News Release

Taking the pulse of giants: Detecting change and its consequences in western mountain ecosystems

Meeting Announcement

Ecological Society of America

To many people, mountains represent the very essence of the American Wild West. Breathtakingly beautiful, seemingly impenetrable, and staggeringly large, Western mountains loom like giants on the horizon. But in spite of their awesome qualities, the Cascades, the Sierra Nevada, and the Rockies are all currently experiencing a great deal of stress as a result of more than a century of habitation and resource extraction by humans. On Sunday, August 6, 2000, some members of the Ecological Society of America will explore the ecological implications and causes of this stress in a symposium entitled, "Stressors in Western Mountain Ecosystems: Detecting Change and Its Consequences." The session, which will be held during the Society's Annual Meeting in Snowbird, Utah, will examine specific stressors and their effects on these ranges.

David Peterson from the US Geological Survey (USGS) will begin the session with a presentation entitled, "Taking a Pulse of the Mountains: Stress and Ecosystem Change in the 20th Century." Stressors that significantly impact mountain ecosystems include climatic variability, exotic species, air pollution, and land use. Most ecological analyses, Peterson says, are typically conducted at small spatial scales. This makes the detection of mountain problems a real challenge. During the last decade, however, research focused on monitoring, synthesis and modeling of ecological situations in the Cascades, the Rockies and the Sierra Nevada has increased. Peterson will outline the ways in which this has helped to quantify many of the stress effects on natural resources at regional and sub-continental scales. Peterson will also address how the detection of environmental change will challenge land managers and policymakers in the next few years.

As the second speaker in the session, Lisa Graumlich from Montana State University will present "1000 years of Climate Change and Ecological Response in Western Montane Forests." Graumlich will focus on some newly available millennial-length records of forests located in the Greater Yellowstone Ecosystem. Included will be discussions about the evidence supporting climatic change, including tree ring, glacial ice and sedimentary records. Graumlich will outline the current trends in climate and tree growth and examine them in respect to long-term patterns of variability. She will also compare past patterns of climatic change and forest response to prospects for climate change in the 21st century.

Throughout the West, the suppression of fire during the last century has dramatically changed the landscape. In their presentation "Altered Disturbance Regimes: Fire, Fuels, and Forest Structure," Nathan Stephenson (USGS) and his colleagues Thomas Swetnam (University of Arizona) and Thomas Veblen (University of Colorado) will examine how this suppression has resulted in denser forests, shifts in species composition, increased fuel loads, and a consequent increase in the occurrence of abnormally severe wildfires. The team will also review how climatic change will affect the quantity and nature of forest fuels through changes in species composition. Paleoecology records will be discussed, as will some direct human influences upon fire regimes.

Thomas Stohlgren from the Natural Resource Ecology Lab at Colorado State University will talk about the effect of exotic plants during his address entitled, "Exotic Species and Biodiversity in Mountain Forests." Vegetation surveys conducted in Colorado's Rocky Mountain National Park and California's Sequoia and Kings Canyon National Park show similar, alarming patterns, says Stohlgren. Wet meadows at lower elevations, riparian zones, open woodlands, and rare habitats are being heavily invaded by exotic plant species. Stohlgren will discuss the implications of these invasions for national park managers and other areas.

As the fifth speaker in the session, Kathy Tonnessen from the National Park Service will summarize what scientists know about the effects of air pollution upon ecosystems in the western mountain ranges, including the coastal ranges of Southern California, in her presentation entitled, "Air Pollution: A Chronic Stressor in Western Mountains." Issues of concern include: visibility-reducing particles; the deposition of nitrogen and sulfur compounds; and ozone. Air pollution threats to species, biogeochemical processes, and human health will be outlined in her presentation. Emerging air pollution issues include elevated concentrations of persistent organic pollutants in snow, the influence of climate change on air pollution, and the effects of prescribed fire on air quality.

As dramatic shifts in land use occur throughout the region, the "Wild West" is quickly becoming the "New West." Andrew Hansen from Montana State University and Richard Knight from Colorado State University will consider the impact of this change in their presentation, "Land Use in the New West: Ecological and Socioeconomic Causes and Consequences." Where once land was used for resource extraction, now there is exurban residential development. In protected areas, these demographic changes are expressed in the rapid growth of recreation. Hansen and Knight will explore the causes of these changes and the consequences for ecosystem and community sustainability. The challenge for the New West, say the researchers, is to manage land use in order to sustain the ecosystem qualities that are attracting newcomers and stimulating the new economic expansion.

Daniel Fagre (USGS) will conclude the symposium with a presentation entitled, "Taking the Pulse of Mountains: Research and Monitoring Networks." Although mountains contribute 50% of the freshwater that humans consume and are home to one tenth of the world's population, they have been monitored and researched less than other ecosystems. But because mountains' steep environmental gradients make changes easier to detect than many lowland areas, and because there is an increased interest in mountains as indicators of global-scale change, more attention is now being paid to the importance of gathering mountain data. Fagre will outline research networks and efforts occurring on global, national and regional levels, and point to opportunities for new research in the future.

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For more information about this session, and all ESA Annual Meeting activities, visit the meetings section of the ESA website: http://esa.sdsc.edu/snowbird2000.htm. The theme of the meeting is "Communicating and Advancing Ecology" and over 3000 scientists are expected to attend.

The Ecological Society of America (ESA) is a scientific, non-profit, over 7000-member organization founded in 1915. Through ESA reports, journals, membership research, and expert testimony to Congress, ESA seeks to promote the responsible application of ecological data and principles to the solution of environmental problems. ESA publishes three scientific, peer-reviewed journals: Ecology, Ecological Applications and Ecological Monographs. Information about the Society and its activities are published in the Society's newsletter, NewSource, and in the quarterly Bulletin.



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