Morphological and haematological parameters in the Algerian mouse (Mus spretus) inhabiting an area contaminated with heavy metals

In the present study morphological (ratio of body weight to body length, weight of internal organs) and haematological parameters (cells count, haemoglobin concentration, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration) were used for monitoring potential effects of metal contaminants on the Algerian mouse (Mus spretus). The study also provided the opportunity to evaluate the use of morphological and haematological characteristics as indicators of a metal stress. Data were taken from a riverside population inhabiting a heavy metal-contaminated site and compared with those collected from a reference population of the same species. With the exception of non-reproductive males, all mice weighed less in the metal-polluted site as compared to the reference site. Spleen and kidney masses were also less in contaminated mice but mean haemoglobin concentration was greater in the polluted group versus controls. Responses of mice from the polluted area may indicate physiological stress due to diminished environmental quality. Results also suggest that M. spretus may be used as an indicator in pollution monitoring.     

Anreicherung,verteilung, umwandlung und ausscheidung von DDT-14C bei Solea solea (Pisces: Soleidae)

Common soles Solea solea (L.) are extremely suitable for studying the fate of pesticides in marine fish by means of laboratory experiments involving small-sized, accurately controlled, closed aquarium systems. In 5 different experiments, a total of 16 fishes of Age Group I were maintained in water of 10°C and 20‰ S continuously filtered through charcoal, and given oral doses of 0.85 μg DDT-¹⁴C up to 5 times/week. A total application of 1.7, 17 or 35 μg DDT-¹⁴C, corresponding to 3, 28, or 57 experimental days, resulted in 72, 60 or 43% DDT-¹⁴C accumulation. After feeding with 17 μg unlabelled DDT over a period of 4 weeks and final feeding with 1.7 μg ¹⁴C-labelled DDT for 2 days, S. solea displayed the same percentage (74%) of accumulated DDT-¹⁴C as after feeding with 1.7 μg DDT-¹⁴C without prior feeding. Therefore, the decreasing accumulation percentages with inereasing doses, i.e., with longer application periods, are due to elimination during the application period. During a period of 2 months in pesticide-free water, S. solea eliminated 62% of the DDT-¹⁴C which it had accumulated after feeding with 17 μg DDT-¹⁴C over a period of 4 weeks. The gastro-intestinal tract is assumed to be a major route of DDT elimination. Independent of dosage, there was a characteristic distribution pattern of accumulated DDT: brain, liver and gastro-intestinal tract ranked highest, while the concentration in skeletal muscle was lowest. Even during the elimination period the pattern appeared unchanged. DDE, DDD and a polar component occurred as metabolites, but in all organs more than 80% of the accumulated DDT remained unchanged. Percentages of metabolites were higher in liver and gastro-intestinal tract than in skeletal muscle. Prolonged exposure to DDT in the diet induced DDT transformation in the gastro-intestinal contents, most probably in the bacterial flora of the gut.     

Bimodality of the combined removal and signs-of-activities estimator for sampling closed animal populations

The possibility of a bimodal log-likelihood function arises with certain data when the combined removal and signs-of-activities estimator is used. Bimodal log-likelihoods may, in turn, yield disjoint confidence intervals for certain confidence levels. The hypothesis that bimodality is caused by the violation of the equal catchability assumption of the removal model, leading to the combination of contradictory data/models in the combined estimator is set forth. Simulations exploring the effect of the violation of removal model assumptions on estimation and inference showed that the assumption of unequal capture probability influenced the frequency of bimodal likelihoods; similarly, extreme parameter values for probability of capture influenced the number of excessively large confidence intervals produced. A sex-specific combined estimator is developed as a remedial model tailored to the problem. The simulations suggest that both the signs-of-activities estimator and the sex-specific estimator perform equally well over the range of simulations presented, though the signs-of-activities estimator is easier to implement.     

Bioindication of a surplus of heavy metals in terrestrial ecosystems

A survey of the methods of boindication of heavy metals in terrestrial ecosystems and their effectiveness for predicting the consequences of environmental stress on organisms is presented. Two main inputs of heavy metals for terrestrial ecosystems have been considered: airborne and soil-borne. Airborne metals can be monitored due to physical adsorption on plant surfaces or due to chemical exchange processes in cell walls. Active biomonitoring widely uses both aspects, however, without predictive values. Meaningful bioindication of soilborne heavy metals can only be achieved by passive monitoring. Due to the different functions of heavy metals in organisms-micronutrients and trace elements-the knowledge of natural background values is important, considering the qualitative aspects of metals in the soil. In exceptional situations morphological and anatomical changes of plant organs will facilitate bioindication; in every case chemical analysis of the concentration of heavy metals is an essential part of the monitoring program. A long-term exposure of organisms to heavy metals will influence the genetic structure of populations. Therefore measurement of heavy metal tolerance of plants has to be a standard procedure in monitoring programs.     

Livestock grazing and habitat for a threatened species: Land-use decisions under scientific uncertainty in the White Mountains,California, USA

The North Fork of Cottonwood Creek, in the White Mountains, Inyo National Forest, California, is a critically important refuge for the Paiute cutthroat trout (Oncorhynchus clarki seleniris), a federally listed threatened species. Habitat for these fish appears to be limited by excessive levels of fine sediment in the channel, and livestock grazing of riparian meadows has been implicated in delivery of sediment to the channel. However, the relationships between land use and sediment yield have not been conclusively determined, in large part because there are no historically ungrazed sites to serve as long-term controls. Accordingly, land-use decisions must be made under scientific uncertainty. To reduce erosion and sedimentation in the stream, the Forest Service spent approximately US$260,000 from 1981 to 1991 to repair watershed damage from livestock grazing, prevent livestock from traversing steep banks, and limit livestock access to the channel. Throughout this period, livestock grazing has continued on these lands, yielding less than $12,000 in grazing fees. In revising its Allotment Management Plan for the basin, the Forest Service rejected the “no-grazing” alternative because it was inconsistent with its Land and Resource Management Plan, which specifies there is to be no net reduction of grazing. Joint appointment with the University of California White Mountain Research Station, East Line Street, Bishop, California 93518, USA.     

Reproducing or dispersing? Using trait based habitat templet models to analyse Orthoptera response to flooding and land use

Habitat templet theory predicts that habitat provides the templet on which evolution shapes species’ multiple traits and thus their characteristic life-history strategies. By analysing entire trait communities (multiple species and traits) in this framework we can enhance our understanding of how species composition changes as environmental constraints vary across the landscape. Here, we study multiple traits of floodplain Orthoptera communities under the influence of two different sources of disturbance, land use and seasonal flooding.The application of two recently developed statistical techniques - qualitative RLQ analysis and subsequent fourth-corner permutation tests - revealed two different life history strategies in Orthoptera as a response to ecological disturbances, resulting from land use management and seasonal flooding. Orthoptera species seem to have developed two complementary strategies: (i) the high active dispersal-low reproduction strategy in intensive land use situations and (ii) the high passive dispersal-high reproduction strategy in areas with high flood disturbance. Disturbance gradients act as trait filters allowing only particular trait combinations i.e. species with particular preadaptations to survive, whereas others go regionally extinct. Reproduction and dispersal capacity seem to be inversely associated with the disturbance gradients. Ovariole number, taken as the measure for reproduction, showed significant phylogenetic signal, which could potentially confound this relationship. Nonetheless, RLQ analyses coupled with fourth-corner permutation tests proved a powerful tool to reveal and disentangle different evolutionary strategies.     

Modelling radioiodine transport across a capillary fringe

Due to its long radioactive half-life, iodine-129 is considered to be an important radionuclide in the context of underground radioactive waste disposal safety assessment. Iodine speciates as iodide (I-) in reducing conditions and iodate (IO3-) in oxidizing conditions. As iodate is more reactive, it is much less mobile than iodide. Consequently, in considering vertically upward transport within a soil profile, iodine will tend to accumulate at the top of the capillary fringe. In this paper, a model of iodine transport across a capillary fringe is developed by coupling equations for variably saturated flow, oxygen dynamics and rate-limited sorption. Model parameters are obtained by consideration of literature values, calibration on soil column data and other supporting laboratory experiments. The results demonstrate the importance of rate kinetics on the migration and bioavailability of radioiodine in the near-surface environment.     

瓦里关气相色谱法大气CO_2和CH_4在线观测数据处理分析

加强我国本底站温室气体数据资源的科学管理与共享,首先应保证观测全流程的标准化和规范化,确立数据处理和质量控制方法.我国青海瓦里关全球本底站自1994年开始了气相色谱-氢火焰离子化检测器法(GC-FID)大气CO2和CH4在线观测,本文详细讨论了该系统原始资料采集、数据信息合并、时间序列检查、观测员级质量控制和专家级质量控制等流程.利用局部近似回归法对大气CO2和CH4数据进行本底值筛分,获得CO2本底数据百分比约占有效数据的72%、CH4占44%.在线观测的CO2和CH4月平均浓度与同期瓶采样分析结果基本一致,相对偏差均在±0.5%以内.经流程化处理和质控的瓦里关大气CO2和CH4本底浓度变化资料已进入全球同化数据库(Globalview-CO2、Globalview-CH4),报送世界温室气体数据中心(WDCGG)并应用于世界气象组织(WMO)温室气体公报和联合国政府间气候变化专门委员会(IPCC)评估.