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If you choose to follow any links to the complete text of articles listed below, you will be leaving the Strategian Web site. If you wish to return to this page from the Web page you are sent to, please use the Back option of your browser. Janice M. Christian and Scott D. Wilson Long-term Ecosystem Impacts of an Introduced Grass in the Northern Great Plains. (... Agropyron cristatum, a perennial tussock grass, was introduced to North America from northern Asia and has subsequently been widely planted on the northern Great Plains [of the United States and Canada] since the 1930s. The authors studied 15 areas of grasslands including 5 areas of undisturbed prairie, 5 areas of successional prairie [long-abandoned cropland that has been allowed to undergo a natural return to native grasses], and 5 areas of abandoned cropland that had been planted with Agropyron cristatum; all 15 areas were located in Grasslands National Park just north of the United States-Canada border. Results indicated that areas planted with Agropyron cristatum had significantly lower species richness and diversity than the other two and contained soils with significantly less available N [nitrogen], total N [nitrogen], and total C [carbon] than soils under successional prairie. The relatively low root mass of the introduced grass was probably responsible for decreased rates of N and C addition to the soil and, because total C was 25% less in soils under A. cristatum than under successional prairie, the planting of Agropyron cristatum over a total of perhaps 10 million hectares of the Great Plains may have left some 3.3-4.8 X 10 to the 14th power grams of carbon [a huge amount] in the atmosphere that would otherwise have been stored as organic matter in the soil by native grasses. With no real differences discovered between the effects on the ecosystem of the undisturbed and successional prairie areas, the authors conclude that the effects of this introduced species extend beyond the displacement of native species and the reduction of diversity, and include the alteration of pools and flows of energy and nutrients in the prairie ecosystem--from the text of the article) Ecology Volume 80, Number 7 (October 1999): 2397-2407. **An abstract of this article is currently available through the Web site of Ecology** Armin Jordan, Jochen Harnisch, Reinhard Borchers, Francois Le Guern, and Hiroshi Shinohara Volcanogenic Halocarbons. (... it has been suggested by some that the natural production of halocarbons including chlorofluorocarbons [CFCs] by volcanoes could account for a significant proportion of the CFCs found in the atmosphere [and thus the amount released into the atmosphere through human activities was less significant]. In this study, fumarole and lava gas samples from four volcanoes [Kuju, Satsuma Iwojima, Mt. Etna, Vulcano] were analyzed. Of the more than 300 organic substances detected in these samples, only one CFC compound was found. The authors conclude that a conservative estimate of the upper limit of global CFC emissions by volcanoes clearly shows that this source is negligible as compared to the atmospheric burden by anthropogenic [or human] activities--from the abstract of the article) Environmental Science & Technology (Web Release Date: February 4, 2000) **An abstract of this article is currently available through the Web site of Environmental Science & Technology** How to find the above journals, magazines, and other publications? See Step 3: Locate of the Information Strategy for details. Questions about any or all of the above? Please let me know. |
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