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: 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=716561
• 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，世界各地的森林正在发生重大变化。在加拿大东部的北方森林，过去35年来木材采伐的向北扩展使年龄级分布从以前以成熟和老森林覆盖类型为主的矩阵转变为现在以年轻森林为主的矩阵。这代表了在整个全新世进化并经历了高度可用的封闭树冠和拱心石结构（如腐烂和死亡的树木）的生物的重大变化。老森林比例的减少特别影响了那些专门栖息于封闭树冠（开杯筑巢者）和腐烂和死亡树木（洞巢筑巢者）的物种。