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

人类同时也在改变着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、野生动物和牲畜对传染病的暴露。值得注意的是，这些疾病包括由蜱虫、苍蝇和蚊子等吸血无脊椎动物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，将大型野生动物移走或用牲畜代替，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众健康和野生动物保护都至关重要。对于像莱姆病这样的蜱传疾病来说尤其如此，在这种疾病中，医疗可能会有问题且费用高昂。本研究旨在了解环境变化和野生动物或牲畜管理对蜱传疾病风险的影响，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，为儿童自然项目中服务不足的五年级学生提供新的科学培训。它将进一步支持一个关于蜱传疾病的公民科学移动电话应用程序，该应用程序既使公众参与数据收集，又提供有关蜱虫数量和蜱传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在本项目的实地和实验室部分接受培训。该项目将在一系列气候条件下，对大量野生动物丧失和牲畜增加对蜱虫数量、蜱传疾病流行率和疾病风险的影响进行机械研究。该研究将使用1)大规模野外封闭实验，在强气候梯度下复制，作为区域环境变化预测的代理；2)在相同气候梯度下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，加州正经历着气候变暖和干燥，大型野生动物数量急剧减少，牲畜数量随之增加。为了了解跨系统的普遍性，本研究将研究对具有不同生活史的多种蜱类的影响。具体而言，本项目将评估以下假设：1)大型野生动物清除对感染蜱密度的影响将因蜱的种类而异，取决于蜱？2)牲畜和大型野生动物在该系统中具有非常相似的影响，其影响与它们的生物量成正比；3)在更干旱的环境中，感染蜱的密度会更低，而在更干旱的气候条件下，大型食草动物对蜱的影响会更强；4)影响的大小和方向会根据蜱的生活史策略而变化。该奖项反映了美国国家科学基金会的法定使命，并通过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，被认为值得支持。

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.