Berechnungen zur Lufthygiene an Autobahnen

Protecting people from excessive noise near freeways is usually achieved by use of walls or wall-mound combinations. Calculations have shown that such walls reduce not only noise but, in addition, NO₂ concentrations can be lowered to 50 [μg/m³]. This papier shows that concentrations lower than the limiting values are possible even under difficult meteorological and topographic conditions. The position and hight of such noise protective walls can be optimized by sensitivity analyses.     

Increased energy expenditure due to increased territorial defense in male lizards after phenotypic manipulation

Fitness tradeoffs are difficult to examine because many fitness variables are correlated and vary in the same direction. Phenotypic manipulation circumvents many of these difficulties, and here we used this technique to examine mechanisms for tradeoffs between increased aggression (territorial defense) and survivorship. The behavioral phenotype of male mountain spiny lizards (Sceloporus jarrovi) was manipulated with testosterone to increase territorial defense, a sexually selected trait. We previously demonstrated that increased territorial defense results in a decrease in survival caused by a lower ratio of energy intake to energy expenditure. Here we measured energy consumption of increased territorial aggression using the doubly labeled water technique in the field and compared males with and without testosterone implants (Fig. 1). In a supplementary study we measured standard metabolic rate using captive lizards given similar testosterone implants to examine if an increase in energy expenditure was a result of only an increase in standard metabolic rate (Fig. 3). Our results indicated that a primary contribution to tradeoffs between increased territorial defense and survivorship could be made by a 31% increase in energy expenditure in the field that is not due to an increase in standard metabolic rate.     

Aristolochic acid content of South-East Asian troidine swallowtails (Lepidoptera: Papilionidae) and of Aristolochia plant species (Aristolochiaceae)

Summary. Analysis of South-East Asian troidine swallowtails revealed high variability in the content of aristolochic acids among individuals. The presence or absence of these compounds depends on the Aristolochia species available as food plant for the larvae. Only one plant species (Aristolochia philippinensis) contained a high concentration of aristolochic acids, while other species from various localities contained none or only marginal amounts. Whether aristolochic acids have a distinct function in chemical defense of these swallowtails is still an open question. Received 11 December 2000; accepted 4 August 2001.     

A statistical evaluation of non-ergodic variogram estimators

Geostatistics is a set of statistical techniques that is increasingly used to characterize spatial dependence in spatially referenced ecological data. A common feature of geostatistics is predicting values at unsampled locations from nearby samples using the kriging algorithm. Modeling spatial dependence in sampled data is necessary before kriging and is usually accomplished with the variogram and its traditional estimator. Other types of estimators, known as non-ergodic estimators, have been used in ecological applications. Non-ergodic estimators were originally suggested as a method of choice when sampled data are preferentially located and exhibit a skewed frequency distribution. Preferentially located samples can occur, for example, when areas with high values are sampled more intensely than other areas. In earlier studies the visual appearance of variograms from traditional and non-ergodic estimators were compared. Here we evaluate the estimators' relative performance in prediction. We also show algebraically that a non-ergodic version of the variogram is equivalent to the traditional variogram estimator. Simulations, designed to investigate the effects of data skewness and preferential sampling on variogram estimation and kriging, showed the traditional variogram estimator outperforms the non-ergodic estimators under these conditions. We also analyzed data on carabid beetle abundance, which exhibited large-scale spatial variability (trend) and a skewed frequency distribution. Detrending data followed by robust estimation of the residual variogram is demonstrated to be a successful alternative to the non-ergodic approach.     

Genetic monogamy in the common loon (Gavia immer)

We conducted behavioral observations and genetic analysis on breeding pairs of common loons in the upper Great Lakes region from 1993 through 1995 to look for behavioral evidence of extrapair copulations (EPCs) and to determine parentage of young. Pairs remained close to each other (usually within 20 m) during the pre-laying period, leaving little opportunity for EPCs to occur. Males and females both maintained physical proximity by approaching each other when they became separated. Copulations were obvious but infrequent, occurring about once every other day during the pre-laying period. Multilocus DNA fingerprinting was consistent with behavioral findings: 58 young from 47 different families were all genetic offspring of parents that raised them. Perfect genetic monogamy (genetic parentage of young by parents that rear them) in loons might arise as a consequence of the need for vigorous territorial defense to prevent territorial takeover. Received: 8 August 1996 / Accepted after revision: 22 March 1997     

A model for energetics and bioaccumulation in marine mammals with applications to the right whale.

We present a dynamic energy budget (DEB) model for marine mammals, coupled with a pharmacokinetic model of a lipophilic persistent toxicant. Inputs to the model are energy availability and lipid-normalized toxicant concentration in the environment. The model predicts individual growth, reproduction, bioaccumulation, and transfer of energy and toxicant from mothers to their young. We estimated all model parameters for the right whale; with these parameters, reduction in energy availability increases the age at first parturition, increases intervals between reproductive events, reduces the organisms' ability to buffer seasonal fluctuations, and increases its susceptibility to temporal shifts in the seasonal peak of energy availability. Reduction in energy intake increases bioaccumulation and the amount of toxicant transferred from mother to each offspring. With high energy availability, the toxicant load of offspring decreases with birth order. Contrary to expectations, this ordering may be reversed with lower energy availability. Although demonstrated with parameters for the right whale, these relationships between energy intake and energetics and pharmacokinetics of organisms are likely to be much more general. Results specific to right whales include energy assimilation estimates for the North Atlantic and southern right whale, influences of history of energy availability on reproduction, and a relationship between ages at first parturition and calving intervals. Our model provides a platform for further analyses of both individual and population responses of marine mammals to pollution, and to changes in energy availability, including those likely to arise through climate change.     

Spatial and temporal genetic homogeneity in the Arctic surfclam (<Emphasis Type="Italic">Mactromeris polynyma</Emphasis>)

Commercially harvested marine bivalve populations show a broad range of population-genetic patterns that may be driven by planktonic larval dispersal (gene flow) or by historical (genetic drift) and ecological processes (selection). We characterized microsatellite genetic variation among populations and year classes of the commercially harvested Arctic surfclam, Mactromeris polynyma, in order to test the relative significance of gene flow and drift on three spatial scales: within commercially harvested populations in the northwest Atlantic; among Atlantic populations; and between the Atlantic and Pacific oceans. We found small nonsignificant genetic subdivision among eight populations from the northwest Atlantic (F _ST = 0.002). All of these Atlantic populations were highly significantly differentiated from a northeast Pacific population (F _ST = 0.087); all populations showed high inbreeding coefficients (F _IS = 0.432). We tested one likely source of heterozygote deficits by aging individual clams and exploring genetic variation among age classes within populations (a temporal Wahlund effect). Populations showed strikingly different patterns of age structure, but we found little differentiation among age classes. In one case, we were able to analyze genetic diversity between age classes older or younger than the advent of intensive commercial harvesting. The results generally suggest spatially broad and temporally persistent genetic homogeneity of these bivalves. We discuss the implications of the results for the biology and management of surfclam populations. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.