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101.
全球变暖和人类居住地地域性变化的影响:鸟类越冬分布的转移 总被引:1,自引:0,他引:1
Ivan Valiela Jennifer L. Bowen 《Ambio-人类环境杂志》2003,32(7):476-480
20世纪末,在美国马萨诸塞州的科德角,由于全球变暖的加剧,鸟类越冬出现了向北迁移的现象,这种北移与全球气温异常和当地冬季最低气温上升是分不开的.这一现象以及最近的其它研究结果都表明:最近的20年期间,全球变暖已造成规模大、范围广的生物地理意义上的变化,并对地球生态系统和人类构成了潜在的威胁.由于城市扩展引起的地方生境的变化主要对栖息地偏北的森林鸟类产生影响.在科德角,当地居民居住地扩大对鸟类栖息地分布的影响,在21世纪初,尚不及温室效应的影响大,但是,如果城市继续扩大,也许其影响会不亚干全球变暖. 相似文献
102.
James F. A. Traniello Marty S. Fujita Rhys V. Bowen 《Behavioral ecology and sociobiology》1984,15(1):65-68
Summary When prey of two sizes (6 and 32 mg) were offered in a choice situation to foragers of the ant Formica schaufussi at different ambient temperatures, significantly more workers rejected the smaller prey at low temperatures, whereas at high temperatures workers accepted the less profitable smaller item. Foragers scavenge for arthropod prey over a temperature range of 15–40°C, and increasing temperature significantly increases a forager's oxygen consumption, an index of energy expenditure. 相似文献
103.
Insular Endemic Plants Lack Defenses Against Herbivores 总被引:3,自引:0,他引:3
104.
Nitrogen sources to watersheds and estuaries: role of land cover mosaics and losses within watersheds 总被引:4,自引:0,他引:4
Across most of the World's coastal zone there has been a geographic transition from naturally vegetated to human-altered land covers, both agricultural and urban. This transition has increased the nitrogen loads to coastal watersheds, and from watersheds to receiving estuaries. We modeled the nitrogen entering the watershed of Waquoit Bay, Massachusetts, and found that as the transition took place, nitrogen loads to watersheds increased from 1938 to 1990. The relative magnitude of the contribution by wastewater, fertilizers, and atmospheric deposition depends on the land cover mosaics of a watershed. Atmospheric deposition was the major input to the watershed surface during this period, but because of different rates of loss within the watershed. wastewater became the major source of nitrogen flowing from the watershed to the receiving estuaries. Atmospheric deposition prevails in watersheds dominated by natural vegetation such as forests, but wastewater may become a dominant source in watersheds where urbanization increases. Increased nitrogen loads resulting from conversion of natural to human-altered watershed surfaces create eutrophication of receiving waters, with attendant changes in water quality, and marked shifts in the flora and food webs of the affected estuaries. Management efforts for restoration of eutrophied estuaries require maintenance of forested land, and control of wastewater and fertilizer inputs, the major terms in most affected places subject to local management. Wastewater and fertilizer nitrogen derive from within the watershed, which means local measures may effectively be used to control eutrophication of receiving waters. 相似文献
105.
J. W. Jones H. D. Bowen J. R. Bradley Jr R. E. Stinner R. S. Sowell 《Ecological modelling》1975,1(4):289-302
A model is presented for predicting boll weevil, Anthonomus grandis Boheman, feeding damage to cotton. The model uses appropriate probability theory based on behavioral components of male and nonreproducing female boll weevils and includes the effects of (1) differential feeding site preferences, (2) previous damage to the sites, and (3) individual insect behavior extended to feeding damage caused by a population of insects. The model is sensitive to both crop and insect parameters. An example of how this model can be used in an insect-crop ecosystem simulation is offered. 相似文献
106.
Based on the available toxicity data and the concentrations of DDTs and HCHs in surface water from the upper reaches of the Huaihe River, overlapping areas of probability density and margin of safety (MOS10) were used to estimate the risk levels of DDTs and HCHs to aquatic organisms. The overlapping areas of α-HCH, γ-HCH, p,p′-DDE, p,p′-DDD, and p,p′-DDT were found to be 9.3 × 10?5, 4.6 × 10?3, 4.3 × 10?2, 2.2 × 10?2, and 4.2 × 10?2, respectively. The risks from DDTs were higher than those from HCHs, the risk from α-HCH being the smallest. The MOS10 values of α-HCH, γ-HCH, p,p′-DDE, p,p′-DDD, and p,p′-DDT were 2.6 × 103, 97, 5.9, 15, and 8.6, respectively, i.e. greater than 1.0, indicating limited overlaps between the distributions of exposure concentrations and of toxicity data, and thus minimal ecological risk. Health risk calculations based on incremental lifetime risks for HCHs and DDTs were conducted to evaluate human cancer risk and non-carcinogenic hazard. The total cancer risks from organochlorine pesticides (OCPs) in the studied area were in the range of 10?8–10?7, lower than the baseline value of acceptable risk (10?6). Non-carcinogenic hazard indices of OCPs ranging from 10?6 to 10?5 were much lower than the threshold values (1.0). These results suggest that the water from the upper reaches of the Huaihe River does not pose any health risk for local residents using river water as a source for drinking water. 相似文献
107.
S. E. Encalada K. A. Bjorndal A. B. Bolten J. C. Zurita B. Schroeder E. Possardt C. J. Sears B. W. Bowen 《Marine Biology》1998,130(4):567-575
Mitochondrial (mt) DNA control region sequences were analyzed for 249 Atlantic and Mediterranean loggerhead turtles (Carettacaretta Linnaeus, 1758) to elucidate nesting population structure and phylogeographic patterns. Ten haplotypes were resolved among
individuals sampled between 1987 and 1993, from ten major loggerhead nesting areas in the region. Two distinct phylogenetic
lineages were distinguished, separated by an average of 5.1% sequence divergence. Haplotype frequency comparisons between
pairs of populations showed significant differentiation between most regional nesting aggregates and revealed six demographically
independent groups, corresponding to nesting beaches from: (1) North Carolina, South Carolina, Georgia and northeast Florida,
USA; (2) southern Florida, USA; (3) northwest Florida, USA; (4) Quintana Roo, Mexico; (5) Bahia, Brazil; and (6) Peloponnesus
Island, Greece. The distribution of mtDNA haplotypes is consistent with a natal homing scenario, in which nesting colonies
separated by a few hundred kilometers represent isolated reproductive aggregates. However, a strong exception to this pattern
was observed in the first group defined by mtDNA data (North Carolina to northeast Florida), which included samples from four
nesting locations spread across thousands of kilometers of coastline. These locations were characterized by a single haplotype
in 104 out of 105 samples, providing inadequate resolution of population divisions. In view of the subdivisions observed elsewhere,
we attribute the lack of differentiation between North Carolina and northeast Florida to recent colonization of these warm
temperate coastlines (after the Wisconsin glaciation) not to ongoing gene flow among spatially distinct nesting locations.
The relationships among observed haplotypes suggest a biogeographic scenario defined by climate, natal homing, and rare dispersal
events. The redefined relationships among nesting aggregations in the western Atlantic region (southeastern USA and adjacent
Mexico) prompt a reconsideration of management strategies for nesting populations and corresponding habitats in this region.
Received: 28 October 1996 / Accepted: 24 October 1997 相似文献
108.
Ben L. O’Connor Yuki Hamada Esther E. Bowen Mark A. Grippo Heidi M. Hartmann Terri L. Patton Robert A. Van Lonkhuyzen Adrianne E. Carr 《Environmental monitoring and assessment》2014,186(11):7075-7095
Large areas of public lands administered by the Bureau of Land Management and located in arid regions of the southwestern United States are being considered for the development of utility-scale solar energy facilities. Land-disturbing activities in these desert, alluvium-filled valleys have the potential to adversely affect the hydrologic and ecologic functions of ephemeral streams. Regulation and management of ephemeral streams typically falls under a spectrum of federal, state, and local programs, but scientifically based guidelines for protecting ephemeral streams with respect to land-development activities are largely nonexistent. This study developed an assessment approach for quantifying the sensitivity to land disturbance of ephemeral stream reaches located in proposed solar energy zones (SEZs). The ephemeral stream assessment approach used publicly-available geospatial data on hydrology, topography, surficial geology, and soil characteristics, as well as high-resolution aerial imagery. These datasets were used to inform a professional judgment-based score index of potential land disturbance impacts on selected critical functions of ephemeral streams, including flow and sediment conveyance, ecological habitat value, and groundwater recharge. The total sensitivity scores (sum of scores for the critical stream functions of flow and sediment conveyance, ecological habitats, and groundwater recharge) were used to identify highly sensitive stream reaches to inform decisions on developable areas in SEZs. Total sensitivity scores typically reflected the scores of the individual stream functions; some exceptions pertain to groundwater recharge and ecological habitats. The primary limitations of this assessment approach were the lack of high-resolution identification of ephemeral stream channels in the existing National Hydrography Dataset, and the lack of mechanistic processes describing potential impacts on ephemeral stream functions at the watershed scale. The primary strength of this assessment approach is that it allows watershed-scale planning for low-impact development in arid ecosystems; the qualitative scoring of potential impacts can also be adjusted to accommodate new geospatial data, and to allow for expert and stakeholder input into decisions regarding the identification and potential avoidance of highly sensitive stream reaches. 相似文献
109.
为了提高Fe2+活化过硫酸盐(PS)过程中Fe2+的利用效率,降低其对自由基的淬灭作用.制备了聚多巴胺复合聚丙烯非织造布(PDA-PP),考察了PDA-PP材料应用于Fe2+/PS体系中,对酸性红B(ARB)的氧化降解性能和机理.结果表明:PDA-PP/Fe2+/PS体系能够更持续地活化PS氧化降解ARB.一方面聚多巴胺中酚羟基使Fe3+还原为Fe2+,保持对PS分解的持续性,另一方面聚多巴胺中的邻苯二酚和氨基对Fe2+的络合作用控制了Fe2+的释放速率,降低了Fe2+对自由基的淬灭.自由基淬灭实验与ESR分析结果表明,羟基自由基(·OH)是PDA-PP/Fe2+/PS体系的主要活性物种.(SO4·-)的产生量少于·OH.研究显示,PDA-PP的加入能有效提高Fe2+/PS体系中Fe2+ 相似文献