Climate Change and Ecosystems of the Southwestern United States
Climate Change and Ecosystems of the Southwestern United States
复制标题
美国西南部的气候变化和生态系统
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
K. Predick
中科院分区：
文献类型：
--
作者：
S. Archer;K. Predick
美国西部的干旱沙漠生态系统特别容易受到气候变化和气候多变性的影响。这一地区的植物和动物生活在水和温度胁迫的生理极限附近。因此，温度或降水制度的轻微变化或极端气候事件的频率和幅度的变化可能会极大地改变物种的组成、分布和丰度，以及干旱土地提供的产品和服务。在美国，干旱土地位于西南部的亚热带炎热沙漠，包括莫哈韦沙漠、索诺兰沙漠和奇瓦瓦沙漠，以及西部山区的温带寒冷沙漠。年降水量很低(<；400毫米)，但不同炎热沙漠的降水量季节性有很大不同(图1)。莫哈韦沙漠以冬季降水为主，因此在凉爽的季节生物活动最活跃。奇瓦瓦沙漠以夏季降水为主，在较热的条件下有生物活动。这三个沙漠中最热的索诺兰沙漠是中等温度的沙漠，冬季和夏季都有降水。这两个沙漠的特点都是生产力低，植物生长缓慢，这两个主要都是缺水的。植被群落通常是沙漠灌丛、灌木草原或沙漠草原/稀树草原，是富有魅力的植物的家园，包括仙人掌、风琴管仙人掌和约书亚树。奇瓦瓦沙漠是北美最大的沙漠，从美国西南部一直延伸到墨西哥中部高地。它被世界野生动物基金会归类为全球200个生态区，这是一个基于科学的全球最具生物优势的栖息地排名。干旱土地目前提供各种产品和服务，包括大型牧场产业、野生动物栖息地、动植物多样性、水流和水质调节、户外娱乐机会以及扩大城市环境的开放空间。
Arid desert ecosystems of the western United States are particularly susceptible to climate change and climate variability. Plants and animals in this region live near their physiological limits for water and temperature stress. Slight changes in temperature or precipitation regimes or a change in the frequency and magnitude of extreme climatic events could therefore substantially alter the composition, distribution, and abundance of species, as well as the products and services that arid lands provide. In the United States, arid lands are located in the subtropical hot deserts of the Southwest, comprised of the Mojave, Sonoran, and Chihuahuan deserts, and the temperate cold deserts of the Intermountain West. Annual precipitation is low (<400 mm), but the seasonality of precipitation differs substantially among hot deserts (Fig. 1). The Mojave Desert is dominated by winter precipitation; thus biological activity is greatest during the cool season. The Chihuahuan Desert is dominated by summer precipitation with biological activity during hotter conditions. The hottest of the three deserts, the Sonoran, is intermediate, receiving both winter and summer precipitation. Each of these deserts is characterized by low productivity and slow plant growth, both of which are primarily water-limited. Vegetation communities are typically desert scrub, shrub– steppe, or desert grassland/savanna and are home to charismatic plants, including saguaro cacti, organ pipe cacti, and Joshua trees. The Chihuahuan Desert is the largest desert in North America, stretching from the southwestern United States deep into the Central Mexican Highlands. It has been classifi ed by the World Wildlife Fund as a Global 200 Ecoregion, a science-based global ranking of the Earth’s most biologically outstanding habitats. Arid lands currently provide a variety of products and services, including a large ranching industry, wildlife habitat, plant and animal diversity, regulation of water fl ow and quality, opportunities for outdoor recreation, and open spaces for expanding urban environments.