MSA: Modeling and Forecasting Shifts in Migratory Patterns Under Changing Hadley Circulation Dynamics

每年有数十亿的昆虫、鸟类和蝙蝠从中美洲和南美洲经墨西哥飞到美国和加拿大。这些迁徙是自然界最壮观和最明显的现象之一。然而，年复一年地启动和引导这些移民的因素仍然知之甚少，特别是对昆虫。一个已知的重要因素是盛行风的方向和强度，但尚未得到很好的理解，这在很大程度上取决于大气环流圈。这些细胞是主要的环境驱动因素，不仅影响盛行风的模式，而且影响地球上生态生物群落的位置。这些环流中最大的一个称为哈德利环流，在大约南纬30°到北纬30°的热带地区活动。在这个单元中，风在赤道周围上升，然后在更高的高度向南北移动。当它们落在热带边缘更近的地面上时，它们带来了干燥的空气，但也有可能携带移民。帝王蝶（Danaus plexippus）是最著名的昆虫迁徙者，在墨西哥的哈德利细胞上升气流的焦点附近越冬，并向北迁徙到德克萨斯州的哈德利细胞沉降附近产卵。然而，哈德利细胞和君主迁移之间的联系迄今尚未探讨。这项研究将研究哈德利细胞在8种蝴蝶（包括帝王蝶）的年度迁徙动态（时间和成功）中的作用，这些蝴蝶穿越墨西哥并进入美国。这项工作将开发移徙模型/教育模块，用于了解地球仪各地的空中移徙者。研究结果将通过研究团队运营的三只蝴蝶网站在利益相关者和公众之间共享，研究结果也将纳入乔治敦大学的定量生态学定期讲座。迁移占全球生态系统中营养物质和生物量的大规模转移，也为物种生存提供了关键策略。然而，由于其巨大的空间范围，移民是一个特别具有挑战性的研究现象。鉴于温度、降水和风等环境驱动因素对迁徙的重要性，环境变化可能对动物迁徙产生重大影响，特别是对昆虫。这项研究将利用全球大气环流单元建立一个框架，以了解长距离移徙。模型将使用来自美国西南部国家生态观测网络（氖）七个站点的数据以及来自几个公民科学蝴蝶监测网络的数据进行验证。此外，该团队将使用气候模型来预测未来不同气候情景下的这些模式。这项研究的具体目标是量化最大的大气环流圈，哈德利环流圈，在何种程度上是昆虫从热带向温带迁移的出发，迁移和到达的机械动力学的基础。这项工作将模拟八种蝴蝶的迁徙，其中三种显示了经典的往返迁徙（例如，该奖项反映了NSF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。

Every year billions of insects, birds, and bats fly from central and South America through Mexico up into the United States and Canada. These migrations are one of the most spectacular and visible phenomena of the natural world. Yet factors that initiate and guide these migrants year after year remain poorly understood, especially for insects. One factor that is known to be important, but not well understood, is the direction and strength of prevailing winds, which are largely determined by atmospheric circulation cells. These cells are dominant environmental drivers impacting not only the pattern of prevailing winds, but also the location of ecological biomes across the Earth. The largest of these cells, called the Hadley cell, operates in the tropical zone approximately from latitude 30°S to 30°N. In this cell, winds rise around the equator and then move both North and South at higher altitudes. As they fall to the ground closer at the edge of the tropics, they bring dry air, but also potentially carry the migrants. Monarch butterflies (Danaus plexippus), the best-known insect migrant, overwinters in Mexico, near the focal point of the Hadley cell updraft and migrates North to lay eggs in Texas, near where the Hadley cell subsides. Yet the connection between Hadley cell and monarch migration to date has not been explored. This study will examine the role of the Hadley cell in the annual migratory dynamics (timing and success) of eight species of butterflies, including monarch, that migrate across Mexico and into the US. This work will develop migration model / educational modules that will be applicable for understanding aerial migrant across the globe. Results will be shared among the stakeholders and public through the three-butterfly websites run by the research team, and the results will also be incorporated into the regular lectures on quantitative ecology at Georgetown University.Migration accounts for massive transfers of nutrients and biomass in ecosystems worldwide and also provides a key strategy for species survival. Yet migration is a particularly challenging phenomenon to study due to its large spatial extent. Given the importance of environmental drivers such as temperature, precipitation, and wind for migration, environmental change may have substantial impacts on animal migration, particularly for insects. This study will develop a framework using global atmospheric circulation cells to understand long-distance migration. Models will be validated using data from seven sites of the National Ecological Observatory Network (NEON) in the southwestern US and also with data from several citizen science butterfly monitoring networks. Further, the team will use climate models to project these patterns into the future under different climate scenarios. The study’s specific objectives are to quantify the degree to which the largest atmospheric circulation cell, the Hadley Cell, underlies the mechanistic dynamics of departure, migration and arrival for insects migrating from the tropics to the temperate zone. This work will model migration of eight butterfly species, three of which show classic round-trip migration (e.g., monarch) and the remaining five migrate one-way only in the fall.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.