The CPCAT as a novel tool to overcome the shortcomings of NOEC/LOEC statistics in ecotoxicology: a simulation study to evaluate the statistical power

Species reproduction is an important determinant of population dynamics. As such, this is an important parameter in environmental risk assessment. The closure principle computational approach test (CPCAT) was recently proposed as a method to derive a NOEC/LOEC for reproduction count data such as the number of juvenile Daphnia. The Poisson distribution used by CPCAT can be too restrictive as a model of the data-generating process. In practice, the generalized Poisson distribution could be more appropriate, as it allows for inequality of the population mean \(\mu\) and the population variance \(\sigma ^2\). It is of fundamental interest to explore the statistical power of CPCAT and the probability of determining a regulatory relevant effect correctly. Using a simulation, we varied between Poisson distribution (\(\mu =\sigma ^2\)) and generalized Poisson distribution allowing for over-dispersion (\(\mu <\sigma ^2\)) and under-dispersion (\(\mu >\sigma ^2\)). The results indicated that the probability of detecting the LOEC/NOEC correctly was \(\ge 0.8\) provided the effect was at least 20% above or below the mean level of the control group and mean reproduction of the control was at least 50 individuals while over-dispersion was missing. Specifically, under-dispersion increased, whereas over-dispersion reduced the statistical power of the CPCAT. Using the well-known Hampel identifier, we propose a simple and straight forward method to assess whether the data-generating process of real data could be over- or under-dispersed.     

德国公司环境报告评估

1994年进行了德国公司环境报告的第一次排名.1995年和1998年又进行了两次排名,以确定环境报告和陈述的数目已增加的程度,及其质量是否有所改善.基于所使用的基准,已经显示公司报告的质量有颇大差异.虽然总体质量有了改善,但大多数报告都有许多重要不足.     

Declining coastal piscivore populations in the Baltic Sea: Where and when do sticklebacks matter?

Intraguild predation interactions make fish communities prone to exhibit alternative stable states with either piscivore or prey fish dominance. In the Baltic Sea, local declines of coastal piscivores like perch (Perca fluviatilis) have been observed to coincide with high densities of sticklebacks (Gasterosteus aculeatus). Mechanisms behind this shift between piscivore and stickleback dominance were studied both experimentally and in field. Results showed that predation by sticklebacks has a strong negative effect on perch larvae survival, but this effect rapidly decreases with increasing perch size, likely due to gape limitations and digestion constraints in sticklebacks. Large spatial and temporal variations in patterns of stickleback migration into perch spawning sites were observed. Whether or not high density of sticklebacks will cause declines in coastal piscivore populations is suggested to depend on the availability of spawning sites in which sticklebacks do not migrate into or arrive late in the reproduction season of coastal piscivores.     

A conceptual framework for understanding illegal killing of large carnivores

The growing complexity and global nature of wildlife poaching threaten the survival of many species worldwide and are outpacing conservation efforts. Here, we reviewed proximal and distal factors, both social and ecological, driving illegal killing or poaching of large carnivores at sites where it can potentially occur. Through this review, we developed a conceptual social–ecological system framework that ties together many of the factors influencing large carnivore poaching. Unlike most conservation action models, an important attribute of our framework is the integration of multiple factors related to both human motivations and animal vulnerability into feedbacks. We apply our framework to two case studies, tigers in Laos and wolverines in northern Sweden, to demonstrate its utility in disentangling some of the complex features of carnivore poaching that may have hindered effective responses to the current poaching crisis. Our framework offers a common platform to help guide future research on wildlife poaching feedbacks, which has hitherto been lacking, in order to effectively inform policy making and enforcement.     

Entfernung von Schwermetallen aus einem Boden mit hohem Schluffanteil

A soil, containing 2.8% organic carbon and a high concentration (76.4%) of small particles (<63 μm), and which had been contaminated over a long period of time by galvanic waste waters (Ni, Cu) and lead wastes, was subjected to detailed analysis and subsequently treated with various extracting solutions in order to remove the heavy metals. For this purpose, representative samples containing 114 mg kg^?1 Cu, 1151 mg kg^?1 Ni and 366 mg kg^?1 Pb were treated with amino acids and solutions containing other complexing agents, as well as with diluted acids, in order to compare the relative effectiveness of these solutions. Satisfactory metal extractions were only achieved by the use of diluted mineral acids, notably hydrochloric acid, which released more than 90% of the nickel and approximately 80% of the copper and lead from the soil. The results obtained with weak complexing agents such as tartaric acid (0.07–2.9%, 24 h) and amino acids (0.01–36%, 24h) were worse. For reprocessing of the hydrochloric acid solutions, a direct precipitation of the heavy metals in their hydroxide forms and selective separation with N-acylthiourea modified polysiloxanes were carried out.     

Evasive response to ultrasound by the crepuscular butterfly<Emphasis Type="Italic"> Manataria maculata</Emphasis>

The crepuscular nymphalid butterfly Manataria maculata was studied in Monteverde cloud forest, Costa Rica, during the dry season reproductive diapause. M. maculata has ears in the form of Vogel's organs located near the base of the forewings. Its behaviour in response to bursts of ultrasonic pulses (26 kHz, 110 dB SPL at 1 m) was condition-dependent. At dusk and dawn the sound consistently elicited evasive responses, similar to those of moths, in flying individuals. In contrast day-roosting individuals always remained motionless although they were alert to other stimuli. The daily movements between day- and night-roosts coincided in time and light intensity with the activity of insectivorous bats. This is the first reported case of ultrasonic hearing connected to evasive flights in a true butterfly (Papilionoidea). It strongly supports the idea that echolocating bats were involved in the evolution of hearing in butterflies.     

Butyltin compounds in sediment and molluscs from the shipping strait between Denmark and Sweden

The distribution of tributyltin (TBT) contamination in the subtidal zone of the waters between Denmark and Sweden was investigated in relation to major international shipping lanes. Sediment and different benthic molluscs were sampled in transects along and perpendicularly to the shipping lanes in the Sound (?resund) and the Kattegat/Skagerrak region. The samples were analysed for TBT and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), using GC-PFPD. In sediments, the TBT concentration ranged from <1 to 19 ng g(-1) dry weight (dw) with a strong correlation between the TBT concentration and the organic fraction in sediment (r(2)=0.90) in the samples collected in the Sound, where the highest concentrations were found. This relationship was not observed in the samples from the Kattegat because the TBT concentration in most sediment samples was below the limit of detection. In the molluscs, TBT and its degradation products were detected in all samples from the entire area with concentrations ranging from 8.1 ng g(-1) dw in Buccinum undatum to 1316 ng g(-1) dw in Nuculana pernula. The deposit-feeding bivalve N. pernula was found to have a particularly high accumulation potential for TBT. In addition, a strong correlation between TBT concentrations in sediment and N. pernula was found. Therefore this species seems to be an ideal organism for monitoring sediment contamination. The TBT concentration in N. pernula was found to decrease gradually along the shipping lanes from the Sound, through the Kattegat and into the Skagerrak.     

Correlates of boldness in three-spined sticklebacks (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>)

Behavioural variation is known to occur between individuals of the same population competing for resources. Individuals also vary with respect to their boldness or shyness. An individuals position along the shy-bold axis may be defined as the extent to which it is willing to trade off potentially increased predation risks for possible gains in resources. Similarly, group living may be interpreted as a trade-off between anti-predatory tactics and foraging efficiency. The responses of three-spined sticklebacks (Gasterosteus aculeatus) were tested across four social contexts to assess relative boldness or shyness and to further examine whether their behaviour would be consistent within and between contexts. Individuals displayed consistent responses within and between the first two contexts: those individuals which resumed foraging rapidly after a simulated aerial predator attack also displayed low shoaling tendencies. Such fish were deemed to be bold, whilst those which displayed the converse behaviour, slow resumption of foraging and a high shoaling tendency, were deemed to be shy. In a third context, bold individuals out-competed shy conspecifics for food. Boldness was also positively correlated with growth over a 6-week period. The position adopted by an individual within a group is usually interpreted as a trade-off between predation risk and foraging efficiency—both are greater at the front of a mobile group. Bold individuals showed significantly stronger tendencies towards front positions than shy conspecifics. The results suggest that, contrary to some previous studies on other animals, bold or shy behaviour in sticklebacks is consistent between contexts.Communicated by T. Czeschlik