Individual and Population Responses to Environmental Change: Allee Effects, Phenotypic Plasticity, and Life History in Fishes

个体和群体对环境变化的反应：阿利效应、表型可塑性和鱼类的生活史

• 批准号: RGPIN-2021-04372
• 负责人: Hutchings, Jeffrey
• 金额: $ 5.58万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745747
• 关键词: Individual; Population; Responses; Environmental; Change

Life-history theory offers explanatory and predictive frameworks for understanding individual and population responses to natural and anthropogenic environmental change. By affecting reproductive success, life histories affect fitness; by affecting fitness, life histories affect population demography. Comprehensive understanding of the causes and consequences of life-history variation is undermined by uncertainties in our ability to predict physiological, life history, demographic, and evolutionary responses to environmental change. It is these uncertainties that stimulate my long-term objective to explore the adaptive significance of within- and among-population variability in life history, by determining how environmental change influences fitness. My short-term objective is to gain insight into the adaptive significance of individual and population responses to environmental change in light of: i) Allee effects; (ii) reaction norms; (iii) regime shifts; and (iv) ecotypic variation. Integral to the dynamics of small populations are Allee effects - positive relationships between abundance (or density) and realized per capita population growth. The greater the magnitude of decline, the greater the likelihood of Allee effects, negatively affecting fitness and recovery. Recent models of density-dependent selection emphasize the importance of rapid evolution, a form of `evolutionary rescue'. However, direct evidence is limited. Using laboratory-based selection experiments on Japanese medaka, I will examine whether demographic and emergent Allee effects generate different selection responses in small populations and different recovery trajectories. Life histories evolve in response to changes in the mean and variance of environmental conditions. However, research has focused almost exclusively on shifts in average temperature rather than shifts in thermal variability, limiting understanding of how thermal variability affects fitness independently of directional changes in mean temperature. Based on experiments on zebrafish, I ask how plasticity (developmental & transgenerational) and thermal fluctuations affect fitness, resistance to heat shock, and tolerance to low-oxygen environments. Environmental change affects biodiversity. Numerous models have generated predictive analyses of how species will respond to global change but few predictions have been ground-truthed. Using a Bayesian change-point detection algorithm, I will determine how anthropogenic and natural `stressors' have affected coastal fish biodiversity, by applying regime-shift analyses to exceptionally long (up to 100 years) datasets. At the intra-specific level of biodiversity, I will explore how environmental change influences the proportional representation of genetically different ecotypes in Atlantic cod, and test the hypothesis that ecotypes are maintained by factors substantive enough to negatively affect the probability of interbreeding or the survival of hybrid offspring.

生活史理论提供了解释和预测框架，了解个人和人口的自然和人为环境变化的反应。通过影响繁殖成功，生活史影响健身;通过影响健身，生活史影响人口统计学。我们预测生理、生活史、人口统计学和进化对环境变化的反应的能力的不确定性破坏了对生活史变化的原因和后果的全面理解。正是这些不确定性激发了我的长期目标，即通过确定环境变化如何影响适应性，探索生活史中种群内和种群间变异的适应意义。我的短期目标是深入了解个人和人口对环境变化的反应的适应意义：（i）Allee效应;（ii）反应规范;（iii）政权转移;和（iv）生态型变异。小种群动态的组成部分是阿利效应-丰度（或密度）与实现的人均人口增长之间的正相关关系。下降的幅度越大，Allee效应的可能性就越大，对健身和恢复产生负面影响。最近的密度依赖选择模型强调了快速进化的重要性，这是一种“进化拯救”的形式。然而，直接证据有限。使用基于实验室的选择实验，日本青鳉，我将研究人口和紧急Allee效应是否产生不同的选择反应，在小群体和不同的恢复轨迹。 生命史的进化是对环境条件的均值和方差变化的反应。然而，研究几乎完全集中在平均温度的变化，而不是热变率的变化，限制了对热变率如何独立于平均温度的方向变化影响健身的理解。基于对斑马鱼的实验，我问可塑性（发育和代际）和热波动如何影响健身，耐热冲击和耐低氧环境。环境变化影响生物多样性。许多模型已经产生了关于物种将如何应对全球变化的预测分析，但很少有预测是真实的。使用贝叶斯变点检测算法，我将确定如何人为和自然的“压力”影响沿海鱼类的生物多样性，通过应用政权转移分析异常长（长达100年）的数据集。在种内生物多样性的水平，我将探讨环境变化如何影响大西洋鳕鱼遗传上不同的生态类型的比例代表性，并测试的假设，即生态类型是由实质性的因素足以产生负面影响的概率杂交或杂交后代的生存。