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51.
The scaling of metabolic rates to body size is widely considered to be of great biological and ecological importance, and much attention has been devoted to determining its theoretical and empirical value. Most debate centers on whether the underlying power law describing metabolic rates is 2/3 (as predicted by scaling of surface area/volume relationships) or 3/4 ("Kleiber's law"). Although recent evidence suggests that empirically derived exponents vary among clades with radically different metabolic strategies, such as ectotherms and endotherms, models, such as the metabolic theory of ecology, depend on the assumption that there is at least a predominant, if not universal, metabolic scaling exponent. Most analyses claimed to support the predictions of general models, however, failed to control for phylogeny. We used phylogenetic generalized least-squares models to estimate allometric slopes for both basal metabolic rate (BMR) and field metabolic rate (FMR) in mammals. Metabolic rate scaling conformed to no single theoretical prediction, but varied significantly among phylogenetic lineages. In some lineages we found a 3/4 exponent, in others a 2/3 exponent, and in yet others exponents differed significantly from both theoretical values. Analysis of the phylogenetic signal in the data indicated that the assumptions of neither species-level analysis nor independent contrasts were met. Analyses that assumed no phylogenetic signal in the data (species-level analysis) or a strong phylogenetic signal (independent contrasts), therefore, returned estimates of allometric slopes that were erroneous in 30% and 50% of cases, respectively. Hence, quantitative estimation of the phylogenetic signal is essential for determining scaling exponents. The lack of evidence for a predominant scaling exponent in these analyses suggests that general models of metabolic scaling, and macro-ecological theories that depend on them, have little explanatory power. 相似文献
52.
The Yamaska River drainage basin in Quebec, Canada, is intensively farmed and heavily polluted with poorly treated domestic and industrial wastes. We investigated the responses of the resident and colonizing components of the benthic macroinvertebrate community to municipal/industrial versus agricultural pollution in the basin, and evaluated the performances of seven diversity and biotic indices for assessing water quality. Samples of riffle-dwelling, infaunal and colonizing invertebrates were collected from 13 stations representing a wide range of types and degrees of pollution using Surber, scoop and artificial substrate samplers. The data were summarized using the indices S (number of taxa), N (number of individuals), H (Shannon-Wiener's diversity index), D (Simpson's diversity index), BBI (Belgian Biotic Index), TBI (a modification of Hilsenhoff's Biotic Index), % CHIR (percentage of arthropods consisting of Chironomidae) and %OLIGO (percentage of total organisms consisting of Oligochaeta). Different components of the community generated somewhat different assessments and were, therefore, complementary. Community composition, expressed as the percentage of individuals contributed by major taxonomic groups, reflected the kinds of stresses at a station more consistently than did any of the indices. S and TBI came closest to ranking control, agricultural and municipal/industrial sites in accordance with our a priori classification, both between months and among sampling methods. %OLIGO usually separated municipal/industrial sites from control sites. Other indices were found to be less sensitive, accurate or temporally stable, or were otherwise inappropriate for use with certain sampling methods or for certain types of pollution. With most of our samples, all of the summary indices suggested that the impact of agricultural practices on stream ecosystems may be as severe as the impacts of municipal and industrial wastes. 相似文献
53.
Determinants of diet in free-ranging baboons Papio anubis were investigated. Foods and non-foods differed significantly in chemical composition, the former being higher in protein and lower in fibre and phenolics. Within the range of items selected, biomass was found to be the single most important factor affecting percentage of total intake and time spent feeding (Figure 1). When this effect of biomass was statistically controlled, independent effects of chemical composition (primarily protein content) and harvesting rate were found. However, while the harvesting rates of foods were positively related to their percentage contribution to total intake, they were either uncorrelated, or, in one case, actually negatively correlated with the percentage of feeding time. A post-hoc model based on Charnov's (1976) marginal value theorem is developed to account for these latter results, and direct evidence for rate-maximising patch use is then presented. It is argued that the apparent complexity of primate diets may in large part be reducible to relatively simple optimization criteria. 相似文献
54.
Mark L. Kram Steve Airhart Daniel Tyler Amy Dindal Andrew Barton John L. McKernan Gregg Gustafson 《补救:环境净化治理成本、技术与工艺杂志》2011,21(3):89-101
Environmental monitoring, data processing, and reporting methods are expensive, labor‐ and resource‐intensive, time‐consuming, and often inaccurate. An innovative project management platform was developed for integrating environmental monitoring sensors, telemetry, geographical information systems, models, and geostatistical algorithms for automatically generating contour maps and time‐stamped renderings of sensor attributes and multivariate analyses. More specifically, algorithms converting sensor‐derived head and solute concentration values allow for automated monitoring of mass flux and discharge to evaluate groundwater remediation system performance and contaminant discharges from aquifers to surface‐water receptors. Life‐cycle costs and carbon footprints were reduced due to the elimination of energy and labor expenditures associated with transportation, data collection, laboratory efforts, report generation, and information dissemination. A brief summary of two demonstrations of this sensor‐based water resources management application is presented. © 2011 Wiley Periodicals, Inc. 相似文献
55.
Despite an abundance of research reaffirming biodiversity's importance to the health of the planet and society, species continue to go extinct at an alarming rate. Why has continued research on the value of biodiversity not had the intended effect and what can be done about it? We considered biodiversity loss as a public value failure and the result of a misalignment between the logic of inquiry (which guides scientists) and the logic of action (which guides practitioners). We drew lessons from our own research to propose the creation of a national biodiversity strategy designed to link the logic of inquiry with the logic of action and coordinate the production of actionable conservation science and informed conservation action. 相似文献
56.
采用厌氧氨氧化反应器(ASBR),分别以普通厌氧活性污泥、混合污泥、好氧活性污泥为种泥,通过对氨氮,NO2^--N等指标监测、分析及污泥颜色的观察,研究采用不同普通活性污泥为种泥启动ASBR的可行性及差异。结果表明.ASBR反应器A和B成功启动,C因反应器故障.启动失败。采用厌氧活性污泥为接种污泥(反应器A),当进水N的容积负荷为kg/(m^3·d)时,氨氮平均去除率为14.4%。P(NO2^--N):p(NH4^+-N)变化量为1.24。采用混合污泥为接种污泥(反应器B).N的容积负荷于前者相同时,氨氮去除率平均29.7%,p(NO2^--N):p(NH4^+-N)变化量为1.27。采用混合普通活性污泥作为种泥培养厌氧氨氧化污泥优于单一厌氧普通活性污泥。 相似文献
57.
Darrin Greenstein Steven Bay Matthew Jacobe Carlita Barton Ken Sakamoto Diana Young Kerry Ritter Ken Schiff 《Environmental monitoring and assessment》2013,185(2):2055-2065
Sediment toxicity was investigated at 222 stations in the Southern California Bight (SCB) during 2008. This represented the first time that assessment methods established by California's new Sediment Quality Objectives program were employed in a survey of this scale. The goal was to determine the extent and magnitude of sediment toxicity in the SCB, how toxicity compared among specific environments, and whether toxicity has changed over the last decade. Two toxicity tests were used: the 10-day amphipod whole sediment survival test with Eohaustorius estuarius and a 48-h embryo development test with the mussel Mytilus galloprovincialis exposed at the sediment–water interface. Less than 1 % of the area of the SCB was found to be toxic to the amphipod test. No toxicity was found in offshore stations, but 14 % of embayment areas were toxic to the amphipods. The mussel test identified 13 % of the embayment areas to be toxic. Estuary and marina locations had the greatest areal extent of toxicity for both tests. The two toxicity methods agreed that sediments were not toxic at over half of the stations tested. The mussel test showed a greater magnitude of response than the amphipod. Sediment toxicity was shown to have declined in both extent and magnitude from levels measured in 1998 and 2003. 相似文献
58.
Environmental service payments: evaluating biodiversity conservation trade-offs and cost-efficiency in the Osa Conservation Area, Costa Rica 总被引:1,自引:0,他引:1
Barton DN Faith DP Rusch GM Acevedo H Paniagua L Castro M 《Journal of environmental management》2009,90(2):901-911
The cost-efficiency of payments for environmental services (PES) to private landowners in the Osa Conservation Area, Costa Rica, is evaluated in terms of the trade-off between biodiversity representation and opportunity costs of conservation to agricultural and forestry land-use. Using available GIS data and an 'off-the-shelf' software application called TARGET, we find that the PES allocation criteria applied by authorities in 2002-2003 were more than twice as cost-efficient as criteria applied during 1999-2001. Results show that a policy relevant assessment of the cost-effectiveness of PES relative to other conservation policies can be carried out at regional level using available studies and GIS data. However, there are a number of data and conceptual limitations to using heuristic optimisation algorithms in the analysis of the cost-efficiency of PES. Site specific data on probabilities of land-use change, and a detailed specification of opportunity costs of farm land, labour and capital are required to use algorithms such as TARGET for ranking individual sites based on cost-efficiency. Despite its conceptual soundness for regional conservation analysis, biodiversity complementarity presents a practical challenge as a criterion for PES eligibility at farm level because it varies depending on the set of areas under PES contracts at any one time. 相似文献
59.
Waste that reflected the average UK composition of household waste was treated by autoclaving at the three set pressure/temperature levels of 2.7 bar/130 degrees C, 6.2 bar/160 degrees C and 15.5 bar/200 degrees C. The biodegradable fraction of the autoclaved household waste (;floc') was manually separated by screening and underwent characterization for its Cd, Cr, Cu, Pb, Hg, Ni, and Zn content. Autoclaving did not guarantee the production of compost/digestate that met the UK specification for compost, BSi PAS100, without restrictions being made on the composition of the waste feedstock. Results indicate that the levels of Zn and Cd associated with floc materials alone could lead to compost limit values being exceeded. For all other potentially toxic elements (PTEs), the estimated excessive (i.e. above levels of compliance) PTEs levels for compost/digestate were mainly due to external (i.e. non-floc) materials, primarily electronic/electrical waste. Batteries may have also contributed to the high levels of Zn and Hg. In this study, for all PTEs examined, with the exception of Cd and Zn, autoclaving had a performance comparable to that of the most effective mechanical biological treatment systems. 相似文献
60.
This study, informed by phenomenology and ethnography, explores urban children’s relationship with their urban environment: In what ways do urban children exhibit “insideness” in their sense of place? This study proposes “insideness” as a conceptual construct to understand urban children’s sense of place in its ecological and dynamic nature. Employing qualitative research methods, the study explores place stories of urban children who live in low-income, immigrant neighborhoods in New York City. The study finds that as children cultivate their sense of place, they construct “insideness” in their sense of place including 1) environmental understanding (i.e., contextualized, comprehensive, and critical understanding of a place), 2) environmental competence (i.e., knowing how to navigate and engage in a place), and 3) diverse, strong affective relationships with a place. Using “insideness” as a conceptual tool, this study discusses children’s emplaced understanding and active and dialogical positionality in the development of their sense of place. 相似文献