Boucher Nicole P, Derocher Andrew E, Richardson Evan S
Department of Biological Sciences University of Alberta Edmonton AB Canada.
Wildlife Research Division, Science and Technology Branch Environment and Climate Change Canada Winnipeg MB Canada.
Ecol Evol. 2020 Mar 24;10(10):4178-4192. doi: 10.1002/ece3.6186. eCollection 2020 May.
Arctic ecosystem dynamics are shifting in response to warming temperatures and sea ice loss. Such ecosystems may be monitored by examining the diet of upper trophic level species, which varies with prey availability. To assess interannual variation in the Beaufort Sea ecosystem, we examined spatial and temporal trends in ringed seal () δC and δN in claw growth layers grown from 1964 to 2011. Stable isotopes were correlated with climate indices, environmental conditions, seal population productivity, and geographic location. Sex and age did not influence stable isotopes. Enriched C was linked to cyclonic circulation regimes, seal productivity, and westward sampling locations. Higher δN was linked to lower sea surface temperatures, a higher percentage of pups in the subsistence harvest, and sample locations that were eastward and further from shore. From the 1960s to 2000s, ringed seal niche width expanded, suggesting a diversification of diet due to expansion of prey and/or seal space use. Overall, trends in ringed seal stable isotopes indicate changes within the Beaufort Sea ecosystem affected by water temperatures and circulation regimes. We suggest that continued monitoring of upper trophic level species will yield insights into changing ecosystem structure with climate change.
北极生态系统动态正随着气温升高和海冰流失而发生变化。此类生态系统可通过研究营养级较高物种的饮食来进行监测，其饮食会随猎物可获得性而变化。为评估波弗特海生态系统的年际变化，我们研究了1964 - 2011年期间环斑海豹（）爪生长层中δC和δN的空间和时间趋势。稳定同位素与气候指数、环境条件、海豹种群生产力及地理位置相关。性别和年龄不影响稳定同位素。富集碳C与生气旋流模式、海豹生产力及向西的采样地点有关。较高δN与较低海面温度、自给性捕猎中海豹幼崽的较高比例以及向东且离岸更远的采样地点有关联。从20世纪60年代到21世纪，环斑海豹的生态位宽度扩大，这表明由于猎物范围扩大和/或海豹活动空间利用范围扩大，其饮食出现多样化。总体而言，环斑海豹稳定同位素的趋势表明，波弗特海生态系统内部的变化受到水温及环流模式的影响。我们建议持续监测营养级较高的物种，这将有助于深入了解气候变化对生态系统结构的影响。
