Vegetation dynamics under fire exclusion and logging in a Rocky Mountain watershed, 1856-1996
Vegetation dynamics under fire exclusion and logging in a Rocky Mountain watershed, 1856-1996
复制标题
DOI：
10.1890/1051-0761(2003)013
复制
发表时间：
2003-04-01
影响因子：
5
通讯作者：
Betz, DW
中科院分区：
文献类型：
--
作者：
Gallant, AL;Hansen, AJ;Betz, DW
土地管理实践的变化如何影响大黄石生态系统的植被格局？这个问题使我们开发了一个确定性的，演替的，植被模型，以“倒转时钟”的研究领域，并评估如何在植被覆盖类型和结构的模式，通过不同时期的管理发生了变化。我们的建模涵盖了美洲原住民使用的最后几十年，随后的欧美定居点，以及相关的间接灭火方法，以及最近的防火和木材采伐实践。模型的结果是惊人的，表明在研究区域的主要森林动态是不破碎的针叶林采伐，但从火驱动的镶嵌草地，灌丛，阔叶林，混交林群落的过渡到针叶为主的景观。对以针叶树为主的林分的预测表明，面积覆盖率从19世纪中期的15%增加到20世纪90年代中期的50%。在同一时期，对白杨为主的林分的预测显示，覆盖率从37%下降到8%。以前由各种年龄段占据的大片土地已经让位于大片土地。成熟的森林。只有4%的研究面积目前覆盖的年轻的立场，所有这些都是针叶。虽然伐木已经取代野火作为一种机制，循环年轻的立场到景观，位置，物种成分，补丁大小，与伐木相关的生态系统动态不模仿那些与火。同样明显的是，这些差异的性质因生物物理环境而异，土地管理者可能会考虑采用生物物理类战略来调整管理目标和恢复工作。
How have changes in land management practices affected vegetation patterns in the greater Yellowstone ecosystem? This question led us to develop a deterministic, successional, vegetation model to "turn back the clock" on a study area and assess how patterns in vegetation cover type and structure have changed through different periods of management. Our modeling spanned the closing decades of use by Native Americans, subsequent Euro-American settlement, and associated indirect methods of fire suppression, and more recent practices of fire exclusion and timber harvest. Model results were striking, indicating that the primary forest dynamic in the study area is not fragmentation of conifer forest by logging, but the transition from a fire-driven mosaic of grassland, shrubland, broadleaf forest, and mixed forest communities to a conifer-dominated landscape. Projections for conifer-dominated stands showed an increase in areal coverage from 15% of the study arcain the mid-1800s to similar to50% by the mid-1990s. During the same period, projections for aspen-dominated stands showed a decline in coverage from 37% to 8%. Substantial acreage previously occupied by a variety of age classes has given way to extensive tracts. of mature forest. Only 4% of the study area is currently covered by young stands, all of which are coniferous. While logging has replaced wildfire as a mechanism for cycling younger stands into the landscape, the locations, species constituents, patch sizes, and ecosystem dynamics associated with logging do not mimic those associated with fire. It is also apparent that the nature of these differences varies among biophysical settings, and that land managers might consider a biophysical class strategy for tailoring management goals and restoration efforts.