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Caribou, water, and ice - fine-scale movements of a migratory arctic ungulate in the context of climate change.

Leblond M, St-Laurent MH, Côté SD - Mov Ecol (2016)

Bottom Line: Although ice phenology did not change significantly during our study, climate projections indicated that ice availability could decrease considerably before the end of the century, generating a ~28 % increase in distance travelled by caribou during the early spring and fall migrations.We demonstrated that ice availability influenced the movements of a migratory arctic ungulate.The long-term conservation of wide-ranging species will ultimately depend on our ability to identify the fine-scale behavioural reactions of individuals to broad-scale changes in climate and land use.

View Article: PubMed Central - PubMed

Affiliation: Caribou Ungava, Département de biologie, and Center for Northern Studies, Université Laval, 1045 avenue de la Médecine, Québec, QC G1V 0A6 Canada.

ABSTRACT

Background: Freshwater lakes and rivers of the Northern Hemisphere have been freezing increasingly later and thawing increasingly earlier during the last century. With reduced temporal periods during which ice conditions are favourable for locomotion, freshwater bodies could become impediments to the inter-patch movements, dispersion, or migration of terrestrial animals that use ice-covered lakes and rivers to move across their range. Studying the fine-scale responses of individuals to broad-scale changes in ice availability and phenology would help to understand how animals react to ongoing climate change, and contribute to the conservation and management of endangered species living in northern environments. Between 2007 and 2014, we equipped 96 migratory caribou Rangifer tarandus caribou from the Rivière-aux-Feuilles herd in northern Québec (Canada) with GPS telemetry collars and studied their space use. We measured contemporary (digital MODIS maps updated every 8 days, 2000-2014) and historical (annual observations, 1947-1985) variations in freshwater-ice availability and evaluated the concurrent responses of caribou to these changes.

Results: Ice had a positive influence on caribou movement rates and directionality, and caribou selected ice and avoided water when moving across or in the vicinity of large water bodies. When ice was unavailable, caribou rarely swam across (6 % of crossings) and frequently circumvented water bodies for several km. Although ice phenology did not change significantly during our study, climate projections indicated that ice availability could decrease considerably before the end of the century, generating a ~28 % increase in distance travelled by caribou during the early spring and fall migrations.

Conclusions: We demonstrated that ice availability influenced the movements of a migratory arctic ungulate. Warmer air temperatures in the Arctic will undoubtedly modify the phenology of ice forming on freshwater lakes and rivers. If migratory caribou are unable to adjust the timing of their migrations, they could be forced to circumvent unfrozen water bodies more frequently and over broader areas, which may increase the distance, time, and energy they use to reach wintering areas. The long-term conservation of wide-ranging species will ultimately depend on our ability to identify the fine-scale behavioural reactions of individuals to broad-scale changes in climate and land use.

No MeSH data available.


Related in: MedlinePlus

Proportion of ice and water on the largest water bodies used by migratory caribou. Ice and water coverages were estimated using 8-day averaged MODIS values from 2000 to 2014. Extreme values of -1.0 and 1.0 respectively represent open water and completely frozen water bodies
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Fig2: Proportion of ice and water on the largest water bodies used by migratory caribou. Ice and water coverages were estimated using 8-day averaged MODIS values from 2000 to 2014. Extreme values of -1.0 and 1.0 respectively represent open water and completely frozen water bodies

Mentions: We only applied this equation to the cells of the MODIS raster grid that encompassed the retained water bodies. Other features (i.e., land, snow, and clouds) were assigned a value. This equation generated values ranging between −1.0 (i.e., open water) and 1.0 (i.e., completely frozen). We plotted this index across years (Fig. 2), and used the Julian days at the x-intercepts as our reference points to study temporal trends between 2000 and 2014. These reference points represented dates when water bodies in our study area went from mostly frozen to mostly thawed (i.e., from a negative to a positive index value), and vice versa. We modeled lake thawing and freezing date trends during the 2000–2014 period using linear regressions in R 3.1.1 [37]. We also explored historical thawing and freezing trends in our region using data collected on Lake Nichicun (Northern Québec, Canada) from 1947 to 1985 (see Additional file 3). Finally, we assessed the relationship between annual breakup or freeze dates of the largest water bodies used by caribou (2000–2014) or of Lake Nichicun (1947–1985) and monthly values of broad-scale climatic oscillations, i.e., the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO; see Additional file 4).Fig. 2


Caribou, water, and ice - fine-scale movements of a migratory arctic ungulate in the context of climate change.

Leblond M, St-Laurent MH, Côté SD - Mov Ecol (2016)

Proportion of ice and water on the largest water bodies used by migratory caribou. Ice and water coverages were estimated using 8-day averaged MODIS values from 2000 to 2014. Extreme values of -1.0 and 1.0 respectively represent open water and completely frozen water bodies
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4837602&req=5

Fig2: Proportion of ice and water on the largest water bodies used by migratory caribou. Ice and water coverages were estimated using 8-day averaged MODIS values from 2000 to 2014. Extreme values of -1.0 and 1.0 respectively represent open water and completely frozen water bodies
Mentions: We only applied this equation to the cells of the MODIS raster grid that encompassed the retained water bodies. Other features (i.e., land, snow, and clouds) were assigned a value. This equation generated values ranging between −1.0 (i.e., open water) and 1.0 (i.e., completely frozen). We plotted this index across years (Fig. 2), and used the Julian days at the x-intercepts as our reference points to study temporal trends between 2000 and 2014. These reference points represented dates when water bodies in our study area went from mostly frozen to mostly thawed (i.e., from a negative to a positive index value), and vice versa. We modeled lake thawing and freezing date trends during the 2000–2014 period using linear regressions in R 3.1.1 [37]. We also explored historical thawing and freezing trends in our region using data collected on Lake Nichicun (Northern Québec, Canada) from 1947 to 1985 (see Additional file 3). Finally, we assessed the relationship between annual breakup or freeze dates of the largest water bodies used by caribou (2000–2014) or of Lake Nichicun (1947–1985) and monthly values of broad-scale climatic oscillations, i.e., the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO; see Additional file 4).Fig. 2

Bottom Line: Although ice phenology did not change significantly during our study, climate projections indicated that ice availability could decrease considerably before the end of the century, generating a ~28 % increase in distance travelled by caribou during the early spring and fall migrations.We demonstrated that ice availability influenced the movements of a migratory arctic ungulate.The long-term conservation of wide-ranging species will ultimately depend on our ability to identify the fine-scale behavioural reactions of individuals to broad-scale changes in climate and land use.

View Article: PubMed Central - PubMed

Affiliation: Caribou Ungava, Département de biologie, and Center for Northern Studies, Université Laval, 1045 avenue de la Médecine, Québec, QC G1V 0A6 Canada.

ABSTRACT

Background: Freshwater lakes and rivers of the Northern Hemisphere have been freezing increasingly later and thawing increasingly earlier during the last century. With reduced temporal periods during which ice conditions are favourable for locomotion, freshwater bodies could become impediments to the inter-patch movements, dispersion, or migration of terrestrial animals that use ice-covered lakes and rivers to move across their range. Studying the fine-scale responses of individuals to broad-scale changes in ice availability and phenology would help to understand how animals react to ongoing climate change, and contribute to the conservation and management of endangered species living in northern environments. Between 2007 and 2014, we equipped 96 migratory caribou Rangifer tarandus caribou from the Rivière-aux-Feuilles herd in northern Québec (Canada) with GPS telemetry collars and studied their space use. We measured contemporary (digital MODIS maps updated every 8 days, 2000-2014) and historical (annual observations, 1947-1985) variations in freshwater-ice availability and evaluated the concurrent responses of caribou to these changes.

Results: Ice had a positive influence on caribou movement rates and directionality, and caribou selected ice and avoided water when moving across or in the vicinity of large water bodies. When ice was unavailable, caribou rarely swam across (6 % of crossings) and frequently circumvented water bodies for several km. Although ice phenology did not change significantly during our study, climate projections indicated that ice availability could decrease considerably before the end of the century, generating a ~28 % increase in distance travelled by caribou during the early spring and fall migrations.

Conclusions: We demonstrated that ice availability influenced the movements of a migratory arctic ungulate. Warmer air temperatures in the Arctic will undoubtedly modify the phenology of ice forming on freshwater lakes and rivers. If migratory caribou are unable to adjust the timing of their migrations, they could be forced to circumvent unfrozen water bodies more frequently and over broader areas, which may increase the distance, time, and energy they use to reach wintering areas. The long-term conservation of wide-ranging species will ultimately depend on our ability to identify the fine-scale behavioural reactions of individuals to broad-scale changes in climate and land use.

No MeSH data available.


Related in: MedlinePlus