NSFGEO-NERC Collaborative Research: Effects of a changing climate on the habitat utilization, foraging ecology and distribution of crabeater seals

在南极半岛西部沿纬度梯度研究食蟹海豹的营养生态、分布和觅食成功的差异。由于全球气候变化和局部环境过程的影响，wAP沿线的大气和海洋正在迅速变化。我们的研究将提高我们理解整个依赖磷虾的大型食肉动物群落将如何应对预计的环境变化的能力。此外，我们有20年前的生态基线数据，包括该物种的运动模式、潜水行为、摄食行为、分布和丰度，以及20世纪90年代中期的历史数据和样本，为我们提供了一个独特的机会和有利的位置来探测这种显眼的南极中掠食性动物及其扩展的捕食者群落的生态变化。食蟹海豹（Lobodon carcinophaga）是南极磷虾（Euphausia superba）在南极海域的主要捕食者。这是由于其高度的生态专门化，丰富度和生物量大，代谢需求高。它对单一猎物资源的高度依赖，加上它是浮冰上的专门居民，使食蟹海豹成为研究磷虾分布变化以及整个生态系统结构潜在变化的绝佳物种：海豹的水平分布是由磷虾的分布决定的，同样，海豹的潜水行为提供了对这种浮游生物在水柱中的垂直分布的见解。考虑到食蟹海豹的日常栖息地需求的两分法，我们的目标是评估这些以前重叠的栖息地现在是否在时间和空间上沿着南极半岛西部分开。考虑到海冰时间和范围的纬度差异。除了食蟹海豹对磷虾的极度依赖外，我们预计，与南部wAP的动物相比，北部wAP的个体已经改变了它们的觅食行为，并产生了更高的能量消耗。或者，食蟹海豹可能已经改变了它们的栖息地使用模式和/或它们的饮食，以应对wAP沿线气候的变化。我们将利用传统的航空调查结合新技术（无人机系统和卫星图像），通过与BAS合作，对wAP内的海豹数量进行普查。空中调查将提供一个基准，我们可以据此验证从这些平台获得的新数据，这在后勤上更容易，成本效益更高。跟踪研究还将提供食蟹海豹的迁徙模式的同步数据，这些数据将用于校正海上个体比例的调查数据。调查和跟踪数据将首先用于确定食蟹海豹的数量是否已经减少，或者由于海冰的减少而向南迁移。其次，开发物种分布的栖息地模型，以定义影响动物进食地点和拖拽地点的变量，确定这些栖息地的差异，并预测这些环境条件的时空共现。

We propose to investigate the differences in the trophic ecology, distribution and foraging success of crabeater seals across a latitudinal gradient along the western Antarctica Peninsula (wAP). As a consequence of global climate change and local environmental processes, the atmosphere and oceans along the wAP are rapidly changing. Our study will enhance our ability to understand how the entire krill-dependent community of large predators will respond to the projected environmental changes. Furthermore, we have ecological baseline data from 20 years ago on movement patterns, diving behavior, feeding behavior, distribution and abundance for the species, as well as historical data and samples from the mid-1990s, providing us with a unique opportunity and advantageous position to detect changes in the ecology of this conspicuous Antarctic mesopredator and the extended predator community.The crabeater seal (Lobodon carcinophaga) is the most important predator of Antarctic krill Euphausia superba in Antarctic waters. This is due to its high degree of ecological specialization, large abundance and biomass, and high metabolic demand. Its high dependence on a single prey resource, combined with being an obligate inhabitant of the pack ice, makes the crabeater seal an excellent species to examine changes in krill distribution as well as potential changes in the structure of the entire ecosystem: the horizontal distribution of the seal is determined by the distribution of krill, and similarly the seals diving behavior provides insights into the vertical distribution of this euphausiid in the water column. Given the dichotomy in the daily habitat requirements of the crabeater seal, we aim to evaluate whether these previously-overlapping habitats are now separating in time and space along the western Antarctic Peninsula. Given the latitudinal differences in sea ice timing and extent. As well as the extreme dependence of crabeater seals on krill, we expect that individuals in the northern wAP have modified their foraging behavior and incur in elevated energetic costs as opposed to animals in the southern wAP. Alternatively, crabeater seals could have modified their habitat usage patterns and/or their diet in response to the changing climate along the wAP.We will use traditional aerial surveys combined with new technologies (UAS and satellite imagery) to census the population of seals in the wAP through a collaboration with BAS. The aerial surveys will provide a benchmark against which we can validate the new data obtained from these platforms, which are logistically easier and more cost-effective. The tracking studies will also provide concurrent data on haulout patterns of crabeater seals that will be used to correct the survey data for the proportion of individuals at sea1. The survey and tracking data will be utilized to first determine if the crabeater seal population has declined and or moved south in response to declining sea ice. Second, develop habitat models of the species distribution to define the variables that influence where the animals are eating versus where they are hauling out, determine how these habitats differ and predict the spatio-temporal co-occurrence of these environmental conditions.