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植物群落。这两种形式的全球变化有可能影响人类、野生动物和牲畜感染传染病。值得注意的是，这些疾病包括由扁虱、苍蝇和蚊子等食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媒介物种的发育速度，或者增加温度诱导的死亡率。同样，移走或用牲畜取代大型野生动物可能会改变这些媒介物种的食物可获得性和繁殖能力。因此，了解这两种形式的环境变化的单独和联合影响对公共卫生和野生动物保护都至关重要。这尤其适用于扁虱传播的疾病，如莱姆病，在这些疾病中，医疗可能会有问题，费用也很高。这项研究旨在了解环境变化和野生动物或牲畜管理将如何影响壁虱传播的疾病风险，以更好地防止疾病传播。值得注意的是，该项目还将支持K-12教育，为自然儿童计划中未得到充分服务的5年级学生提供新的科学培训。它将进一步支持公民科学移动电话应用程序，该应用程序既能让公众收集数据，又能提供有关壁虱数量和壁虱传播疾病风险的有价值的信息。许多来自服务不足背景的本科生和研究生将接受这一项目的实地和实验室部分的培训。该项目将从机械上研究在一系列气候条件下，大量野生动物的损失和家畜的增加对壁虱数量、壁虱传播疾病流行率和疾病风险的影响。这项研究将使用1)大规模的野外围栏实验，作为区域环境变化预测的替代气候梯度，以及2)同一气候梯度的大规模观测研究，并利用野生动物/牲畜密度的自然变化。该项目将在加利福尼亚州进行，加州正在经历气候变暖和干燥，大型野生动物数量急剧减少，同时牲畜数量也在增加。为了了解跨系统的共性，这项研究将调查不同生活史的多个扁虱物种的影响。具体地说，该项目将评估以下假设：1)大型野生动物迁徙对受感染的硬蜱密度的影响将因扁虱物种的不同而有所不同？S，2)牲畜和大型野生动物在这个系统中具有非常相似的影响，影响与它们的生物量成比例，3)受感染的硬蜱密度在更干旱的环境中会更低，大型食草动物对扁虱的影响在更干旱的气候中会更强。4)影响的大小和方向将根据滴答生活史战略的不同而有所不同。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势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.