SG: Collaborative Research: Effects of changing wildlife communities across climatic contexts on tick-borne disease in California

人类正在同时改变环境和野生动物群落。这两种形式的全球变化有可能影响人类、野生动物和牲畜接触传染病。值得注意的是，这些疾病包括由吸血无脊椎动物（如蜱虫、苍蝇和蚊子）携带和传播的病媒传播疾病。环境条件的变化可能会增加这些病媒物种的发育速度，或增加温度引起的死亡率。同样，迁移大型野生动物或以牲畜取代大型野生动物可能会改变这些病媒物种的食物供应和繁殖能力。因此，了解这两种形式的环境变化的单独和综合影响对公共卫生和野生动物保护至关重要。对于蜱传疾病尤其如此，如莱姆病，医疗治疗可能存在问题且昂贵。本研究旨在了解环境变化和野生动物或牲畜管理如何影响蜱传疾病风险，以更好地预防疾病传播。值得注意的是，该项目还将支持K-12教育，为服务不足的五年级学生提供新的科学培训。 它将进一步支持关于蜱虫传播疾病的公民科学移动的电话应用程序，该应用程序既使公众参与数据收集，又提供关于蜱虫丰度和蜱虫传播疾病风险的宝贵信息。 许多来自服务不足背景的本科生和研究生将接受本项目现场和实验室部分的培训。该项目将在一系列气候条件下，机械地检查大量野生动物损失以及牲畜增加对蜱虫丰度、蜱传疾病流行率和疾病风险的影响。该研究将使用1）大规模的野外围封实验，在强气候梯度上复制，作为区域环境变化预测的代理，以及2）在相同气候梯度上进行大规模观测研究，并利用野生动物/牲畜密度的自然变化。该项目将在加州进行，该地区正在经历气候变暖和干燥，大型野生动物数量急剧下降，牲畜数量随之增加。为了了解系统的一般性，本研究将调查对具有不同生活史的多种蜱虫物种的影响。具体而言，本项目将评估以下假设：1）大型野生动物清除对受感染蜱虫密度的影响将因蜱虫种类而异，具体取决于蜱虫？的生活史，2）牲畜和大型野生动物将在这个系统中产生非常相似的影响，其影响与其生物量成比例，3）在更干旱的环境中，受感染蜱虫的密度将较低，大型食草动物对蜱虫的影响在更干旱的气候中将更强，和4）影响的大小和方向将根据蜱虫生活史策略而变化。该奖项反映了NSF的法定使命，并被认为值得通过以下方式予以支持：使用基金会的知识价值和更广泛的影响审查标准进行评估。

Humans are concurrently changing the environment and wildlife communities. These two forms of global change have the potential to impact human, wildlife, and livestock exposure to infectious disease. Notably, these include vector-borne diseases which are carried and transmitted by blood-feeding invertebrates such as ticks, flies, and mosquitoes. Changes in environmental conditions may increase development rates of these vector species, or increase temperature-induced mortality. Similarly, removing or replacing large wildlife with livestock may alter food availability and reproductive ability for these vector species. Understanding the separate and combined impacts of these two forms of environmental change is thus of critical importance for both public health and wildlife conservation. This is particularly true for tick-borne diseases, like Lyme disease, where medical treatment can be problematic and costly. This study aims to understand how tick-borne disease risk will be impacted by environmental change and wildlife or livestock management to better prevent disease transmission. Notably this project will also support K-12 education by providing new scientific training to underserved 5th grade students in the Kids in Nature program. It will further support a Citizen Science mobile phone application on tick borne disease, which both engages the public in data collection and provides valuable information on tick abundance and risk of tick-borne disease. Many undergraduate and graduate students from underserved backgrounds will receive training in both field and lab components of this project. This project will mechanistically examine the effects of large wildlife loss coupled and the addition of livestock on tick abundance, tick-borne disease prevalence, and disease risk, under a range of climatic conditions. The study will use 1) a large-scale field exclosure experiment, replicated across a strong climate gradient serving as a proxy for regional environmental change predictions, and 2) a large-scale observational study across the same climate gradient and utilizing natural variation in wildlife/livestock densities. This project will be conducted in California, which is experiencing both warming and drying climates and strong declines in large wildlife with concomitant increases in livestock. In order to understand generality across systems, this study will investigate impacts on multiple tick species with variable life histories. Specifically, this project will evaluate the following hypotheses: 1) the effects of large wildlife removal on density of infected ticks will vary by tick species depending on the tick?s life history, 2) livestock and large wildlife will have very similar effects in this system, with effects proportionate to their biomass, 3) density of infected ticks will be lower in more arid environments and the effects of large herbivores on ticks will be stronger in more arid climates, and 4) both the magnitude and direction of the effect will vary based on tick life history strategy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.