Marine and Environmental Sciences Department, Hampton University, Hampton, VA, United States of America.
Antarctic Ecosystem Research Division, Southwest Fisheries Science Center, NOAA Fisheries, La Jolla, CA, United States of America.
PLoS One. 2023 Aug 11;18(8):e0284640. doi: 10.1371/journal.pone.0284640. eCollection 2023.
Leopard seals (Hydrurga leptonyx) are top predators that can exert substantial top-down control of their Antarctic prey species. However, population trends and genetic diversity of leopard seals remain understudied, limiting our understanding of their ecological role. We investigated the genetic diversity, effective population size and demographic history of leopard seals to provide fundamental data that contextualizes their predatory influence on Antarctic ecosystems. Ninety leopard seals were sampled from the northern Antarctic Peninsula during the austral summers of 2008-2019 and a 405bp segment of the mitochondrial control region was sequenced for each individual. We uncovered moderate levels of nucleotide (π = 0.013) and haplotype (Hd = 0.96) diversity, and the effective population size was estimated at around 24,000 individuals (NE = 24,376; 95% CI: 16,876-33,126). Consistent with findings from other ice-breeding pinnipeds, Bayesian skyline analysis also revealed evidence for population expansion during the last glacial maximum, suggesting that historical population growth may have been boosted by an increase in the abundance of sea ice. Although leopard seals can be found in warmer, sub-Antarctic locations, the species' core habitat is centered on the Antarctic, making it inherently vulnerable to the loss of sea ice habitat due to climate change. Therefore, detailed assessments of past and present leopard seal population trends are needed to inform policies for Antarctic ecosystems.
豹形海豹（Hydrurga leptonyx）是顶级掠食者，对其南极猎物物种具有重要的自上而下的控制作用。然而，豹形海豹的种群趋势和遗传多样性仍未得到充分研究，限制了我们对其生态角色的理解。我们调查了豹形海豹的遗传多样性、有效种群大小和种群历史，为了解它们对南极生态系统的捕食影响提供了基本数据。在 2008 年至 2019 年的南极夏季，我们从南极半岛北部采集了 90 只豹形海豹样本，并对每个个体的线粒体控制区 405bp 片段进行了测序。我们发现了中等水平的核苷酸（π=0.013）和单倍型（Hd=0.96）多样性，有效种群大小估计约为 24000 只（NE=24376；95%置信区间：16876-33126）。与其他破冰鳍足类动物的研究结果一致，贝叶斯天空线分析也表明在末次冰盛期存在种群扩张的证据，这表明历史上的种群增长可能是由于海冰丰度的增加而促进的。尽管豹形海豹可以在较温暖的亚南极地区找到，但该物种的核心栖息地集中在南极，因此由于气候变化导致海冰栖息地的丧失，其本身就很脆弱。因此，需要对过去和现在的豹形海豹种群趋势进行详细评估，以为南极生态系统的政策提供信息。
