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921.
Branislav Igic David R. Greenwood David J. Palmer Phillip Cassey Brian J. Gill Tomas Grim Patricia L. R. Brennan Suzanne M. Bassett Phil F. Battley Mark E. Hauber 《Chemoecology》2010,20(1):43-48
The known chemical basis of diverse avian eggshell coloration is generated by the same two classes of tetrapyrrole pigments
in most living birds. We aimed to extend the evolutionary scope of these patterns by detecting pigments from extinct birds’
eggs. In our samples biliverdin was successfully extracted from subfossil shell fragments of the blue-green egg-laying upland
moa Megalapteryx didinus, while protoporphyrin was extracted from the beige eggs of two other extinct moa species. Our data on pigment detection from
eggshells of other extant paleognath birds, together with published information on other modern lineages, confirm tetrapyrroles
as ubiquitous and conserved pigments contributing to diverse eggshell colours throughout avian evolution. 相似文献
922.
Robert J. Hawley Brian P. Bledsoe Eric D. Stein Brian E. Haines 《Journal of the American Water Resources Association》2012,48(4):722-744
Hawley, Robert J., Brian P. Bledsoe, Eric D. Stein, and Brian E. Haines, 2012. Channel Evolution Model of Semiarid Stream Response to Urban‐Induced Hydromodification. Journal of the American Water Resources Association (JAWRA) 48(4): 722‐744. DOI: 10.1111/j.1752‐1688.2012.00645.x Abstract: We present a novel channel evolution model (CEM) that qualitatively describes morphologic responses of semiarid channels to altered hydrologic and sediment regimes associated with urbanization (hydromodification). The CEM is based on southern California data from 83 detailed channel surveys, hundreds of synoptic surveys, and historical analyses of aerial photographs along 14 reaches. Channel evolution sometimes follows the well‐known sequence described by Schumm et al. (Incised Channels: Morphology, Dynamics, and Control, Water Resources Publications, Littleton, Colorado, 1984) for incising, single‐thread channels; however, departures from this sequence are common and include transitions of single thread to braided evolutionary endpoints, as opposed to a return to quasi‐equilibrium single‐thread planform. Thresholds and risk factors associated with observed channel response are also presented. In particular, distance to grade control and network position emerged as key controls on channel response trajectory. The CEM and quantitative extensions provide managers with a framework for understanding channel responses and rehabilitation alternatives, and may be transferable to other semiarid settings. It also offers insights regarding channel susceptibility to hydromodification, highlights key boundary conditions for high‐risk channels, and underscores critical knowledge gaps in predicting the complex, discontinuous response trajectories that are highly prevalent in urbanized watersheds. 相似文献
923.
Natalie C.G. Freeman Paul J. Lioy Alan H. Stern 《Journal of the Air & Waste Management Association (1995)》2013,63(6):948-953
ABSTRACT The purpose of this study was to determine the influence of chromate production waste site remediation on residential Cr concentrations in house dust. Twenty-three homes in Jersey City, NJ, were identified as having had high (>500 u,g/gm, median 739 u,g/gm), medium (100-400 u,g/gm, median 245 u,g/gm), or low (<100 u,g/gm, median 48 u,g/ gm) Cr in house dust during a study conducted in 19921993 prior to site remediation. House dust samples were collected on four visits from each home between November 1996 and February 1998, extracted with HNO3, and analyzed for Cr with an inductively coupled plasma-mass spectrometer. Homes that had low Cr concentrations in 1992-1993 continued to have low Cr concentrations (median 1 u,g/g). In contrast, substantial declines in Cr concentrations were found in the house dust collected from homes located near the remediated waste sites: previously high-level homes had a median of 50 u,g/g and mid-level homes had a median of 34 u,g/g. Site remediation had a beneficial effect on household loadings of Cr, since no differences in post-remediation house dust Cr concentrations were found among the three groups. 相似文献
924.
Application of Conservation Biology Research to Management 总被引:1,自引:0,他引:1
Abstract: We conducted a survey of all primary authors of "Contributed Papers" and "Research Notes" in Conservation Biology from 1987 to 1998 to assess the perceived effectiveness of published management recommendations. No systematic survey has previously assessed the degree to which authors believe that resource managers are using the growing body of research published in Conservation Biology . In March 1999, we sent surveys to 667 authors of 790 published papers, asking whether their papers included management recommendations, whether such recommendations have been used in practice, and why they believed they have or have not been used. We received completed surveys from 198 authors of 223 papers. The percentage of papers that included management recommendations increased from 1987 to 1991, then stabilized at about 75%. Author perception of the use of management recommendations generally increased over the 5 years from 1994 to 1998. Initiatives of federal, state, and local agencies were the most often-cited cause of successful implementation of management recommendations, accounting for over half of all such cases. Our survey suggests that authors in Conservation Biology have increased the use of explicit management recommendations in their papers and that authors believe their recommendations are being used to an increasing degree. 相似文献
925.
Jack Chen Jeremy Avise Alex Guenther Christine Wiedinmyer Eric Salathe Robert B. Jackson Brian Lamb 《Atmospheric environment (Oxford, England : 1994)》2009,43(36):5771-5780
A regional modeling system was applied with inputs from global climate and chemistry models to quantify the effects of global change on future biogenic emissions and their impacts on ozone and biogenic secondary organic aerosols (BSOA) in the US. Biogenic emissions in the future are influenced by projected changes in global and regional climates and by variations in future land use and land cover (LULC). The modeling system was applied for five summer months for the present-day case (1990–1999, Case 1) and three future cases covering 2045–2054. Individual future cases were: present-day LULC (Case 2); projected-future LULC (Case 3); and future LULC with designated regions of tree planting for carbon sequestration (Case 4). Results showed changing future meteorology with present-day LULC (Case 2) increased average isoprene and monoterpene emission rates by 26% and 20% due to higher temperature and solar insolation. However when LULC was changed together with climate (Case 3), predicted isoprene and monoterpene emissions decreased by 52% and 31%, respectively, due primarily to projected cropland expansion. The reduction was less, at 31% and 14% respectively, when future LULC changes were accompanied by regions of tree planting (Case 4). Despite the large decrease in biogenic emission, future average daily maximum 8-h (DM8H) ozone was found to increase between +8 ppbv and +10 ppbv due to high future anthropogenic emissions and global chemistry conditions. Among the future cases, changing LULC resulted in spatially varying future ozone differences of ?5 ppbv to +5 ppbv when compared with present-day case. Future BSOA changed directly with the estimated monoterpene emissions. BSOA increased by 8% with current LULC (Case 2) but decreased by 45%–28% due to future LULC changes. Overall, the results demonstrated that on a regional basis, changes in LULC can offset temperature driven increases in biogenic emissions, and, thus, LULC projection is an important factor to consider in the study of future regional air quality. 相似文献
926.
Yangjian Zhang Hong S. He William D. Dijak Jian Yang Stephen R. Shifley Brian J. Palik 《Environmental management》2009,44(2):312-323
To achieve the overall objective of restoring natural environment and sustainable resource usability, each forest management
practice effect needs to be predicted using a simulation model. Previous simulation efforts were typically confined to public
land. Comprehensive forest management practices entail incorporating interactions between public and private land. To make
inclusion of private land into management planning feasible at the regional scale, this study uses a new method of combining
Forest Inventory and Analysis (FIA) data with remotely sensed forest group data to retrieve detailed species composition and
age information for the Missouri Ozark Highlands. Remote sensed forest group and land form data inferred from topography were
integrated to produce distinct combinations (ecotypes). Forest types and size classes were assigned to ecotypes based on their
proportions in the FIA data. Then tree species and tree age determined from FIA subplots stratified by forest type and size
class were assigned to pixels for the entire study area. The resulting species composition map can improve simulation model
performance in that it has spatially explicit and continuous information of dominant and associated species, and tree ages
that are unavailable from either satellite imagery or forest inventory data. In addition, the resulting species map revealed
that public land and private land in Ozark Highlands differ in species composition and stand size. Shortleaf pine is a co-dominant
species in public land, whereas it becomes a minor species in private land. Public forest is older than private forest. Both
public and private forests have deviated from historical forest condition in terms of species composition. Based on possible
reasons causing the deviation discussed in this study, corresponding management avenues that can assist in restoring natural
environment were recommended. 相似文献
927.
Brian D. Keller Daniel F. Gleason Elizabeth McLeod Christa M. Woodley Satie Airamé Billy D. Causey Alan M. Friedlander Rikki Grober-Dunsmore Johanna E. Johnson Steven L. Miller Robert S. Steneck 《Environmental management》2009,44(6):1069-1088
Marine protected areas (MPAs) provide place-based management of marine ecosystems through various degrees and types of protective actions. Habitats such as coral reefs are especially susceptible to degradation resulting from climate change, as evidenced by mass bleaching events over the past two decades. Marine ecosystems are being altered by direct effects of climate change including ocean warming, ocean acidification, rising sea level, changing circulation patterns, increasing severity of storms, and changing freshwater influxes. As impacts of climate change strengthen they may exacerbate effects of existing stressors and require new or modified management approaches; MPA networks are generally accepted as an improvement over individual MPAs to address multiple threats to the marine environment. While MPA networks are considered a potentially effective management approach for conserving marine biodiversity, they should be established in conjunction with other management strategies, such as fisheries regulations and reductions of nutrients and other forms of land-based pollution. Information about interactions between climate change and more “traditional” stressors is limited. MPA managers are faced with high levels of uncertainty about likely outcomes of management actions because climate change impacts have strong interactions with existing stressors, such as land-based sources of pollution, overfishing and destructive fishing practices, invasive species, and diseases. Management options include ameliorating existing stressors, protecting potentially resilient areas, developing networks of MPAs, and integrating climate change into MPA planning, management, and evaluation. 相似文献
928.
Reconnecting to the Biosphere 总被引:3,自引:0,他引:3
Folke C Jansson A Rockström J Olsson P Carpenter SR Chapin FS Crépin AS Daily G Danell K Ebbesson J Elmqvist T Galaz V Moberg F Nilsson M Osterblom H Ostrom E Persson A Peterson G Polasky S Steffen W Walker B Westley F 《Ambio》2011,40(7):719-738
Humanity has emerged as a major force in the operation of the biosphere, with a significant imprint on the Earth System, challenging social-ecological resilience. This new situation calls for a fundamental shift in perspectives, world views, and institutions. Human development and progress must be reconnected to the capacity of the biosphere and essential ecosystem services to be sustained. Governance challenges include a highly interconnected and faster world, cascading social-ecological interactions and planetary boundaries that create vulnerabilities but also opportunities for social-ecological change and transformation. Tipping points and thresholds highlight the importance of understanding and managing resilience. New modes of flexible governance are emerging. A central challenge is to reconnect these efforts to the changing preconditions for societal development as active stewards of the Earth System. We suggest that the Millennium Development Goals need to be reframed in such a planetary stewardship context combined with a call for a new social contract on global sustainability. The ongoing mind shift in human relations with Earth and its boundaries provides exciting opportunities for societal development in collaboration with the biosphere--a global sustainability agenda for humanity. 相似文献
929.
The transport and fate of the pharmaceutical carbamazepine (CBZ) were investigated in the Dan Region Reclamation Project (SHAFDAN), Tel-Aviv, Israel. Soil samples were taken from seven subsections of soil profiles (150 cm) in infiltration basins of a soil aquifer treatment (SAT) system. The transport characteristics were studied from the release dynamics of soil-resident CBZ and, subsequently, from applying a pulse input of wastewater containing CBZ. In addition, a monitoring study was performed to evaluate the fate of CBZ after the SAT. Results of this study indicate adsorption, and consequently retardation, in CBZ transport through the top soil layer (0-5 cm) and to a lesser extent in the second layer (5-25 cm), but not in deeper soil layers (25-150 cm). The soluble and adsorbed fractions of CBZ obtained from the two upper soil layers comprised 45% of the total CBZ content in the entire soil profile. This behavior correlated to the higher organic matter content observed in the upper soil layers (0-25 cm). It is therefore deduced that when accounting for the full flow path of CBZ through the vadose zone to the groundwater region, the overall transport of CBZ in the SAT system is essentially conservative. The monitoring study revealed that the average concentration of CBZ decreased from 1094 ± 166 ng L−1 in the recharged wastewater to 560 ± 175 ng L−1 after the SAT. This reduction is explained by dilution of the recharged wastewater with resident groundwater, which may occur as it flows to active reclamation wells. 相似文献
930.
Determining sources of dissolved organic carbon and disinfection byproduct precursors to the McKenzie River, Oregon 总被引:2,自引:0,他引:2
Kraus TE Anderson CA Morgenstern K Downing BD Pellerin BA Bergamaschi BA 《Journal of environmental quality》2010,39(6):2100-2112
This study was conducted to determine the main sources of dissolved organic carbon (DOC) and disinfection byproduct (DBP) precursors to the McKenzie River, Oregon (USA). Water samples collected from the mainstem, tributaries, and reservoir outflows were analyzed for DOC concentration and DBP formation potentials (trihalomethanes [THMFPs] and haloacetic acids [HAAFPs]). In addition, optical properties (absorbance and fluorescence) of dissolved organic matter (DOM) were measured to provide insight into DOM composition and assess whether optical properties are useful proxies for DOC and DBP precursor concentrations. Optical properties indicative of composition suggest that DOM in the McKenzie River mainstem was primarily allochthonous--derived from soils and plant material in the upstream watershed. Downstream tributaries had higher DOC concentrations than mainstem sites (1.6 +/- 0.4 vs. 0.7 +/- 0.3 mg L(-1)) but comprised < 5% ofmainstem flows and had minimal effect on overall DBP precursor loads. Water exiting two large upstream reservoirs also had higher DOC concentrations than the mainstem site upstream of the reservoirs, but optical data did not support in situ algal production as a source of the added DOC during the study. Results suggest that the first major rain event in the fall contributes DOM with high DBP precursor content. Although there was interference in the absorbance spectra in downstream tributary samples, fluorescence data were strongly correlated to DOC concentration (R2 = 0.98), THMFP (R2 = 0.98), and HAAFP (R2 = 0.96). These results highlight the value of using optical measurements for identifying the concentration and sources of DBP precursors in watersheds, which will help drinking water utilities improve source water monitoring and management programs. 相似文献