Global environmental change is having profound effects on the ecology of infectious disease systems, which are widely anticipated to become more pronounced under future climate and land use change. Arthropod vectors of disease are particularly sensitive to changes in abiotic conditions such as temperature and moisture availability. Recent research has focused on shifting environmental suitability for, and geographic distribution of, vector species under projected climate change scenarios. However, shifts in seasonal activity patterns, or phenology, may also have dramatic consequences for human exposure risk, local vector abundance and pathogen transmission dynamics. Moreover, changes in land use are likely to alter human–vector contact rates in ways that models of changing climate suitability are unlikely to capture. Here we used climate and land use projections for California coupled with seasonal species distribution models to explore the response of the western blacklegged tick (Ixodes pacificus), the primary Lyme disease vector in western North America, to projected climate and land use change. Specifically, we investigated how environmental suitability for tick host‐seeking changes seasonally, how the magnitude and direction of changing seasonal suitability differs regionally across California, and how land use change shifts human tick‐encounter risk across the state. We found vector responses to changing climate and land use vary regionally within California under different future scenarios. Under a hotter, drier scenario and more extreme land use change, the duration and extent of seasonal host‐seeking activity increases in northern California, but declines in the south. In contrast, under a hotter, wetter scenario seasonal host‐seeking declines in northern California, but increases in the south. Notably, regardless of future scenario, projected increases in developed land adjacent to current human population centers substantially increase potential human–vector encounter risk across the state. These results highlight regional variability and potential nonlinearity in the response of disease vectors to environmental change.

中文翻译：

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预计的气候和土地利用变化会改变加利福尼亚州西部黑脚tick的物候，季节性寻求宿主的适宜性和人类遭遇的风险。

全球环境变化正在对传染病系统的生态产生深远影响，人们普遍认为，在未来的气候和土地利用变化下，传染病系统将变得更加明显。疾病的节肢动物媒介对非生物条件（例如温度和湿度）的变化特别敏感。最近的研究集中于在预计的气候变化情景下改变环境对媒介物种的适应性和地理分布。但是，季节性活动方式或物候的变化也可能对人类接触风险，局部病媒丰度和病原体传播动态产生重大影响。此外，土地利用的变化很可能以不大可能捕捉到气候适应性变化模型的方式改变人类与媒介的接触率。太平洋凤仙花），这是北美西部地区主要的莱姆病媒介，可预测气候和土地利用的变化。具体而言，我们调查了整个加利福尼亚州对tick宿主寻求环境的适应性如何随季节变化，季节性适应性变化的程度和方向如何在整个加利福尼亚州之间有所不同，以及土地利用变化如何在全州范围内改变了人类tick接触者的风险。我们发现，在不同的未来情况下，加利福尼亚州对气候和土地利用变化的媒介反应会因地区而异。在更热，更干燥的情况下以及更极端的土地利用变化下，北部加利福尼亚州季节性寄主活动的持续时间和程度有所增加，而南部则有所下降。相反，在更热，更潮湿的情况下，北加州的季节性寄主下降，而在南部则有所增加。值得注意的是 不管未来的情况如何，与当前人口中心相邻的发达土地的预计增加，将大大增加全州潜在的人类媒介遭遇风险。这些结果突出了疾病媒介对环境变化的响应中的区域变异性和潜在的非线性。