Viewpoint: Western juniper expansion: is it a threat to arid northwestern ecosystems?
Viewpoint: Western juniper expansion: is it a threat to arid northwestern ecosystems?
复制标题
观点：西部杜松扩张：对西北干旱生态系统构成威胁吗？
DOI：
--
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
A. J. Belsky
中科院分区：
文献类型：
--
作者：
A. J. Belsky
太平洋西北地区的许多牧场主、牧场管理者和牧场科学家都认为西部杜松（Juniperus occidentalis Hook.）是一种入侵杂草，它会减少水的渗透，使泉水和溪流干涸，增加侵蚀，减少生物多样性，降低牲畜和野生动物饲料的质量和数量。尽管几乎没有科学证据支持这些观点，但它们目前被用作控制公共和私人土地上杜松的理由。从20世纪40年代到60年代，人们对西南部和大盆地的松柏林地持类似观点，当时也采取了控制林地扩张的措施。控制西部杜松进一步蔓延和降低其在林地中的密度的压力正在增加。由于缺乏关于西部杜松在西北扩张的环境影响的信息，本文主要回顾了早期对西南和大盆地的小杜松林地的研究证据。这些研究否定了类似的假设，即松柏扩张对生态系统特性的有害影响，并对目前控制西北地区西部杜松的基本原理提出了质疑。这些研究还表明，尽管杜松的扩张可能会改变草原和灌丛的物种组成并减少草本生物量，但它们对河流，水生生物，土壤性质或野生动物栖息地几乎没有有害影响。
Many ranchers, rangeland managers, and range scientists in the Pacific Northwest consider western juniper (Juniperus occidentalis Hook.) to be an invading weed that reduces water infiltration, dries up springs and streams, increases erosion, reduces biodiversity, and reduces the quality and quantity of forage for livestock and wildlife species. Although there is little scientific evidence supporting most of these beliefs, they are currently being used as rationales for controlling juniper on public and private lands. Similar views were held about pinyon-juniper woodlands in the Southwest and Great Basin from the 1940's through the 1960's, when efforts were also made to control woodland expansion. Pressures to control the further spread of western juniper and reduce its density in woodlands are increasing. Because of the paucity of information on the environmental effects of western juniper expansion in the Northwest, this paper primarily reviews evidence from earlier studies of pinyon-juniper woodlands in the Southwest and Great Basin. These studies rejected similar assumptions about the deleterious effects of pinyon-juniper expansion on ecosystem properties and call into question current rationales for controlling western juniper in the Northwest. These studies also suggest that while the expansion of juniper might alter species composition and decrease herbaceous biomass in grasslands and shrublands, they have few detrimental effects on streamflow, aquatic organisms, soil properties, or wildlife habitat.