Plant secondary compounds abound in every plant mother nature has to offer. From common garden vegetables to poisonous plants, there are secondary compounds in every plant any animal, as well as we, chooses to eat. In the past, secondary compounds were mostly considered waste products of plant metabolism, but over the last several decades research has shown that these compounds play an active role in plant and animal behavior, health, and productivity. Though often seen only in terms of their negative impacts on intake and production, we are becoming increasingly aware of their beneficial roles in plant, animal, and human health. Providing herbivores with a diversity of plants to make up their diet allows them to regulate and mix foods so as to better utilize primary and secondary compounds, as well as enhancing economic and ecological performance. The secondary compound gramine is an alkaloid found in reed canarygrass that is proteinaceous in nature. Endophyte-infected tall fescue contains the alkaloids perlolidine, perloline and ergotamine, which are all steroidal in nature. Tannins have a high affinity for binding proteins, and saponins are non-polar steroidal compounds with a high affinity for binding to lipids in the gastro-intestinal tract of animals. These findings suggest that animals ingesting foods with alkaloids may increase their preference for tannin or saponin-containing foods to reduce the negative impacts of these secondary compounds. Moreover, tannins and saponins hasten alkaloid excretion from the body, which might also allow animals to eat more high-alkaloid forages when presented with tannins first. I tested the hypothesis that cattle and sheep foraging behavior is influenced by eating different combinations and sequences of forages containing secondary compounds. In pen and pasture trials, I showed that 1) sheep fed basal diets high in alkaloids (gramine or ergotamine) ate more when supplemented with food containing either tannins or saponins ; 2) cattle that ate a 30-minute meal of tall fescue(alkaloid) subsequently preferred birdsfoot trefoil(tannin) to alfalfa (saponin), while cattle that first ate reed canarygrass(alkaloid) subsequently preferred alfalfa(saponin) to birdsfoot trefoil (tannin) ; and 3) cattle spent more time grazing tall fescue and reed canarygrass when they first ate birdsfoot trefoil (high in tannins) and alfalfa (high in saponins), respectively, than when they ate these forages in the reverse sequence.

This research examined the diets of angora goats on a sagebrush bunchgrass rangeland. Research objectives were to 1) determine the effects of a positive conditioning method on both mature and immature angora goats; and 2) to quantify plant selection and provide preliminary information as to the potential for using goats to rehabilitate degraded sagebrush rangelands. Goat diets were ascertained using focal - animal bite-count observations during five consecutive seasons, summer 1990 through summer 1991. Treatment group goats were conditioned for 8 months by including ever- increasing amounts of sagebrush (Artemisia tridentate subspp. wyomingensi) in their daily ration, up to 25% of their total intake. Conditioning effects were evaluated in a rangeland setting by comparing relative amounts of sagebrush consumption between groups. Our results indicate that while conditioning did not significantly impact sagebrush consumption, young animals consumed significantly more sagebrush than adults. Additionally, learning throughout the first year altered dietary selection by the second summer. Both does and kids were primarily gramnivorous, however there was strong seasonality in species preference and a significant age difference in diets selected. Age differences in the plant species selected persisted throughout the study until the summer of 1991 when kids were eighteen months old. / Graduation date: 1993

Thesis (M.S.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references (leaves 97-103). Also available on the World Wide Web.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

The objective of this study was to evaluate the effects of mesquite overstory removal and modifications of soil properties due to mulching treatments on herbaceous production. The three overstory treatments were complete removal of mesquite overstory with no removal of regrowth, complete removal of mesquite overstory with removal of regrowth and an untreated control. The mulching treatments included applications of chip mulch, commercial compost, lopped-and-scattered mesquite branchwood and a control. Both overstory treatments resulted in an increase of over 20% in total annual herbaceous production. The overstory treatment of complete removal of mesquite overstory with no removal of regrowth had the greatest impact on fall production of native herbaceous species during years of relatively high precipitation, at times increasing production by almost 2-fold. Mulching treatments had no effect on herbaceous production; however, soil pH and plant available phosphorus was affected by some of the mulching treatments.

The vegetation index products from the Moderate Resolution Imaging Spectroradiometer (MODIS) are designed to provide consistent, spatial and temporal comparisons of global vegetation conditions. The objective of this dissertation was to validate the robustness and global implementation of two MODIS VI algorithms, including the normalized difference vegetation index (NDVI) and "enhanced" vegetation index (EVI). Their performances have been evaluated in: (1) the normalization of canopy background (brightness) variations and the extraction of biophysical parameters across different canopy structures; (2) the characterization of seasonal vegetation profiles (phenological, intra-annual); and (3) spatial and temporal discrimination of vegetation differences (inter-annual). The validation was accomplished through multiple means, including canopy radiative transfer models which were utilized to extract pure vegetation spectra and "true" VI value free of background contamination for varying canopy structures and vegetation amount. The experimental field- and airborne-based radiometry and satellite imagery at multiple spatial resolutions were also coupled and scaled-up for comparison with coarse spatial resolution MODIS VI products to quantify characteristics of semiarid rangeland vegetation. The results showed that NDVI was advantageous in yielding biophysical relationships applicable across varying canopy types, but required knowledge of soils for biophysical estimations. The EVI provided biophysical relationships sensitive to canopy structure, thus requiring knowledge of canopy type for biophysical assessments. The MODIS VI products were successfully validated, radiometrically, by coupling field and the MODLAND Quick Airborne Looks (MQUALS) observations to high spatial resolution imagery (AVIRIS and ETM+), and appeared robust across the two parallel sites for depicting their ecological equivalents. MODIS multitemporal VI profiles were able to depict phenological activity, length of the growing season, peak and onset of greenness, and leaf turnover. Among the sensors tested, spatial resolution was found to be most important for discriminating the major land cover subtypes within the two parallel semiarid rangelands, and spectral resolution had major effects on capturing seasonal contrast due to atmosphere influences. The validation strategy utilized in this study to successively aggregate the integrity-inherent multiple fine spatial resolution data to the coarse MODIS pixel sizes appeared to perform well, thus showing potentials in the validation of other satellite products.

Multi-cultural demands of public lands in the United States continue to challenge federal land managers to address social and cultural concerns in their planning efforts. Specifically, these individuals lack adequate knowledge of cultural concerns as well as a consistent strategy for acquiring that knowledge for use in decision-making. Current federal approaches to cultural concerns include public participation, conservation partnerships, government-to-government consultations with American Indian tribes, cultural resource inventories, and landscape analysis. Since cultural knowledge arises from human-nature relationships and shared perceptions of natural environments, and landscapes are the ultimate expression of such knowledge, an exploratory methodology was developed for a different approach to understanding cultural concerns through landscape perceptions. Using cultural landscape theories and applications from the natural and social sciences, this study examined the landscape perceptions of four groups concerned with management planning of the Baboquivari Wilderness Area in southern Arizona: the Bureau of Land Management, landowners of the Altar Valley, recreationists, and members of the Tohono O'odham Nation. The methodology is based on a human nature relationships rather than cultural aspects or features. It takes a holistic approach that differs from other perception studies by including: emic aspects of data collection and analysis; a spatial component: triangulation of data collection through narrative and graphic descriptions; conducting ethnographic, on-site interviews; and consensus analysis and small-sample theory. The results include: verification of four cultural groups; two levels of consensus---in the population of concern, and in each group---that overlap in some aspects of landscape perception; descriptions of four cultural landscapes that illustrate similarities and differences among the groups, and include patterns and representations of spatial relationships; an effective methodology for revealing cultural concerns that are not identified through public forums, and with potential for application by agencies at the field office level.

Ecosystem management is positioned as the modern paradigm of resource management. Fire management activities within the natural resource management agencies, under the adoption of an ecosystem management approach, supports an increased focus upon prescribed and manager-ignited fire programs. A review of past national fire policies and the effects they have had upon ecosystem conditions today further supports the role for prescribed fire. Under an ecosystem management approach, resource managers need to consider the effects of fire management activities over longer temporal and broader spatial scales. Examining the ecological, social, political, and economic aspects surrounding fire management activities on these scales will help ensure healthier ecosystems in perpetuity. Although the suppression of wildfires will remain a necessary component to fire management activities today, there needs to be an increased effort to reintroduce fire into ecosystems and to recognize fire as a natural component vital to maintaining ecosystem health.

<p> Sharp-tailed grouse habitat on the Dakota Prairie Grasslands are assessed by habitat structure with the use of the Robel pole to measure visual obstruction readings (VOR). The purpose of this study was to determine 1) if all selected ecological sites (loamy, thin loamy, and claypan) are biologically capable of producing high structure (VOR > 3.5 in) with 3 years of protection from livestock grazing and 2) if strong and consistent correlations exist between standing crop and visual obstruction among ecological sites and across years. Results showed that 1) all selected ecological sites were biologically capable of producing high structure, 2) strong correlations between standing crop and visual obstruction were not consistent among ecological sites and across years, 3) year effects were evident in plant community composition, and 4) 2,534 kg/ha (se &plusmn; 205.3) of standing crop provides the mean threshold to determine if the selected ecological sites are biologically capable. </p>

The research accomplished in this dissertation used both mathematical and statistical techniques to extract and evaluate measures of landscape temporal dynamics and spatial structure from remotely sensed data for the purpose of mapping wildlife habitat. By coupling the landscape measures gleaned from the remotely sensed data with various sets of animal sightings and population data, effective models of habitat preference were created. Measures of temporal dynamics of vegetation greenness as measured by National Oceanographic and Atmospheric Administration's Advanced Very High Resolution Radiometer (AVHRR) satellite were used to effectively characterize and map season specific habitat of the Sonoran pronghorn antelope, as well as produce preliminary models of potential yellow-billed cuckoo habitat in Arizona. Various measures that capture different aspects of the temporal dynamics of the landscape were derived from AVHRR Normalized Difference Vegetation Index composite data using three main classes of calculations: basic statistics, standardized principal components analysis, and Fourier analysis. Pronghorn habitat models based on the AVHRR measures correspond visually and statistically to GIS-based models produced using data that represent detailed knowledge of ground-condition. Measures of temporal dynamics also revealed statistically significant correlations with annual estimates of elk population in selected Arizona Game Management Units, suggesting elk respond to regional environmental changes that can be measured using satellite data. Such relationships, once verified and established, can be used to help indirectly monitor the population. Measures of landscape spatial structure derived from IKONOS high spatial resolution (1-m) satellite data using geostatistics effectively map details of Sonoran pronghorn antelope habitat. Local estimates of the nugget, sill, and range variogram parameters calculated within 25 x 25-meter image windows describe the spatial autocorrelation of the image, permitting classification of all pixels into coherent units whose signature graphs exhibit a classic variogram shape. The variogram parameters captured in these signatures have been shown in previous studies to discriminate between different species-specific vegetation associations. The synoptic view of the landscape provided by satellite data can inform resource management efforts. The ability to characterize the spatial structure and temporal dynamics of habitat using repeatable remote sensing data allows closer monitoring of the relationship between a species and its landscape.