Effects of forest management on dead wood supply and implications for biodiversity

木质碎片（WD），包括倒下的木材和树枝，被认为是许多生物的重要资源，但对森林管理措施特别敏感。尽管WD对生物多样性的重要性已得到广泛认可，而且在森林经营规划中也普遍存在维持野生动物栖息地和生态功能的WD保留指南，但目前对其基础和有效性还没有充分了解。拟议的研究将使用可操作的实地研究和基于计算机的建模来解决安大略省北部东北部的这些差距。具体目标将是：1)在不同砍伐程度的地区进行实地研究，以确定关键的指标分类群，并更好地了解栖息地供应关系（重点关注腐殖质昆虫[依赖枯木和垂死木材的昆虫]、真菌和小型哺乳动物的关键群体）；2)参数化一个建模框架，在这个框架中，可以调查特定管理措施对WD栖息地供应的短期和长期影响。需要验证的关键假设包括：1)当地WD供应的减少将导致某些生物群体的定植减少，从而导致WD物种丰富度的净减少；2)小型哺乳动物的种群密度、生产力、迁徙和觅食行为会随着湿地数量和质量的变化而变化；3)面对新的生物量需求，现有的林地保留指南将被证明不适合长期的、林分水平的生物多样性保护。野外工作将集中在参考的旧生长地块，传统的和生物量的砍伐，以及一个操纵性的实验，在40-65年的2.25公顷的研究地块中，所有、一半或没有砍伐的WD被移除。该研究具有特别重要的意义，因为它是：1)开创了先例，因为它利用强大的实验设计和新颖的技术来提供关于生物多样性指标和WD供应阈值的关键信息；2)将研究收获实践与长期WD栖息地供应之间的关系，包括在操作规模的生物燃料收获中。

Woody debris (WD), which includes both downed wood and snags, is thought to be an important resource for many organisms, but one that is especially sensitive to forest management practices. Although the importance of WD for biodiversity is widely recognized, and indeed WD retention guidelines to sustain wildlife habitat and ecological function are ubiquitous in forest management planning, their basis and effectiveness at present is not fully understood. The proposed research will use manipulative field studies and computer-based modelling to address these gaps in boreal northeastern Ontario. Specific objectives will be to: 1) undertake field studies in areas of different levels of downed WD removal to identify key indicator taxa and to better understand habitat supply relationships (with a focus on key groups of saproxylic insects [those dependent upon dead and dying wood], fungi, and small mammal fauna) and 2) parameterize a modelling framework in which short- and long-term effects of particular management practices on WD habitat supply can be investigated. Key hypotheses to be tested include: 1) reductions in the local supply of WD will result in reduced colonization among certain groups of organisms, with net reduction of species richness of WD; 2) small mammal population densities and productivity, movements, and foraging behaviour will vary in response to variation in the quantity and quality of WD; and 3) existing guidelines for WD retention will prove inadequate for long-term, stand-level conservation of biodiversity in the face of new biomass demands. Field work will focus on reference old-growth plots, conventional and biomass clearcuts, and a manipulative experiment in which all, one-half, or no downed WD was removed from 40-65 year-old, 2.25 ha study plots. The research is of particular significance in that it is: 1) precedent setting in that it makes use of a powerful experimental design and novel techniques to provide critical information on biodiversity indicators and WD supply thresholds and 2) will examine the relationship between harvesting practices and long-term WD habitat supply, including in operational-scale biofuel harvests.