Scaling habitat loss and fragmentation of old forests on bird communities in boreal landscapes

北方景观中鸟类群落的栖息地丧失和老森林破碎化

• 批准号: RGPIN-2019-07075
• 负责人: Drapeau, Pierre
• 金额: $ 2.91万
• 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: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=739295
• 关键词: Scaling; habitat; loss; fragmentation; old

Forests worldwide are undergoing major changes as a result of human activity. In the eastern boreal forest of Canada, the northern expansion of timber harvesting in the last 35 years has shifted the age-class distribution from a matrix formerly dominated by mature and old forest cover types to a matrix that is now dominated by young forests. This represents a major change for organisms that evolved and experienced high availability of closed canopy and keystone structures such as decaying and dead trees throughout the Holocene. This reduced proportion of old forests specifically affects species that are specialised on closed canopy (open-cup nesters) and on decaying and dead trees (cavity nesters). Landscape-scale sensitivity of birds to loss and fragmentation of old forest cover has usually been assessed in the neighbourhood of bird sampling stations (500 m to 2-km radius). Such approaches provide insightful knowledge on species responses at local scales. They are, however, limited for extrapolating how such patterns translate at the level of regional populations, across the entire forest mosaic. To do so large-scale bird surveys over biomes are required. Breeding Bird Atlas (BBA) projects, which have recently incorporated fine-grain scale surveys (point counts), now provide such opportunities for investigating bird populations' responses to habitat changes over large geographic regions. This proposal measures at the scale of Québec's commercial boreal forest the effects of shifting the forest age structure from an old to a young forest mosaic on the response of bird communities. We combine extensive (regional, BBA data) and intensive (local, field studies) approaches on open-cup and cavity nesters to: 1) assess the regional-scale effects of loss and fragmentation of old forests on populations of sensitive birds; 2) determine how the dynamics of regeneration in harvested landscapes enables the resilience of old forest bird communities; 3) measure how local habitat quality and connectivity of old forests are drivers in bird species nesting and foraging ecology. By scaling-up the response of bird populations and communities to old forest loss and fragmentation from local to regional effects, the proposed research program will contribute to groundbreaking advances in our understanding of the cumulative effects of timber-harvesting regimes on boreal biodiversity in human-modified landscapes. The use of a trait-based approach (open-cup and cavity nesters) in addition to traditional taxonomic diversity will provide an original perspective to pinpoint critical habitat drivers to which the functional diversity of boreal bird communities responds. From a conservation planning perspective, the proposed research will produce innovative science-based guidelines for developing policies in the Canadian boreal forest that better meet the long-term challenges of maintaining biodiversity and sustainable forest management in a rapidly changing world.

由于人类活动，全世界的森林正在发生重大变化。在加拿大东部的北方森林中，过去35年中北部木材收获的北部扩展使年龄级的分布从以前由成熟和旧森林覆盖类型主导的基质转变为现在以年轻森林为主的基质。这代表了生物的重大变化，这些生物会进化并经历了整个全新世的封闭顶篷和基石结构（例如腐烂和死树）的高可用性。减少的旧森林的比例特别影响了专门用于封闭的顶篷（开放式巢穴）以及腐烂和死树（腔巢）的物种。通常在鸟类采样站（500 m至2 km半径）的附近评估了鸟类对旧森林覆盖物的损失和分裂的景观尺度敏感性。这种方法为局部尺度的物种反应提供了深刻的知识。但是，它们受到推断如何在整个森林马赛克地区转化这种模式在区域人群水平上的转化。为了做到这一点，需要大规模的鸟类调查。繁殖鸟类图集（BBA）项目最近纳入了细粒度量表调查（点数），现在为研究鸟类种群对大型地理区域的栖息地变化的反应提供了这种机会。该提案以魁北克商业北方森林的规模进行衡量，从而将森林时代结构从古老的森林马赛克转移到鸟类群落的反应的影响。我们将广泛的（区域，BBA数据）与开放式巢穴和腔巢穴的强化（局部，野外研究）结合在一起：1）评估旧森林损失和碎片对敏感鸟类种群的损失和碎片的区域尺度影响； 2）确定收获景观中再生的动态如何使旧森林鸟类社区的韧性具有弹性； 3）衡量旧森林的当地栖息地质量和连通性是鸟类筑巢和觅食生态学的驱动因素。通过扩大鸟类种群和社区对旧森林损失的反应以及从局部效应到区域影响的分裂，该计划将有助于我们理解木材收获方案对人类修饰的景观中北方生物多样性的累积影响的突破性进步。除了传统的分类多样性之外，使用基于特质的方法（开放式和腔巢）将提供原始的观点，以确定北极鸟类社区功能多样性的关键栖息地驱动因素。从保护计划的角度来看，拟议的研究将制定基于创新的科学指南，以在加拿大北方森林中制定政策，以更好地应对在迅速变化的世界中维持生物多样性和可持续森林管理的长期挑战。