Testing ecological and evolutionary hypotheses for geographic range limits

测试地理范围限制的生态和进化假设

• 批准号: RGPIN-2020-04611
• 负责人: LeeYaw, Julie
• 金额: $ 2.04万
• 依托单位: University of Lethbridge
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=716238
• 关键词: Testing; ecological; evolutionary; hypotheses; geographic

Understanding species' geographic distributions is a central goal in ecology and has emerged as a pressing scientific need as we strive to address the effects of climate change on biodiversity. Towards this end, my research focuses on understanding the ecological and evolutionary drivers of species' range limits. My past work has demonstrated that range limits often closely align with the limits of suitable habitat for species. Yet, departures from this pattern, as well as numerous cases whereby species have failed to track climate change, highlight the need to further probe the ecological factors influencing range limits. Furthermore, explaining range limits ultimately requires determining why adaptation fails at the edge of the range. These needs motive three short-term objectives: 1. Explain variation in the extent to which species occupy their potential range. Whether range limits reflect the limits of suitable habitat or constraints on dispersal may depend on features of the landscape and on species traits. My lab will use spatial data to model suitable habitat and the potential ranges of ten amphibian species. Using these models, we will test whether the steepness of environmental gradients, the dispersal capabilities of species, and/or local colonization and extinction dynamics influence the extent to which species fill their potential ranges in different places. 2. Evaluate the effects of species interactions at range limits. The importance of species interactions to range limits is highly debated. Furthermore, there are conflicting ideas as to whether species interactions are more or less impactful when abiotic conditions are stressful. My lab will use eDNA to quantify changes in the frequency of species interactions towards the low elevation, putatively benign, range limits of three amphibians and will experimentally test whether the effects of these interactions on each species varies across abiotic conditions associated with high versus low elevation limits. 3. Test genetic constraints on adaptation at the edge of the range. Both the random loss of genetic variation and the movement of genetic variants between sites following dispersal may influence genetic diversity at range limits and thus the adaptive potential of peripheral populations. My lab will use genomic data to quantify genetic variation and population connectivity at the edge of the range of the long-toed salamander. We will then test whether the extent to which populations demonstrate genomic signatures of maladaptation predicts field-based measurements of individual performance. Apart from enriching our understanding of species' range limits, this research will provide advanced skills training for 5 graduate and >5 undergraduate students. The skills and knowledge gained by students will equip them for a variety of careers and allow them to make meaningful contributions to scientific discovery and application.

了解物种的地理分布是生态学的中心目标，随着我们努力解决气候变化对生物多样性的影响，这已成为一项紧迫的科学需求。为此，我的研究重点是了解物种活动范围限制的生态和进化驱动因素。我过去的工作表明，活动范围的限制往往与物种的适宜栖息地的限制密切相关。然而，偏离这一模式，以及物种未能跟踪气候变化的众多案例，突显了进一步探索影响范围限制的生态因素的必要性。此外，解释范围限制最终需要确定为什么适应在范围边缘失败。这些需求推动了三个短期目标： 1.解释物种占据其潜在范围的程度的变化。范围限制是否反映了适宜栖息地的限制或对扩散的限制，可能取决于地貌特征和物种特征。我的实验室将使用空间数据来模拟10个两栖动物物种的合适栖息地和潜在的活动范围。利用这些模型，我们将测试环境梯度的陡度、物种的扩散能力和/或局部殖民和灭绝动态是否影响物种在不同地方填补其潜在范围的程度。 2.在射程范围内评估物种相互作用的影响。物种相互作用对射程限制的重要性引起了激烈的争论。此外，对于当非生物条件紧张时，物种之间的相互作用是更有影响还是更少影响，存在着相互矛盾的观点。我的实验室将使用EDNA来量化三种两栖动物在低海拔范围内相互作用的频率变化，并将通过实验测试这些相互作用对每个物种的影响是否在与高海拔限制和低海拔限制相关的非生物条件下有所不同。 3.在范围的边缘测试适应的遗传约束。遗传变异的随机丧失和遗传变异在扩散后在地点之间的移动都可能影响范围限制下的遗传多样性，从而影响外围种群的适应潜力。我的实验室将使用基因组数据来量化长趾蜥蜴范围边缘的遗传变异和种群连通性。然后，我们将测试人群表现出适应不良的基因组签名的程度是否可以预测基于现场的个人表现测量。 除了丰富我们对物种范围限制的理解外，这项研究还将为5名研究生和5名本科生提供高级技能培训。学生获得的技能和知识将使他们为各种职业做好准备，并使他们能够为科学发现和应用做出有意义的贡献。