Department of Geography

College of Liberal Arts

California State University, Long Beach


Abstracts of Conference Presentations


Mr. Noel A. Ludwig

is presenting:

"OSDANP" a new method for generating quantitative expert recommendations, applied to fires in California watersheds," to the Association of American Geographers, Denver, March 2005.

I present a new decision support technique for incorporating the expertise of scientists and land managers into determination of ideal mean fire intervals (MFIs) for southern California chaparral and associated plant communities. The predominant response to the hazard of wildfires near the wildland-urban interface is the setting of prescribed burns. However, in California and elsewhere, guidelines for the timing of prescribed burns typically remain vague, even for specific sites. Indeed, the very efficacy of these prescribed burns has become controversial in recent years. As a result, there is no agreement on the ideal MFIs for management of chaparral and related communities in southern California. The new technique demonstrated here is designed to generate quantitative environmental management recommendations using the Analytic Network Process (ANP), called Objective-Scale Decisions with ANP (OSDANP). I show its worth by using expert input to craft a program for the timing of MFIs for five vegetation communities typical of the wildland-(sub)urban interface in southern California. The location for the case study is the San Dimas Experimental Forest (SDEF) just north of Los Angeles. Criteria considered include wildfire risk, biodiversity, peak stormflow, nitrate concentrations in runoff, and management costs. RHESSys (Regional Hydro-Ecologic Simulation System), a distributed hydroecologic model, is then used to simulate and analyze certain effects of the OSDANP- designed MFI recommendations for these plant communities.

Mr. Ludwig also presented:

"Optimized Prescribed Burning of California's Mediterranean-Type Vegetation: A New Multiobjective, Analytic Network Process Technique," to the Association of American Geographers, Philadelphia, March 2004.

California's predominant method for reducing wildfire hazard is the setting of prescribed burns under amenable weather conditions. In Mediterranean-type vegetation worldwide, prescribed fires reduce wildfire frequency, severity, and area burned. The ecosystem-regulated fuel buildup properties of this vegetation also make it an ideal candidate for prescribed burn management plans.

I demonstrate a new technique to quantitatively optimize environmental management plans using the Analytic Network Process (ANP) and expert input to craft a program for the timing of prescribed burn fire rotation intervals (FRIs) in five typical California vegetation communities located in the San Dimas Experimental Forest north of Los Angeles. This ANP optimization considers wildfire risk, smoke production, plant species and community diversity, peak stormflow and mean annual runoff, soil movement, nitrate runoff, production of herbivore forage, monetary cost, and impact on viewsheds for all five plant communities. ArcView is used to visually compare results. The resulting synthesized ANP score is not an ordinal ranking of FRI alternatives but rather a set of recommended, quantitative FRIs_one optimal FRI for each plant community. Not only does it produce an optimal FRI in absolute years, but it produces one FRI for each plant community. In essence, five separate optimization procedures are performed in one process, and each procedure produces an absolute number. Instead of a mere ranking of alternatives, the end result is a comprehensive program of fire management tailored to each of the five plant communities.

He also presented:

"Gold in Them Thar Hills: Do We Need to Protect Deep-Sea Hydrothermal Vents?" to the Association of American Geographers, Los Angeles, 19-23 March 2002.

Deep-sea hydrothermal vents, first discovered in 1977, are of great interest to biologists, geologists, and--increasingly--mining companies. To date, biologists have described more than 500 new species and 150 new genera from vents throughout the world's oceans. Scientific research has caused some minor damage to these communities, for example by blinding vent shrimp with floodlights and breaking off "black smoker" spires intentionally and accidentally. However, since 1997 governments have issued or considered leases to several vent sites in the southwest and western Pacific, where gold and silver concentrations in polymetalic sulfides appear sufficient to justify the cost of extraction. Experts estimate that such mining may commence within a decade, and could have a negative impact on the quality of these sites for both resident fauna and scientific study. Although vent ecosystems appear to be extremely resilient to natural changes in their environment, these developments nonetheless raise the question of whether some vent sites should be placed off-limits to mining or even certain scientific investigation practices. This poster will give an overview of the known disribution of vent communities, as well as sulfide deposits at which venting and biological activity have ceased. I will then use legal, geologic, biogeographic, and economic information to assess whether certain vent sites may merit being set aside by either national governments or the international community as under some form of protected status.

Mr. Ludwig also presented:

"Discretization of HRUs in a Mixed-Use Subtropical Watershed: Hydrologic Modeling in Windward Oahu, Hawaii Using SWAT" to the American Geophysical Union, San Francisco, December 2002.


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Last revised: 02/05/05