On the ecology and biogeography of alpine tundra arachnids

In the course of the discussion about the effects of manmade Climate Change on ecosystems, alpine regions of the earth have become a major focus. Alpine ecosystems are generally considered to be especially sensitive towards environmental changes. Thus, alpine research concentrates on ecosystematic processes along gradients at various scales. Within this setting of gradiental dependency, alpine ecosystem research often makes use of spacetime substitution. However, the research on spatial and temporal ecological patterns is mostly limited to the analysis of vegetation patterns; studies on spatial patterns of zoological species composition are underrepresented. Yet, especially epigeic arachnids show some characteristics which makes them valuable proxies in processoriented ecosystem research: on the one hand arachnids occur in high abundances in alpine habitats, on the other hand they are often described to be sensitive towards diverse abiotic and biotic factors. This thesis aims to tackle this research gap by investigating spatial and temporal patterns of arachnids in alpine and arctic habitats. Afurther focus lies on the aranchids' adaptation strategies in relation to tangible environmental conditions within their habitats. Of special interest is, whether and to what extent supposedly harsh alpine environmental factors affect the lifehistory and reproductive traits of arachnids at multiple scales. Therefore, a network along a continentality, an elevational and (micro) topographic gradients has been installed. The network consists of pitfall traps and data loggers, recording microclimatic factors. Furthermore, vegetation composition and snow height and distribution were recorded. This multiscale network was implemented at two research areas in Southern Norway: one is situated in the more oceanic part close to Stranda (Møre og Romsdal), while the other site near Vågå (Oppland) is characterized by a rather continental climate. With regard to the spatial patterns of Araneae, the results of this study, show a pronounced annidation along the elevational as well as the topographic gradient. Surprisingly, the influence of continentality weakens above the treeline in favor of smallscale environmental factors (Chapter 2). It is generally assumed that body sizes of spider individuals decrease with elevation and the increase of adverse environmental conditions. In this study, this trend could not be verified for the wolf spider Pardosa palustris. In fact, the elevationrelated environmental conditions were superimposed by topographic influences. However, in direct comparison of the two research sites, specimens caught at the more continental site were significantly larger than at the oceanic site. This denotes a rather prolonged life history trait in the continental part Vågå (Chapter 3). Focussing on the elevational adaptation of reproductive strategies of five wolf spiders of the genus Pardosa with partly differing habitat preferences, no common adaptation patterns along three elevational gradients in the continental research area could be identified. The assumption, that females would with increasing elevation decrease the number of eggs in favor of a larger egg size could not be verified (Chapter 4). One of the most common epigeic species trapped within this study has been the Opilionid species Mitopus morio. Here, we could show, how macroas well as microclimatic conditions influence the activity pattern of M. morio along different environmental gradients (Chapter 5). As a result of the great amount of trapped epigeic Artropods, it was possible to describe a new species and its habitat for Fennoscandia: the Oribatid mite Provertex kuhnelti could be confirmed at an alpine ridge in the oceanic research site. With this finding, the distribution of Provertex kuhnelti can now be described as “boreoalpine” (Chapter 6). In summary it can be stated that in relation to the multiscale approach and the sampling along three environmental gradients this thesis enables for the identification of driving forces for species annidation. Moreover, some of the influences of ecological parameters on lifehistory and reproductive traits could be identified. This thesis underlines the importance of measuring environmental parameters on a fine scale to better understand alpine tundra ecosystems

Drought sensitivity of Empetrum nigrum shrub growth at the species' southern lowland distribution range margin

The ongoing warming of the Earth's atmosphere is projected to cause a northward shift of species' distributions, as they track their climatic optimum. In the rapidly warming Arctic, this has already led to an increase of shrubs in tundra ecosystems. While this northern expansion of woody biomass has been studied relatively extensively over the last decade, little research has been devoted to shrub growth responses at the southern margins of Northern Hemisphere shrubs. Here, we studied shoot length growth, its responses to climate over the period 2010-2017, and differences in leaf C and N content of the evergreen dwarf shrub Empetrum nigrum, as well as the vegetation composition and soil parameters at four sites located along a gradient of increasing dune age on the island Spiekeroog, northern Germany. The sites are located in the tri-national UNESCO world heritage site, the Wadden Sea. E. nigrum has a predominantly circum-arctic-boreal distribution and its southern distribution margin in European lowlands runs through northern Germany, where it is retreating northwards. We found a negative response to autumn (surface) temperatures and previous summer surface temperatures and/or a positive response to summer precipitation of E. nigrum growth, except at the oldest dune with the strongest E. nigrum dominance. Growth rates and plant species diversity declined with dune age. Our results suggest that E. nigrum growth is drought sensitive at its European southern range margin. We hypothesize that this sensitivity may form the basis for its northward retreat, which is supported by recent observations of E. nigrum dieback in Germany after the extreme drought in 2018 and model projections

A cross-sectional study of self-reported chemical-related sensitivity is associated with gene variants of drug-metabolizing enzymes

BACKGROUND: N-acetyltransferases (NAT) and glutathione S-transferases (GST) are involved in the metabolism of several ubiquitous chemical substances leading to the activation and detoxification of carcinogenic heterocyclic and aromatic amines. Since polymorphisms within these genes are described to influence the metabolism of ubiquitous chemicals, we conducted the present study to determine if individuals with self-reported chemical-related sensitivity differed from controls without self-reported chemical-related sensitivity with regard to the distribution of genotype frequencies of NAT2, GSTM1, GSTT1, and GSTP1 polymorphisms. METHODS: Out of 800 subjects who answered a questionnaire of ten items with regard to their severity of chemical sensitivity 521 unrelated individuals agreed to participate in the study. Subsequently, genetic variants of the NAT2, GSTM1, GSTT1, and GSTP1 genes were analyzed. RESULTS: The results show significant differences between individuals with and without self-reported chemical-related sensitivity with regard to the distribution of NAT2, GSTM1, and GSTT1 gene variants. Cases with self-reported chemical-related sensitivity were significantly more frequently NAT2 slow acetylators (controlled OR = 1.81, 95% CI = 1.27–2.59, P = 0.001). GSTM1 and GSTT1 genes were significantly more often homozygously deleted in those individuals reporting sensitivity to chemicals compared to controls (GSTM1: controlled OR 2.08, 95% CI = 1.46–2.96, P = 0.0001; GSTT1: controlled OR = 2.80, 95% CI = 1.65–4.75, P = 0.0001). Effects for GSTP1 gene variants were observed in conjunction with GSTM1, GSTT1 and NAT2 gene. CONCLUSION: The results from our study population show that individuals being slow acetylators and/or harbouring a homozygous GSTM1 and/or GSTT1 deletion reported chemical-related hypersensitivity more frequently

Judicial decision-making within political parties: A political approach

How do German intra-party tribunals manage internal conflicts? More specifically, why do they accept some cases for trial but reject others? Required by law to strictly adhere to implement rule of law standards, German intra-party tribunals are designed to insulate conflict regulation from politics. Meanwhile, research on judicial politics highlights the role of political and strategic considerations in accepting cases for trial. Building on the latter, we develop a theory that emphasizes tribunals’ political concerns such as winning elections. We test our hypotheses with a mixed-effects logit model on a novel data set covering 1088 tribunal decisions in six German parties from 1967 until 2015. Our findings indicate that political factors exert a strong effect on tribunal case acceptance. Tribunals are more likely to accept cases when suffering electoral loss and after losing government office. Moreover, tribunals dismiss cases more easily when their parties display relatively high levels of policy agreement

Adaptability of Millets and Landscapes: Ancient Cultivation in North-Central Asia

Millet is a highly adaptable plant whose cultivation dramatically altered ancient economies in northern Asia. The adoption of millet is associated with increased subsistence reliability in semi-arid settings and perceived as a cultigen compatible with pastoralism. Here, we examine the pace of millet’s transmission and locales of adoption by compiling stable carbon isotope data from humans and fauna, then comparing them to environmental variables. The Bayesian modelling of isotope data allows for the assessment of changes in dietary intake over time and space. Our results suggest variability in the pace of adoption and intensification of millet production across northern Asia.</jats:p

Assessment of variation in immunosuppressive pathway genes reveals TGFBR2 to be associated with risk of clear cell ovarian cancer.

BACKGROUND: Regulatory T (Treg) cells, a subset of CD4+ T lymphocytes, are mediators of immunosuppression in cancer, and, thus, variants in genes encoding Treg cell immune molecules could be associated with ovarian cancer. METHODS: In a population of 15,596 epithelial ovarian cancer (EOC) cases and 23,236 controls, we measured genetic associations of 1,351 SNPs in Treg cell pathway genes with odds of ovarian cancer and tested pathway and gene-level associations, overall and by histotype, for the 25 genes, using the admixture likelihood (AML) method. The most significant single SNP associations were tested for correlation with expression levels in 44 ovarian cancer patients. RESULTS: The most significant global associations for all genes in the pathway were seen in endometrioid ( p = 0.082) and clear cell ( p = 0.083), with the most significant gene level association seen with TGFBR2 ( p = 0.001) and clear cell EOC. Gene associations with histotypes at p < 0.05 included: IL12 ( p = 0.005 and p = 0.008, serous and high-grade serous, respectively), IL8RA ( p = 0.035, endometrioid and mucinous), LGALS1 ( p = 0.03, mucinous), STAT5B ( p = 0.022, clear cell), TGFBR1 ( p = 0.021 endometrioid) and TGFBR2 ( p = 0.017 and p = 0.025, endometrioid and mucinous, respectively). CONCLUSIONS: Common inherited gene variation in Treg cell pathways shows some evidence of germline genetic contribution to odds of EOC that varies by histologic subtype and may be associated with mRNA expression of immune-complex receptor in EOC patients

Parasitoids indicate major climate-induced shifts in arctic communities

Climatic impacts are especially pronounced in the Arctic, which as a region is warming twice as fast as the rest of the globe. Here, we investigate how mean climatic conditions and rates of climatic change impact parasitoid insect communities in 16 localities across the Arctic. We focus on parasitoids in a widespread habitat,Dryasheathlands, and describe parasitoid community composition in terms of larval host use (i.e., parasitoid use of herbivorous Lepidoptera vs. pollinating Diptera) and functional groups differing in their closeness of host associations (koinobionts vs. idiobionts). Of the latter, we expect idiobionts-as being less fine-tuned to host development-to be generally less tolerant to cold temperatures, since they are confined to attacking hosts pupating and overwintering in relatively exposed locations. To further test our findings, we assess whether similar climatic variables are associated with host abundances in a 22 year time series from Northeast Greenland. We find sites which have experienced a temperature rise in summer while retaining cold winters to be dominated by parasitoids of Lepidoptera, with the reverse being true for the parasitoids of Diptera. The rate of summer temperature rise is further associated with higher levels of herbivory, suggesting higher availability of lepidopteran hosts and changes in ecosystem functioning. We also detect a matching signal over time, as higher summer temperatures, coupled with cold early winter soils, are related to high herbivory by lepidopteran larvae, and to declines in the abundance of dipteran pollinators. Collectively, our results suggest that in parts of the warming Arctic,Dryasis being simultaneously exposed to increased herbivory and reduced pollination. Our findings point to potential drastic and rapid consequences of climate change on multitrophic-level community structure and on ecosystem functioning and highlight the value of collaborative, systematic sampling effort