Use of Basic Biological Information for Rapid Prediction of the Response of Species to Habitat Loss

Abstract:  Much research has focused on identifying traits that can act as useful indicators of how habitat loss affects the extinction risk of species, and the results are mixed. We developed 2 simple, rapid-assessment models of the susceptibility of species to habitat loss. We based both on an index of range size, but one also incorporated an index of body mass and the other an index combining habitat and dietary specialization. We applied the models to samples of birds (Accipitridae and Bucerotidae) and to the lemurs of Madagascar and compared the models' classifications of risk with the IUCN's global threat status of each species. The model derived from ecological attributes was much more robust than the one derived from body mass. Ecological attributes identified threatened birds and lemurs with an average of 80% accuracy and endangered and critically endangered species with 100% accuracy and identified some species not currently listed as threatened that almost certainly warrant conservation consideration. Appropriate analysis of even fairly crude biological information can help raise early-warning flags to the relative susceptibilities of species to habitat loss and thus provide a useful and rapid technique for highlighting potential species-level conservation issues. Advantages of this approach to classifying risk include flexibility in the specialization parameters used as well as its applicability at a range of spatial scales.     

Mathematical analysis of change in forest carbon use efficiency with stand development: A case study on Abies veitchii Lindl.

Changes in carbon use efficiency (CUE), which is defined as the ratio of net primary production (NPP) to gross primary production (GPP), were analyzed for Abies veitchii Lindl. forests with respect to stand development by developing a simple mathematical model incorporating data on physiological variables and leaf mass ratio. A decrease in CUE with stand development was successfully expressed as a function of stand biomass (y) based on the following three assumptions: (1) a power-law relationship between mean respiration and mean individual tree mass, (2) a power-functional relationship between mean gross primary production and mean individual tree mass, and (3) self-thinning relationship between stand biomass and density. Based on this model, a parameter of CUE–y relationship was defined, and it was clarified that CUE decrease with stand development is caused not by the ratio of specific respiration rate to specific gross photosynthetic rate, but by leaf mass ratio. Since CUE is high in young forests, helpful information on selecting woody species when planting seedlings was provided from the viewpoints of reducing CO₂ in the atmosphere and global warming.     

Fish consumption reduces transfer of BDE47 from dam to murine offspring

Fish and seafood are important contributions to a healthy diet, but also contain persistent organic pollutants (POPs) like polybrominated diphenylethers (PBDEs) and polychlorinated biphenyls (PCBs). Discrepancies have been found between intake and accumulated levels of POPs, where fish consumers have had similar levels of POPs to the general population. Similarly fish oil consumption has been found to reduce accumulation of POPs. This study examined the accumulation of BDE47 or PCB153 in mice fed diets with different nutritional composition, using female mice with pre-weanling pups exposed through gestation and lactation. A fish-based diet was compared to a standard casein-based rodent diet. All diets had low background levels of environmental contaminants and were spiked with BDE47 or PCB153 to levels representing a realistic (∼0.004 μmol kgbw⁻¹ d) or a high dietary exposure (∼1.3 μmol kgbw⁻¹ d). Accumulation of BDE47 or PCB153 in offspring tissues after 18 d lactation reflected the maternal exposure levels. However, the pups of dams fed a fish-based diet had consistently lower BDE47 accumulation in liver, fat and stomach than pups from casein-fed dams. Similarly the pups of dams fed a high dose of PCB153 in a fish diet also accumulated less PCB153 than pups of the dams fed a casein diet, although not significant. In conclusion, the fish based diets seemed to reduce transfer of BDE47 and PCB153 from dams to pups. The study highlights that in-depth knowledge about nutritional impact on toxicokinetics is of great interest to vulnerable consumers.     

Quantification of carbamazepine and atrazine and screening of suspect organic contaminants in surface and drinking waters

A new approach for the identification of suspect trace organic contaminants in drinking and surface waters is presented. Samples were initially analyzed using a target determination method for two contamination tracers, carbamazepine (CBZ) and atrazine (ATZ). This method used offline solid-phase extraction and online solid-phase extraction techniques coupled to liquid chromatography-triple quadrupole mass spectrometry to accelerate the sample preparation process and improve method performance. CBZ and ATZ were found respectively in 31% and 56% of the samples, and concentrations were usually <20 ng L⁻¹. These samples were re-analyzed with a similar method on a quadrupole time-of-flight mass spectrometer to identify suspect contaminants by means of exact mass measurements and isotope patterns. A database of 264 common organic contaminants was built and used in conjunction with a Molecular Feature algorithm to identify the presence of these substances in drinking and surface water collected from different sources at various locations across Canada. Several organic contaminants were identified in the samples, but only the presence of caffeine, desethylatrazine, simazine and venlafaxine could be verified by comparison to pure standards. The presence of desethylatrazine was also confirmed by MS/MS experiments. These results suggest that target analysis for tracers of organic contamination may be a helpful tool to prioritize samples which should be further screened for suspect contaminants. This study also shows that the combination of separation techniques (offline and online SPE, LC) contribute to advance the applicability of high-resolution mass spectrometry for the identification of trace organic contaminants by accelerating the preparation step, reducing complexity and increasing analyte concentrations for optimal detection.     

Stable carbon isotope analysis (δ13C values) of polybrominated diphenyl ethers and their UV-transformation products

Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the δ¹³C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in ¹³C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in ¹³C because of more stable bonds between ¹³C and bromine. As a result, the δ¹³C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the δ¹³C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios <1 are typical for native congeners (e.g. in DE-71) while the reversed ratio (>1) is typical of transformation products.     

Reduced ozone by air filtration consistently improved grain yield in wheat

This study considered effects of reduced [O₃] on wheat yield. Open-top chamber charcoal filtered air treatments were compared with non-filtered treatments for field-grown wheat. 30 experiments meeting requirements were found, representing nine countries in North America, Europe and Asia. 26 experiments reported improved yield and 4 experiments reduced yield by filtration, a significant positive effect. Average yield improvement was 9%. Average daytime [O₃] was reduced by filtration from 35 to 13 nmol mol⁻¹. Filtration efficiency was 63% for O₃ and 56% for SO₂. For NO_x it was observed that NO₂ was reduced and NO increased by filtration. Thus, filters convert NO₂ to NO. Most experiments reported low or very low [SO₂] and [NO_x]. Thus, O₃ can be concluded to be the main phytotoxic component in the experiments. Elevated [NO₂] was observed in one experiment. The conclusion is that current [O₃] over large parts of the world adversely affect wheat yield.     

粤赣高速公路K3边坡光纤监测与数值模拟对比分析

本文采用基于FLAC3D软件的数值模拟方法,对粤赣高速公路K 3边坡工程锚杆的应力应变状态进行数值模拟,分析了全长粘结式锚杆的荷载传递机理;根据运用基于自发布里渊背向散射原理(BOTDR)的分布式光纤应变传感技术对锚杆的轴向应变进行的监测数据,分析了工程锚杆的变形特征。数值模拟与实测数据的对比分析表明,模拟曲线与监测曲线反映的工程锚杆的变形特征具有较高的一致性,验证了应用FLAC3D有限差分软件模拟锚杆-框架体系应力应变特征的合理性,以及基于BOTDR的锚杆应变分布监测的可行性。     

膜萃取邻甲酚废水的传质特性研究

构造了卷绕式及管束式两种膜组件,采用均质硅橡胶膜,以氢氧化钠溶液为萃取液来萃取邻甲酚废水.通过考察邻甲酚初始浓度、两相流动状态、两相压差(△P)和温度等因素对传质过程的影响,研究了邻甲酚废水的膜萃取过程与机制.结果表明,初始质量浓度为21.93 g/L的邻甲酚废水很适合直接进行膜萃取;当△P<0.07 MPa时,总传质系数(Kov)随△P的增大而略有减小.当△P>0.07 MPa时,Kov随△P增大而显著增大,由实验数据拟合得到总的膜萃取传质模型.且该模型的实验值与理论值的相对误差在5%以内,满足工业设计要求.     

某公路隧道围岩稳定性及支护方式分析

跟踪某隧道施工,进行地质素描和节理统计,通过赤平投影分析节理发育分布规律,建立岩体结构模型;根据隧道围岩结构模型,运用离散元分析方法计算围岩稳定性,并结合现场塌方分析围岩破坏模式。通过离散元分析及时支护和无支护情况下围岩稳定性,探讨钢格栅锚杆组合进行初次支护的力学机理;根据现场钢格栅承受压力和隧道收敛监测,分析某隧道施工中围岩和支护体系的稳定性,总结出隧道施工中安全事故的主要原因,并给出合理的支护建议。     

Enhanced degradation of bioremediation residues in petroleum-contaminated soil using a two-liquid-phase bioslurry reactor

A study was performed to determine the potential of two-liquid-phase (TLP) bioslurry reactors using silicon oil as solvent for degradation of residual contaminants in petroleum-contaminated soil. The residues were characterized by gas chromatography–mass spectrometry and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. This allowed for the identification of a mixture of residual biomarkers, metabolic byproducts, oxygenated and hetero-polynuclear aromatic hydrocarbons in the contaminated soil. The removal amount of total extractable organics (TEO) was 15 900 mg kg⁻¹ soil in the TLP reactor within 12 weeks. However, TEO remained intact in the bioslurry reactor without the addition of silicon oil for the duration of the experiment, due to high toxicity of metabolites to the microorganisms. The availability of TEO was calculated using a mild extraction with Triton X-100, and the amount of TEO extracted was in accord with the amount of biodegraded TEO. Significantly reduced toxicity in soil was observed at week 12 through TLP remediation. Dehydrogenase activity in the bioslurry reactor was strongly suppressed. Fluorescein diacetate was significantly hydrolyzed by the composition of bioremediation residues in the contaminated soil. Microbial adhesion to the solvent was revealed by the determination of microbial activity in the water-immiscible-liquid.