Boreal birds reproductive activity and persitence in older forests

北方鸟类的繁殖活动和在古老森林中的持久性

• 批准号: 227576-2009
• 负责人: Drapeau, Pierre
• 金额: $ 2.11万
• 依托单位: Université du Québec à Montréal
• 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=497621
• 关键词: Boreal; birds; reproductive; activity; persitence

In the eastern Canadian boreal forest it is well documented that even-aged management is shifting the land base into a much younger mosaic of forest cover types, considerably reducing the mature to old-growth portion of the age-class distribution of natural forests. Provided the increasing context of human influence in this ecosystem, older forest cover types (> 100 years) are likely to become habitats of concern from a biological conservation standpoint. The persistence in time of a reduced proportion of the land base in older forests should also affect populations of species associated with these habitats or their attributes. Better knowledge of the response of older forest species is thus critical in the assessment of the sustainability of boreal forest bird communities. In the last decade several studies have documented the occupancy (presence-absence or relative abundance) patterns of boreal birds in older forests. Findings converge towards the fact that boreal birds' responses to habitat loss and fragmentation induced by timber harvesting were not as strong as those in temperate forest ecosystems, perhaps because land conversion is low and total forest cover does not change. Much less is known about the effects of loss of older forests on reproductive activity of forest birds. In this research program we measure and compare in dynamic natural and managed landscapes: (1) the reproductive activity of open-cup (ovenbird in boreal mixed-wood and golden-crowned kinglet in black spruce forests) and cavity excavators (woodpeckers) in forest remnants and undivided forest tracks (2) habitat quality of forest remnants and larger forest tracks as resource patches with regards to both foraging and nesting requirements of cavity excavators (3) the probability of persistence of these target species in reduced older forest habitat given their population size (density of territorial males) and reproductive performance (reproductive and nesting success).

在加拿大东部的北方森林，有充分的文件证明，平均年龄的管理正在把土地基础转变成一种更年轻的森林覆盖类型，大大减少了天然林年龄级分布中从成熟到成熟的部分。如果人类对这一生态系统的影响越来越大，从生物保护的角度来看，较老的森林覆盖类型（> 100年）很可能成为令人关切的生境。较老的森林中土地面积比例减少的情况长期持续下去，也会影响到与这些生境或其属性有关的物种的数量。因此，更好地了解老的森林物种的反应是至关重要的，在评估北方森林鸟类群落的可持续性。在过去的十年中，几项研究记录了北方鸟类在古老森林中的占用（存在-不存在或相对丰度）模式。调查结果趋于一致的事实是，北方鸟类的栖息地的损失和破碎化引起的木材采伐的反应并不强烈的温带森林生态系统，也许是因为土地转换率低，森林总覆盖率没有变化。人们对老森林的消失对森林鸟类生殖活动的影响知之甚少。在这项研究计划中，我们测量和比较动态的自然景观和管理景观：（1）开杯的繁殖活动（寒带杂木林的炉鸟和黑云杉林的金冠小王）和洞穴挖掘机（啄木鸟）在森林遗迹和未分割的森林足迹（2）关于洞穴挖掘者觅食和筑巢需求的森林遗迹和较大森林足迹作为资源斑块的栖息地质量（3）考虑到这些目标物种的种群规模（领地雄性的密度）和繁殖能力（繁殖和筑巢成功率），它们在已减少的较老森林生境中持续生存的可能性。