A nearly monospecific stand of Lehmann lovegrass (Eragrostis lehmanniana Nees.) was grazed by cattle during two summer growing seasons to simulate short duration grazing. Grazing treatments were timed to coincide with preboot, boot to early inflorescence and hard seed phenological stages. During each treatment, grazing intensity on individual plants included heavy, moderate or light intensities. In 1990 maximum regrowth occurred when plants were grazed during boot to early inflorescence and at a light grazing intensity. In 1991, plants grazed during preboot or boot to early inflorescence and at a light or moderate intensity produced higher regrowth amounts than the other treatments. Plants grazed during boot to early inflorescence recovered significantly faster than plants grazed during preboot in 1990 and 1991. In 1990 lightly grazed plants recovered biomass faster than plants grazed at heavier intensities. In 1991 plants grazed at light and moderate grazing intensities recovered significantly faster than heavily grazed plants. Heavily grazed plants never produced enough regrowth to resemble moderately or lightly grazed plants within one growing season.

Management strategies are needed to reduce the rate at which brown-headed cowbirds (Molothrus ater) parasitize their hosts. I investigated whether vegetation management could be used to reduce parasitism by seeking differences in nest-site microhabitats of hosts in a riparian area of central Arizona. During 1993 and 1994, I quantified vegetation characteristics in 0.04 ha plots centered on 128 nests of 4 commonly parasitized species and 4 infrequently parasitized species. I compared characteristics between (1) parasitized and unparasitized nests of common hosts, and (2) nests of common and infrequent hosts. Factors associated with outcome of parasitism were vegetation volume at nest, size of nest substrate, distance from nest to visual obstruction below nest, and presence of large trees near the nest. Whether nests belonged to common hosts or infrequent hosts was best predicted by nest height. My results indicate riparian areas should be managed for large trees and numerous shrubs when the goal is to reduce parasitism.

This paper suggests that environmental degradation is a symptom of a corrupt worldview. The dominant Western worldview construes the world as an aggregate of component parts having an antithetical, competitive relationship. This dualistic arrangement which divides and then negates the "other" conditions people to value aggression and power, and inevitably results in violence. Nature, in this hierarchical caste system is regarded as inferior, inert, or evil. Behavior and social institutions, such as the Christian religion, science and capitalist economy both reflect and reproduce these destructive values. Ecofeminism, by contrast, offers an alternative worldview more conducive to environmental prosperity. It regards the cosmos holistically, with all components having an equally valid, albeit distinctive, significance. This orientation emphasizes compassion and communion rather than fear and subjugation. Dissociating from the ego-based mindset of domination which underpins social and environmental decay allows the possibility of transforming consciousness and establishing an ecological worldview.

Whitebark pine (Pinus albicaulis Engelm.) tree-ring chronologies of 700 to greater than 1,000 years in length were developed for four sites in the Sawtooth-Salmon River region, central Idaho. These ring-width chronologies are used to (1) assess the dendrochronological characteristics of this species, (2) detect annual mortality dates of whitebark pine attributed to a widespread mountain pine beetle (Dendroctonus ponderosae Hopk.) epidemic during the 1909 to 1940 period, and (3) establish the response of whitebark pine tree ring-width growth to climate variables. Crossdating of whitebark pine tree-ring width patterns was verified. Ring-width indices had low mean sensitivity (0.123-0.174) typical of high elevation conifers in western North America, and variable first order autocorrelation (0.206-0.551). Mortality of dominant whitebark pine caused by mountain pine beetle had a maxima at 1930 on all four sites. Response functions and correlation analyses with state divisional weather records indicate that above average radial growth is positively correlated with winter and spring precipitation and inversely correlated with April temperature. These correlations appear to be a response to seasonal snowpack. Whitebark pine is a promising species for dendroclimatic studies.

Determination of reproductive success in birds is important for understanding population dynamics, habitat quality, and features necessary for breeding. I incorporated behavioral observations, nest monitoring, and a reproductive ranking index (Vickery et al. 1992) to (1) categorize painted redstarts (Myioborus pictus), solitary vireos (Vireo solitarus plumbeus), and western wood-pewees (Contopus sordidulus) as breeders or nonbreeders, (2) locate nests, (3) monitor nest status, and (4) determine nest success and parasitism rates in 14 canyons of the Huachuca and Santa Rita mountains, Arizona during 1994-1995. I built logistic regression models for each species that correctly classified 58-68% of successful nesters from unsuccessful nesters, 62-85% of areas used by birds from random sites along the canyons, and at each nest, I correctly classified 39-60% of successful nest sites from unsuccessful nest sites and 87-95% of nest sites from nonoverlapping sites in areas of use. These models can be used to determine areas that would promote occupancy and successful nesting by these 3 species.

This study was conducted to determine behavior patterns of the jumping spider Habronattus oregonensis. Time budgets show spiders spend their time out and about, eating, interacting with other spiders, and in hidden behaviors with out and about behaviors dominating. Agonistic encounters occur in the field and were staged in the laboratory. Whether a spider keeps control of the area is determined differently for males than females. In male-male interactions, the size of the spider as measured by weight is important in winning a skirmish regardless of familiarity with an area (residency). For female-female agonistic interactions, however, residency does affect the outcome. In interactions between male-female pairs, the male readily courts the female. Mature virgin females readily accept a mate; other females do not. Finally, experiences from university research were used to develop lesson plans for student study at the secondary level in biology classrooms.

The purpose of this study was to reconstruct historical fire regimes along an elevation and vegetation gradient in the Sacramento Mountains, NM. I cross-dated fire-scarred specimens to reconstruct the fire history within two mixed-conifer, four ponderosa pine, and two pinon-juniper stands. Prior to Euro-American settlement, historical fire intervals were estimated at 6 years in ponderosa pine, 10 years in mixed-conifer, and 27 years in pinon-juniper forests. To evaluate whether Native Americans may have influenced historical fire regimes, I cross-dated scars from peeled trees found within the study area. Comparison between scar dates, historical records, and variations in fire frequencies did not show a regional effect on historical fire regimes by Mescalero, but suggested that they may have had a local impact on fire frequencies of the late 1700's. Following Euro-American settlement (ca. 1880) fire was nearly absent from the study area due to livestock grazing and fire suppression.

Geographic range and numbers of buff-breasted flycatchers (Empidonax fulvifrons) have decreased in Arizona. I conducted surveys to locate additional populations. Results suggested that some small populations have disappeared since 1980, but that other small populations have increased. I estimated reproductive success using an index based on adults' behavior. I measured vegetation in used areas, nest sites, and available areas. I used logistic regression to compare used to available areas and nest sites to used areas. Used vs. available comparisons indicated that buff-breasted flycatchers used areas dominated by pines, with a sparse oak understory. I found significant associations between buff-breasted flycatcher presence and vegetation type, structural stage, canopy cover, and forest patch width. I developed a habitat model to help manage this rare species. I recommend continued monitoring of buff-breasted flycatcher populations and creation of open pine forest with an open understory of oak. Fire may facilitate development of potential habitat.

The dynamics of crappie populations in southwestern reservoirs are not well documented. In order for managers to enhance a crappie fishery, they need to understand the factors that control populations. I examined potential limiting factors for black crappie in 4 sequential reservoirs on the Salt River, Arizona. Only in Roosevelt Reservoir, the uppermost reservoir, were crappie relatively abundant. I identified 3 possible limiting factors. Apache, Canyon, and Saguaro reservoirs lacked sufficient spawning substrates. All 4 reservoirs lacked sufficient cover. Finally, the lower 3 reservoirs are less productive during the fall according to chlorophyll a levels than Roosevelt Reservoir. Low productivity may have resulted in fewer zooplankton and possibly a limited forage base for juvenile crappie. Options such as spawning platforms, artificial cover, fertilization, and stocking are discussed as ways to improve the crappie fishery in these reservoirs.

Little is known about habitat selection by elf owls (Micrathene whitneyi) and western screech-owls (Otus kennicottii). From 1994 to 1996 in the Sonoran Desert, I used point counts and nest searches to examine habitat selection by both species at multiple spatial scales. The abundance of both species had a positive association with percent cover of washes and mesquite (Prosopis spp.) at the scale of the study area. At both the scale of the study area and the nesting area, elf owls selected areas with high densities of mature saguaros (Carnegiea gigantea) and saguaro cavities. Elf owls nested only in woodpecker cavities in saguaros, whereas western screech-owls nested in both saguaro cavities and in natural cavities in mesquite. Western screech-owls nested nearly exclusively in gilded flicker (Colaptes chrysoides) cavities when they nested in saguaros. Patterns of nest cavity selection by elf owls suggest they may choose cavities that provide thermoregulatory advantages. I give management recommendations based on my findings.