Thesis (M.S.)--Oregon State University, 1992. / Typescript (photocopy). Includes bibliographical references (leaves 42-46). Also available on the World Wide Web.

My study was designed to answer two main questions: 1. ) Do the bees, through their foraging behavior, alter the rates of salmonberry nectar productivity? 2. ) Do the plants, through their rates of nectar secretion, alter the foraging behavior of the bees? Since there are well-documented examples of morphological coadaptations between plants and their pollinators, it was reasonable to suppose that physiological/behavioral coadaptations exist as well. Thus I hypothesized that the above questions would be answered in the affirmative. Though the two questions have been individually studied by several biologists, I felt it important to examine the possible reciprocal responses of plants and pollinators as they occur in a natural community context. Nectar productivity of salmonberry flowers (Rubus spectabilis, Pursh) was investigated using flowers isolated for various lengths of time from insect visitors. Nectar volumes were extracted using micropipettes and sugar concentrations were determined with a hand refractometer. Volumes and sugar concentrations were then used to calculate calories/hour. Nectar standing crop (calories/flower) was similarly derived using untagged flowers. During the study I monitored temperature, sunshine levels, relative humidity, date of sampling, time of sampling, and the androecium diameters of all flowers sampled. It was found that an increase in experimental extraction rate brought about a corresponding decrease in productivity. This result is opposite to that reported by other authors, yet it was found that this result was not due to flower damage or to artificial fertilization of flowers. This flower response to simulated visitation frequency may be of competitive advantage to flowers not being used by pollinators present in the area, Productivity and nectar standing crop decreased as the salmonberry flowering season progressed, and decreased throughout the course of each day as relative humidity fell and air temperatures increased. This decline in productivity reflected decreases in volumes of nectar secreted, though sugar concentrations increased with increasing sunshine levels. Younger flowers apparently secreted calories/hour at higher rates than older flowers, this again reflecting trends in volumes of nectar secreted. In each sample of ten flowers, there were four which secreted at rates significantly higher than the remaining six. Further, the four most productive flowers secreted at more predictable rates in trends of the environmental variables monitored during the study. Throughout the season there was a dramatic increase of .bumblebees (Bombus sitkensis, Nylander) observed at patches of salmonberry flowers. Throughout each day, the bees increased in density as sunshine levels and temperatures increased and relative humidity fell. The bees foraged from the more productive younger flowers more frequently than older flowers, and increasingly foraged from older flowers as nectar abundance in all flowers declined through the day and season. In addition, they may also have been avoiding increasing numbers of flowers they approached, though this conclusion must remain tentative. Bumblebee behavior was more predictable during the early morning hours of each day as opposed to hours in the afternoon. It is postulated that, this was because bumblebees experience more uniform energy conditions in the morning. Based on the distribution curves of nectar resources and bee density, it is postulated that plants compete for pollinators early in the day and early in the season, while bees compete for nectar later in the day and later in the season. This hypothesis is further supported by observations on the shifts in bee foraging behaviors. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 100-106). Also available on the World Wide Web.

One serious problem faced by the forest industry in the Pacific Northwest is poor regeneration of commercial trees on land which is harvested and subsequently dominated by brush species. In Coastal Oregon, salmonberry is one of these brush species. Detailed investigations of field sites indicate that light intensity in the brush stands was low but sufficient for germination and early growth of Douglas-fir seedlings and soil moisture percentages and nutrient levels were high enough to support early Douglas-fir growth. Laboratory tests demonstrated the presence of leachable phytotoxins in the leaves of salmonberry. The hypothesis resulting from this study is that salmonberry releases a phytotoxin that in synergism with environmental stresses (i.e., light), suppresses germination and growth of Douglas-fir seedlings in the field.

This thesis is a case study using paleoethnobotanical analysis of Kilgii Gwaay, a 10,700-year-old wet site in southern Haida Gwaii to explore the use of plants by ancestral Haida. The research investigated questions of early Holocene wood artifact technologies and other plant use before the large-scale arrival of western redcedar (Thuja plicata), a cultural keystone species for Haida in more recent times. The project relied on small-scale excavations and sampling from two main areas of the site: a hearth complex and an activity area at the edge of a paleopond. The archaeobotanical assemblage from these two areas yielded 23 plant taxa representing 14 families in the form of wood, charcoal, seeds, and additional plant macrofossils. A salmonberry and elderberry processing area suggests a seasonal summer occupation. Hemlock wedges and split spruce wood and roots show evidence for wood-splitting technology. The assemblage demonstrates potential for site interpretation based on archaeobotanical remains for the Northwest Coast of North America and highlights the importance of these otherwise relatively unknown plant resources from this early time period. / Graduate / cohenjenny2@gmail.com