Headwater streams in forested landscapes are generally lacking in primary productivity and rely on allochthonous inputs to fuel secondary production. This close association with the forested landscape makes these streams sensitive to terrestrial disturbances. In the Greater Yellowstone Ecosystem (GYE) a climate change induced mountain pine beetle (Dendroctonus ponderosae, MPB) outbreak has been decimating whitebark pine (Picea albicaulis, WbP) forests over an extremely short time period. Among the possible implications of widespread WbP die-off, I predicted an increase in litter inputs to headwater streams and an increase in the quality (nitrogen content) of these litter inputs both of which would alter rates of organic matter processing and invertebrate communities in headwater streams. To test these predictions I quantified the mode of transport and rate of litter inputs to headwater streams in the GYE within ten streams distributed between two basins of differing levels WbP mortality and surveyed benthic invertebrate populations within those streams to determine whether MPB-mediated WbP mortality had an effect on detritivore communities. In addition, I carried out an experiment to compare differences in decomposition between needles from healthy WbP and those killed by MPB in a single stream within the high-mortality basin. Inputs of WbP needles were higher to streams in the basin with greater WbP mortality and these inputs were primarily entering streams via vertical transport. However, despite the increased quantity of inputs into these streams I found that invertebrate densities declined as WbP mortality increased. Furthermore, I discovered that naturally senescent needles from healthy trees decomposed faster than needles from MPB-killed trees despite higher nutrient levels in the MPB-altered needles. Although MPB attack does result in WbP litter with higher C:N than that which is associated with healthy trees, these needles may also contain elevated levels of defense compounds with insecticidal and anti-fungal properties. Further research is needed to determine whether possible MPB-induced increases in monoterpene concentrations affect needle decomposition. However, my results indicate that MPB infestations slow rates of nutrient processing in headwater streams despite an increase in litter quantity and quality.

Thesis (Ph.D.)--North Carolina State University, 2006. / (UnM)AAI3223123. Advisers: Ronald Sederoff; Thomas Wentworth. Source: Dissertation Abstracts International, Volume: 67-06, Section: B, page: 2912.

Thesis (Ph.D.)--University of Massachusetts Amherst, 2005. / (UnM)AAI3193944. Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 5853. Director: Todd K. Fuller.

Thesis (Ph.D.)--University of California, Berkeley, 2003. / (UnM)AAI3206946. Adviser: Wayne M. Getz. Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0060.

Thesis (Ph.D.)--University of Hawai'i at Manoa, 2006. / (UnM)AAI3216089. Adviser: Will McClatchey. Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2310.

Parsons (1953) found Utah's posted hunting unit system regulated hunting pressures over much of the state's pheasant range. He found inequalities of hunting, pressure among the posted hunting units because of their individualistic methods used to determine the number of hunting permits to be sold. Utah State Department of Fish and Game personnel recommend the number of permits to be sold by the hunting unit; but often, the hunting unit officers use the desired level of hunting pressure, size of cock harvest, and revenue from permit sales as decisive factors. By regulating hunting pressure on their own lands, the posted hunting units thereby regulate the hunting pressure on adjacent nonposted lands by excluding the supernumerary hunters from their units.

Coloniality and nest defence were examined in black brant <i>Branta bernicla nigricans</i> and lesser snow geese Chen caerulescens caerulescens. Increased nest density had no effect on nest survival, egg survival, or likelihood of partial clutch predation in snow geese. In brant, nest survival declined as nest density increased in 1992 and with increased distance from shore in 1993. Brant with conspecific nearest neighbours were less likely to suffer partial clutch predation in 1993, but not in 1992. Egg survival in brant increased with nest density in 1993, but decreased as density increased in 1992, however, the decrease occurred only in nests with three or four eggs. Nesting at high densities, in central positions, or far from shorelines commonly travelled by glaucous gulls <i>Larurs hyperboreus</i> and parasitic jaegers <i>Stercorarius parasiticus</i>, the primary egg predators in this study, did not provide geese with a nest or egg survival advantage because effects were lacking in snow geese and were inconsistent and contradictory in brant. Female snow geese had very high nest attendance and both sexes had high territory attendance so snow goose nests were rarely unattended during incubation. Brant had lower nest attendance than snow geese, and due to a lack food near their nests, brant left their territories to feed resulting in lower territory attendance as well. Although male brant were capable of defending the nest from avian predators and usually remained on their territories when females were absent, males were less effective defenders than incubating females. Increased vigilance and decreased resting by female brant as incubation progressed provided support for the prediction, from parental investment theory, that nest guarding effort would increase with offspring age, but there were no changes in male brant or in snow geese. However, declining nest and territory attendance by female brant and males of both species contradicted predictions from parental investment theory but were consistent with an increased need to forage as nutrient reserves declined through incubation as expected due to energetic constraints.

The demography of ovenbirds (<i>Seiurus aurocapillus</i>) was compared in landscapes highly fragmented by agriculture, moderately fragmented by commercial harvesting, and in contiguous boreal forest of Saskatchewan. Various survey techniques demonstrated that ovenbirds were less common in small, isolated forest patches in fragmented landscapes relative to contiguous forest. Male ovenbirds in fragmented landscapes (84 to 87% paired) had a lower probability of attracting females relative to males in contiguous forest (97%). Competition for territories was intense, as removal experiments demonstrated the presence of non-territorial male floaters. However, floaters were more common in contiguous forest, indicating this habitat was most preferred. Nesting success was lower in small farm fragments (29%) than the other landscapes (43 to 58%), due to high nest predation. Apparent annual survival of males was lower in small farm fragments (30%) relative to the other landscapes (57 to 60%). The difference in adult survival among landscapes was not caused by increased mortality in small farm fragments, but likely occurred because failed breeders (20% annual return rate) dispersed more than successful breeders (50%). Overall, small farm fragments were population sinks, where the number of adult birds lost to mortality and emigration exceeded the number of young produced. However, population size was constant over the length of the study indicating that populations in small farm fragments were rescued from extinction by immigration of birds from contiguous forest, where excess juveniles were produced. Populations in farm fragments were more likely to be rescued from local extinction by first time breeders (95% first time breeders) than the other landscapes (65 to 75%). <p>Increased turnover in small farm fragments, also resulted in a greater proportion of first time breeders (60%) in small farm fragments than the other landscapes (44 to 46%). These results support the idea that forest songbirds select habitat in a ideal preemptive manner. Younger individuals seem to be forced to settle in low-quality farm fragments, due to competition from older birds in the more optimal contiguous forest. Forest fragmentation bad a negative impact on ovenbirds and likely is an important factor influencing the decline of this and other Neotropical migrant species.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: A, page: 2700. Adviser: Bruce M. Hannon. Includes bibliographical references (leaves 167-184) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 0869. Adviser: Uriel D. Kitron. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.