Biodiversity Research Institute, 276 Canco Road, Portland, ME, 04103, USA.
Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.
Ecotoxicology. 2020 Dec;29(10):1830-1842. doi: 10.1007/s10646-020-02175-7. Epub 2020 Mar 30.
Mercury (Hg) is a potent neurotoxin that biomagnifies within food webs. Adverse effects have been documented for avian species related to exposure of elevated Hg levels. High elevation, boreal forests generally receive higher atmospheric Hg deposition and regional studies have subsequently identified elevated blood Hg concentrations in songbird species inhabiting these montane habitats. The overall goal of this study was to investigate spatial and seasonal Hg exposure patterns in songbird species along an elevational gradient on Whiteface Mountain in the Adirondack Park of New York State. Songbird blood samples were collected from June-July in 2009 and 2010 along an elevational gradient at 13 study plots (450-1400 m) with a focus on Catharus thrushes, including the hermit thrush, Swainson's thrush, and Bicknell's thrush. The main results of this study documented: (1) an overall linear pattern of increasing blood Hg concentrations with increasing elevation, with additional analysis suggesting a nonlinear elevational pattern of increasing blood Hg concentrations to 1075 m, followed by decreasing concentrations thereafter, for all Catharus thrush species across the elevational gradient; and (2) an overall nonlinear seasonal pattern of increasing, followed by decreasing blood Hg concentrations across target species. Avian exposure patterns appear driven by elevated atmospheric Hg deposition and increased methylmercury bioavailability within high elevation habitats as compared with low elevation forests. Seasonal patterns are likely influenced by a combination of complex and dynamic variables related to dietary selection and annual molting cycles. Considering that few high elevation analyses have been conducted within the context of regional songbird research, this project complements the results from similar studies and highlights the need for further monitoring efforts to investigate environmental Hg contamination within avian communities.
汞（Hg）是一种强效的神经毒素，在食物网中具有生物放大作用。已有研究记录了与升高的 Hg 水平暴露相关的鸟类物种的不良反应。高海拔地区的森林通常会接收更高的大气 Hg 沉降量，随后的区域研究也确定了在栖息于这些高山生境的鸣禽物种中，血液 Hg 浓度升高。本研究的总体目标是研究在纽约州阿迪朗达克公园的 Whiteface 山上的海拔梯度上，鸣禽物种的空间和季节性 Hg 暴露模式。在 2009 年和 2010 年 6 月至 7 月期间，在 13 个研究点（450-1400 m）沿海拔梯度采集了鸣禽血液样本，重点研究了包括隐士莺、斯旺森莺和比氏莺在内的卡塔鲁斯莺。本研究的主要结果记录如下：（1）总体上，血液 Hg 浓度随海拔升高呈线性增加模式，进一步分析表明，在海拔梯度上，所有卡塔鲁斯莺种的血液 Hg 浓度呈非线性增加模式，在升高至 1075 m 后浓度降低；（2）各目标物种的血液 Hg 浓度总体上呈非线性季节性增加后降低模式。鸟类的暴露模式似乎是由大气 Hg 沉降量升高以及高海拔生境中甲基汞生物利用度增加所驱动的，而这与低海拔森林相比则有所不同。季节性模式可能受到与饮食选择和年度换羽周期相关的复杂和动态变量的综合影响。考虑到在区域鸣禽研究背景下，很少有关于高海拔地区的分析，因此本项目补充了类似研究的结果，并强调需要进一步监测努力，以调查鸟类群落中的环境 Hg 污染。
