801 resultados para Fragmented Landscape


Relevância:

20.00% 20.00%

Publicador:

Resumo:

To determine the influence of fire and thermokarst in a boreal landscape, we investigated peat cores within and adjacent to a permafrost collapse feature on the Tanana River Floodplain of Interior Alaska. Radioisotope dating, diatom assemblages, plant macrofossils, charcoal fragments, and carbon and nitrogen content of the peat profile indicate ~600 years of vegetation succession with a transition from a terrestrial forest to a sedge-dominated wetland over 100 years ago, and to a Sphagnum-dominated peatland in approximately 1970. The shift from sedge to Sphagnum, and a decrease in the detrended tree-ring width index of black spruce trees adjacent to the collapse coincided with an increase in the growing season temperature record from Fairbanks. This concurrent wetland succession and reduced growth of black spruce trees indicates a step-wise ecosystem-level response to a change in regional climate. In 2001, fire was observed coincident with permafrost collapse and resulted in lateral expansion of the peatland. These observations and the peat profile suggest that future warming and/or increased fire disturbance could promote permafrost degradation, peatland expansion, and increase carbon storage across this landscape; however, the development of drought conditions could reduce the success of both black spruce and Sphagnum, and potentially decrease the long-term ecosystem carbon storage.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Over the past 25 years, betting on sports in the United States has grown dramatically with the majority of wagers being placed in illicit markets. Only 1% of an estimated 500 billion dollar sports betting industry in the United States is done legally. With this much at stake, the incentives to alter the outcome of the games are high. Corrupt gamblers can “fix” the match by offering payments to players to “throw the game,” that is, to predetermine the outcome in exchange for a payment (match fixing). This paper addresses whether match fixing in college basketball can be detected and contained with the current policies. A mixed method design will be used to identify possible “triggers” in Nevada Casino betting line movements that might warrant an investigation of cheating in the games. If match fixing can be detected at acceptable levels of probability, then current federal prohibitive law on sports betting might no longer be appropriate. Additionally, a survey will be administered to bettors in Nevada to analyze perceptions of the game’s integrity, further eroding the logic of current law.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thesis (Master's)--University of Washington, 2016-06

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thesis (Master's)--University of Washington, 2016-06

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thesis (Ph.D.)--University of Washington, 2016-05

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thesis (Ph.D.)--University of Washington, 2016-04

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Notwithstanding the increasingly fragmented organizational relationships within Colombo's urban governance system, the cooperative nature of stakeholder relationships lends a high level of coherence to the overall system. Since 1995, Colombo's solid waste management system has been characterized by the increased role of the private sector, community-based organizations and NGOs. Whilst the increasingly fragmented nature of this system exhibits some deeply ingrained problems, there are also a number of positives associated with the increased role of civil society actors and, in particular, the informal sector. Reforming regulatory frameworks so as to integrate some of the social norms that are integral to the lives of the majority of urban residents will contribute to regulatory frameworks being considerably more enforceable than is currently the case. Such reform requires that institutional and regulatory frameworks need to be flexible enough to adapt to the changing social, political and economic context. In the Colombo case, effective cooperation between public sector and civil society stakeholders illustrates that adaptive institutional arrangements grounded in pragmatism are feasible. The challenge that arises is to translate these institutional arrangements into adaptive regulatory frameworks - something that would require a significant mind shift on the part of planners and urban managers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We conducted a demographic and genetic study to investigate the effects of fragmentation due to the establishment of an exotic softwood plantation on populations of a small marsupial carnivore, the agile antechinus (Antechinus agilis), and the factors influencing the persistence of those populations in the fragmented habitat. The first aspect of the study was a descriptive analysis of patch occupancy and population size, in which we found a patch occupancy rate of 70% among 23 sites in the fragmented habitat compared to 100% among 48 sites with the same habitat characteristics in unfragmented habitat. Mark-recapture analyses yielded most-likely population size estimates of between 3 and 85 among the 16 occupied patches in the fragmented habitat. Hierarchical partitioning and model selection were used to identify geographic and habitat-related characteristics that influence patch occupancy and population size. Patch occupancy was primarily influenced by geographic isolation and habitat quality (vegetation basal area). The variance in population size among occupied sites was influenced primarily by forest type (dominant Eucalyptus species) and, to a lesser extent, by patch area and topographic context (gully sites had larger populations). A comparison of the sex ratios between the samples from the two habitat contexts revealed a significant deficiency of males in the fragmented habitat. We hypothesise that this is due to male-biased dispersal in an environment with increased dispersal-associated mortality. The population size and sex ratio data were incorporated into a simulation study to estimate the proportion of genetic diversity that would have been lost over the known timescale since fragmentation if the patch populations had been totally isolated. The observed difference in genetic diversity (gene diversity and allelic richness at microsatellite and mitochondrial markers) between 16 fragmented and 12 unfragmented sites was extremely low and inconsistent with the isolation of the patch populations. Our results show that although the remnant habitat patches comprise approximately 2% of the study area, they can support non-isolated populations. However, the distribution of agile antechinus populations in the fragmented system is dependent on habitat quality and patch connectivity. (C) 2004 Elsevier Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The late Early to early Middle Eocene Okanagan Highlands fossil sites, spanning -1000 km north-south (northeastern Washington State, southern British Columbia) provide an opportunity to reconstruct biotic communities across a broad upland landscape during the warmest part of the Cenozoic. Plant taxa from these fossil sites are characteristic of the modern eastern North American deciduous forest zone, principally the mixed mesophytic forest, but also include extinct taxa, taxa known only from eastern Asian mesothermal forests, and a small number of taxa restricted to the present-day North American west coast coniferous biome. In this preliminary report, paleoclimates and forest types are reconstructed using collections from Republic in Washington State, USA., and Princeton, Quilchena, Falkland, McAbee, Hat Creek, Horsefly, and Driftwood Canyon in British Columbia, Canada. Both leaf margin analysis (LMA) and quantitative bioclimatic analysis of identified nearest living relatives of megaflora indicated upper microthermal to lower mesothermal moist environments (MAT -10-15 degrees C, CMMT > 0 degrees C, MAP > 100 cm/year). Some taxa common to most sites suggest cool conditions (e.g., Abies, other Pinaceae; Alnus, other Betulaceae). However, all floras contain a substantive broadleaf deciduous element (e.g., Fagaceae, Juglandaceae) and conifers (e.g., Metasequoia) with the bioclimatic analysis yielding slightly higher MAT than LMA. Thermophilic (principally mesothermal) taxa include various insects, the aquatic fern Azolla, palms, the banana relative Ensete, taxodiaceous conifers, Eucommia and Gordonia, taxa which may have occurred near their climatic limits. The mixture of thermophilic and temperate insect and plant taxa indicates low-temperature seasonality (i.e., highly equable climate).