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。生物必须应对不断到来的不利生存条件。因此，世界各地的物种都在进化的压力下安排它们的“生命周期”或“生活史”，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，导致生命史与动植物理想环境条件之间的不匹配，损害了种群的持久性和生态稳定性。适应性进化提供了一种机制来缓冲这些不匹配。来自世界各地的关于生命史时间表变化的证据越来越多，这向我们表明，要了解生命史如何“适应”环境周期和周期变化，尽管它们每天都很熟悉，但仍有很多工作要做。用数据和实验检验理论观点是必不可少的。海洋沿岸生境在多个时间尺度上受到明显周期的影响，如日、潮、月、季节和多年波动。潮间带甲壳类动物加利福尼亚Tigriopus的种群占据了整个东太平洋海岸线上的岩石海岸，这些海岸在涨潮时以不同的间隔周期性地被海浪扫过。该项目开发了数学模型，以揭示生活史变化和适应定期变化的环境的基本规则，并通过高效和高度复制的现场收集和实验室操作实验，在经历不同潮汐干扰的加利福尼亚虎蛸种群中测试假设。除了产生广泛适用的理论和丰富的开放获取数据外，研究人员还与当地Makah部落的学生在实地地点附近进行采样和自然历史研究，以加强服务不足的农村社区的STEM教育。此外，该项目扩大了国家。通过培养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和数据分析方面的科学能力。自然种群如何在多变的环境中生存一直是生态学和进化中一个长期存在的问题。特别是，周期变异性在自然界中很常见，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）。然而，对于如何适应周期以及如何将生活史按比例调整以适应波动来缓冲环境中的变化，缺乏一个一般的概念框架。海洋环境在潮汐和季节等一系列时间尺度上可预测地波动，并为研究周期性环境中的种群持久性和进化提供了独特的机会。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活史优化。海洋潮间带桡足动物加利福尼亚虎足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在野外完全采样，潮汐周期的短时间尺度、生成时间短和频繁采样的容易性将提供一个密集的生态进化模式数据集，以响应自然干扰制度。试点研究已经在实验室中建立了实验种群，并证明加州虎爪鼠可以对模拟干扰频率（周期性和随机）进行仔细的操纵，并无缝地转化为模型框架。在周期性和随机环境中对生命史进行建模、现场参数化和实验调查的结合，是研究环境中生命史多样性问题的一种新颖而全面的方法。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受到干扰时种群命运的预测，这是由于气候变化而在许多生态系统中预期的。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。

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.