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151.
Sonter Laura J. Gordon Ascelin Archibald Carla Simmonds Jeremy S. Ward Michelle Metzger Jean Paul Rhodes Jonathan R. Maron Martine 《Ambio》2020,49(4):892-902
Ambio - Offsetting—trading losses in one place for commensurate gains in another—is a tool used to mitigate environmental impacts of development. Biodiversity and carbon are the most... 相似文献
152.
Bao Ha Leili Zamini Jeremy Monn Samuel Njoroge Laban Thimo Maria Ondeti 《Journal of environmental science and health. Part. B》2018,53(3):161-170
Water quality assessment was conducted on the Ruiru River, a tributary of an important tropical river system in Kenya, to determine baseline river conditions for studies on the aquatic fate of N-methyl carbamate (NMC) pesticides. Measurements were taken at the end of the long rainy season in early June 2013. Concentrations of copper (0.21–1.51 ppm), nitrates (2.28–4.89 ppm) and phosphates (0.01–0.50 ppm) were detected at higher values than in uncontaminated waters, and attributed to surface runoff from agricultural activity in the surrounding area. Concentrations of dissolved oxygen (8–10 ppm), ammonia (0.02–0.22 ppm) and phenols (0.19–0.83 ppm) were found to lie within normal ranges. The Ruiru River was found to be slightly basic (pH 7.08–7.70) with a temperature of 17.8–21.2°C. The half-life values for hydrolysis of three NMC pesticides (carbofuran, carbaryl and propoxur) used in the area were measured under laboratory conditions, revealing that rates of decay were influenced by the electronic nature of the NMCs. The hydrolysis half-lives at pH 9 and 18°C decreased in the order carbofuran (57.8 h) > propoxur (38.5 h) > carbaryl (19.3 h). In general, a decrease in the electron density of the NMC aromatic ring increases the acidity of the N-bound proton removed in the rate-limiting step of the hydrolysis mechanism. Our results are consistent with this prediction, and the most electron-poor NMC (carbaryl) hydrolyzed fastest, while the most electron-rich NMC (carbofuran) hydrolyzed slowest. Results from this study should provide baseline data for future studies on NMC pesticide chemical fate in the Ruiru River and similar tropical water systems. 相似文献
153.
Sather ME Mathew J Nguyen N Lay J Golod G Vet R Cotie J Hertel T Aaboe E Callison R Adam J Keese D Freise J Hathcoat A Sakizzie B King M Lee C Oliva S San Miguel G Crow L Geasland F 《Journal of environmental monitoring : JEM》2008,10(11):1319-1325
Ambient ammonia monitoring using Ogawa passive samplers was conducted in the Four Corners area and eastern Oklahoma, USA during 2007. The resulting data will be useful in the multipollutant management of ozone, nitrogen oxides, and visibility (atmospheric regional haze) in the Four Corners area, an area with growing oil/gas production and increasing coal-based power plant construction. The passive monitoring data also add new ambient ammonia concentration information for the U.S. and will be useful to scientists involved in present and future visibility modeling exercises. Three week integrated passive ammonia samples were taken at five sites in the Four Corners area and two sites in eastern Oklahoma from December, 2006 through December, 2007 (January, 2008 for two sites). Results show significantly higher regional background ammonia concentrations in eastern Oklahoma (1.8 parts per billion (ppb) arithmetic mean) compared to the Four Corners area (0.2 ppb arithmetic mean). Annual mean ammonia concentrations for all Four Corners area sites for the 2007 study ranged from 0.2 ppb to 1.5 ppb. Peak ambient ammonia concentrations occurred in the spring and summer in both areas. The passive samplers deployed at the Stilwell, Oklahoma site compared favorably with other passive samplers and a continuous ammonia monitoring instrument. 相似文献
154.
Most agricultural information is reported by government sources on a state or county basis. The purpose of this study was
to demonstrate use of geospatial data, the 2002 Agricultural Cropland Data Layer (CDL) for the mid-Atlantic region, to characterize
agricultural, environmental, and other scientific parameters for the Chincoteague Bay subbasin using geographic information
systems. This study demonstrated that agriculture can be characterized accurately on subbasin and subwatershed bases, thus
complimenting various assessment technologies. Approximately 28% of the dry land of the subbasin was cropland. Field corn
was the largest crop. Soybeans, either singly or double-cropped with wheat, were the second most predominant crop. Although
the subbasin is relatively small, cropping practices in the northern part were different from those in the southern portion.
Other crops, such as fresh vegetables and vegetables grown for processing, were less than 10% of the total cropland. A conservative
approximation of the total pesticide usage in the subbasin in 2002 was over 277,000 lbs of active ingredients. Herbicides
represented the most frequently used pesticides in the subbasin, both in number (17) and in total active ingredients (over
261,000 lbs). Ten insecticides predominated in the watershed, while only small quantities of three fungicides were used. Total
pesticide usage and intensity were estimated using the CDL. Nutrient inputs to cropland from animal manure, chemical fertilizer,
and atmospheric deposition were modeled at over 30 million pounds of nitrogen and over 7 million pounds of phosphorous. Crops
under conservation tillage had the largest input of both nutrients. 相似文献
155.
156.
Warren Y. Brockelman Ulrich Reichard Uthai Treesucon Jeremy J. Raemaekers 《Behavioral ecology and sociobiology》1998,42(5):329-339
We report observations on reproduction, natal dispersal, pair formation, and group structure based on longitudinal observations
of several white-handed gibbon (Hylobates lar) groups spanning 18 years. Our observations are at odds with the traditional view that gibbons live in nuclear family groups
consisting of a pair of adults and their offspring, and that parents exclude young from the family territory when they reach
adult size. In the relatively dense Khao Yai study population, dispersing young usually obtain mates by replacing adults in
existing territories, which creates non-nuclear families. Six subadults, five males and one female, matured and dispersed
at an average age of 10 years, or about 2 years after reaching adult size. Average natal dispersal distance was 710 m, or
between one and two territories away. At least two dispersing males replaced adults in neighboring groups. In one case, forcible
displacement of the resident male resulted in a group which included a young juvenile presumably fathered by the previous
male, two younger juveniles (probably brothers) from the new male's original group, and (later) offspring of the new pair.
Social relations within this heterogeneous group remained harmonious: the adults groomed all the young and play occurred between
all preadult members. In only two out of a total of seven cases of dispersal seen did two subadults pair and disperse into
new territorial space. Nonreproducing subadults which delay dispersal may be tolerated by the adults provided that they contribute
benefits to the adults or their offspring. Possible benefits include behaviors such as grooming, social play with juveniles,
and support of the adult male in defending the territory. Delayed dispersal is probably advantageous in a saturated environment
where there is no room for floaters, but subadults may also gain indirect fitness benefits by aiding siblings and other relatives.
Received: 24 January 1997 / Accepted after revision: 12 January 1998 相似文献
157.
During the last two decades, the importance of sulphur dioxide as a pollutant has moved away from its association with suspended particulate matter, to it being a precursor of SO
4
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aerosol (acidic e.g. sulphuric acid, or neutralised e.g. ammonium sulphate). Co-located concentration data of sulphur dioxide and SO
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, at nine monitoring sites situated in predominantly rural areas in the United Kingdom, collected over the time period 1979–1995, have been analysed. The time series for both species are discussed for the sites. Further analysis has shown that there is a degree of correlation between sulphur dioxide and SO
4
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for most of the sites considered. This correlation is of approximately the same level for most of the sites taken independently and together, and in most cases the slopes and intercepts associated with the simple empirical model equations arising from the correlation analysis, are of the same order of magnitude. The implementation of these site-dependent model equations within dispersion models for the prediction of the concentration of airborne sulphate aerosol from knowledge of sulphur dioxide concentration is discussed. Furthermore, the correlation analysis revealed the influence of transported sulphate aerosol on the local concentration, especially during high concentration episodes. 相似文献
158.
Adaptation as a Political Process: Adjusting to Drought and Conflict in Kenya’s Drylands 总被引:3,自引:3,他引:0
In this article, we argue that people’s adjustments to multiple shocks and changes, such as conflict and drought, are intrinsically
political processes that have uneven outcomes. Strengthening local adaptive capacity is a critical component of adapting to
climate change. Based on fieldwork in two areas in Kenya, we investigate how people seek to access livelihood adjustment options
and promote particular adaptation interests through forming social relations and political alliances to influence collective
decision-making. First, we find that, in the face of drought and conflict, relations are formed among individuals, politicians,
customary institutions, and government administration aimed at retaining or strengthening power bases in addition to securing
material means of survival. Second, national economic and political structures and processes affect local adaptive capacity
in fundamental ways, such as through the unequal allocation of resources across regions, development policy biased against
pastoralism, and competition for elected political positions. Third, conflict is part and parcel of the adaptation process,
not just an external factor inhibiting local adaptation strategies. Fourth, there are relative winners and losers of adaptation,
but whether or not local adjustments to drought and conflict compound existing inequalities depends on power relations at
multiple geographic scales that shape how conflicting interests are negotiated locally. Climate change adaptation policies
are unlikely to be successful or minimize inequity unless the political dimensions of local adaptation are considered; however,
existing power structures and conflicts of interests represent political obstacles to developing such policies. 相似文献
159.
Erika von Schneidemesser Jiabin Zhou Elizabeth A. Stone James J. Schauer Radwan Qasrawi Ziad Abdeen Jacob Shpund Arye Vanger Geula Sharf Tamar Moise Shmuel Brenner Khaled Nassar Rami Saleh Qusai M. Al-Mahasneh Jeremy A. Sarnat 《Atmospheric environment (Oxford, England : 1994)》2010,44(30):3669-3678
A study of carbonaceous particulate matter (PM) was conducted in the Middle East at sites in Israel, Jordan, and Palestine. The sources and seasonal variation of organic carbon, as well as the contribution to fine aerosol (PM2.5) mass, were determined. Of the 11 sites studied, Nablus had the highest contribution of organic carbon (OC), 29%, and elemental carbon (EC), 19%, to total PM2.5 mass. The lowest concentrations of PM2.5 mass, OC, and EC were measured at southern desert sites, located in Aqaba, Eilat, and Rachma. The OC contribution to PM2.5 mass at these sites ranged between 9.4% and 16%, with mean annual PM2.5 mass concentrations ranging from 21 to 25 ug m?3. These sites were also observed to have the highest OC to EC ratios (4.1–5.0), indicative of smaller contributions from primary combustion sources and/or a higher contribution of secondary organic aerosol. Biomass burning and vehicular emissions were found to be important sources of carbonaceous PM in this region at the non-southern desert sites, which together accounted for 30%–55% of the fine particle organic carbon at these sites. The fraction of measured OC unapportioned to primary sources (1.4 μgC m?3 to 4.9 μgC m?3; 30%–74%), which has been shown to be largely from secondary organic aerosol, is relatively constant at the sites examined in this study. This suggests that secondary organic aerosol is important in the Middle East during all seasons of the year. 相似文献
160.
Reconstructions of Columbia River Streamflow from Tree‐Ring Chronologies in the Pacific Northwest,USA
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Jeremy S. Littell Gregory T. Pederson Stephen T. Gray Michael Tjoelker Alan F. Hamlet Connie A. Woodhouse 《Journal of the American Water Resources Association》2016,52(5):1121-1141
We developed Columbia River streamflow reconstructions using a network of existing, new, and updated tree‐ring records sensitive to the main climatic factors governing discharge. Reconstruction quality is enhanced by incorporating tree‐ring chronologies where high snowpack limits growth, which better represent the contribution of cool‐season precipitation to flow than chronologies from trees positively sensitive to hydroclimate alone. The best performing reconstruction (back to 1609 CE) explains 59% of the historical variability and the longest reconstruction (back to 1502 CE) explains 52% of the variability. Droughts similar to the high‐intensity, long‐duration low flows observed during the 1920s and 1940s are rare, but occurred in the early 1500s and 1630s‐1640s. The lowest Columbia flow events appear to be reflected in chronologies both positively and negatively related to streamflow, implying low snowpack and possibly low warm‐season precipitation. High flows of magnitudes observed in the instrumental record appear to have been relatively common, and high flows from the 1680s to 1740s exceeded the magnitude and duration of observed wet periods in the late‐19th and 20th Century. Comparisons between the Columbia River reconstructions and future projections of streamflow derived from global climate and hydrologic models show the potential for increased hydrologic variability, which could present challenges for managing water in the face of competing demands. 相似文献