Geo-Ecological Study of Historic and Prehistoric Land Use in the Hopi Buttes area, Navajo Nation, Arizona Map showing Hopi Buttes and the surrounding area. Introduction This project examines land use, climatic variability, and their related impacts on land-surface conditions in the ecologically sensitive Hopi Buttes region of the Navajo Nation. Research on separate aspects of the ecosystem includes bedrock geology, surficial processes, soil and water quality, and plant ecology, as well as the history of human habitation. Collaborative work with Navajo tribal members provides information for education and community-based land-use planning. The Hopi Buttes area is a semi-arid region (1800 km2) where rapid growth of the largest population of Native Americans will increasingly stress the carrying capacity of lands upon which people are dependent for their livelihood. Humans have continuously inhabited this area since at least AD 600. The Hopi Buttes are erosion resistant remnants of volcanoes. Springs and water wells within Hopi Buttes are located within these volcanic structures. Understanding the depth and style of volcanic activity, subsequent fragmentation of volcanic deposits, and pre-volcanic bedrock are important for characterization of the local aquifer systems and potential well sites. Hopi Buttes, near Dilkon, Arizona. View toward the west. Pines and junipers for scale. Photo credit: Louis J. Maher, Dept. of Geology and Geophysics, Univ. of Wisconsin, Madison   We will examine the interrelations of humans to ecosystem function, including the effects of agriculture, settlement, grazing, and mining on soils, vegetation, and water. Information from geological and biological disciplines will help explain population shifts revealed by the archaeological record and significant changes in the physical and biological environment in historic times. Changes in surficial features, vegetation, meteorological conditions, and patterns of settlement in space and time will be analyzed as map layers in a digital format. Lava-capped Bidahoochi Butte on red Triassic shale of the Painted Desert northeast of Dilkon, Arizona. Photo credit: Louis J. Maher, Dept. of Geology and Geophysics, Univ. of Wisconsin, Madison Changes in vegetation and land surface features over time are documented by repeat photography. These historic data are compared with current vegetation conditions to develop a model of vegetation change during recent history, to reveal links of vegetation type to landscape change, land use, and bedrock geology, and to show time-related changes in the plant community. Sand dune west of Dilkon, Arizona, with Elephant Butte and Pyramid Butte in background. Sand dune activity is related to the distribution and type of plants in an area. Plants hold sand and soil in place, but die off during periods of drought. Plant communities are transformed by variations in climate and land use. Sources of water in the Hopi Buttes area commonly contain high concentrations of potentially toxic trace elements including arsenic. Ten percent of sampled water sources contain more arsenic than the U.S. Environmental Protection Agency (EPA) historic standard of 50 µg/L and 40% contain more than 10 µg/L. Medical experts have linked elevated levels of arsenic in drinking water to adverse human health effects such as cancer, diabetes, and heart ailments. The high incidence of disease, particularly diabetes, among Native American inhabitants emphasizes the need to understand the distribution and origin of elements like arsenic contained in the water sources of Hopi Buttes. Local water composition is the result of water reacting with rock and sediment in the area. Analyses of water and associated rocks will be conducted as part of a risk assessment and to evaluate the implications of land use on water quality. Well east of White Cone, Arizona. An investigation of water supplies will establish the cause for poor water quality in some wells, and outline areas where suitable water can be found. The oral accounts by the Navajo people also provide information on the frequency of events related to variations in climate and land use. Research of historical accounts by Spanish explorers and examination of Navajo oral history will augment physical science investigations with records of present and changing land-use practices, past changes in landscape and vegetation, and knowledge of extreme weather events for comparison with the climatic record. Native American cultures have relied upon strong oral traditions and personal experience for the passage of environmental knowledge. This knowledge has been critical for efficient and successful hunting, gathering, and planting. Oral accounts include descriptions of events, activities, and relationships that tie people to particular places at particular times. These richly detailed accounts provide information on places, plants, animals, and events, all of which serve as valuable climate markers for calibration with other records.   Information from Hopi Buttes will be used to assess the following factors, so that we may plan for our future and the future of our children: - Climate variability - Fluctuations in human populations and living practices - Plant community changes - Surface stability - Soil productivity and moisture retaining capacity - Concentrations and dispersal of toxic elements in soil and water   For more information, please contact: Margaret Hiza U.S. Geological Survey 2255 N. Gemini Drive Building 3 Flagstaff, AZ 86001 Telephone: 928-556-7366 E-mail: mhiza@usgs.gov U.S. Department of the Interior, U.S. Geological Survey This page is http://esp.cr.usgs.gov/hopibuttes/ Maintained by ESP Web Team Last modified Wed 15-Mar-2006 14:35:34 MST Policies and Disclaimers