In most temperate coniferous forests, the vast majority of vascular plant species richness can be found in the understory layer. While the large-scale conversion of forests to plantations has made it increasingly important to understand how understory . . .

Russian Peak, at an elevation of 8200 feet, is situ­ated in the Salmon Mountains, a north-south trending range centrally located within the Klamath Region of northwest­ern California. The Salmon Mountains are drained by the Scott River on the east and . . .

Harbor seals have been listed as a species likely to benefit from new Marine Protected Areas (MPAs) in California as part of the Marine Life Protection Act. Whereas seals may experience direct and indirect effects from these MPAs as a whole, the impac . . .

Five species of western gooseberries (Ribes: Grossulariaceae) hybridize to varying degrees in northwestern California and southwestern Oregon. Pollinator surveys and hand-pollination experiments were conducted to identify reproductive barriers between . . .

Disturbances such as wildfire play a major role in the diversity, structure, and composition of plant communities, however, little is known about the differential impacts of fire across landscapes that vary in characteristics such as soil nutrients an . . .

Spotted fever group (SFG) rickettsiae have been shown to cause many human and animal diseases. SRG rickettsial phylotypes G021 and G022 were recently detected in Ixodes pacificus ticks from Napa and California using quantitative real time polymerase c . . .

The dominant plant in Humboldt Bay salt marshes is Spartina densiflora, a species of cordgrass apparently introduced from South America. At several salt marshes and restoration sites around Humboldt Bay, distribution of this plant has increased signif . . .

Numerous studies have analyzed the effect of habitat fragmentation on plant pollinators and herbivores. These studies describe the decrease in pollinator services and seed set in small and isolated patches due to pollinator preference for large, conti . . .

The genus Ribes displays extensive floral diversity. The pollinator shift model suggests that such diversity is an outcome of species shifting to specialize on new pollinators. To test this model, I surveyed the flower visitors of 14 Ribes species at . . .

For over a century, increases in the abundance of woody plant species in savannas have been occurring worldwide, and this woody plant encroachment directly threatens the existence of savanna ecosystems. Savannas are known for their striking compositio . . .

The disease chytridiomycosis has caused population declines in hundreds of amphibian species worldwide, and is caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). One promising method to combat the disease is to augment the amphibian’ . . .

Studying the impacts on a community following the introduction of an exotic species is of increasing importance in the field of marine science. Recent investigations of marine biological invasion have primarily focused on studying the negative interac . . .

Humboldt Bay, in far northern California receives a large amount of sediment, predominantly silts and clays from the surrounding watersheds at an estimated 62,532 metric tons/yr. (Barrett 2004). Fine grained sediments such as silts and clays have a hi . . .

Populations of flying squirrels occupying oak and oak-pine forests of the Mesoamerican highlands represent the least studied and most poorly known members of the genus Glaucomys. Traditionally, these Mesoamerican populations have been considered to be . . .

Increased suspended sediment inputs to streams as a result of human activities and disturbance have been identified as a principle source of stream impairment. Allochthonous energy inputs to riverine food webs, in the form of terrestrial leaf litter, . . .

The Great Gray Owl (Strix nebulosa) is listed as a State of California endangered species due to their low population of approximately 100 individuals. Annual surveys and long-term monitoring efforts are frequently conducted to determine the status of . . .

Genetic structure and diversity of populations can impact the productivity and resilience of ecosystems. In Humboldt Bay, California (USA) eelgrass (Zostera marina) is the dominant marine plant at low intertidal and shallow subtidal elevations where i . . .

Napa County is located within a global biodiversity hotspot, and is one of ten localized areas in California that contain the highest numbers of native and endemic plant species. Conservation of rare taxa is an important issue and the research present . . .

Bat migration ecology is an important, yet understudied facet of natural history and conservation. We know little about the movement patterns of migrating bats and the physiological demands that bats experience in preparation for and during migration. . . .

The southern distribution of the northern red-legged frog (Rana aurora) extends only into the three most northern coastal counties of California and seems to be restricted to the coastal belt. Because of recent declines in the population and destructi . . .

In forests native pathogens accelerate tree decline, increase stand structural heterogeneity, and alter tree community composition. In northern California, white fir (Abies concolor var. lowiana) and Douglas-fir (Pseudotsuga menziesii var. menziesii) . . .

Riffle sections of eight streams in northern California were sampled for aquatic insects using a kick net. Eleven chemical and physical stream parameters were measured at each riffle sampled. Biological data was analyzed using Simpsons diversity index . . .

The North East Pacific coastline is a diversity hotspot for many marine organisms, including seaweeds, which live in complex habitats influenced by tectonics, glaciation, and ocean circulation. This is the first study to thoroughly survey population g . . .

Over the past several years, ecologists have begun to recognize that the role played by positive plant-plant interactions, specifically facilitation, in communities is under appreciated. Despite this recognition, little is known about how these positi . . .

As populations of a species decline, an understanding of habitat use and regional variation in population health can aid in focusing conservation efforts. Western Pond Turtle (Actinemys marmorata) populations have declined throughout much of their ran . . .

Point count and species-specific surveys are widely used to infer avian abundance and species richness. However, advancements in bioacoustic technology enable automated survey alternatives that can expand the landscape coverage with equivalent personn . . .

Although many studies have investigated the effect of invasive plants on native plant species, few studies have considered their effect on pollination success. Since invasive plants potentially compete with native plants for pollinator services, the f . . .

Forest stands occurring on coastal dunes along the western margin of Humboldt Bay, California are isolated fragments of a regional forest type that stretches discontinuously along the Pacific Coast from northern California to Alaska. I used aerial pho . . .

Marine fouling communities contain a plethora of sessile colonial invertebrates. These invertebrates come in many different shapes which occupy space and compete for resources in different ways. It has been theorized that these organisms be placed int . . .

Ultramafic parent materials in northern California and southwestern Oregon have given rise to one of the largest serpentine regions in the world. This area is dominated by sparse, fire-prone coniferous forests and shrublands which are apparently highl . . .

Due to the many misconceptions about science and the general lack of scientific literacy in our society, there is a need to better distribute accurate, comprehensible scientific ideas in an engaging way. Science education films can be powerful tools i . . .

The Oregon spotted frog (Rana pretiosa), endemic to the Pacific Northwest, was once considered widespread in complex, warm water wetlands. Over 70% of historic populations are thought to be extirpated with range-wide habitat loss exceeding 90%. Using . . .

Bees (Hymenoptera) represent one of the primary pollinators in most natural and managed ecosystems world-wide. Current concerns for a global decline in bee populations emphasize the need to better understand the factors that shape bee communities. Alt . . .

Understanding the effects of biotic and abiotic pressures on commercially important marine species is crucial to their successful management. The red abalone (Haliotis rufescensis) is a commercially important mollusc, whose shell surface is frequently . . .

This work is a taxonomic study of nine species in the ectomycorrhizal fungal family Boletaceae (Basidiomycota) from Neotropical rainforests of Guyana, in northeastern South America. Morphospecies collections from the following genera were studied: Tyl . . .

Diaulula sandiegensis (Cooper, 1862), a northern Pacific nudibranch, has considerable phenotypic variation in dorsal spotting pattern throughout its range. Experiments were conducted to test the possibility that D. sandiegensis is a complex of unrecog . . .

Spotted Fever Group (SFG) Rickettsiae are important zoonoses affecting both people and dogs. Rocky Mountain spotted fever (RMSF) caused by Rickettsia rickettsii, is the most well-known zoonotic SFG; historically in California cases were identified fro . . .

Predictions of low genetic variation and low levels of inbreeding depression in small plant populations were tested on Astragalus agnicidus, a species with only one known population. Loss of alleles through drift and increased inbreeding (followed by . . .

In 1992 the rapidly developing demand for taxol led to consideration of a possible Pacific yew harvest in northwestern California. Deer browsing has prevented regeneration of Canada yew in some areas. Knowing that deer populations have been high in th . . .

Desert water courses are topographically distinct features with periodic flooding, which are floristically rich and structurally complex. This study was undertaken to determine if plant species and vegetation types change along desert water courses as . . .

Nearly all animals are able to detect forms of chemical stimuli. In amphibians, chemoreceptive capabilities are used in a wide variety of contexts, including the detection of predators, conspecifics, and food. The focus of this project was the use of . . .

Boiling Springs Lake is a pristine, oligotrophic, acidic hot spring in Lassen Volcanic National Park. In 2008, 25 isolates from BSL were tested for resistance to 14 different antimicrobial compounds or a sub-set of the 14 antimicrobial agents. All iso . . .

Eight species of the ectomycorrhizal (ECM) genus Sarcodon (Bankeraceae, Thelephorales, Basidiomycota) are described as new to science. Sarcodon quercophilus, and Sarcodon umbilicatus are described from Quercus (Fagaceae) cloud forests within the Maya . . .

Habitat fragmentation can have negative effects throughout an ecosystem, but its impact is dependent on the spatial scale at which community members respond to the environment. Because solitary bees are central-place foragers, their access to floral r . . .

Oct4 is a POU class V transcription factor that functions to maintain the pluripotent state of embryonic stem cells by activating or repressing the transcription of hundreds of target genes (Boyer et al. 2005). Aberrant expression of Oct4 has been rep . . .

Determining the factors that shape arthropod communities has a long history in ecology. I examined the direct and indirect effects of nitrogen availability on plant productivity and plant community composition to assess their effects on arthropod comm . . .

Many turtle species require aquatic and terrestrial habitats during different times in their life history for foraging, mating, nesting, estivation and overwintering. The status of many turtle populations depends directly on the condition of both envi . . .