Institute for Circumpolar Health Studies, University of Alaska, Anchorage, 3211 Providence Drive, Anchorage, AK 99508 USA.
Hopland Research & Extension Center, University of California Division of Agriculture and Natural Resources, 4070 University Road, Hopland, CA 95449 USA.
Ticks Tick Borne Dis. 2021 Sep;12(5):101789. doi: 10.1016/j.ttbdis.2021.101789. Epub 2021 Jul 13.
In the western United States, Ixodes pacificus Cooley & Kohls (Acari: Ixodidae) is the primary vector of the agents causing Lyme disease and granulocytic anaplasmosis in humans. The geographic distribution of the tick is associated with climatic variables that include temperature, precipitation, and humidity, and biotic factors such as the spatial distribution of its primary vertebrate hosts. Here, we explore (1) how climate change may alter the geographic distribution of I. pacificus in California, USA, during the 21 century, and (2) the spatial overlap among predicted changes in tick habitat suitability, land access, and ownership. Maps of potential future suitability for I. pacificus were generated by applying climate-based species distribution models to a multi-model ensemble of climate change projections for the Representative Concentration Pathway (RCP) 4.5 (moderate emission) and 8.5 (high emission) scenarios for two future periods: mid-century (2026-2045) and end-of-century (2086-2099). Areas climatically-suitable for I. pacificus are projected to expand by 23% (mid-century RCP 4.5) to 86% (end-of-century RCP 8.5) across California, compared to the historical period (1980-2014), with future estimates of total suitable land area ranging from about 88 to 133 thousand km, or up to about a third of California. Regions projected to have the largest area increases in suitability by end-of-century are in northwestern California and the south central and southern coastal ranges. Over a third of the future suitable habitat is on lands currently designated as open access (i.e. publicly available), and by 2100, the amount of these lands that are suitable habitat for I. pacificus is projected to more than double under the most extreme emissions scenario (from ~23,000 to >51,000 km). Of this area, most is federally-owned (>45,000 km). By the end of the century, 26% of all federal land in the state is predicted to be suitable habitat for I. pacificus. The resulting maps may facilitate regional planning and preparedness by informing public health and vector control decision-makers.
在美国西部，太平洋硬蜱（Ixodes pacificus Cooley & Kohls）（螨目：硬蜱科）是引起人类莱姆病和粒细胞无形体病的主要媒介。蜱的地理分布与气候变量有关，包括温度、降水和湿度，以及生物因素，如主要脊椎动物宿主的空间分布。在这里，我们探讨了（1）在 21 世纪，气候变化可能如何改变美国加利福尼亚州太平洋硬蜱的地理分布，以及（2）预测的蜱栖息地适宜性、土地利用和所有权变化之间的空间重叠。通过将气候物种分布模型应用于代表浓度路径（RCP）4.5（中度排放）和 8.5（高排放）情景的气候变化预测多模型集合，生成了未来太平洋硬蜱潜在适宜性的地图。对于两个未来时期：本世纪中叶（2026-2045 年）和本世纪末（2086-2099 年）。与历史时期（1980-2014 年）相比，加利福尼亚州的太平洋硬蜱气候适宜区预计将增加 23%（本世纪中叶 RCP 4.5）至 86%（本世纪末 RCP 8.5），未来适宜土地总面积估计在 88 万至 133 万 km 之间，约占加利福尼亚州的三分之一。到本世纪末，预计适宜面积增加最大的地区是加利福尼亚州西北部和中南部以及南部沿海山脉。未来三分之一以上的适宜栖息地位于目前指定为开放获取（即公共可用）的土地上，到 2100 年，在最极端排放情景下（从~23,000 到>51,000 km），这些土地适宜太平洋硬蜱的数量预计将增加一倍以上。在这一地区，大部分土地归联邦所有（>45,000 km）。到本世纪末，预计该州 26%的联邦土地将成为太平洋硬蜱的适宜栖息地。这些地图可能通过为公共卫生和虫媒控制决策者提供信息，促进区域规划和准备。
