Habitat filter, priority efect and ecological engineering (feedbacks) of dominant species in post-fire succession

在加拿大东部营养贫乏的黑云杉-卡尔米亚森林中，伐木和火灾经常导致广泛的白垩石楠丛形成，这干扰了针叶树的再生。对白垩系荒原的持续时间和动态的了解还不够。一些人认为它会持续几年到几十年，另一些人则认为基于树木年轮和古生物证据的交替稳定状态。这种认识对可持续森林管理和保护至关重要。针叶林更新的失败或延迟会导致森林生产力的丧失和多层森林向简化的低生长石楠地的转变。据报道，美国Kalmia heath有限的地区拥有不成比例的大量稀有物种。卡尔米亚荒原作为稀有物种的栖息地尚未在加拿大进行过测试。我的研究计划的长期目标是了解栖息地和植物群落对森林干扰的反应，特别是优势林下物种和冠层物种之间的相互作用。我将我的应用研究问题纳入当代更广泛的生态概念。在接下来的五年里，我将集中在四个短期目标上：1)测试火灾后苗床的生物物理特性及其栖息地过滤阈值；2)确定火灾后黑桫椤是否具有明显的生长阶段，并具有包括稀有植物在内的特征物种组成；3)确定黑桫椤的种群生物学和寿命；4)测试黑桫椤和均匀树龄黑云杉对群落结构的植物-土壤反馈效应。本研究将揭示苗床过滤对北方针叶林下次生林演替的重要意义和优先效应。它将创造关于Kalmia健康长寿的新知识，这对加拿大东部的土地管理具有重要意义。

Logging and fire in the nutrient poor black spruce-Kalmia forest of eastern Canada often leads to extensive ericaceous heath formation, which interferes with conifer regeneration. Not enough is known about the duration and dynamics of the ericaceous heath. Some suggest it lasts for several years to several decades others suggest alternate stable states based on tree ring and paleocological evidence. This understanding is critical in sustainable forest management and conservation. Failure or delay in conifer regeneration translates into loss of forest productivity and transformation of multi-layered forest to simplified low growing heathland. Limited areas of Kalmia heath in the US is reported to harbor disproportionately large number of rare species. Kalmia heath as a habitat for rare species has not been tested in Canada. The long-term goal of my research program is to understand the habitat and plant community response to forest disturbance particularly the interactions between the dominant understory and canopy species. I frame my applied research questions into contemporary broader ecological concepts. In the next five years I shall concentrate on four short-term objectives: 1) to test the biophysical property of post-fire seedbed and their habitat filtering thresholds, 2) to determine if post-fire Kalmia heath has distinct growth phases with characteristic species composition including rare plants, 3) to determine the population biology of Kalmia and longevity of Kalmia heath, and 4) to test plant-soil feedback effects of Kalmia and even-aged black spruce on community structure. This research will discover the significance of seedbed filter and priority effect on secondary succession in the boreal forest with ericaceous understory. It will create new knowledge on longevity of Kalmia heath which has significant land management implications in eastern Canada.