Effects of multiple rotations of uneven-age forest management on mammal, insect, and fungus biodiversity in central Ontario

安大略省中部不同年龄森林管理多次轮作对哺乳动物、昆虫和真菌生物多样性的影响

• 批准号: RGPIN-2017-06756
• 负责人: Malcolm, Jay
• 金额: $ 1.75万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=658568
• 关键词: Effects; multiple; rotations; uneven; age

In the decades prior to the 1970s, forest exploitation in south-central Ontario resulted in strong shifts in forest composition towards deciduous, shade-tolerant species. Although intended to be sustainable, modern forest management practices also may be altering these forests over the long term, with important implications for biodiversity. Several long-term studies indicate that single tree selection, the predominant forest management activity in the region, is having long-term effects on forest composition and structure. Importantly, despite the maintenance of tree diameter distributions reminiscent of unmanaged stands, the evenly distributed, small gaps created during harvesting have led to a compositional shift favouring shade-intolerant species, with a loss of mid-tolerant species and coniferous species. In addition, the emphasis on stand improvement and timber values has meant reductions in the abundances of large trees, diseased and dying trees, downed logs, and standing dead trees. Unfortunately, multi-rotation studies of effects on biodiversity have not been undertaken. Studies of first-rotation impacts indicate that some mature forest taxa remain at low abundances even at the end of the rotation, with the possibility that populations will be further reduced after multiple rotations. In addition, structural changes are expected to equilibrate only after several rotations, with important implications for key faunal groups. My overall objective is to test whether single-tree selection in south-central Ontario sustains biodiversity over multiple rotations. Specific objectives are to: 1) compare habitat structure and abundances of key indicator taxa (small mammals, insects, and fungi) among forest stands that have been harvested 1-2 times, 3-4 times, or are unmanaged and 2) include an among-stand perspective by examining the effects of neighbouring stand composition and structure on responses. Small mammal research will make use of live trapping; insect research will focus on communities from flight interception and pitfall traps; fungal sampling will include both area searches of fruiting bodies and DNA-based sampling of downed wood; and landscape level assessments will make use of forest resource inventory information and remotely-sensed ADS40 and LiDAR imagery. Early-successional species are expected to be most common and diverse in young post-harvest stands, whereas abundances of late seral, woody debris, and conifer associated species will decline with the number of rotations, especially where nearby conifer cover and unmanaged stands are rare and isolated. Functional shifts among insect and fungal communities are expected to result in reductions in the diversity of saproxylic and weakly-dispersing species. This will be the first study to examine biodiversity implications of single tree selection after multiple rotations.

在1970年代之前的几十年中，安大略省中南部的森林剥削导致森林组成向落叶，耐遮阳的物种的强烈转变。尽管打算是可持续的，但现代森林管理实践也可能会在长期内改变这些森林，对生物多样性产生重要影响。几项长期研究表明，单一树（该地区主要的森林管理活动）对森林组成和结构产生了长期影响。重要的是，尽管维持树直径分布，让人联想到未托管的林木，但在收获期间产生的均匀分布的小缝隙导致了成分转移，有利于阴影 - 耐智能物种，并损失了中耐晶体和有针叶物种。此外，重点是改善林分和木材价值，这意味着大树，患病和垂死的树木，倒下的原木以及枯萎的枯树的大量减少。不幸的是，尚未进行对生物多样性影响的多旋转研究。首次复发影响的研究表明，即使在旋转结束时，某些成熟的森林分类单元仍处于较低的丰富度，并且可能在多次旋转后进一步降低种群。此外，预计仅在几次旋转后才能平衡结构变化，对关键动物基团的重要影响。我的总体目标是测试在安大略省中南部的单树选择是否在多个旋转中维持生物多样性。具体目标是：1）比较森林林分中的栖息地结构和关键指标分类单元（小型哺乳动物，昆虫和真菌）的丰度，这些森林摊位已经收获了1-2次，3-4次，或者是未经托管的，而2）包括一个近距离观察邻近架子组成和结构对响应的影响。小型哺乳动物研究将利用实时捕获；昆虫研究将集中于飞行拦截和陷阱陷阱的社区。真菌采样将包括对水果物体的区域搜索和落下木材的基于DNA的采样；景观水平评估将利用森林资源库存信息以及远程感知的ADS40和LIDAR图像。预计早期成熟的物种在年轻的收获后架上最常见和多样化，而后来的Seral，木质碎片和针叶树相关的物种随着旋转的数量而下降，尤其是在附近的针叶树覆盖物和不受管理的台阶是罕见和孤立的情况下。预计昆虫和真菌群落之间的功能转移会导致盐酸和弱分散物种的多样性减少。这将是第一个研究多个旋转后单树选择生物多样性含义的研究。