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851.
852.
Douglas F. Bertram 《Conservation biology》1995,9(4):865-872
I examined the decline of Ancient Murrelets ( Synthliboramphus antiquus ), a small, burrow-nesting seabird, at Langara Island. The island's seabird colony was historically one of the largest colonies of Ancient Murrelets in British Columbia—perhaps in the world—with an estimated 200,000 nesting pairs. I reviewed historical information and compared the results of surveys from 1981 and 1988 that employed the same census protocol. The extent of the colony, a potential index of population size, declined from 101 ha in 1981 to 48 ha in 1988. Burrow density increased during the same period, however, suggesting that the colony bad consolidated. In 1988, the population estimate was 24,200 ± 4000 (S.E.) breeding pairs compared to 22,000 ± 3700 in 1981. in 1988, 29% of the burrows that were completely searched contained bones of Ancient Murrelets. Bones were most common in burrows located in abandoned areas of the colony and were least common where burrow occupancy was high. The discovery of adult Ancient Murrelets killed in their burrows by introduced rats, combined with the high proportion of burrows with bones, suggests that rats ( Rattus rattus and R. norvegicus ) have contributed significantly to the decline of the population. In addition, the presence and activities of a salmon-fishing fleet in the 1950s and 1960s may also be linked to the decline of the Langara Ancient Murrelet population during that period because these fisheries are known to have caused heavy mortality through fatal light attraction and drowning in gill nets. The combined effects of ongoing predation by introduced rats and—to a lesser extent—previous, episodic fishery-induced mortality are probable causes for the population decline. 相似文献
853.
ABSTRACT: At a time when productive water resources research is essential to protecting the quality of and wisely using our limited water resources, pervasive trends toward consumerism, fiscal restraint, centralized management, and using research for other social objectives threaten research productivity. The research prioritization and management structure that these trends have created was examined in the microcosm of its application at the Utah Water Research Laboratory. The result indicated that ephemeral prioritization and the failure of research users to target researchers to their own particular needs is diluting productivity. Incremental research prioritization and greater use of advisory councils in facilitating user-researcher interaction are suggested as corrective approaches, but the only firm conclusion at this point in time must be that empirical studies of the performance of alternatives in research management structure are solely needed. 相似文献
854.
Jay?K.?Goldberg Alisa?K.?Wallace Stacey?L.?WeissEmail author 《Die Naturwissenschaften》2017,104(9-10):81
Sex pheromones can perform a variety of functions ranging from revealing the location of suitable mates to being honest signals of mate quality, and they are used in the mate selection process by many species of reptile. In this study, we determined whether the skin lipids of female striped plateau lizards (Sceloporus virgatus) can predict the reproductive quality of females, thereby having the potential to serve as pheromones. Using gas chromatography/mass spectrometry, we identified 17 compounds present in skin lipids of female lizards. Using principal component analysis to compare the skin lipid profile of receptive and non-receptive females, we determined that an uncharacterized compound may allow for chemical identification of receptive mates. We also compared extracted principal components to measures of female fitness and reproductive qualities and found that the level of two 18 carbon fatty acids present in a female’s skin lipids may indicate her clutch size. Finally, we compared the information content of the skin lipids to that of female-specific color ornaments to assess whether chemical and visual cues transmit different information or not. We found that the chroma of a female’s orange throat patch is also related to her clutch size, suggesting that chemical signals may reinforce the information communicated by visual ornamentation in this species which would support the “backup signals” hypothesis for multiple signals. 相似文献
855.
Paul Kirshen Chris Watson Ellen Douglas Allen Gontz Jawon Lee Yong Tian 《Mitigation and Adaptation Strategies for Global Change》2008,13(5-6):437-451
With dense population and development along its coastline, the northeastern United States is, at present, highly vulnerable to coastal flooding. At five sea level stations in the United States, from Massachusetts to New Jersey, sea level rise (SLR) trends and tidal effects were removed from the hourly sea level time series and then frequency analysis was performed on the positive remaining anomalies that represent storm surge heights. Then using eustatic SLR estimates for lower and higher greenhouse gas emissions scenarios and assumed trends in local sea level rise, new recurrence intervals were determined for future storm surges. Under the higher emissions scenario, by 2050, the elevation of the 2005 100-year event may be equaled or exceeded at least every 30 years at all sites. In more exposed US cities such as Boston, Massachusetts and Atlantic City, New Jersey, this could occur at the considerably higher frequency of every 8 years or less. Under the lower emissions scenario, by 2050, the elevation of the 2005 100-year event may be equaled or exceeded at least every 70 years at all sites. In Boston and Atlantic City, this could occur every 30 years or less. 相似文献
856.
Baia Luana V. Luna Aderval S. Leito Juliana P. S Carvalho de Souza Wallace Figueiredo Marco A. G. Carvalho Ana P. 《Journal of Material Cycles and Waste Management》2022,24(2):606-617
Journal of Material Cycles and Waste Management - In this work, the synthesis of biochar from several biomass wastes to act as matrix for urea was investigated. The objective was to select the most... 相似文献
857.
Santana Antônio H. Araújo José A. S. Bento Amanda M. S. Santos Ana R. Santos Leocácia G. Gomes Hiago de O. da Costa José Galberto M. Menezes Jorge Marcell C. Coutinho Henrique Douglas Melo Filho Francisco José de P. Teixeira Raimundo Nonato P. 《Environmental geochemistry and health》2021,43(4):1583-1597
Environmental Geochemistry and Health - The contamination of bodies of water by potentially hazardous elements has in recent decades become an environmental problem that poses serious risks to... 相似文献
858.
Silva Wesley Douglas Oliveira Morais Danielle Costa Urtiga Marcella Maia 《Environment, Development and Sustainability》2022,24(8):10443-10469
Environment, Development and Sustainability - An integrative negotiation model is proposed so that watershed committees (WSC) can deal better with conflicts over alternatives for protecting water... 相似文献