I examined the relationship between exotic and native cavity-nesting birds in the Sonoran desert near Tucson, Arizona during 1988 and 1989. I attempted to limit cavity availability in 1989 by plugging cavities that were unused, or used by exotics, in 1988 with rubber test tube stoppers. Numbers of nests of any species did not significantly change between 1988 and 1989. Control plots showed similar results. I found no significant negative correlations between number of nests of European starlings (Sturnus vulgaris) and any other cavity-nesting species. Of the cavity characteristics examined, species only differed in size of cavity openings. My data indicate that exotic and native cavity-nesting birds were not competing for nest cavities. An excess of available nest cavities is the probable reason for this lack of competition. Temporal differences in cavity use among species may have helped contribute to the abundance of cavities.

Habitat use of Merriam's turkey (Meleagris gallopavo merriami) was characterized in the Prescott National Forest, Arizona, between March 1991 and August 1992. Roost sites were generally found in canyons or on hillsides, and contained a large number of ponderosa pine trees, and Gambel oak seedlings and trees. Turkeys fed on juniper berries, generally in small groups of large juniper trees within ponderosa pine stands. Turkeys fed on acorns in stands of Gambel oak on hillsides. Turkeys feeding on grass/forb vegetation tended to be on flat areas with a large amount of forb and grass cover. Turkeys loafed under Gambel oak, in areas with large amounts of Gambel oak growth near openings, on hillsides or in canyons. Turkeys also loafed under juniper trees; these areas had a large basal area of alligator juniper and high numbers of Gambel oak seedlings.

This study evaluated the influence of Lehmann lovegrass (Eragrostis lehmanniana Nees) on the densities and spatial distributions relative to mesquite (Prosopis velutina Woot.) of two native grasses, Arizona cottontop (Digitaria californica (Benth.) Henr.) and Rothrock grama (Bouteloua rothrockii Vasey), in the semi-desert grassland. Also evaluated were the affects of independent variables range site, elevation, and proportion mesquite cover on these relationships. General Linear Model analyses showed no association between Lehmann lovegrass and either the densities or the distributions of the native species. Arizona cottontop showed an affinity for mesquite cover, while Rothrock grama and Lehmann lovegrass both showed an aversion to mesquite canopy. The relationship of Rothrock grama to mesquite cover was affected by range site. The relationship of Lehmann lovegrass to mesquite cover became less averse with increasing elevation and as its density increased. These results contradict suggestions that Lehmann lovegrass is associated with declines in native grasses.

This study was conducted to determine if suburban development adjacent to Saguaro National Monument (SNM) affected coyote (Canis latrans) populations. I estimated density, described grouping behaviors, and analyzed the diets of coyotes living near the interface of SNM and Tucson, Arizona from November 1991 to December 1992. I used a mark-resighting method to estimate the density of coyotes in a 13 km² area. Seven territorial groups (n = 48 coyotes) lived in the 13 km² area. Group size varied among behavioral seasons. I compared diets of coyotes between 2 areas: suburban and rural. Coyote scats from the suburban area contained less (P < 0.05) plant material annually, and less mammal material during coyote breeding and gestation periods than the scats from the rural area. Dog food, bread, and other human related items comprised 35% of the coyotes' annual diets in the suburban area. Supplemental sources of food in the suburban area helped support high densities of coyotes.

Brown and rainbow trout perennially dominated Bright Angel Creek; native species (flannelmouth and bluehead suckers) generally occurred only during spawning (March and April-May, respectively) and initial rearing of juveniles (bluehead sucker only). Flannelmouth suckers spawned at depths between 20-40 cm, currents between 0.4-0.8 m/sec, and over loosely compacted substrates (gravel, rock). Speckled dace abundance had markedly decreased since previous investigations, possibly due to brown trout becoming the dominant predator in the stream. Four native and 6 non-native species were taken in Kanab Creek; spawning was documented for bluehead sucker and speckled dace. Small bluehead suckers (160 mm) were perennial residents below a barrier 6.2 km above the mouth. Larger individuals (>200 mm) were absent in winter, but spawned in the lower 3.2 km of the stream in April and early May. Bluehead suckers spawned in shallow waters (25 cm), slow currents (0.25 m/sec), and over loosely compacted substrates (pebble, gravel).

Reproductive success and survival of birds often are impractical to measure. Therefore, biologists frequently rely on measures of bird abundance alone to evaluate habitat quality for breeding birds. I examined whether results from standard survey techniques for birds during the breeding season reflected number of nesting pairs and reproductive success of 5 passerine species. Abundance of 3 species was positively associated with number of nesting pairs, but the relationship between abundance and reproductive success varied among these species. Differences in detectability of breeding males may partly explain why abundance and number of nesting pairs were related in some species and not in others. Variations in the availability and quality of habitat patches among plots could produce the different relationships I observed between abundance and reproductive success. My results suggest that measures of reproductive success as well as abundance should be used to determine habitat quality for breeding birds.

The stability of lower treeline in the southwestern United States has been the subject of recent debate. An understanding of seed predation and dispersal is required to evaluate these predictions. Experimental plots were established along the oak woodland/semi-desert grassland boundary to investigate seed predation and dispersal of emory oak, a common lower treeline species. An aviary experiment investigated acorn selection by grey-breasted jays, important emory oak seed dispersers. I found sufficient acorn dispersal for emory oak recruitment in adjacent grassland, and that seed predation does not limit oak recruitment in adjacent grasslands; in fact, acorns dispersed into adjacent grasslands are more likely to escape predation. I determined that grey-breasted jays select and cache acorns in a manner favorable to oak recruitment. Taken collectively, these studies and other research into emory oak life history stages illustrate mechanisms by which rapid downslope shifts in lower treeline can occur.

Pima pineapple cactus (Coryphantha scheeri var. robustispina) (PPC) is listed as endangered by the US Fish and Wildlife Service. This taxon occurs south of Tucson, Arizona and Sonora, Mexico. Knowledge of this plant's distribution, growth, and reproduction is important for management. Research has documented reduced plant vigor and lack of reproduction within Lehmann lovegrass stands. PPC density and seedling presence were described at five sites in two different vegetation types. Field observations of 72 plants at five sites were monitored from fall 1993 through summer of 95 and shadehouse studies were conducted. This research resulted in five conclusions: (1) fire-induced mortality of PPC may be related to Lehmann lovegrass, (2) PPC grows vegetatively in the spring, (3) flower buds are initiated in May and open after a few summer rains, (4) seed germination follows several summer rains, and (5) cross-pollination produces significantly more PPC seeds than self-pollination.

Ecologists suspect that owls select specific areas based on prey availability. My objective was to determine and compare distributions and abundances of Mexican spotted owl prey species' within different vegetation types in the canyons and mesas of the Manti-LaSal National Forest in Utah. I conducted live-trapping during summer and fall, 1994-95. Woodrat species (Neotoma spp.) are the Mexican spotted owls primary prey species as determined by percent biomass. Peromyscus spp. are also important in terms of frequency. Woodrats were only captured in the canyons and were primarily captured within the pinyon (Pinus spp.) - juniper (Juniperus spp.) vegetation type. The Mexican spotted owls in southeastern Utah spend >75% of their time within the canyons and forage within pinyon-juniper stands in the canyons. Maintaining the present state of pinyon-juniper stands within the canyons may benefit Mexican spotted owl populations in the Manti-LaSal National Forest.

"Incorporation of the Principles of Nature in Architecture; Sun, Shade and Temperature Control in the Sonoran Desert" is a study of the adaptations of selected plants and animals to the unique climatic features of the desert environment. The lessons learned from this study are abstracted from the natural setting and presented in a systematic way to illustrate the incorporation of their adaptive principles into architecture. Living organisms continuously adapt to the changes of their environment and contribute a regenerative cycle of natural processes. Biotechnology adds important issues to the design process, including economy of resources, protection and thermal regulation in harmony with the fluctuations of the natural environment. The interaction of interior and exterior architectural space is a benefit, not a constraint, for the environment and its inhabitants. This biotechnological method can become a viable part of the traditional architectural design process.