Abstracts of Papers Presented (1991 APCG Meeting in Tucson)

ABSTRACTS OF PAPERS PRESENTED (1991 APCG Meeting in Tucson) STUART AITKEN, San Diego State University, and TIMOTHY J. FIK, University of Florida The Context of Change in Households after the Birth of a Child We discuss questions related to changes in household members’ activities and responsibilities after the birth of a child. A five-year study, to be initiated in San Diego in September 1991, will compare household members’ time allocations and spatial adjustments as productive and reproductive activities are transformed. We areparticularlyinterestedinchangingresponsibilitiesamongsthouseholdmembers andchangingrelationshipswith thesociospatial structureoftheurbanenvironment. It seems reasonable to assume that different types of behavioral potential will be manifest in “nuclear” families, dual-income families, households of unrelated adults, extended families, and single-parent households. LUC ANSELIN, University of California, Santa Barbara and ARTHUR GETIS, San Diego State University Elements of a Spatial Analysis Module for General Purpose Geographic Information Systems Geographic information systems have tended to focus attention on the display and organization of information in spatial data bases. As a result, most commercial general purpose GIS implementations offer rather limited statistical tools for the analysis of spatial data. Since spatial dependence is probably the rule rather than theexception in spatial datasets, andsince itsexistenceinvalidatesmanyproperties of standardstatistical techniques, we propose thattheconceptof spatial dependence act as the focus for an analytical module. We then attempt to answer the question: what are the elements of data analysis that should be integrated into a general purpose GIS? We identify four organizational themes for the determination of the analytical elements: data selection, data manipulation, exploratory analysis, and confirmatory analysis. Examples of techniques are given for each theme. JAMES G. ASHBAUGH, Portland State University Barging on the Columbia: Thirty Years of Change In a paper published in the 1961 APCG Yearbook, I discussed barging on the Columbia River. In the last thirty years John Day Dam has been completed on the 143 144 APCG YEARBOOK • VOLUME 54 • 1992 Columbia and four additional dams have been built on the Snake River. The Columbia-Snake system in now navigable to Lewiston, Idaho. Improved naviga­ tion, to an enlarged hinterland, has resulted in large increases in the movement of wheat to the Columbia Riverports. Potatoes, foranexpanding market inJapan, are also barged. Upstream cargo of fertilizer has increased in response to the larger marketarea. The original lock at Bonneville Dam was too narrow to accommodate bargessideby side. Anew lock,underconstruction,willbeopeninl993. Proposals for the enhancement of Columbia River salmon runs include drawing down navigation pools to aid in the downstreammovement of smolt. This would have an effect on barging. TIKI L. BARON, University of California, Los Angeles Anthropogenic Influences on the Biogeography of California Clapper Rails All three subspecies of clapperrails in California (Rallus longirostris obsoletus, R. 1. levipes, and R. 1. yumanensis) are endangered. Their status is a result of the combined pressures of hunting and reduction of suitable wetland habitat. I compared trends in hunting and wetland loss in California to an analysis of rail distribution and population trends over the last century. Each subspecies shows a differentresponsepattern to human influences. Both theCaliforniaclapperrail and the light-footed clapperrail suffered severe losses owing tooverhunting aroundthe turn of the century. Once protective laws were passed, California clapper rails regained much of their former abundance. Later, they experienced sharp declines corresponding to the loss of many San Francisco Bay wetlands. The light-footed railneverregainedits former status andcontinued to decline as SouthernCalifornia wetlands disappeared. The Yumaclapperrail, apparently never subjected to heavy hunting, experienced an expanded distribution owing to the creation of habitat around the Salton Sea and along the lower Colorado River. KENNETH A. BARRICK, University ofAlaska, Fairbanks Wildfire Interpretation in Yellowstone National Park The scope of the 1988 wildfires in Yellowstone National Park forced a national debate about the role of fire in park wildlands that are valued for both ecological naturalness and public recreation. Fire aftereffects are now superimposed on the geologic, wildlife, andotherremarkable attributes atYellowstone. Two years after the fires, 27 percent of the park’s roadside displays are related to fire interpretation (geology 27 percent, wildlife 31 percent, and history 15 percent), and museum exhibits are now dedicated to the fires. The interpretive content falls into two general categories. First, there is anobjective explanation of the...