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Volume 26
Number 1
Spring 2009
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Published: 4 Sep 2015 (online)  •  14 Sep 2015 (in print)
The importance of research archives in national parks
Can marine reserves enhance fishery yield?
How far should a marine protected area extend to provide refuge for fish near coral reefs?
  Effects of increased nitrogen deposition in wilderness areas
Ecological traps: Implications for the conservation of animal populations
Alternative approaches to reserve design
The role of genetics in understanding landscape-level ecological processes
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Effects of increased nitrogen deposition in wilderness areas

Editor's Note: Following is a journal article summary of Canon Scholar Thomas Mexner's research by his Canon Scholar colleague Elizabeth Brusati.

By Elizabeth Brusati
Elizabeth Brusati was a 2001 Canon Scholar from the University of California, Davis. She is a project manager with the California Invasive Plant Council.

URBANIZATION IN THE SOUTHWEST and associated air pollution from cities such as Los Angeles, Phoenix, and Denver have led to atmospheric nitrogen deposition in adjacent ecosystems and elevated nitrate levels in stream networks. Few studies have examined the added impact of disturbance, specifically fire, on hydrologic and biogeochemical processes against this background of elevated atmospheric deposition in southern California. Understanding the extent to which fire may reduce nitrate concentrations and improve water quality in these semiarid areas is important, particularly because prescribed fire is often used as a management tool in such fire-influenced ecosystems.

The authors investigated the effects of .re on nitrate levels in streams in chaparral ecosystems within the San Dimas Experimental Forest, located 40 kilometers (25 mi) northwest of Los Angeles. This site allowed comparisons of nitrate concentrations in an unburned area (control) with concentrations in a prescribed-burn area over a 15-year period. Fire was expected to improve water quality by releasing accumulated nitrogen and reducing nitrate levels in streams. However, the results of this study indicate that such a response did not occur in this ecosystem. After an initial, dramatic increase in the export of nitrogen immediately following the burn, the concentration of nitrates remained higher for a period of seven years in the burned area compared with the unburned area. This postfire behavior differed from response in other ecosystems, e.g., mesic or humid areas, where nitrate levels decline more rapidly and remain low for a longer period following a .re. The authors conclude that prescribed .re in chaparral ecosystems is not effective in ameliorating high nitrogen deposition rates from nearby urban areas and suggest that reducing nitrogen emissions at the source is needed to protect ecosystems from atmospheric pollution, particularly watersheds and streams in wilderness areas.


Meixner, T., M. E. Fenn, P. Wohlgemuth, M. Oxford, and P. Riggan. 2006. N saturation symptoms in chaparral catchments are not reversed by prescribed fire. Environmental Science and Technology 40:2887–2894.

Thomas Meixner was a 1997 Canon Scholar from the University of Arizona. He is an associate professor of hydrochemistry in the Department of Hydrology and Water Resources at the University of Arizona.

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From the Guest Editor(s)
In This Issue
  Information Crossfile
Book Reviews
Masthead Information
The Canon National Parks Science Scholars Program: A legacy of science for national parks
Science for parks / parks for science: Conservation-based research in national parks
The rock and ice problem in national parks: An opportunity for monitoring climate change impacts
1,000 feet above a coral reef: A seascape approach to designing marine protected areas
Management strategies for keystone bird species: The Magellanic woodpecker in Nahuel Huapi National Park, Argentina
Climate change and water supply in western national parks
Mercury in snow at Acadia National Park reveals watershed dynamics
Organic pollutant distribution in Canadian mountain parks
Building an NPS training program in interpretation through distance learning
Musical instruments in the pre-Hispanic Southwest
Societal dynamics in grizzly bear conservation: Vulnerabilities of the ecosystem-based management approach
Linking wildlife populations with ecosystem change: State-of-the-art satellite ecology for national-park science
Whale sound recording technology as a tool for assessing the effects of boat noise in a Brazilian marine park
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