A conceptual model for migratory tundra caribou to explain and predict why shifts in spatial fidelity of breeding cows to their calving grounds are infrequent

Gunn, Anne; Poole, Kim G.; Nishi, John S.

doi:10.7557/2.32.2.2274

Cited by 18 publications

(30 citation statements)

References 29 publications

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“…One explanation is that there was a true numerical decline in Beverly herd size as death rates consistently exceeded birth and recruitment rates. The shift in calving distribution to the Ahiak herd's calving ground between 2006 and 2009 was a consequence of the collapse in calving densities as the remaining Beverly cows switched to maintain the advantages of gregarious calving (Gunn et al, 2012). If this explanation is correct, then the Beverly herd is no longer identifiable as a distinct herd.…”

Section: Introductionmentioning

confidence: 93%

“…The Beverly herd has three immediate neighbouring herds with traditional calving grounds recorded through Aboriginal knowledge and aerial surveys: the Qamanirjuaq traditional calving grounds about 400 km to the southeast (Heard, 1983;BQCMB, 1999a, b), the Bathurst calving grounds about 450 km to the northwest (Heard, 1983;Gunn et al, 2012), and the Ahiak calving grounds 250 km north along the Queen Maud Gulf coast (Heard et al, 1987;Gunn et al, 2000Gunn et al, , 2013a (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

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What Happened to the Beverly Caribou Herd after 1994?

Adamczewski¹,

Gunn²,

Poole³

et al. 2015

ARCTIC

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The Beverly herd was one of the first large migratory herds of barren-ground caribou (Rangifer tarandus groenlandicus) defined in northern Canada on the basis of annual return of breeding females to traditional calving grounds near Beverly Lake in Nunavut. In 1994, herd size was estimated at 276 000 ± 106 600 (SE) adult caribou, but monitoring was minimal from 1994 to 2007. The next calving ground survey in 2002 revealed that caribou densities had dropped by more than half since 1994; annual surveys following from 2007 to 2009 demonstrated an extreme decline in numbers of calving cows, and by 2011, no newborn calves were seen there. We examine two possible explanations for the declining use of the traditional Beverly calving grounds from 1994 until their abandonment by 2011. One explanation is that a true numerical decline in herd size occurred, driven in at least the later stages by low cow survival and poor calf productivity, which led the remaining Beverly cows to switch to the neighbouring Ahiak calving ground 250 km to the north in 2007 – 09 and join that herd. An alternative explanation is that the decline on the traditional Beverly calving grounds was largely due to a distributional shift to the north of the Beverly herd that may have begun in the mid-1990s. We suggest that the former explanation is the more likely and that the Beverly herd no longer exists as a distinct herd. We acknowledge that gaps in monitoring of Beverly and Ahiak caribou hamper definitive evaluation of the Beverly herd’s fate. The large size sometimes achieved by barren-ground caribou herds is not a guarantee of persistence; monitoring shortfalls may hamper management actions to address declines.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

What Happened to the Beverly Caribou Herd after 1994?

Adamczewski¹,

Gunn²,

Poole³

et al. 2015

ARCTIC

Self Cite

View full text Add to dashboard Cite

show abstract

“…The distribution of barren-ground caribou is density-dependent such that range expansion and contraction are a function of the size of the herd (Simmons et al 1979, Bergerud et al 1984, Heard and Calef 1986, Messier et al 1988, Couturier et al 1990, Gunn et al 2012. Gunn et al (2013) reported that the winter range of the Bathurst herd has contracted since 2002, corresponding to the decline of the herd.…”

Section: Introductionmentioning

confidence: 99%

“…Heard and Calef (1986) and Heard and Williams (1992) suggested that tundra wolf populations respond numerically to changing caribou densities. Space-use patterns of barrenground caribou are density-dependent where the expansion and contraction of their range is a function o f the population size of the herd (Simmons et al 1979, Bergerud et al 1984, Heard and Calef 1986, Messier et al 1988, Couterier et al 1990, Gunn et al 2012. When caribou are abundant, the herd returns earlier to the southern portions of the summer range and within closer proximity to the denning areas of wolves, thus providing wolves with greater access to prey when the nutritional demands of pups are high.…”

Section: Introductionmentioning

confidence: 99%

“…Estimates in 2014 indicate the population has decreased below 30,000 animals (Adamczewski et al 2014), representing a > 90% decline in abundance. At large spatiotemporal scales, range use patterns of barren-ground caribou, including the extent of distribution, are density-dependent (Simmons et al 1979, Bergerud et al 1984, Heard and Calef 1986, Messier et al 1988, Couturier et al 1990, Gunn et al 2012). …”

Section: Introductionmentioning

confidence: 99%

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Denning ecology of barren-ground wolves in the central Canadian Arctic.

Klaczek¹

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Seasonal patterns of spatial fidelity and temporal consistency in the distribution and movements of a migratory ungulate

Joly

Gurarie

Hansen

et al. 2021

Ecology and Evolution

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How animals use their range can have physiological, ecological, and demographic repercussions, as well as impact management decisions, species conservation, and human society. Fidelity, the predictable return to certain places, can improve fitness if it is associated with high‐quality habitat or helps enable individuals to locate heterogenous patches of higher‐quality habitat within a lower‐quality habitat matrix. Our goal was to quantify patterns of fidelity at different spatial scales to better understand the relative plasticity of habitat use of a vital subsistence species that undergoes long‐distance migrations. We analyzed a decade (2010–2019) of GPS data from 240 adult, female Western Arctic Herd (WAH) caribou (Rangifer tarandus) from northwest Alaska, U.S.A. We assessed fidelity at 2 spatial scales: to site‐specific locations within seasonal ranges and to regions within the herd's entire range by using 2 different null datasets. We assessed both area and consistency of use during 6 different seasons of the year. We also assessed the temporal consistency of migration and calving events. At the scale of the overall range, we found that caribou fidelity was greatest during the calving and insect relief (early summer) seasons, where the herd tended to maximally aggregate in the smallest area, and lowest in winter when the seasonal range is largest. However, even in seasons with lower fidelity, we found that caribou still showed fidelity to certain regions within the herd's range. Within those seasonal ranges, however, there was little individual site‐specific fidelity from year to year, with the exception of summer periods. Temporally, we found that over 90% of caribou gave birth within 7 days of the day they gave birth the previous year. This revealed fairly high temporal consistency, especially given the spatial and temporal variability of spring migration. Fall migration exhibited greater temporal variability than spring migration. Our results support the hypothesis that higher fidelity to seasonal ranges is related to greater environmental and resource predictability. Interestingly, this fidelity was stronger at larger scales and at the population level. Almost the entire herd would seek out these areas with predictable resources, and then, individuals would vary their use, likely in response to annually varying conditions. During seasons with lower presumed spatial and/or temporal predictability of resources, population‐level fidelity was lower but individual fidelity was higher. The herd would be more spread out during the seasons of low‐resource predictability, leading to lower fidelity at the scale of their entire range, but individuals could be closer to locations they used the previous year, leading to greater individual fidelity, perhaps resulting from memory of a successful outcome the previous year. Our results also suggest that fidelity in 1 season is related to fidelity in the subsequent season. We hypothesize that some differences in patterns of range fidelity may be driven by seasonal...

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A conceptual model for migratory tundra caribou to explain and predict why shifts in spatial fidelity of breeding cows to their calving grounds are infrequent

Cited by 18 publications

References 29 publications

What Happened to the Beverly Caribou Herd after 1994?

What Happened to the Beverly Caribou Herd after 1994?

Denning ecology of barren-ground wolves in the central Canadian Arctic.

Seasonal patterns of spatial fidelity and temporal consistency in the distribution and movements of a migratory ungulate

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