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ArcticNet Annual Research Compendium (2012-13)

Population Dynamics of Migratory Caribou in Nunavik/Nunatsiavut

Project LeaderSteeve Côté (Université Laval)

Network InvestigatorsMarco Festa-Bianchet (Université de Sherbrooke), Christian Dussault (Université du Québec à Rimouski), Jean-Pierre Tremblay (Université Laval)

Collaborators and Research AssociatesKyle Joly (Alaska National Park Service); Elyn Humphreys (Carleton University); LeeAnn Fishback (Churchill Northern Studies Centre); Skarphéðinn G. Þórisson (East Icenland Natural History Institute); Leonid Kolpashikov (Extreme North Agricultural Research Institute); David Elliott, John Pisapio, Isabelle Schmelzer (Government of Newfoundland and Labrador (Environment and Conservation) Debbie Jenkins (Government of Nunavut); Christine Cuyler (Greenland Institute of Natural Resources); Perry Barboz, Kris Hundertmark (University of Alaska Fairbanks); Brett Elkin (Government of the Northwest Territories); Luise Hermanutz (Memorial University of Newfoundland); Vincent Brodeur, Serge Couturier, Denis Vandal, Charles Jutras, Stéphane Rivard (Ministère des Ressources Naturelles et de la Faune); Joaquín Ortego (Museo Nacional de Ciencias Naturales, Spain); Knut Roed (Norwegian School of veterinary science); Diane Chaumont, Maja Rapaic (Ouranos); Paul Grogan, Paul Treitz (Queen’s University); Taras Sipko (Russian Academy of Sciences); R. Justin Irvine (The James Hutton Institute); Peter Lafleur (Trent University); Antoine Guisan, Loïc Pellissier (Université de Lausanne); Stéphane Lair (Université de Montréal); Esther Lévesque (Université du Québec à Trois-Rivières); Louis Bernatchez, Stéphane Boudreau, Nicolas Lecomte, Émilie Champagne, Caroline Hins (Université Laval); Jeffrey Welker (University of Alaska Anchorage); Susan Kutz, Marco Musiani (University of Calgary); Marina Kolodova (University of Lomonosov Moscow); Parker Katherine (University of Northern British Columbia); Jill Johnstone (University of Saskatchewan); David Paetkau (Wildlife genetics international)

Post-Doctoral FellowsGlenn Yannic (Université Laval)

PhDBen Dalziel (Cornell University); Mael Le Corre, Joëlle Taillon (Université Laval)

MScJulie Ducrocq (Université de Montréal); Melanie Pachkowski, Masters Student (Université de Sherbrooke); Alexandre Rasiulis, Valérie Saucier, Alice-Anne Simard (Université Laval)

Northern HQPMichael Kwan, Peter May, Manon Simard (Makivik Corporation)

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Key Messages• Body mass should be collected in priority when

assessing body condition of caribou as it integrates variation in protein and fat reserves.

• Caribou calves were 8 % heavier at birth and 20 % heavier at weaning in a herd at low population size (i.e. Rivière-George herd) compared to one at high population size (i.e. Rivière-aux-Feuilles herd). These results suggest that the impact of population size may differ depending on season, because of different energetic demands faced by mothers and offspring.

• Adult female mass and hind foot length in spring predict pregnancy rates in caribou.

• We developed a life history model that can be used to estimate population sizes between aerial censuses. Our results allowed us to close the debate about the 2001 population census for the Rivière-aux-Feuilles herd, with an estimate of 630 000.

• Despite a recent re-definition and expansion, our work revealed that legally designated Wildlife Habitats in Québec on average protected less than 20 % of the Rivière-George and Rivière-aux-Feuilles calving grounds. Clearly, protection of calving grounds must consider the dynamic use of space by adult females.

• The fall migration patterns of migratory caribou in Northern Québec and Labrador had tended to stabilise in recent years. Changes in the spring and fall migratory routes occurred simultaneously with changes in the use of winter ranges. In both seasons, snow conditions seem to be the key factor driving changes in migratory behavior.

• Our results supported by both microsatellites and mtDNA divided populations of Rangifer into two geographically structured lineages. The first lineage covers a vast portion of the species range, from Eurasia to North-western America, including Greenland, Svalbard, and the Canadian archipelago. The second lineage includes herds distributed from the island of Newfoundland to the interior plains of Canada.

• Forecasting the range of the species in 2080, we predict a strong modification of the distribution of caribou. Under the severe climatic warming scenario considered, our model predicts the distribution of caribou to become even more restricted to high latitudes than today, with possible extinctions in the most southern regions.

• Caribou from the Rivière-aux-Feuilles and Rivière-George herds harbored higher Besnoitia tarandi burden compared to the other herds sampled herds in North-America.

• Our results indicate that Mycobacterium avium subspecies paratuberculosis (MAP) is present in several caribou herds of different ecotypes in northern Canada and Greenland and that MAP circulates within wildlife populations that do not have ongoing contact with domestic livestock.

• Our results highlight that the potential for compensatory growth in dwarf birch is surpassed under heavy browsing pressure independently of the fertilisation regime. In the context of the worldwide decline in caribou herds, the reduction in browsing pressure could act synergistically with global climate change to promote the current shrub expansion reported in subarctic regions.

• Preliminary results on space use of wolves revealed that they undertake long migrations along side caribou. Black bears appear to concentrate on the calving grounds of the Rivière-George herd.

Objectives1. To determine life-history variation in known-age

individuals, more specifically to assess longitu-dinally age-specific survival and reproduction of radio-collared animals and transversally the age distribution of harvested animals (Ph.D 1 – J. Taillon, M.Sc. 1 – M. Pachkowski, M.Sc. 5 – A. Rasiulis; Collaborators – V. Brodeur and S. Cou-turier).

2. To analyze habitat selection of migratory caribou

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at different scales in all seasons, in particular in relation to migration routes and anthropogenic disturbance. To continue modeling the effects of climate change on the distribution of caribou. To use remote sensing tools to link changes in veg-etation phenology and movements of caribou (Ph.D 2 – M. Le Corre, Ph.D 3 – B. Dalziel).

3. To determine the genetic structure of caribou/reindeer populations throughout their circumpo-lar distribution. To assess the connectivity and gene flow between caribou/reindeer populations and determine the importance of migratory cari-bou for the conservation of the threatened seden-tary (forest) ecotype of caribou (Post-doc 1 – G. Yannic; Collaborators – L. Bernatchez, K. Røed, K. Hundertmark, D. Paetkau, C. Cuyler, M. Mu-siani, D. Jenkins, M. Kholodova).

4. To study the impact of parasites (e.g. Besnoitia, liver flukes) on the ecology of caribou and the health of indigenous people. To compare parasite diversity of caribou from Québec with those else-where in the Arctic (M.Sc. 2 – J. Ducrocq, MSc 6 – Alice-Anne Simard; Collaborators – S. Kutz, B. Elkin, S. Lair).

5. To expand the vegetation and habitat project to include the relationships between soil-vegetation characteristics and the grazing ecology of caribou in an interactive ecological model using a spatial-ly explicit approach, and a replicated greenhouse experiment (M.Sc. 3 – E. Champagne, M.Sc. 4 – V. Saucier; Collaborators – E. Lévesque, L. Her-manutz, P. Grogan).

6. To study the impact of predation by wolves and black bears on the population dynamics of cari-bou by initiating a large-scale monitoring pro-gram of predators using satellite collars (PhD 4– to be determined, Ph.D 5 – to be determined).

Introduction

Migratory caribou (Rangifer tarandus) are central to the ecology of northern areas and are at the heart

of this region’s culture and economy. Despite major monitoring and research efforts, caribou remain poorly known, making their management problematic. Most caribou populations have witnessed major variations in their abundance in the past and their numbers are still changing today (Vors and Boyce 2009). Climate change will likely have multiple effects on the northern habitats of migratory caribou. For example, more snow or rain in late winter could compromise movements and foraging behaviour (Weladji and Holand 2003, Tyler 2010). A milder climate will shorten the period when hydroelectric reservoirs are frozen, which could influence the timing of migration, the choice of migratory routes and even increase the risk of mass drownings. These expected effects could have repercussions on the energy balance and survival of animals as well as on dispersal between populations (Boulet et al. 2007). Changes in the spring phenology of plants (Post and Stenseth 1999) could lead to a phase shift between the period of abundance of high-quality food and the peak of lactation (Pettorelli et al. 2007). Given the scope of anticipated climate change, there is much concern about its potential effects on caribou and on the interactions between plants and caribou.

Several major hydroelectric and mining projects have been developed within the habitat of migratory caribou in Québec and Labrador(Jean and Lamontagne 2005), and more are planned. The cumulative effects of human disturbance may reduce the availability or quality of essential habitats such as calving grounds (Johnson et al. 2005, Taillon et al. 2012). The assessment of the impact of human activities on caribou space use and the habitat of caribou as well as on the choice of migratory routes is essential to understand its population dynamics (Bolger et al. 2008).

A decrease in the abundance and distribution of caribou could have negative repercussions on Aboriginal Peoples and on the outfitting industry of Northern Québec and Labrador. The recent decline of the Rivière-George herd raised questions about the sustainability of sport and subsistence harvest on this

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herd and a greater knowledge of population dynamics is needed to ensure the conservation of this resource. A long-term research program is essential to improve the management and conservation of migratory caribou. Several characteristics of caribou (long life expectancy, reproduction over 5 to 10 years, influence of age on reproduction and survival rates) necessarily imply major temporal variations in the dynamics of populations. To understand the impact of factors that are dependent and independent of density (e.g. climate factors), it is necessary to analyze a long time series covering a wide range of conditions.

We concentrate our research on the two large herds of migratory caribou in northern Québec and Labrador, the Rivière-George and Rivière-aux-Feuilles herds. These populations have been monitored for >20 years through satellite collars by the Ministère des Ressources naturelles et de la Faune du Québec, a major partner in our research program, and more recently by Caribou Ungava. Both herds are central to the economy and traditional life of northern peoples. The future demography of migratory caribou facing climate change and industrial development of the North is essential to understand in the context of the Integrated Regional Impact Studies of ArcticNet and the up-coming Plan Nord of the Québec government.

Activities

Fieldwork activities

• February and March 2012 – We replaced collars nearing the end of their battery life on 43 caribou of both Rivière-George and Rivière-aux-Feuilles herds. Six collars were installed on wolves. We conducted fieldwork in partnership with the MRNF and the Government of Labrador.

• June 2012 – We captured and weighed 30 newborns in each caribou herd. We fitted 15 new satellite collars on yearling female caribou from the Rivière-aux-Feuilles herd. We also fitted 12 new satellite collars on yearling females and 4 on adult males of the Rivière-George herd. Four radio-collars from dead caribou were recovered.

Finally, 4 black bears and one wolf were fitted with satellite collar on the Rivière-aux-Feuilles herd range and 10 black bears on the Rivière-George herd range. We conducted fieldwork in partnership with the MRNF and the Government of Labrador.

• June to August 2012 – We monitored vegetation in our experimental design installed in the caribou summer habitat at Deception Bay, Nunavik. We also monitored shrub species in the 15 exclosures (9m2 each) installed in 2011. We conducted fieldwork in partnership with Xstrata – Mine Raglan.

• October 2012 – We continued the monitoring of reproductive success of radiocollared females (calf presence/absence). We also recovered 14 collars in mortality mode and 2 black bear collars on the Rivière-George herd range. We replaced satellite collars at the end of their battery-life on 7 caribou of both herds. We conducted the classification of more than 4000 individuals from each of the Rivière-George and Rivière-aux-Feuilles herds and performed a recruitment survey for both herds. We conducted fieldwork in partnership with the MRNF and Government of Labrador.

Meetings, conferences and workshops

• May 2012 – We organized the third annual symposium of Caribou Ungava at Université Laval. Researchers, students, wildlife managers, outfitters and partners participated in the conferences.

• May 2012 – We held a spring meeting of the scientific committee of the caribou project to plan fieldwork activities for the summer.

• November 2012 – We held a fall meeting with all the collaborators of the project to present an overview of fieldwork activities in 2012, to plan research activities for 2013 and to initiate work for the renewal of our NSERC-CRD grant.

• Spring, Summer and Autumn 2012 – We

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presented our results at the International Polar Year 2012 Conference, the 50th annual meeting of the Centre for Northern Studies, the annual meeting of Québec’s Outfitters, the 14th North American Caribou Workshop, the 37th annual meeting of the Société Québécoise pour l’Étude Biologique du Comportement, and the 8th Arcticnet annual scientific meeting.

Results

Objective 1. To determine life-history variation in known-age individuals, more specifically to assess longitudinally age-specific survival and reproduction of radio-collared animals and transversally the age distribution of harvested animals.

1.1 - 1.2 - 1.3 Our major results concerning the effects of maternal characteristics on juvenile mass, size and fat storage, on conception probability, and on the effects of population size on maternal phenotype and fat reserves were presented in our report last year. Most of those results are now published or submitted, in:

• Taillon, J., V. Brodeur, M. Festa-Bianchet and S. D Côté. 2012. Is mother condition related to offspring condition in migratory caribou at calving and weaning? Canadian Journal of Zoology 90: 393-402.

• Taillon, J., V. Brodeur, M. Festa-Bianchet and S. D Côté. 2011. Variation in body condition of migratory caribou at calving and weaning – which measures should we use? Ecoscience 18: 295-303.

• Pachkowski, M. D., S. D. Côté and M. Festa-Bianchet. Spring-loaded reproduction: effects of body condition and population size on fertility in migratory caribou (Rangifer tarandus). Submitted to Canadian Journal of Zoology, December 2012

1.4 Information on demographic parameters such as

survival and reproduction is central to understand population dynamics (Lebreton et al. 1992, Sandercock 2006). Although changes in fecundity and recruitment rates may have a substantial impact on population growth (Blakesley et al. 2010), any changes in adult survival rates in long-lived species can become key drivers of temporal variation in population size (Gaillard et al. 2000, Saether et al. 2000). Using data from long-term satellite monitoring of migratory caribou, we sought to evaluate the survival rate of adults from both herds in Québec-Labrador and assess environmental factors influencing survival. Adult female survival for both herds was stable throughout the study period, with a few exceptions in each herd (Figure 1). Survival was dramatically lower in the Rivière-George herd than in the Rivière-aux-Feuilles herd. Females in the Rivière-aux-Feuilles herd had an average survival of 88 % (CV = 0.110, ĉ < 1) between 1993 and 2011. Adult female survival rarely dropped below 85 % and only twice, in 2002 and 2007 did it fall below 70%. In contrast, females of the Rivière-George herd had an average survival of only 72 % (CV = 0.105, ĉ < 1) between 1991 and 2011 with yearly

survival lower than 80 % in each year except 2001.

Demographic parameters not only provide a better understanding of past population trends (Arthur et

Figure 1. Annual survival rate of adult female caribou from the Rivière-George herd (RGH) and Rivière-aux-Feuilles herd (RAFH), with 95% confidence intervals. Labels indicate the number of individuals monitored each year.

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al. 2003), they can also be used to predict future population sizes (Kruse et al. 2004, Heppell et al. 2005). In addition, population estimates based on demographic parameters offer an alternative to other population monitoring techniques such as aerial censuses or capture-mark-recapture estimates (Fancy et al. 1994, Arthur et al. 2003). We used adult female, adult male and yearling annual survival, calf winter survival, fall calf recruitment and fall sex ratio to construct a deterministic life history model to estimate historic annual population size for the Rivière-aux-Feuilles and Rivière-George herds. Survival rates were calculated using long-term satellite monitoring while calf recruitment and sex ratio were observed annually during the fall classification. We took as our baseline aerial population estimates from 1991. This model estimates that the Rivière-aux-Feuilles herd reached a maximum of approximately 629 000 individuals in 2001 and 2002. The population then dropped to approximately 366 000 in 2010 before increasing slightly to 389 000 in 2012. For 2011, the model estimated a population size within 55 000 caribou of that estimated with an aerial census (less than the 95 % confidence interval of 98 900 of the aerial census) using an initial population size dating back 20 years (Figure 2). A similar model was used to estimate annual population sizes for the Rivière-George herd between 2001 and 2012 (Figure 3). Using the estimated population size from the 2001 aerial

census we were able to estimate the 2010 population size within 5 500 individuals of the 2010 census count (IC = 12 602). For 2012, the model population size estimate was approximately 9 700 individuals over the census estimate of 27 600 (CI = 2 760).

As with other ungulate species, adult female survival is very important for caribou population dynamics (Gaillard et al. 1998). Juvenile survival and calf recruitment, however, are thought to be much more variable and therefore can have a great net impact on population dynamics (Gaillard et al. 2000). We have found that calf recruitment variability was not significantly different from the variability in female survival rates for both Rivière-aux-Feuilles herd (P = 0.38) and Rivière-George herd (P = 0.12). Furthermore, a closer look at the Rivière-aux-Feuilles herd during phases of decline, stability and growth, revealed that yearly variability was greatest during the decline (Figure 4). We compared the coefficients of variation (CV) seen in figure 4 to CVs from other caribou herds across North-America and found that herds experiencing a decline often had a CV > 0.15 while stable or growing herds had CV < 0.10.

1.5 Currently, no calving ground of migratory caribou in North America is under permanent protection, although small portions of the annual ranges of a few herds are protected (Hummel and Ray 2008). In the late 1990s, the Québec Provincial Government designated the

Figure 2. Aerial census data (with 95% confidence intervals) and annual population size estimates obtained from a life history model between 1991 and 2012 for the Rivière-aux-Feuilles caribou herd.

Figure 3. Aerial census data (with confidence intervals) and annual population size estimates obtained from a life history model between 2001 and 2012 for the Rivière-George caribou herd.

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calving grounds of both herds of migratory caribou in Northern Québec and Labrador as Wildlife Habitat, legally prohibiting activities that could be detrimental to caribou habitat within the defined area. Wildlife Habitats were first mapped based on calving ground aerial surveys in 1991 and 1993. Their boundaries were updated in 2004 based on satellite locations of caribou females. We assessed changes in size and location of calving grounds based on 15 years of aerial surveys (1973–1988) and 20 years of satellite telemetry locations (1990–2010), and evaluated the proportion of annual calving grounds within protected Wildlife Habitat. The annual size and location of calving grounds changed substantially over time: calving ground size remained relatively stable for the Rivière-aux-Feuilles herd but it declined over 85 % for the Rivière-George herd. Calving grounds moved 300 km northward in the Ungava peninsula for the Rivière-aux-Feuilles herd and shifted over 230 km back and forth to the Labrador coast for the Rivière-George herd. Despite recent modifications, legally designated Wildlife Habitats in Québec typically protect less than 20 % of the Rivière-George and Rivière-aux-Feuilles calving grounds. From 1993 to 2003, an average of 27 ± 5 % (range: 0–52 %) of the Rivière-George annual calving grounds was inside the designated Wildlife Habitat. After the re-definition of the Wildlife Habitat in 2004, the percentage of overlap declined to 10 ± 4 % (range: 0–26 %) from 2004 to 2010 (Figure 5). Overlap between Rivière-aux-Feuilles calving grounds and Wildlife Habitat was low both before and after the redefinition of the Wildlife Habitat in 2004 (1995–2003: 11 ± 4 %, range: 0–36 %; 2004–2010: 23

± 3%, range: 13–31%) (Figure 5). These results are now published:

• Taillon, J., M. Festa-Bianchet and S. D. Côté. 2012. Shifting targets in the tundra: protection of migratory caribou calving grounds must account for spatial changes over time. Biological Conservation 147:163-173.

Asterisks indicate years when there was no overlap between the calving ground and Wildlife Habitat.

Objective 2. To analyze habitat selection by migratory caribou at different scales in all seasons, in particular in relation to migration routes and anthropogenic disturbance. To continue modeling the effects of climate change on the distribution of caribou. To use remote sensing tools to link changes in vegetation phenology and movements of caribou.

2.1 In environments with high seasonal variability

Figure 5. Percentage of overlap between annual calving grounds of the Rivière-George (RG) and Rivière-aux-Feuilles (RAF) migratory caribou herds, and Wildlife Habitats protecting caribou habitat in Northern Québec, Canada. The gray line separates the years before and after Wildlife Habitats were updated. No calving ground estimates were available in 2002 and 2004 for the RG.

Figure 4. Comparison of variability (centered around zero) of annual adult female survival during phases of population decline (2002-2007), growth (1991-2001) and stability (2008-2012) for the Rivière-aux-Feuilles caribou herd.

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such as northern environments, migration is an important large-scale habitat selection process allowing animals to follow seasonal changes in resource availability (Albon and Langvatn 1992) and escape predation pressure (Hebblewhite and Merrill 2007). The migratory caribou of the Rivière-George and Rivière-aux-Feuilles herds perform a long spring migration to reach calving grounds and summer ranges, and a fall migration to return to winter ranges in the boreal forest. Our objective was to discriminate movements within the summer and winter ranges from migration movements and to determine the timing and spatial patterns of migration. We used the First-Passage Time analysis (Fauchald and Tveraa 2003) to characterize caribou movements and to obtain an index that combined both movement rate and path tortuosity throughout the year. We discriminated between different kinds of movements using a model selection procedure locating breakpoints that divided the movement paths in bouts of homogeneous means (Lavielle 2005). We also used the Net-Square

Displacement (Bunnefeld et al. 2011) to better discriminate migratory movements in the fall.

Using data from more than 400 females collared with Argos transmitters between 1987 and 2011, we found different patterns of spring migration for each herd but also changes in the migration pattern for a given herd through time. Last year’s report summarized our findings concerning the use of winter ranges and spring migration. For the fall migration, we identified three types of movements (phases). The first phase is a pre-migratory movement that starts following a short pause in September (Figures 6, 7). This movement can be directed towards the winter range (Figure 6a) or not (Figures 6b, 6c). The second phase starts following a short break or a directional change in the migration and is directed towards the winter range. The third phase is a post-migratory movement that occurs after a break in December, and that we observed in 43 % of the Rivière-aux-Feuilles herd and in 24 % of the Rivière-George herd trajectories (Figures 6c,

Figure 6. Examples of fall migrations. a) migration with a first phase directed toward the winter range, b) migration with a first phase not directed toward the winter range, c) migration with a post-migratory movement occurring in December (third phase. Locations are recorded every 5 days and the path is completed with a point every 12 hours assuming a linear movement and a constant speed between 2 locations.

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7). Through the study period, we observed changes in migration patterns. In the 90s, migration was very variable as caribou used multiple winter areas. There was no clear migration route during that period (Figure 8). In the 2000s, the Rivière-aux-Feuilles herd stopped using the northern wintering area and the Rivière-George herd stopped using the western wintering

areas, resulting in a stabilization of the migration route on a North-East/South-West axis for the Rivière-aux-Feuilles herd and a North-West/South-East axis for the Rivière-George herd (Figure 8). The migration distance also decreased for the Rivière-George herd after abandonment of the western wintering areas.

Figure 7. Example of the relationship between first-passage time (FPT, blue line) and net-square displacement (NSD, black line), from July to March, for an individual caribou displaying a fall migration with 3 phases (fig. 1c). The first phase (P1) starts in late September (drop in FPT). The peak of NSD in October corresponds with the start of the second phase (P2) that ends at the arrival on the wintering area in late November (high FPT). The third phase (P3) starts after a short break and ends in mid-January.

Figure 8. Changes of the fall migration pattern in the Rivière-aux-feuilles (RFH) and Rivière-George (RGH) herds between 1997 and 2011. Each line shows the migratory path of one caribou in one year.

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2.2 Major effects of climate changes are expected in northern environments, including changes in the timing of natural processes (Parmesan and Yohe 2003). For example, snow melt is expected to occur sooner, river and lake ice-free periods to last longer and the length of the growing season to increase, with an earlier peak in vegetation productivity. These ongoing changes in caribou habitat could directly impact the timing and course of their migrations. We conducted preliminary analyses to assess how climate affects the timing of the spring and fall migrations in the two herds. We used the North Atlantic Oscillation index (NAO, Hurrel 1995) and a Canadian Regional Climate Model (CRCM v4.3, de Elia and Côté 2010) with a 45 km resolution to obtain monthly meteorological data (temperature, precipitation, snow water equivalent) that we used to investigate the influence of climate on

the starting and ending dates of migrations. Using the CRCM data, we calculated the average value of the climate data observed near each caribou on a monthly basis for each individual. We performed that analysis on 700 spring migration paths and 800 fall migration paths recorded during the last two decades.

Temperatures increased during the study period, mostly in winter (Figure 9). We tested the effects of temperature, precipitations, snow water equivalent and NAO on departure and arrival dates of the spring and fall migrations. We used weather data from February, March and April to investigate variations in the departure date of the spring migration, and May and June for the arrival date. We respectively used weather data from September and October, and from

Figure 9. Changes in monthly temperatures since 1989 in the range of the Rivière-George (RGH) and Rivière-aux-Feuilles (RFH) herds.

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Table 1. Selected variables from generalized linear mixed models of the timing of caribou migration: date ~ temp. + precip. + swe (snow water equivalent) + NAO (North Atlantic Oscillation), with individual as a random factor, to investigate variations in the departure (a) and the arrival (b) dates of the spring migration and the departure (c) and arrival (d) dates of the fall migration. Variables having a significant effect are indicated with the sign of their coefficient in bold. We selected the most parsimonious models using the Akaike Information Criterion and used model averaging when necessary.

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November and December to investigate changes in the departure and arrival date of the fall migration. For the spring departure date, there was a positive effect of the NAO for the Rivière-aux-Feuilles herd and a negative effect of temperature for the Rivière-George herd in February, suggesting an earlier departure date during mild winters (Table 1a). The arrival date seemed to be delayed during early springs with high precipitations (Table 1b) as an early snow melt and ice break-up will impede caribou movements during migration. On the other hand, the positive relationship between arrival date and June snow water equivalent and NAO of May (Table 1b) indicates that the arrival is delayed when snow is still abundant on calving grounds. A late snow melt will likely limit the accessibility of foraging resources to caribou. For the fall migration, there was a negative effect of the snow water equivalent and NAO on departure date (Table 1c). Departure date was advanced when winter was early and caribou seemed to stay up north until resources were no longer available. The arrival date on wintering areas was affected by weather conditions prevailing in November for the Rivière-aux-Feuilles herd and December for the Rivière-George herd (Table 1d). The negative relationship between arrival date and temperature (Table 1d) indicates that caribou arrive sooner on the winter range when winter is late, likely because late snow fall and late freeze-up facilitate displacements during the migration. The effect of snow water equivalent (Table 1d) indicates that migration also ends sooner when snow is deep. The cost of movements increase, forcing caribou to end their migration sooner.

2.3 Population dynamics emerge from the behaviors of individuals aggregated over space and time. There has been a recent surge of interest in collective movement, which has been shown to have the potential to affect population dynamics in surprising ways. However, most investigations into collective motion have been simulation-based, and the predictions of these models have not often been empirically tested, particularly in large vertebrates. A good example of collective motion in large vertebrates is migration: it is ubiquitous, and its stability may depend on the dynamics of collective

behavior in increasingly variable environments. Here, with migratory caribou, we fitted an advection diffusion model by kernel smoothing regression with bandwidths chosen by cross validation, accounting from 20 % of the variation in velocity. Particles released in this velocity field followed the centroid of the herd. However, the residual velocities were highly correlated in the manner consistent with collective mobility. A preliminary model which included the velocities of nearby caribou captured 50 % of the variation in velocity. When we parameterized a simple canonical model of collective mobility with the parameters estimated from the caribou data, we found that much more simple advection-diffusion maps could produce the same migration paths, and that this system was not sensitive to environmental noise.

Objective 3. To determine the genetic structure of caribou/reindeer populations throughout their circumpolar distribution. To assess the connectivity and gene flow between caribou/reindeer populations and determine the importance of migratory caribou for the conservation of the threatened sedentary (forest) ecotype of caribou.

Understanding how species responded to climatic variability in the past is fundamental for anticipating the effects of ongoing climate change. Surprisingly, the locations of diversity hotspots that should be prioritized in conservation are poorly known in arctic species, which are likely to be the most affected by current climate change. Here we propose a multi-disciplinary approach to quantitatively estimate climate-related past and future changes of genetic diversity in caribou, based on the use of range-wide phylogeographic DNA data analyses and past and future species distribution modeling. A total of 1297 samples were obtained from across the entire native range of caribou, including Alaska (USA), Canada, Greenland, Iceland, Svalbard, Norway, Finland, and the Russian Federation. All samples were successfully genotyped at 16 microsatellite markers. In addition, we sequenced the mitochondrial cytochrome b (cyt

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b – 1143 bp) gene for a subset of samples (n=345) from across the species range. Analyses revealed the existence of two large distinct genetic lineages within caribou, as inferred by a Bayesian genetic clustering (Figure 10A). The phylogenetic reconstructions based on the cytochrome b sequences corroborate previous results on microsatellite data (data reported last year). The two lineages are geographically structured. The first lineage consists of herds located from Newfoundland to the Rocky Mountain foothills, including sedentary woodland caribou, the two migratory caribou herds from Québec / Labrador and mountain caribou from the Torngat Mountains and Gaspesie. The second lineage shows a wider circumpolar distribution. This clade includes migratory caribou, boreal and mountain sedentary and migratory

as well as sedentary reindeer from Western Europe. The timing of the coalescence between the two caribou clades was estimated at 0.300 Myr (95 % highest posterior densities (HPDs): 0.184 – 0.430), during the middle Pleistocene, a time of widespread continental glaciations in North America, which predates the onset of the Last Glacial Maximum (LGM: 21±2kyr BP). During the LGM, extensive climatically suitable areas for caribou were identified in Euro-Beringia, whereas small suitable areas remained south of the ice-sheet covering North America (Figure 10B). This implies more severe population contractions in North America than in the Euro-Beringia region. As the climate began to warm up, the Euro-Beringia and North America clusters expanded their ranges to their current distribution (Figure 10C). The observed secondary

Figure 10. A) Worldwide population genetic structure of caribou/reindeer. We used the program STRUCTURE, based on 16 microsatellite loci typed for 1,297 individuals, to assign samples to one of two genetic clusters: blue for the North American clade and red for the Euro-Beringian clade. B) Hindcasted distribution of caribou genetic lineages, as defined by species distribution modeling during the last glacial maximum, -21kyr ago. C) Current distribution of the two clades. Light blue regions correspond to areas covered by ice C) Predicted distribution of caribou in 2080 under the A1B IPCC4 climate change scenario from the global ocean-atmosphere climate model based on the Hadley Centre climate model (HadCM3). Sienna and yellow regions represent future suitable and unsuitable areas for caribou, respectively.

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contact between the two main hindcasted centers of distribution predicted by simulations of species historical migration is located along a suture line that almost perfectly matches the contact zone predicted by genetic data (85 % of match between the Figures 10A and 10C). Forecasting the range of the species in 2080, we predict a strong modification of the distribution of caribou (Figure 10D). Eighty-nine percent of suitable areas are predicted to be lost for the North America genetic cluster and model predict a loss of 60 % of suitable area for the Euro-Beringia region.

Objective 4. To study the impact of parasites (Besnoitia, liver flukes) on the ecology of caribou and the health of indigenous people. To compare parasite diversity between caribou from Quebec and the rest of the Arctic.

4.1 Prevalence and intensity of parasites in caribou can affect body condition, population dynamics (May and Anderson 1978; Kutz et al. 2012) and, on the socio-economic side, meat quality for First Nations, Inuits and sport hunters. Considering these factors,

prevalence and intensity of some caribou parasites were evaluated in details. Eight barren-ground caribou herds were compared for Besnoitia tarandi infection. Rangifer tarandus is considered the primary intermediate host for this protozoan tissue-dwelling parasite. Results of prevalence and intensity are detailed in last year report and are now published:

Ducrocq, J., G. Beauchamp, S. Kutz, M. Simard, B. Elkin, B. Croft, J. Taillon, S. D. Côté, V. Brodeur, M. Campbell, D. Cooley, C. Cuyler and S. Lair. 2012. Comparison of gross visual and microscopic assessment of four anatomic sites to monitor Besnoitia tarandi in barren-ground caribou (Rangifer tarandus groenlandicus. Journal of Wildlife Diseases 48:732-738.

We developed a standardized protocol to monitor prevalence and intensity of Besnoitia in barren-ground caribou herds. The best measure of infection is microscopic evaluation of a skin section of the metatarsal region. We identified some risk factors that explain variability in B. tarandi infection: males and

Figure 11. Prevalence (proportion of infected individuals in the host population; ± SE) of six of the main macro-parasites of migratory caribou for the Rivière-George herd (RGH; n=696) and the Rivière-aux-Feuilles herd (RAFH; n=229) since 1978 and 1987, respectively.

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young caribou are more at risk of being infected than adult females. These results are also published:

Ducrocq, J., G. Beauchamp, S. Kutz, M. Simard, J. Taillon, S. D. Côté, V. Brodeur and S. Lair. 2013. Variables associated with Besnoitia tarandi prevalence and cyst density in barren-ground caribou (Rangifer tarandus) populations. Journal of Wildlife Diseases 49:29-38.

Finally, we evaluated infection by Mycobacterium avium subspecies paratuberculosis (Map), a well-known pathogen in domestic ruminants. Wild species such as caribou also appears to be susceptible to clinical Map infection. These results are now published:

Forde, T., K. Orsel, J. De Buck, D. Cooley, S. D. Côté, C. Cuyler, T. Davison, B. Elkin, A. Kelly, M. Kienzler, R. Popko, J. Taillon, A. Veitch and S. Kutz. 2012. Detection of Mycobacterium avium subspecies paratuberculosis in several herds of arctic caribou (Rangifer tarandus ssp.). Journal of Wildlife Diseases 48:918-924.

4.2 The ecological niche of arctic parasites is constrained by environmental conditions. Climate changes could therefore affect host-parasite relationships. Multiple studies predict an increase in development and transmission rates, in spatial distribution and in the number of annual generation of parasites in the Arctic, in addition to increased host susceptibility (Kutz et al. 2004, Kutz et al. 2005, Hoberg et al. 2008). Individual characteristics of caribou can also influence parasitism: prevalence and intensity vary with sex and age of individuals. Population density could also modify host-parasite dynamics, although a lag in parasite response can occur in high seasonality environments. We recruited in 2012 an M.Sc. student to quantify prevalence and the intensity of seven caribou macroparasite (Fascioloïdes magna, Taenia hydatigena, Echinococcus granulosus, Taenia krabbei, Hypoderma tarandi, Dictyocaulus viviparus and Cephenemyia trompe) in the Rivière-George and Rivière-aux-

Feuilles herds. We will also compare body condition to parasitism, while accounting for changes in population size. To achieve this second objective, we will obtain data from the CARMA network collaborators. The strength of this study resides in the numbers of years (>20 for some herds) for different herd sizes, seasons and individuals of different sex and age. The final data base should include >2000 individuals from across the Arctic. Preliminary results for the Rivière-George and Rivière-aux-Feuilles herds indicate high variation of prevalence rates between parasite species but also between herds (Figure 11).

Objective 5. To expand the vegetation and habitat project to include the relationships between soil-vegetation characteristics and the grazing ecology of caribou, in an interactive ecological model using a spatially explicit approach, and a replicated greenhouse experiment.

5.1 Nunavik and Nunatsiavut have experienced rapid climate change during the last two decades. A reduction of the period of snow and ice cover at a rate of 1 day/year was accompanied by an increase in mean ground temperature of over 2 °C (Allard and Lemay 2012). Climate change simulations for the 2041-2070 period suggest that these changes will continue and will be especially important in the Ungava Peninsula.

Figure 12. Estimated biomass of American Dwarf Birch (Betula glandulosa) and Gramineae after four years of simulated temperature increase (dark bar = elevated temperature using open-top chambers, light bars = normal temperature) at Deception Bay, Nunavik. Error bars represent 95 % IC.

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The impact of these changes on the phenology of plants and the composition of plant communities could affect resource availability for caribou (Post et al. 2008). We aimed to evaluate the influence of climate change on the availability of caribou food resources using a simulated experiment. Since 2009, we mimic short- and long-term temperature increases with open-top chambers and nitrogen fertilization respectively, while also simulating variable caribou browsing pressure. Surprisingly, results after four years of treatment suggest a reduction of both American dwarf birch (Betula glandulosa) and Gramineae biomass under increased temperatures (Figure 12). The fertilization treatment strongly increased the biomass of Gramineae (Figure 13).

5.2 Densification of the shrub layer has been recently reported in subarctic regions (Myers-Smith et al. 2011) including the Ungava peninsula (McManus et al. 2012, Ropars and Boudreau 2012, Tremblay et al. 2012), suggesting a potential increase in forage for caribou. Shrubs are a source of protein and constituted 36 to 66 % of the diet of lactating female caribou in the 1990s (Crête et al. 1990). We investigated the tolerance of dwarf birch to variable browsing pressures through the simulation experiment described in 5.1. As related in last year’s report, dwarf birch can tolerate moderate, but not heavy browsing pressure. Yet, the availability

of birch browse is reduced even at moderate browsing pressure. We explain this apparent contradiction by a reduction in the overall number of long shoots (Figure 14). Long shoots are responsible for branch elongation. As they are located at the distal end of branches accessible to caribou, they can have a strong influence on browse availability from the caribou perspective. Those results are now published:

Champagne, E., J.-P. Tremblay and S. D. Côté. 2012. Tolerance of an expanding subarctic shrub, Betula glandulosa, to simulated caribou browsing. Plos One 7:e51940.

5.3 Many authors recently suggested that vertebrate herbivores may contribute to spatial variation in the responses of erect shrubs to climate change (Pajunen 2009; Naito and Cairns 2011, Yu et al. 2011). Olofsson

Figure 14. Growth allocation to short and long shoots in Betula glandulosa after two years of simulated browsing (0, 25 or 75% of available twigs stripped of their leaves) near Deception Bay, Nunavik. Different letters over bars indicate a posteriori least square mean differences in simulated browsing level for each year on transformed data; (α = 0.05).

Figure 13. Estimated biomass of American Dwarf Birch (Betula glandulosa) leaves and Gramineae after four years of nitrogen fertilization simulating long-term effects of climate changes (dark bar = N fertilization, light bars = no fertilization) at Deception Bay, Nunavik. Error bars represent 95% IC.

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et al. (2009) even concluded that herbivores can inhibit climate-driven shrub expansion on the tundra. The change in the abundance of the Rivière-aux-feuilles herd offers an opportunity to evaluate the relationships between caribou abundance and climate on shrub densification. A comparison of high resolution aerial photographs from 1972 and a satellite image from 2010 from the Deception River valley revealed no change in the horizontal cover of erect shrub during this period (Figure 15), while temperatures increased by 3°C in Salluit (Lévesque 2009). We attribute this stagnation to an increase in the caribou population from an estimated 56 K in 1975 (Le Hénaff 1976) to 630 000 in 2001 (Couturier et al. 2004). Browsing pressure was high in 2010, as more than 70 % of the three main shrub species had more that 50 % of their shoots browsed.

5.4 Browsing effects on shrubs can persist multiple years after release from heavy browsing (Crête and Doucet 1998) and thus, affect resource availability for caribou over the long term. In 2011, we installed a series of 15 small exclosures (9 m2) designed to protect erect willows (Salix planifolia and S. glauca) from

browsing. Willows are heavily browsed by caribou in summer. We will compare the growth of protected shrubs to shrubs exposed to browsing and produce recovery curves by gradually removing exclosures (n=3 per year). This approach will allow us to identify the length of recovery windows at low browsing pressure required for the recovery of erect willows.

5.5 While the American dwarf birch was a dominant summer forage of the Rivière-George and Rivière-aux-Feuilles herds in the 1990’s (Crête et al. 1990), there are reports of a much lower selection for birch (Betula glandulosa and B. nana) in northwest North-America. We aim to evaluate the compositional (macroelements, phenolic, lignin) and functional (digestibility) attributes of B. glandulosa over the North American range of migratory caribou and relate its chemical characteristics to soil fertility (C, N, P, pH and bulk density). In collaboration with P. Grogan (Queens U.), we developed a sampling protocol for leaf, soil and caribou faeces that was sent to research teams from Alaska to Labrador. We have already received 115 samples from 25 sites. Analyses will be conducted in summer 2013.

Objective 6. To study the impact of predation by wolves and black bears on the population dynamics of caribou through a large-scale satellite-monitoring program on predators.

Wolves are considered the main predator of caribou (Bergerud et al. 2008) but their impact on the population dynamics of migratory caribou is unknown. The migration of caribou to calving grounds at high latitudes is thought to be partly a response to wolf predation. The ecology of black bears may also be greatly influenced by migratory caribou, especially on and near calving grounds where bear predation is thought to be a major source of mortality. The ecology of black bears in areas with access to caribou and in areas far from calving grounds may be very different. To investigate these questions, we began in 2011 a satellite-monitoring program of both predator species. Fourteen black bears and 14 wolves in total on both caribou herd ranges have been equipped with satellite

Figure 15. Differences in shrub cover (in number of cover class: (0) 0%, (1) 1-5%, (2) 6-25%, (3) 16-25%, (4) 26-50%, (5) 51-75%, (6) 76-90%, (7) 91-100) between 1972 and 2010 near Deception Bay, Nunavik. Red cells represents areas where shrub cover contracted between 1972 and 2010 while green cells represents areas where shrub cover expanded.

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collars. Preliminary results show that individual wolves from the Rivière-aux-Feuilles herd range perform large seasonal movements comparable to that of the caribou migration (Figure 16). This observation is surprising because wolves in northern Québec were expected to be non-migratory. Black bears on the Rivière-George range appear to congregate on calving grounds and locations indicate an attraction towards high-density caribou concentrations. We will continue to collars predators alongside our fieldwork on caribou. The recruitment of two graduate students on this project is planned for late 2013-2014 because

we need to secure other funding for the large costs of captures and the satellite program.

Discussion

Objective 1. To determine life-history variation in known age individuals, more specifically to assess longitudinally age-specific survival and reproduction of radio-collared animals and

transversally the age distribution of harvested animals.

1.1 – 1.2 – 1.3. The discussion of these results is presented in the report from last year and the papers cited in the results section. We will focus in the sections below on new results.

1.4 Our results led the government of Québec and the Hunting, Fishing and Trapping Coordinating Committee to use 630 000 as the 2001 population estimate for the Rivière-aux-Feuilles herd. Earlier, there had been doubts about the reliability of that estimate, which had very wide confidence intervals. Results from our model are also being used to elaborate hunting quotas in the upcoming management plan for this herd. The observation that the decline of the Rivière-aux-Feuilles herd is much less dramatic than previously thought, coupled to the observation that the herd has been relatively stable since 2008 allows for cautious optimism for this herd. However, the very low calf recruitment and survival rates observed for the Rivière-George herd added to the concordant results of aerial censuses and our model indicate an ongoing dramatic decline. Conservation efforts for Rangifer populations have been hindered by a lack of data, specifically reliable population estimates that are fundamental for the management of any wild populations (Williams et al. 2002). Aerial population censuses in remote regions are costly (Morellet et al. 2007) such that population estimates are infrequent and often have wide confidence intervals. Management decisions, however, must be taken on an urgent basis, creating a lag between the availability of reliable data and decisions on policies or quotas for harvested wild species (Nilsen et al. 2012, Strand et al. 2012). Our study demonstrates that life history models can be used to accurately predict population sizes between censuses as well as confirm, dispute or add precision to classic census methods.

Although calf recruitment and juvenile survival are generally more variable than adult female survival in ungulates, we have found that for migratory caribou this is not always the case. The variability in annual survival of adult females seems to increase during phases of decline. This information

Figure 16. Locations of satellite-tagged wolves within the Rivière-aux-Feuilles caribou herd range between October 15th 2012 and January 1st 2013. Each color represents a different wolf and yellow dots represent the last location of each wolf.

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can further contribute to management decisions in the absence of census data, as increased variability in adult female survival appears to indicate a declining population.

1.5 Combining data from earlier aerial surveys and recent telemetry monitoring, we identified major changes in the size and location of two migratory herds over time. In Northern Québec, shifts in calving grounds could be related to changes in population size that can induce range degradation, or to changes in habitat preference. Sharma et al. (2009) predicted that, according to a Canadian General Circulation Model climate change scenario, seasonal ranges of the Rivière-aux-Feuilles and Rivière-George herds should change substantially over the next 50 years. The Rivière-George herd may become restricted to the northeastern Québec-Labrador Peninsula in the winter, spring, and summer, while the Rivière-aux-Feuilles herd may expand its distribution relative to its current range. These projections of potential changes in size and location of calving range (Sharma et al. 2009) imply that fixed areas are unlikely to provide long-term protection to the calving grounds of migratory caribou. In Northern Québec, only 10–27 % of annual calving grounds of migratory caribou in recent years were within designated Wildlife Habitats, which provide legal protection of critical habitats. Wildlife Habitats cover very large areas, and the Québec government has made efforts to redefine their locations to cope with temporal changes in calving ground locations. Nevertheless, current Wildlife Habitats perform poorly at protecting calving grounds that are large and dynamic over time. Protection of calving grounds of migratory caribou must consider the dynamic use of space by adult females. We recommend using ongoing monitoring to better protect calving grounds of migratory caribou. The boundaries of these areas could be reviewed every 3–5 years depending on changes in the location of calving grounds and population demography. At each review, they should be compared with actual recent locations of parturient caribou, and modified as required.

Objective 2. To analyze habitat selection at different scales for migratory caribou in all

seasons, in particular in relation to migration routes and anthropogenic disturbance. To continue modeling the effects of climate change on the distribution of caribou. To use remote sensing tools to link changes in vegetation phenology and movements of caribou.

2.1 Similar to the spring migration, the fall migration patterns of migratory caribou in Northern Québec and Labrador tended to stabilise in recent years. Changes in the spring and fall migratory routes occurred simultaneously with changes in the use of winter ranges, and large changes in population dynamics. The abandonment of the western winter areas by the Rivière-George herd followed the decline of that herd, while the Rivière-aux-Feuilles herd continued to use those areas. On the other hand, the abandonment of the northern wintering area by the Rivière-aux-Feuilles herd likely occurred following changes in resource availability linked to winter snow conditions. In addition to snow depth, ice cover of lakes and flow regime of rivers also determines the cost of migration (Weladji and Holand 2006), and observed climate in early spring and late winter may have impacted the selection of migratory routes. In the near future, we will perform habitat selection analyses for caribou during migration to identify the environmental factors influencing migration patterns.

2.2 The effects of weather conditions on the timing of migration differed between seasons and the potential impacts of expected climate change could also differ between the fall and spring migrations. Our results show that arrival on calving grounds is delayed in years with an early spring, which may have consequences for the timing of birth. Thus, expected climate changes could negatively impact caribou. However, late onset of winter seems to facilitate the fall migration and as caribou show a high variation in migration patterns and winter range use, impacts of expected climate changes could possibly be weaker than in spring than in the fall. In both seasons, snow conditions seem to be a key factor driving changes in migratory behavior, likely because snow characteristics affect the costs of movements (Weladji and Holand 2006) and limit resource accessibility (Miller and

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Gunn 2003). We used the snow water equivalent to estimate average snow depth, but we need to also take into account snow cover and resource availability. The next step of our study will be to include snow cover data from MODIS imagery (Armstrong and Brodzik 2005) and NDVI (Normalized Difference Vegetation Index) in analyses. In the context of an ongoing worldwide decline of most caribou and reindeer herds, our study will help to understand how climate influences spring and autumn migrations and to estimate how expected climate changes will affect migratory caribou.

2.3 We showed an important role for collective behavior in shaping and maintaining the stability in caribou migration patterns. Simulations of collective movement suggest that large-scale patterns formation in animal groups can be controlled by pairwise interactions among neighbouring individuals. This suggests that maybe simple rules could scale up to generate this behavior. Here we took a signal-processing approach to a large dataset on the movement of migratory caribou to ask about the importance of collective behaviour in shaping migration patterns. We compared a model where caribou motion at the population level is governed by an advection-diffusion model to a similar model where nearby individuals align their velocities. Further analyses should allow to disentangle the role of environmental factors and collective behavior in shaping decisions of migration routes.

Objective 3. To determine the genetic structure of caribou/reindeer populations throughout their circumpolar distribution. To assess the connectivity and gene flow between caribou/reindeer populations and determine the importance of migratory caribou for the conservation of the threatened sedentary (forest) caribou ecotype.

We found a strong phylogeographic structure in the circumpolar distribution of caribou. Bayesian multilocus genotype clustering analyses based on microsatellite markers and phylogenetic reconstruction

of mitochondrial DNA samples consistently divided caribou populations into two geographically structured lineages. The first lineage covers a vast portion of the species range, from Eurasia to North-western America (hereafter termed Euro-Beringia), including Greenland, Svalbard, and the Canadian archipelago. As such, it likely represents the largest and most important origin of the current species’ gene pool, ancestrally distributed across a vast part of northern Eurasia and extending into northern North America through the Beringian land bridge. The second lineage has a more restricted distribution and includes herds distributed from the island of Newfoundland to the interior plains of Canada (hereafter termed North America). The oldest caribou fossils (dated to 1.6 Myr) have been found in eastern Beringia, suggesting a Beringian origin of the genus.

Strongly supporting these results, species distribution modeling identified two main climatically suitable areas of distribution for caribou during the Last Glacial Maximum. At the earliest time analyzed (-21 kyr BP), the species was more widespread in Eurasia than today, when its range was reduced in North America. During the late Pleistocene, the Euro-Beringian region was characterized by large continuous areas of tundra throughout much of Siberia and central Eurasia (Andersen and Borns 1997), potentially supporting large populations of Arctic herbivores (Zazula et al. 2003, Lorenzen et al. 2011). In North America, the ice sheets reached their largest extent some 20-kya when they covered much of the continent (Dyke et al. 2002). We conclude that the climatic variations characterizing the last 21 millenia largely drove the range contractions and expansions – and resulting genetic structure - of caribou.

Forecasting the range of the species for 2080, our results predict strong modification of the distribution of caribou. In contrast to temperate species, cold-adapted species show contracted refugial distributions during interglacial periods, such as the current one (Stewart et al. 2010). Under the severe climatic warming scenario considered, our model predicts the

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distribution of caribou to become even more restricted to high latitudes than today, with possible extinctions in the most southern regions. Climate change, however, is expected to influence the two clades differently. The North America genetic cluster is likely to become increasingly fragmented and may disappear from most of its current range (89 % of suitable area predicted to be lost). The Euro-Beringia region is predicted to be less dramatically affected by climate change (60 % of suitable area lost), likely supporting in the future (as observed in the past) large populations with high genetic diversity.

Our results support the idea that climatic changes have profound demographic and genetic consequences on caribou populations. In particular, we showed that among the two caribou lineages identified, the Euro-Beringian that occurs in larger and climatically more suitable areas is also likely to better adapt to future climate change than the North American lineage, which shows lower genetic diversity due to smaller effective population sizes and the lower climatic stability characterizing its past and current distribution. These results caution that the long-term persistence of North American populations under climate change may be reduced by the limited genetic diversity observed in this lineage.

Objective 4. To study the impact of parasites (e.g. Besnoitia, liver flukes) on the ecology of caribou and the health of indigenous people. To compare parasite diversity between caribou from Quebec and the rest of the Arctic.

4.1 Besnoitia tarandi prevalence and cyst density in a caribou population can be affected by variables such as sex, age, time of sampling, as well as the source of selection of animals. The slightly higher prevalence of B. tarandi observed in males suggests that males may be either more susceptible to the parasite or have increased exposure to infective stages. Higher observed prevalence of B. tarandi in caribou sampled during postsummer compared to the early summer season of the same year suggested that transmission

is increased during the summer. Since caribou are exposed to biting insects (mosquitoes/Culicidae and black flies/Simuliidae families) from late June to August (Toupin et al. 1996), this observation supports the hypothesis that these arthropods play a dominant role in transmission of B. tarandi in caribou. The effect of B. tarandi on caribou populations is unclear; however, the relationship between this parasite, its hosts, and the environment warrants further investigation, especially in the context of rapid climate change in the northern environments and in the face of widespread declines in many caribou populations (Vors and Boyce 2009). Future research should focus on comparisons with other caribou populations, subspecies, elucidating the B. tarandi transmission cycle, and evaluating the potential effect of this parasite on winter survival.

4.2 Understanding the health and dynamics of wildlife populations can be enhanced by comparative studies across time and across populations and geographic regions. Our comparative approach to investigating parasite diversity and abundance across caribou herds will provide first, baseline information on parasite diversity and abundance across herds, and second, novel insight into contemporary and historical factors influencing parasite distribution and transmission dynamics. Preliminary data on abundance and diversity of parasite fauna in the Rivière-George and Rivière-aux-Feuilles herds suggest that there are very different ecological conditions occurring for these herds despite the proximity and seasonal sympatry of the herds. The Rivière-George herd is possibly the North American caribou herd showing the highest diversity of parasites. Further research should take a holistic approach to explore what factors may be driving these patterns. Our research will provide the first comparative survey of Rangifer health across a broad geographic range.

Objective 5. To expand the vegetation and habitat project to include the relationships between soil-vegetation characteristics and the grazing ecology of caribou in an interactive ecological

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model using a spatially explicit approach, and a replicated greenhouse experiment.

5.1 To simulate climate change, many experiments, including ours, used portable greenhouses simulating short-term increase of ground surface temperature and active layer depth. Common responses are an increase in biomass (Henry and Molau 1997, Klein et al. 2007) or no response to enhanced temperature (Molau and Edlund 1994). Thus, our preliminary results indicating a reduction in both American dwarf birch and Gramineae biomass are unexpected and need further investigation. We are currently examining if the higher evapotranspiration caused by increased temperatures could explain these results. Greater nitrogen assimilation by Gramineae could explain their increased growth under fertilization compared to birch (Köchy and Wilson 2000). Higher Gramineae availability and the compensatory response of birch to moderate browsing pressure (Champagne et al. 2012) could maintain high forage abundance for caribou under current and predicted climate changes.

5.2 American dwarf birch is expanding in central Nunavik (McManus et al. 2012, Ropars and Boudreau 2012, Tremblay et al. 2012) and could provide an abundant summer resource for caribou. The availability of birch browse, however, is reduced by browsing of as little as 25 % of available shoots. This relation between browsing and resource availability could thus temper the positive effects of shrub expansion. This project is completed and a second manuscript will be submitted soon for publication.

5.3 The similar shrub cover between 1972 and 2010 in the Deception River valley contradicts the increase reported in central Nunavik (McManus et al. 2012, Ropars and Boudreau 2012, Tremblay et al. 2012). As temperature increased by 3 °C in the nearby village of Salluit during the same period, our results suggest that caribou browsing could have prevented shrub expansion. We cannot exclude that a threshold in temperature has yet to be attained for shrub cover to increase. In contrast to other reports of shrub cover increases, our study is located in the continuous

permafrost zone and in the herbaceous tundra, which could explain the differences in the results. Our study supports the hypothesis that grazing-controlled response to environmental change is a primary driver of shrubs densification, with climate (warming) as a secondary driver (Hofgaard et al. 2010). This herbivore-driven masking of expected climate-driven densification of the shrub layer highlights the necessity to consider changes in caribou population when studying “shrubification”. This project is completed and a manuscript will be submitted in the next few months.

5.4 Studies conducted at the peak of the Rivière-George caribou herd in the late 1980’s suggested that damage to the habitat from heavy browsing is a factor influencing the initial phase of population decline in caribou (Messier 1991, Crête and Huot 1993). We also know that the suppression of erect shrubs can persist over many years (Crête and Doucet 1998). The planned unfencing experiment on willows will allow us to understand the recovery dynamics of preferred erect shrubs species. Erect shrubs such as willows are key components of the tundra ecosystem contributing to the structure of the habitat and providing cover and food for different animal species.

5.5 The apparently high use of dwarf birch by migratory caribou in northern Québec (Crête et al. 1990, Manseau 1996) compared to the rest of the Arctic is intriguing. The distribution and abundance of alternative species in western North America may explain the discrepancy between these areas and northern Québec. This project is a large collaborative work involving 25 sites throughout the Arctic to study the chemical and functional characteristics of B. glandulosa and to relate them to soil characteristics to explain its use and non-use by caribou.

Objective 6. To study the impact of predation by arctic wolves and black bears on the population dynamics of caribou by initiating a large-scale satellite-monitoring program on predators.

Unexpectedly, we found that almost all satellite-tagged

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wolves were migratory, leaving the winter range just before the caribou and ‘waiting’ for them near calving grounds, and returning to the winter range in the fall approximately at the same time as caribou. We are continuing our program on wolves with new captures planned for late February 2013. In addition to space use and migration, we will address wolf-caribou and black-bear caribou interactions spatially. The schedule of locations will allow the identification of kill sites of wolves to calculate predation rates (Webb et al. 2008). Because we will have spatial data on both predators and caribou, we will produce Resource Selection Function maps of predation risk and relate them to the spatial behavior of caribou (Metz et al. 2012.). We will also determine the contribution of caribou to the diets of wolves and black bears using analyses of feces, stable isotopes, and DNA barcoding. We plan to compare life-history traits of predators that have access to caribou or not. Finally, our data will allow us to determine the impact of predation on the population dynamics of both caribou herds.

Conclusion

Recent declines in the number of migratory caribou in Northern Québec and Labrador could have negative social and economical implications, particularly for northern arctic and subarctic native cultures that rely on caribou for subsistence as well as for the outfitting industry. Changes in the distribution of caribou, as well as decreases in abundance, are expected to continue in the near future. We anticipate that the negative effects of changes in the distribution of animals and reduced abundance of caribou will be higher than the anticipated positive effects of an earlier and longer period of vegetation growth. Recent data suggest that caribou abundance and distribution will change in the near future and it has already started. Our recent work on the large variation in the size and distribution of calving grounds of both herds (Taillon et al. 2012) is a good example of changes to come. Managers, stakeholders and communities should be prepared for a lower abundance of animals and a less predictable distribution, further away from communities. Future

research will continue to address the factors explaining variations in the population dynamics of caribou, including consequences for survival and reproduction, impacts of climate, predators and gene flow between herds, as well as the response of caribou habitat to different climate change scenarios. Management efforts focusing on preserving high quality habitat, limiting anthropogenic landscape disturbances, mitigating greenhouse gases to reduce the potential effects of climate change, and managing hunting in a sustainable manner, could alleviate stressors on migratory caribou in the Québec-Labrador peninsula.

Acknowledgements

Part of this research project is funded by a Collaborative Research and Development (CRD) grant from the Natural Sciences and Engineering Research Council of Canada (NSERC) in collaboration with Hydro-Québec, Xstrata Nickel - Mine Raglan, Makivik Corporation, First Air and the Quebec Outfitters Federation. The Ministère des Ressources naturelles et de la Faune du Québec is also an important partner providing financial and technical resources. The Government of Newfoundland and Labrador also provide technical resources and expertise for the work on the Rivière-George herd. We thank many other partners for their financial or logistic support: Centre d’études nordiques, International polar year, Ouranos, Fédération québécoise des chasseurs et pêcheurs, Fondation de la Faune du Québec, Canada Foundation for Innovation, Institute for Environmental Monitoring and Research, Indian and Northern Affairs - Northern Scientific Training Program, the CircumArctic Rangifer Monitoring and Assessment Network, the Canadian Wildlife Federation, Conférence des élus de la Baie-James and Fonds vert du Gouvernement du Québec.

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Publications

(All ArcticNet refereed publications are available on the ASTIS website (http://www.aina.ucalgary.ca/arcticnet/).

Champagne, E., 2012, Conséquences de la tolérance au broutement du bouleau glanduleux sur les ressources alimentaires du caribou, M. Sc. thesis, 76 pp.

Champagne, E., Plante, S., Ropars, P., Boudreau, S., Lévesque, E. and Tremblay, J.-P., 2012, Caribou vs Climate Change: Status Quo in Shrub Abundance, ArcticNet 8th Annual Scientific Meeting, Vancouver, BC, Canada.

Champagne, E., Tremblay, J.-P. and Côté, S. D., 2012, Tolerance of an Expanding Subarctic Shrub, Betula glandulosa, to Simulated Caribou Browsing, PLoS ONE, e51940.

Champagne, E., Tremblay, J.-P. and Côté, S. D., 2012, De la tolérance à la défense structurelle: modulation de la disponibilité du bouleau glanduleux par le broutement du caribou, 3e colloque annuel de Caribou Ungava, Québec, Qc, Canada.

Champagne, E., Tremblay, J.-P. and Côté, S. D., 2012, Can Tolerance Create Structural Defence? Modulation of Dwarf Birch Availability by Caribou Herbivory, International Polar Year 2012 Conference, Montréal, Qc, Canada.

Côté, S. D., 2012, La recherche sur le caribou migrateur au Québec-Labrador 2009-2014 & 2014-2019, Rencontre annuelle des Pourvoyeurs du Québec, Québec, QC, Canada.

Couturier, S., Brodeur, V., Crowley, S., Elliott, D., Le Corre, M., Taillon, J. and Côté, S. D., 2012, Rises and Crashes in Two Migratory Caribou Herds in Northern Québec and Labrador, International Polar Year 2012 Conference, Montréal, Qc, Canada.

Ducrocq, J., Beauchamp, G., Kutz, S., Simard,

M., Elkin, B., Croft, B., Taillon, J., Côté, S. D., Brodeur, V., Campbell, M., Cooley, D., Cuyler, C. and Lair, S., 2012, Comparison of Gross Visual and Microscopic Assessment of Four Anatomic Sites to Monitor Besnoitia tarandi in Barren-ground Caribou (Rangifer tarandus groenlandicus), Journal of Wildlife Diseases v.48, no.3, 732-738.

Ducrocq, J., Beauchamp, G., Kutz, S., Simard, M., Taillon, J., Côté, S. D., Brodeur, V. and Lair, S., 2013, Variables Associated with Besnoitia tarandi Prevalence and Cyst Density in Barren-ground Caribou (Rangifer tarandus) Populations., Journal of Wildlife Diseases, v.49, no.1, 29-38.

Forde, T., Orsel, K., De Buck, J., Cooley, D., Côté, S. D., Cuyler, C., Davison, T., Elkin, B., Kelly, A., Kienzler, M., Popko, R., Taillon, J., Veitch, A. and Kutz, S., 2012, Detection of Mycobacterium avium subspecies paratuberculosis in Several Herds of Arctic Caribou (Rangifer tarandus ssp.), Journal of Wildlife Diseases v.48, no.4, 918-924.

Le Corre, M., Côté, S. D. and Dussault, C., 2012, Effects of Climate on the Timing of the Spring and Fall Migration of Migratory Caribou, ArcticNet 8th Annual Scientific Meeting, Vancouver, BC, Canada.

Le Corre, M., Côté, S. D. and Dussault, C., 2012, Migration Patterns and Effects of Climate on the Phenology of Caribou Migration During Autumn, International Polar Year 2012 Conference, Montréal, Qc, Canada,

Le Corre, M., Dussault, C. and S. D. Côté, 2012, En route vers les aires d’hivernage: patron et phénologie de la migration d’automne, 3e colloque annuel de Caribou Ungava, Québec, Qc, Canada.

Pachkowski, M. D., 2012, Dynamique des populations de caribous migrateur (Rangifer tarandus) basée sur des indices de condition corporelle, Faculté des Sciences, Université de Sherbrooke, Sherbrooke (QC), Canada, 89.

Pachkowski, M., Festa-Bianchet, M. and S. D. Côté, 2012, Dynamique des populations de caribous

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migrateurs basée sur des indices de condition corporelle, 3e colloque annuel de Caribou Ungava, Québec, Qc, Canada.

Pachkowski, M., Festa-Bianchet, M. and S. D. Côté., 2012, Spring Loaded Reproduction: Effects of Body Condition and Population Size on Gestation Rate in Migratory Caribou, International Polar Year 2012 Conference, Montréal, Qc, Canada.

Rasiulis, A. L., Côté, S. D. and Festa-Bianchet, M., 2012, Survival and Demography of Migratory Caribou in Northern Québec and Labrador, ArcticNet 8th Annual Scientific Meeting, Vancouver, BC, Canada.

Rasiulis, A. L., Côté, S. D. and Festa-Bianchet, M., 2012, Survival and Demography of Migratory Caribou, 14th North American Caribou Workshop, Fort St.John, BC, Canada.

Rasiulis, A., Côté, S. D. and Festa-Bianchet, M., 2012, Survie et démographie des caribous migrateurs au Québec et au Labrador, 37e Congrès annuel de la Société Québécoise d’Étude Biologique du Comportement, Montréal, QC, Canada.

Rasiulis, A., Festa-Bianchet, M. and Côté, S. D., 2012, Variations de la survie annuelle et saisonnière des caribous migrateurs: analyses préliminaires, 3e colloque annuel de Caribou Ungava, Québec, Qc, Canada.

Saucier, V., Tremblay, J.-P. and Côté, S. D., 2012, Can Browsing by Caribou Limit the Positive Effect of Climate Warming on Arctic Shrubs, 37e Congrès annuel de la Société Québécoise d’Étude Biologique du Comportement, Montréal, QC, Canada.

Saucier, V., Tremblay, J.-P. and Côté, S. D., 2012, Interactions entre les changements climatiques et le broutement sur les ressources estivales du caribou migrateur, 3e colloque annuel de Caribou Ungava, Québec, Qc, Canada.

Saucier, V., Tremblay, J.-P. and S. D. Côté, 2012, Experimental Simulation of Climate Warming, Nutrient Availability and Caribou Browsing :

Responses of an Erect Shrubs’ Biomass, ArcticNet 8th Annual Scientific Meeting, Vancouver, BC, Canada.

Taillon, J., 2012, Conservation of Migratory Mammals: Changes in Climate, Changes in Paradigms, Seminars offert by The Canadian Section of The Wildlife Society.

Taillon, J., Barboza, P. and Côté, S. D., 2012, Nitrogen Allocation to Offspring and Milk Production in a Capital Breeder, Ecology.

Taillon, J., Barboza, P. S., Côté, S. D., 2012, L’analyse isotopique: un outil pour mieux comprendre l’allocation maternelle?, 3e colloque annuel de Caribou Ungava, Québec, Qc, Canada.

Taillon, J., Brodeur, V., Festa-Bianchet, M. and Côté, S. D., 2012, Contrasting Body Condition of Migratory Caribou Female-Calf Pairs at Calving and Weaning, International Polar Year 2012 Conference, Montréal, Qc, Canada.

Taillon, J., Festa-Bianchet, M. and Côté, S. D., 2012, A Challenge for Conservation: Spatio-Temporal Changes in the Use of Calving Grounds by Migratory Caribou, The Wildlife Society symposium: Ecology, conservation, and management of ungulate migration, Portland, Oregon, États-Unis.

Taillon, J., Festa-Bianchet, M. and Côté, S. D., 2012, Tout est une question de “timing” ! Phénologie de la migration printanière et de l’utilisation de l’aire de mise bas, 3e colloque annuel de Caribou Ungava, Québec, Qc, Canada.

Taillon, J., Festa-Bianchet, M. and Côté, S. D., 2012, When Timing Is the Key: Timing of Spring Migration and Pattern of Use of Calving Ground by Migratory Caribou, International Polar Year 2012 Conference, Montréal, Qc, Canada.

Yannic, G., Bernatchez, L. and Côté, S. D., 2012, Génétique des populations de Rangifer: une approche circumpolaire, 3e colloque annuel de Caribou Ungava, Québec, Qc, Canada.

population dynamics of migratory caribou in nunavik ... · population dynamics of migratory caribou...

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