Riparian wetlands are among the most valuable landscapes in the arid southwest. Since they are sources for water and green vegetation, they are unique compared to surrounding desert landscapes. They also offer the potential for a wide range of commodity and non-commodity based land uses. In a rapidly urbanizing setting, commodity based uses such as housing, retail, and industrial development often come into conflict with non-commodity based uses such as recreation and wildlife, water and nature preservation. The purpose of this study was to deduce public value orientations toward the rapidly urbanizing riparian landscapes of Tucson, Arizona through an assessment of residents' attitudes and perceptions regarding those landscapes. Theoretical constructs addressing the relationship between attitudes and perceptions and varying conditions of residential setting, proximity, familiarity, and human influence in the landscape were also assessed. Data were collected by mail survey and by a photo-surrogate landscape assessment technique which provided data on scenic quality and the appropriateness of various land uses. Results indicate that the strongest differences across residential settings, proximity, familiarity, and human influence occur for perceptions of existing landscape conditions. Weaker differences occur for perceptions of change and opinions on planning, management, and growth. No differences were found on land use preferences. Although perceptions differ about what currently exists in the landscape, respondents are unified in their preferences for future land use. This suggests that landscape assessments based only on perceptions of existing conditions may not accurately reflect public values for future land uses. Public value orientations were found to be associated with: (1) careful planning to control growth; (2) conservation of water resources; (3) preservation and rehabilitation of natural vegetation, wildlife habitat, open space, and other non-commodity resources, and (4) development of compatible flood control structures. Results suggest that the changes occurring in the study area are incompatible with respondents' preferences for future land uses.

I studied selenium contamination at Cibola National Wildlife Refuge (Cibola NWR) in the lower Colorado River Valley, California and Arizona. My objectives were to: (1) determine whether local irrigation practices resulted in exposure of fish to toxic levels of selenium; (2) assess the risks to humans of consuming fish from Cibola NWR; (3) assess whether diversity and abundance of fish were related to selenium concentrations or other water quality variables. Water, sediment, fish, crayfish, and aquatic plants were collected from sites which received irrigation return flows and sites which did not. Selenium was below toxic levels at sites receiving irrigation return flows. Selenium was at the toxicity threshhold for fish at two sites receiving water directly from the Colorado River. Concentrations of selenium in fillets of largemouth bass (Micropterus salmoides) from one lake exceeded levels that elicit consumption advisories in California. Most people would be unlikely to consume toxic amounts of fish, but an advisory should be posted to inform people about potential risks. Gill nets were used to determine species diversity and abundance. There were no strong correlations between selenium levels and indices of species richness and equitability. There was a consistent inverse relationship between selenium levels and catch-per-unit-effort for all species combined. This inverse relationship suggested that selenium may be one of a suite of factors limiting abundance of fish. Correlations between indices of species diversity and abundance and values of water quality variables generally were not significant. Temperature and salinity may have limited abundance of some species seasonally. Increases in selenium levels at sites that are already at the toxicity threshhold could impair reproduction of sensitive species. Population declines and concern about edibility of fish could impair the recreational fishery. Therefore, site-specific ways to reduce selenium accumulation should be studied and implemented. Site-specific limnological conditions may play a role in accumulation of selenium to toxic levels, but major sources of selenium appear to be upstream in the Colorado River basin rather than local agricultural practices. Therefore, selenium input to the Colorado River from sources throughout the basin should be monitored and reduced where possible.

Vegetational responses to changes in exposures within a constant slope range were studied on the Shallow Upland Range Sites and Granitic Hills Range Site in the Chihuahuan semidesert grasslands in Central Arizona. Sixteen exposures with slopes between 11 and 17 degrees were chosen for subsample sites. Environmental, complete soil descriptions, and vegetational composition data were taken. All data were analyzed using analyses of variance, ordination programs, and regression analyses to determine climate, soils, and vegetational relationships among exposures. The resulting data indicated that the geological lithologic unit on which the soils formed was the most important factor affecting apparent vegetational type. In this study, the data obtained from the complete soil profile descriptions contributed little information to the understanding of vegetational responses. Soil surface characteristics and surface soil horizon properties influenced soil moisture relationships. The conservation of soil moisture appeared to be more important to plant communities than did the total moisture holding capacity of the soil continuum. Monthly precipitation reliability and soil surface reflectances were environmental factors affecting plant communities occurring on different exposures. Fall/spring, winter/spring, and spring soil temperature interactions were the most important environmental factors affecting vegetation on different sloping exposures. All exposures within each of the four sample locations had vegetational components that were similar to the vegetational components of other exposures but all exposures were found to have different plant communities. Each exposure within a given slope range is a phase and/or subphase of currently used range site descriptions. A range site that is based on a potential natural community at one type location cannot be extrapolated across broad geographical expanses to define vegetative potentials for other areas having similar vegetative aspects. Range site descriptions must be site specific for one geographical rangeland that has had the same historical uses.

Papago Indian fields located in southern Arizona and northern Sonora, Mexico are examples of a food production strategy that was developed within the constraints of a water-limited environment. Although only a small percentage of the fields cultivated at the turn of the century remain in cultivation, extant fields are vestiges of an agricultural tradition that has persisted in arid lands for centuries. An examination of the documentary history of non-Indian observations of Papago agriculture and water control from 1697 to 1934 reveals numerous practices and features that are no longer apparent within or around remaining fields. Yet by learning from oral historical accounts of elderly Papago, and analyzing O'odham lexemes (native Papago terms) which guide farmers' management of fields, it is possible to gain a sense of folk science which Papago developed to successfully farm without permanent surface water reserves. Selected concepts from the folk science of the Papago are used as a point of departure in understanding the ecological processes which function within their fields. Standard field ecology methods were adapted to empirically test certain hypotheses relating to these ecological processes. Results include confirmation that Papago fields are situated in a variety of physiographic positions, and that ‘ak-ciñ arroyo mouth' farming is a misnomer. Papago crops exhibit many of the same drought-escaping adaptations as wild summer desert ephemerals for seed production during the brief summer rainy season, which varies from year to year in the date of its initiation. These adaptations greatly contribute to crop success. There are no significant differences in the diversity of herbaceous plants found in Papago fields compared to the diversity found in adjacent, uncultivated environments. Of the many nutrients analyzed in cultivated and uncultivated floodplain soils, only potassium was significantly richer in fields than in uncultivated floodplains; other differences were statistically insignificant. Floodwashed organic detritus, rather than the floodwaters themselves, appear to play the major role in renewing field soil fertility in certain localities. It is concluded that indigenous concepts which have long guided the management of traditional agricultural systems are of heuristic value in understanding how these farming systems function ecologically.

Management, under the concepts of multiple-use and adaptive management, requires the assessment of potentials and limitations of the natural ecosystems to provide satisfaction to human needs, to protect long term productivity, and preserve biological diversity. Overstory-understory relationships were developed for ponderosa pine (Pinus ponderosa) ecosystems to help managers to evaluate herbage production potentials. Secondary data sources from the Beaver Creek and the Heber Watersheds were divided as follows: igneous soils, igneous clay loam, igneous loam-sandy loam, sedimentary soils, alluvium, and sandstone. Regression models were fitted to the raw data by the least squared method. The dependent variables were herbage production (lb/ac) by component; namely total, grass and grass like plants, forbs and half shrubs, and shrubs. The independent variables were total and ponderosa pine basal area (ft 2 /ac). Semilogarithmic models fitted the data from igneous soils, while logarithmic transformations of hyperbolic models fitted the data from sedimentary soils. For igneous soils, ponderosa pine basal area suffice for adequate predictions of herbage production. Significant differences were found between equations for alluvium and sandstone. The resulting equations for ponderosa pine integrate the core of the model UNDER. Mathematical functions developed elsewhere are included in UNDER to compute herbage production in pinyon-juniper and mixed conifer ecosystems. UNDER is linked to other simulators by MICROSIM. MICROSIM, a multiple-resource simulation model, is a tool to assist in the assessment of potentials of forest and woodlands of Arizona. MICROSIM is a menu driven program for IBM or compatibles it contains the module Flora, for estimating plant responses, and module Fauna, to evaluate impacts on animals. Further development of MICROSIM should include the linkage to more modules and models, and to Geographical Information Systems.

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The Arizona Nature Conservancy's Hassayampa River Preserve is 50 miles northwest of Phoenix near the town of Wickenburg. Four miles of the largely ephemeral Hassayampa River are perennial within the preserve, supporting one of the finest remaining cottonwood-willow forests in the state. Stream flows are affected by wells pumping ground water directly from the alluvial aquifer and may be influenced by wells which intercept lateral inflow from the regional basin-fill aquifer. Developing effective management strategies to protect base flow conditions (∼4 cfs) depends on a clear understanding of the surface and ground-water systems in the preserve. Provided that ground water developers near Wickenburg recognize and incorporate the interconnected nature of each hydrologic system, perennial flow within the preserve is not believed to be immediately threatened. (Abstract shortened with permission of author.)

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No description available.