Vegetation Change and Park Purposes in the High Elevations of Yosemite National Park, California
Vegetation Change and Park Purposes in the High Elevations of Yosemite National Park, California
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加利福尼亚州优胜美地国家公园高海拔地区的植被变化和公园目的
DOI：
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发表时间：
1987
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影响因子：
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通讯作者：
T. Vale
中科院分区：
文献类型：
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作者：
T. Vale
摘要约塞米蒂国家公园高海拔地区过去80年来的植被变化被确定为59个场景，最初拍摄于世纪之交，并于1984年和1985年重新拍摄。由此产生的照片对表明：（1）krummholz的高度和密度增加了（2）森林线上部的森林密度增加了（3）草地被树木入侵了（4）局部稀疏森林的密度增加了（5）许多圆顶和岩石斜坡上的树木数量增加了。灭火，气候波动和牲畜放牧的变化的可能原因进行了探讨。管理计划，以扭转这种植被变化所造成的现代人类的国家公园的目的进行评估。我认为，这些目的是最好的，通过认识到这两个生态目标的合法性，这可能是进一步管理的植被密集，和人文的目标，这可能是通过保持一个景观免费服务。
Abstract Vegetation changes over the past 80 years in the high elevations of Yosemite National Park were identified with 59 scenes originally photographed at the turn of the century and rephotographed in 1984 and 1985. The resulting photo pairs suggest that (1) krummholz has increased in height and density (2) forests at the upper forest line have increased in density (3) meadows have been invaded by trees (4) local patches of thin forest have increased in density and (5) trees on many domes and rock slopes have increased in number. Fire suppression, climatic fluctuations, and livestock grazing are explored as possible causes of the changes. Management programs to reverse such vegetation changes caused by modern humans are evaluated in terms of the purposes of national parks. I argue that these purposes are best met by recognizing the legitimacy of both ecological goals, which may be furthered by managing the vegetation intensively, and humanistic goals, which may be served by maintaining a landscape free...