Patterns and causes of temporal variation in tree seed production

树木种子生产时间变化的模式和原因

• 批准号: 46315-2011
• 负责人: Greene, David
• 金额: $ 2.77万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=507043
• 关键词: Patterns; causes; temporal; variation; tree

Masting behavior (defined as the spatially synchronous and temporally episodic production of seed crops) in tree species is of tremendous importance in ecology (e.g. dramatic trophic effects for deer and rodents; eruptions of granivorous bird populations; pollen flux in anemophilous species; etc). It is also quite important in forestry-the unpredictable nature of masting events has favored the more expensive but more reliable regeneration option of planting. As of now the only consensual statements one might make are that a mast year is of regional extant with inter-annual pollen and ovule production closely linked, most species within a region are not synchronized with one another, and weather undoubtedly plays a major role (generating resources and/or cues for bud differentiation). The proposed study has a number of objectives including a global examination of the dependence on masting on latitude, altitude, longitude, and life history traits such as aerial seedbanks and obligate bird dispersal of some Pine species. I will extend my on-going data set from 6 to 11 years, measuring ovulate cones per basal area of Picea glauca (white spruce) and the very close-related P. engelmannii (Engelmann spruce) in the same 68 stands from Colorado to the Arctic Ocean (Inuvik), and from interior Alaska to Newfoundland; and then I will use these data to test models of reproduction that are resource-based, cue-based, or a combination of resource and cue. Further, I will compare the effect of resources vs weather cues in governing annual reproductive output in a series of experiments in young white spruce stands in western Alberta, central Manitoba, and northwest Quebec by inducing water stress during normal years, irrigation during very dry years, removal of immature female cones during mast years, and installation of artificial clusters of cones to imitate the shading of real cones during mast years. Finally, I will relate cones per basal area and area burned in four spatially independent regions of the boreal forest to ascertain if big fire years are typically followed by mast crops.

树种的桅杆行为（定义为种子作物在空间上同步和时间上间歇性的生产）在生态学中具有极其重要的意义（例如，对鹿和啮齿动物的巨大营养作用；食粮鸟类种群的爆发；风媒物种的花粉通量等）。这在林业中也非常重要——桅杆事件的不可预测性有利于更昂贵但更可靠的种植再生选择。到目前为止，人们可能做出的唯一一致的声明是，肥大年是区域性现存的，年际花粉和胚珠的产生密切相关，一个区域内的大多数物种彼此不同步，并且天气无疑起着重要作用（产生芽分化的资源和/或线索）。拟议的研究有许多目标，包括对桅杆对纬度、海拔、经度和生活史特征（例如空中种子库和某些松树物种的专性鸟类传播）的依赖性进行全球检查。我将把我正在进行的数据集从 6 年延长到 11 年，测量从科罗拉多州到北冰洋 (Inuvik)、从阿拉斯加内陆到纽芬兰的相同 68 个林分中的云杉 (Picea glauca)（白云杉）和关系非常密切的 P. engelmannii (Engelmann spruce) 的每个基底面积的排卵球；然后我将使用这些数据来测试基于资源、基于线索或资源和线索组合的复制模型。此外，我将在艾伯塔省西部、曼尼托巴省中部和魁北克省西北部的幼龄白云杉林中进行一系列实验，比较资源与天气因素对控制年繁殖产量的影响，方法是在正常年份诱导水分胁迫，在非常干旱的年份进行灌溉，在丰年期间去除未成熟的雌球果，并在丰年期间安装人工球果簇以模仿真实球果的阴影。 最后，我将把每个基础面积的锥体和北方森林四个空间独立区域的燃烧面积联系起来，以确定大火年份之后是否通常会出现肥大作物。