Data from: Edge influence on vegetation at natural and anthropogenic edges of boreal forests in Canada and Fennoscandia

1. Although anthropogenic edges are an important consequence of timber harvesting, edges due to natural disturbances or landscape heterogeneity are also common. Forest edges have been well-studied in temperate and tropical forests, but less so in less productive, disturbance-adapted boreal forests. 2. We synthesized data on forest vegetation at edges of boreal forests and compared edge influence among edge types (fire, cut, lake/wetland; old vs. young), forest types (broadleaf vs. coniferous) and geographic regions. Our objectives were to quantify vegetation responses at edges of all types and to compare the strength and extent of edge influence among different types of edges and forests. 3. Research was conducted using the same general sampling design in Alberta, Ontario and Quebec in Canada, and in Sweden and Finland. We conducted a meta-analysis for a variety of response variables including forest structure, deadwood abundance, regeneration, understorey abundance and diversity, and nonvascular plant cover. We also determined the magnitude and distance of edge influence using randomization tests. 4. Some edge responses (lower tree basal area, tree canopy and bryophyte cover; more logs; higher regeneration) were significant overall across studies. Edge influence on ground vegetation in boreal forests was generally weak, not very extensive (distance of edge influence usually < 20 m) and decreased with time. We found more extensive edge influence at natural edges, at younger edges and in broadleaf forests. The comparison among regions revealed weaker edge influence in Fennoscandian forests. 5. Synthesis. Edges created by forest harvesting do not appear to have as strong, extensive or persistent influence on vegetation in boreal as in tropical or temperate forested ecosystems. We attribute this apparent resistance to shorter canopy heights, inherent heterogeneity in boreal forests and their adaptation to frequent natural disturbance. Nevertheless, notable differences between forest structure responses to natural (fire) and anthropogenic (cut) edges raise concerns about biodiversity implications of extensive creation of anthropogenic edges. By highlighting universal responses to edge influence in boreal forests that are significant irrespective of edge or forest type, and those which vary by edge type, we provide a context for the conservation of boreal forests.1. 尽管人为边缘（anthropogenic edges）是木材采伐的重要生态后果，但由自然干扰或景观异质性形成的边缘也十分常见。学界已对温带与热带森林的林缘开展了充分研究，但对生产力较低、适应频繁干扰的寒温带针叶林（boreal forests）的林缘研究相对不足。 2. 本研究整合了寒温带针叶林林缘的植被数据，对比了不同边缘类型（火干扰边缘、采伐边缘、湖泊/湿地边缘；老龄边缘与幼龄边缘）、森林类型（阔叶林（broadleaf forest）与针叶林（coniferous forest））以及地理区域间的林缘效应差异。本研究的目标为量化各类林缘的植被响应，并比较不同边缘与森林类型间林缘效应的强度与影响范围。 3. 研究采用统一的通用采样方案，在加拿大阿尔伯塔省、安大略省与魁北克省，以及瑞典与芬兰开展。针对森林结构、枯木丰度、森林更新、林下植被丰度与多样性、非维管植物盖度（nonvascular plant cover）等多项响应变量，本研究开展了元分析（meta-analysis）；同时通过随机检验（randomization tests）确定了林缘效应的强度与影响距离。 4. 整体而言，部分林缘响应（如较低的树木胸高断面积、树冠盖度与苔藓植物盖度，更多的枯木，更高的更新率）在所有研究中均表现显著。寒温带针叶林林缘对地面植被的效应整体较弱且影响范围有限（林缘效应距离通常小于20米），并随时间推移逐渐减弱。研究发现，自然边缘、幼龄边缘以及阔叶林内的林缘效应影响范围更广。区域对比结果显示，芬诺斯坎底亚（Fennoscandian）地区森林的林缘效应相对更弱。 5. 综合分析表明：与热带或温带森林生态系统相比，森林采伐形成的人为边缘对寒温带针叶林植被的影响并未表现出同等强度、广度与持续性。我们将这一抗性归因于寒温带针叶林较矮的冠层高度、自身固有的景观异质性，以及其对频繁自然干扰的适应性。尽管如此，自然（火干扰）与人为（采伐）边缘对森林结构的响应存在显著差异，这引发了人们对大规模人为边缘创建对生物多样性影响的担忧。本研究明确了寒温带针叶林内不受边缘与森林类型影响的普遍林缘响应，以及随边缘类型变化的差异化响应，从而为寒温带针叶林的保护提供了科学依据。