Relations between forest disturbance, in-stream wood and aquatic habitat over river networks

摘要森林溪流中的溪流内木材或大木质碎屑(LWD)是鱼类种群栖息地和盖度的最重要贡献之一。随钻测井在REACH尺度上已经得到了广泛的研究。然而，人们对LWD在多个空间尺度上的变异性及其生态功能知之甚少。Swanson(2003)提出，从景观的角度来研究河流网络和时间上的LWD生态是未来最需要的研究方向之一。人们普遍认为，森林的可持续性必须在时间和空间尺度上定义。因此，研究自然干扰有助于理解时间尺度上的生态过程和模式。由于频繁的野火，这对加拿大的森林尤其重要。由NSERC发现基金资助，我的第一个五年(2002-2006)研究项目主要关注BC内陆收获和野火干扰的森林流域的LWD长期动态(时间尺度)。这项新提出的研究(2007-2011年)将在多个空间尺度上针对河流网络上的随木消散生态。我的具体目标包括：(1)量化不同溪流顺序的LWD负荷及其生态功能之间的关系；(2)比较上述野火和收获干扰之间的关系；以及(3)确定控制LWD数量和在河网上分布的关键机制。我的长期研究目标是：(1)在空间和时间尺度上整合LWD负荷和功能的信息，以全面了解LWD生态；(2)将我们的结果与加拿大亚北方流域的可持续森林和流域管理联系起来。

SummaryIn-stream wood or large woody debris (LWD) in forested streams is one of most important contributions of habitat and cover for fish populations. LWD has been intensively studied at the reach scale. However, little is known about variability of LWD and its ecological functions at multiple spatial scales.  Swanson (2003) suggested that a landscape perspective on LWD ecology over river networks and through time is one of the most needed future research directions. It is widely accepted that forest sustainability must be defined in temporal and spatial scales.  Studying natural disturbance is useful for understanding ecological processes and patterns at temporal scales. This is particularly important for the Canadian forests because of frequent wildfire.   Funded by a NSERC discovery grant, my first five-year (2002-2006) research project mainly focused on LWD long-term dynamics (temporal scales) in harvested and wildfire-disturbed forest watersheds in the BC interior. This new proposed research (2007-2011) will target LWD ecology over river networks at multiple spatial scales. My specific objectives include: (1) quantification of relations between LWD loadings and their ecological functions at various stream orders; (2) comparison of the above relations between wildfire and harvesting disturbances; and (3) determination of key mechanisms controlling LWD amount and distribution over river networks.  My long-term research goals are: (1) to integrate information of LWD loadings and functions at both spatial and temporal scales to fully understand LWD ecology; and (2) to link our results with sustainable forest and watershed management in the Canadian sub-boreal watersheds.