Eco-Evolutionary Response to the Scale of Temporal Environmental Fluctuation

环境条件的周期性变化，如潮汐或季节，构成了自然界的一个共同主题。有生命的有机体必须应对不断到来的不利生存条件。因此，世界各地的物种都面临着进化的压力，需要安排它们的“生命周期”或“生命历史”，以适应它们所处的环境周期制度。最近的气候变化改变了许多生态系统的历史周期模式，如季节长度，导致生活史与动植物理想环境条件之间的不匹配，损害了种群的可持续性和生态稳定。自适应进化提供了一种缓冲这些失配的机制。从世界各地积累的生活史时间表变化的证据告诉我们，要了解生活史如何与环境周期和周期的变化“匹配”，尽管它们每天都很熟悉，但仍有很多工作要做。用数据和实验来检验理论观点是至关重要的。海洋沿海生境受多个时间尺度上发生的明显周期的影响，如日变化、潮汐变化、月球变化、季节变化和多年波动。潮间带甲壳动物的种群在整个东太平洋海岸线上占据着岩石海岸，在涨潮时周期性地以不同的间隔被潮汐冲刷。该项目开发了数学模型，以揭示在定期变化的环境中生活史变化和适应的基本规律，并使用高效和高度重复的野外收集和实验室操作实验，测试经历不同潮汐干扰的加州虎种群的假说。除了提供广泛适用的理论和丰富的开放获取数据外，调查人员还与现场附近的当地玛卡部落学生进行抽样和自然历史研究，以加强服务不足的农村社区的STEM教育。此外，该项目还通过培训本科生和研究生在实验设计、种群生态学和生活史进化的理论建模以及数据分析方面的能力来扩大国家-S的科学能力。自然种群如何在多变的环境中持续存在一直是生态学和进化论中的一个长期问题。特别是，周期性变化在自然界中很常见，许多物种表现出可预测的生活史策略，遵循自然界的周期(例如物候学)。然而，对于如何适应周期以及生命历史的波动如何缓冲环境变化，缺乏一个一般的概念框架。海洋环境在一系列时间尺度上的波动是可预测的，例如潮汐和季节，为研究周期性环境中的种群持久性和演变提供了独特的机会。开发了一个通用的数学框架，在周期性变化的环境中探索生命历史优化。海洋潮间带桡足类动物Tigriopus calforncus是测试模型预测和激励扩展的理想选择。许多孤立的种群可以完全在野外进行采样，潮汐周期的短时间尺度、短的世代时间和易于频繁的采样将提供响应自然干扰制度的生态进化模式的密集数据集。初步研究已经在实验室建立了实验种群，并证明了虎口虎对模拟干扰频率(周期性和随机)的谨慎操纵，这些频率无缝地转换到模型框架中。对周期性和随机环境中的生活史进行建模、现场参数化和实验研究相结合，是解决环境中生活史多样性问题的一种新的、全面的方法。最后，对周期性环境中进化机制的一般理解可以改善对自然周期被扰乱时种群命运的预测，这是由于气候变化而在许多生态系统中预期的。这一奖项反映了NSF的法定使命，并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。

Cyclical variations in environmental conditions, like tides or seasons, comprise a common theme in nature. Living organisms must cope with repetitive arrivals of unfavorable conditions for survival. Therefore species around the world are under evolutionary pressure to schedule their "life cycles" or "life histories" to fit the environmental cycle regimes within which they reside. Recent climate change has shifted historical cyclical patterns in many ecosystems, such as season length, resulting in mismatches between life histories and the ideal environmental conditions of plants and animals, to the detriment of population persistence and ecological stability. Adaptive evolution offers a mechanism that may buffer these mismatches. Accumulating evidence of shifts in life history schedules from around the world shows us that much remains to be done to understand how life histories are "fit" to environmental cycles, and to changes in cycles, despite their everyday familiarity. Testing theoretical ideas with data and experiments is essential. Marine coastal habitats are subject to conspicuous cycles occurring at multiple time scales, such as diel, tidal, lunar, seasonal, and multi-annual fluctuations. Populations of the intertidal crustacean Tigriopus californicus occupy rocky shore across the entire eastern Pacific coastline in upper tidepools that are periodically wave-swept at high tide at varying intervals. This project develops mathematical models to uncover fundamental rules of life history variation and adaptation in regularly varying environments, and tests hypotheses across Tigriopus californicus populations experiencing varying tidal disturbances using efficient and highly replicated field collections and manipulative experiments in the lab. Beyond producing broadly applicable theory and abundant open-access data, the investigators engage with local Makah Tribe students near field sites for sampling and natural history studies to enhance STEM education in an underserved rural community. Furthermore, the project expands the nation?s scientific capacity by training undergraduate and graduate students in experimental design, theoretical modelling in population ecology and life history evolution, and data analysis.How natural populations persist in variable environments has been a long-standing question in ecology and evolution. In particular, cyclical variability is common in nature, and many species show predictable life history strategies that follow cycles in nature (e.g. phenology). However, a general conceptual framework is lacking for how adaptation to cycles occurs and how the scaling of life histories to fluctuations buffers changes in the environment. Marine environments fluctuate predictably across a range of temporal scales, such as tidal and seasonal, and provide unique opportunities to study population persistence and evolution in cyclical environments. A general mathematical framework is developed that explores life history optimization in the context of cyclically varying environments. The marine intertidal copepod Tigriopus californcus is ideal for testing model predictions and motivating extensions. Many isolated populations can be sampled entirely in the field, and the short timescale of tide cycles, short generation times, and ease of frequent sampling will provide a dense dataset of eco-evolutionary patterns in response to natural disturbance regimes. Pilot studies have established experimental populations in the laboratory, and have proven that Tigriopus californcus is amenable to careful manipulations of simulated disturbance frequency (both cyclical and stochastic) that seamlessly translate to the model framework. The combination of modelling, field parameterization, and experimental investigation of life histories in cyclical and stochastic environments is a novel and holistic approach to the question of life history diversity within an environment. Finally, a general understanding of evolutionary mechanisms in cyclical environments can improve predictions of the fate of populations when natural cycles are perturbed, which is expected across many ecosystems due to climate change.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.