new pressures on the relatively small arctic fox from intraguild predation and competition. In this context, adequate timing of moulting is critical, while reduced snow cover duration and extent is expected to increase the frequency of mismatches of a white winter coat on a snowless background. In this study, I investigated the possibility of arctic foxes to adapt to changing inter-annual environmental conditions, by looking at plasticity in their spring moult phenology. The study was conducted in one of today’s largest inland subpopulation of arctic foxes, where the two main morphs, white and blue, co-occur. Using images obtained from remote wildlife camera traps, I characterized the moult progression of 176 individual arctic foxes, from initiation (start date) to completion (end date), over the period 2011-2018. Interannual climatic conditions over this period varied considerably, including both particularly warm and particularly cold years, and governed the timing and rate of the spring moult. Snow cover duration was found to be the strongest driver of the phenology of moulting, with foxes losing fur earlier and at a faster rate with decreasing numbers of days with snow on the ground. Temperature was another predictor, complementary to snow cover, and a shift towards later moulting under colder conditions was recorded. Lastly, white foxes were found to moult earlier than blue individuals only in warm years with particularly short snow cover durations. These results suggest that arctic foxes are capable of matching local environmental conditions through plasticity in their spring moulting phenology, potentially offsetting some of the detrimental consequences of climate change-induced stressors on the species.}},
author = {{Laporte-Devylder, Lucie}},
language = {{eng}},
note = {{Student Paper}},
title = {{Climatic variability as a driver of spring moult phenology in a population of arctic foxes in Norway}},
year = {{2021}},
}