Landscape Heterogeneity and Disturbance Interactions in a Subalpine Watershed in Northern Colorado, USA
Landscape Heterogeneity and Disturbance Interactions in a Subalpine Watershed in Northern Colorado, USA
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DOI：
10.1111/j.1467-8306.2003.09304002.x
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发表时间：
2003-12
期刊：
影响因子：
--
通讯作者：
E. Howe;W. Baker
中科院分区：
文献类型：
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作者：
E. Howe;W. Baker
摘要影响落基山脉亚高山森林的主要干扰有三种：吹落、虫害和火灾。这些扰动可能在时间和空间上相互影响，形成一个马赛克状的扰动斑块。1997年，一场严重的风暴刮倒了北方科罗拉多1万多公顷的亚高山森林。以前的干扰影响排污的空间格局在一个有代表性的部分排污中叉麋鹿河流域？树木年代学证据和地理信息系统被用来重建干扰历史，以及干扰历史（即，1997年的排污情况进行了调查。火灾状况在时间和空间上都有变化，面积加权平均火灾间隔/火灾轮换为108至195年。替代林分的火灾似乎对火灾状况影响最大，但也发现了非替代林分火灾的证据。朝南，海拔较低的斜坡是最有可能燃烧的环境。在18世纪中期和19世纪中后期发现了严重程度较低的云杉甲虫干扰，可能与区域性爆发有关。放牧和灭火可能会影响树木再生和火灾频率模式。每一个干扰事件发生在不同的严重程度在整个景观，部分影响，由以前的干扰的严重程度的模式。斑块年龄对1997年的排污模式有贡献，但这种关系是复杂的。植被镶嵌影响排污的空间格局，导致新的复杂性和维持景观异质性。
Abstract Three major disturbances affect subalpine forests in the Rocky Mountains: blowdown, insect outbreaks, and fire. These disturbances may influence one another temporally and spatially, creating a mosaic of disturbance patches. In 1997, a severe windstorm blew down trees on over 10,000 ha of subalpine forest in northern Colorado. Did previous disturbances influence the spatial pattern of blowdown in a representative part of the blowdown in the Middle Fork Elk River watershed? Dendrochronological evidence and a geographic information system were used to reconstruct the disturbance history, and the relationship between disturbance history (i.e., patch age) and the 1997 blowdown was examined. The fire regime varies temporally and spatially, with an area-weighted mean fire interval/fire rotation of 108 to 195 years. Stand-replacing fires appear to have had the most impact on the fire regime, but evidence of non-stand-replacing fires was also found. South-facing, lower-elevation slopes were the settings most likely to burn. Low-severity spruce-beetle disturbance was found in the mid-1700s and mid- to late 1800s, possibly related to regional outbreaks. Sheep-grazing and fire suppression may have influenced tree-regeneration and fire-frequency patterns. Each disturbance event occurred with varying severity across the landscape, influenced, in part, by the patterns of severity of previous disturbances. Patch age contributed to the pattern of the 1997 blowdown, but the relationship is complicated. The vegetation mosaic influenced spatial patterns of blowdown, resulting in new complexity and maintaining landscape heterogeneity.