Svalbard reindeer population size and trends in four sub-areas of Edgeøya

Reimers, Eigil

doi:10.3402/polar.v31i0.11089

Cited by 8 publications

(10 citation statements)

References 25 publications

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“…Thus, we conservatively modeled density-independent mortality by lowering adult (and calf ) survival rates in 2006 to 15-20% and 20-25% in 2012. These reductions are comparable to those experienced by other predator-free herds (Reimers 1982, Leader-Williams 1988, Reimers 2012.…”

Section: Population Dynamicssupporting

confidence: 63%

Irruptive dynamics of introduced caribou on Adak Island, Alaska: an evaluation of Riney‐Caughley model predictions

et al. 2014

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Abstract. Large mammalian herbivores introduced to islands without predators are predicted to undergo irruptive population and spatial dynamics, but only a few well-documented case studies support this paradigm. We used the Riney-Caughley model as a framework to test predictions of irruptive population growth and spatial expansion of caribou (Rangifer tarandus granti ) introduced to Adak Island in the Aleutian archipelago of Alaska in 1958 and 1959. We utilized a time series of spatially explicit counts conducted on this population intermittently over a 54-year period. Population size increased from 23 released animals to approximately 2900 animals in 2012. Population dynamics were characterized by two distinct periods of irruptive growth separated by a long time period of relative stability, and the catalyst for the initial irruption was more likely related to annual variation in hunting pressure than weather conditions. An unexpected pattern resembling logistic population growth occurred between the peak of the second irruption in 2005 and the next survey conducted seven years later in 2012. Model simulations indicated that an increase in reported harvest alone could not explain the deceleration in population growth, yet high levels of unreported harvest combined with increasing density-dependent feedbacks on fecundity and survival were the most plausible explanation for the observed population trend. No studies of introduced island Rangifer have measured a time series of spatial use to the extent described in this study. Spatial use patterns during the post-calving season strongly supported Riney-Caughley model predictions, whereby high-density core areas expanded outwardly as population size increased. During the calving season, caribou displayed marked site fidelity across the full range of population densities despite availability of other suitable habitats for calving. Finally, dispersal and reproduction on neighboring Kagalaska Island represented a new dispersal front for irruptive dynamics and a new challenge for resource managers. The future demography of caribou on both islands is far from certain, yet sustained and significant hunting pressure should be a vital management tool.

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Section: Population Dynamicssupporting

confidence: 63%

Irruptive dynamics of introduced caribou on Adak Island, Alaska: an evaluation of Riney‐Caughley model predictions

et al. 2014

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“…As a result, polar bears and reindeer are together for longer periods, a situation in which interactions between them could occur more frequently (Derocher et al, 2000). Nevertheless, we do not anticipate short-term effects on reindeer other than temporary and local changes in distribution and behavior (Reimers, 2012). The possibility for behavioral changes of both reindeer and polar bears in response to future increased interactions calls for a follow up study.…”

Section: Discussionmentioning

confidence: 78%

“…In a comparative study of vigilance and fright behavior of wild reindeer in southern Norway (Reimers et al, 2012) and Svalbard (Reimers et al, 2011), we found Svalbard reindeer to be less vigilant than mainland wild reindeer, but the differences were surprisingly small. Several studies have documented effects of relaxed selection on antipredator behavior in mammals, but at present show no consistency regarding the speed at which preydiscriminative abilities are lost (Caro, 2005).…”

Section: Introductionmentioning

confidence: 65%

“…Last week of our field work on Edgeøya, Svalbard in July/ August 2006 (Reimers et al, 2011(Reimers et al, , 2012, we witnessed a polar bear stalk a group of four reindeer in our study area on Edgeøya (Fig. 1).…”

Section: Introductionmentioning

confidence: 91%

“…The present total reindeer summer population in Edgeøya is unknown, but was estimated at 1730 ‫ע‬ 451 (SD) for the period 1969-1996 (Øritsland, 1998). The study area was surveyed, and the number of reindeer was estimated at 181 animals in 2006, down from 227 animals in 1976 (Reimers, 2012).…”

Section: Introductionmentioning

confidence: 99%

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