Microbial communities in alpine environments are exposed to several environmental factors related to elevation and local site conditions and to extreme seasonal variations. However, little is known on the combined impact of such factors on microbial community structure. We assessed the effects of seasonal variations on soil fungal and bacterial communities along an elevational gradient (from alpine meadows to a glacier forefield, 1930–2519 m a.s.l.) over 14 months. Samples were taken during all four seasons, even under the winter snowpack and at snowmelt. Microbial community structures and abundances were investigated using Terminal Restriction Fragment Length Polymorphism (T-RFLP) and quantitative PCR (qPCR) of the 16S and 18S rRNA genes. Illumina sequencing was performed to identify key bacterial groups in selected samples. We found that the soil properties varied significantly with the seasons and along the elevational gradient. For example, concentrations of soluble nutrients (e.g., NH4+-N, SO42−-S, PO43−-P) significantly increased in October but decreased drastically under the winter snowpack. At all times, the alpine meadows showed higher soluble nutrient concentrations than the glacier forefield. Microbial community structures at the different sites were strongly affected by seasonal variations. Under winter snowpack, bacterial communities were dominated by ubiquitous groups (i.e., beta-Proteobacteria, which made up to 25.7% of the total reads in the glacier forefield). In the snow-free seasons, other groups (i.e., Cyanobacteria) became more abundant (from 1% under winter snow in the glacier forefield samples to 8.1% in summer). In summary, elevation had a significant effect on soil properties, whereas season influenced soil properties as well as microbial community structure. Vegetation had a minor impact on microbial communities. At every elevation analyzed, bacterial, and fungal community structures exhibited a pronounced annual cycle.

A 14 kb region of genomic DNA containing the X-linked Anopheles gambiae eye colour gene, white, was cloned and sequenced. Genomic clones containing distinct white+ alleles were polymorphic for the insertion of a small transposable element in intron 3, and differed at 1% of nucleotide positions compared. Sequence was also determined from a rare 2914 bp cDNA. Comparison of cDNA and genomic sequences established an intron-exon structure distinct from Drosophila white. Despite a common trend in Anopheles and Drosophila of weak codon bias given low levels of gene expression, codon usage by Anopheles gambiae white was strongly biased. Overall amino acid identity between the predicted mosquito and fruitfly proteins was 64%, but dropped to 14% at the amino terminus. To correlate phenotypically white-eyed strains of A. gambiae with structural lesions in white, five available strains were analysed by PCR and Southern blotting. Although these strains carried allelic mutations, independently generated by gamma radiation (three strains) or spontaneous events (two strains), no white lesions were detected. Significantly, another non-allelic X-linked mutation, causing an identical white-eyed phenotype, has been correlated with a structural defect in the cloned white gene (Benedict et al., 1995). Taken together, these observations suggest that the white-eyed mutants analysed in the present study carry mutations in a second eye colour gene and are most likely white+.

Spatial variation in pathogen-mediated selection is predicted to influence the evolutionary trajectory of host populations and lead to spatial variation in their immunogenetic composition. However, to date few studies have been able to directly link small-scale spatial variation in infection risk to host immune gene evolution in natural, nonhuman populations. Here, we use a natural rodent-Borrelia system to test for associations between landscape-level spatial variation in Borrelia infection risk along replicated elevational gradients in the Swiss Alps and Toll-like receptor 2 (TLR2) evolution, a candidate gene for Borrelia resistance, across bank vole (Myodes glareolus) populations. We found that Borrelia infection risk (i.e., the product of Borrelia prevalence in questing ticks and the average tick load of voles at a sampling site) was spatially variable and significantly negatively associated with elevation. Across sampling sites, Borrelia prevalence in bank voles was significantly positively associated with Borrelia infection risk along the elevational clines. We observed a significant association between naturally occurring TLR2 polymorphisms in hosts and their Borrelia infection status. The TLR2 variant associated with a reduced likelihood of Borrelia infection was most common in rodent populations at lower elevations that face a high Borrelia infection risk, and its frequency changed in accordance with the change in Borrelia infection risk along the elevational clines. These results suggest that small-scale spatial variation in parasite-mediated selection affects the immunogenetic composition of natural host populations, providing a striking example that the microbial environment shapes the evolution of the host's immune system in the wild.

Glacial phases during the Pleistocene caused remarkable changes in species range distributions, with inevitable genetic consequences. Specifically, during interglacial phases, when the ice melted and new habitats became suitable again, species could recolonize regions that were previously covered by ice, such as high latitudes and elevations. Based on theoretical models and empirical data, a decrease in genetic variation is predicted along recolonization routes as a result of the consecutive founder effects that characterize the recolonization process. In the present study, we assessed the relative importance of historical and contemporary processes in shaping genetic diversity and differentiation of bank vole (Myodes glareolus) populations at different elevations in the Swiss Alps. By contrast to expectations, we found that genetic variation increased with elevation. Estimates of recent migration rates and a contrasting pattern of genetic differentiation observed at the mitochondrial cytochrome b gene and nuclear microsatellites support the hypothesis that higher genetic diversity at high elevation results from contemporary gene flow. Although historical recolonization processes can have marked effects on the genetic structure of populations, the present study provides an example where contemporary processes along an environmental gradient can reverse predicted patterns of genetic variation.

88 89 90 Tõnu Talvi 91 Environmental Board of the Estonian Ministry of Environment, Viidumäe, 93343 Saaremaa, 92 Estonia 93 94 Manuela von Arx 95 KORA -Carnivore Ecology and Wildlife Management, Thunstrasse 31, 3074 Muri b. Bern, 96 Switzerland 97 98 Figure legends: 160. 105 N. of tables: 1 106 N. of figures: 4 107 N. of references: 30 108 109 SUMMARY 110 • Sharing space with large carnivores on a human-dominated continent like Europe results 111 in multiple conflictful interactions with human interests, of which depredation on 112 livestock is the most widespread. Wildlife management agencies maintain compensation 113 programs for the damage caused by large carnivores, but the long-term effectiveness of 114 such programs is often contested. Therefore, understanding the mechanisms driving large 115 carnivore impact on human activities is necessary to identify key management actions to 116 reduce it. 117 • We conducted an analysis of the impact by all four European large carnivores on sheep 118 husbandry in 10 European countries, during the period 2010-2015. We ran a hierarchical 119 Simultaneous Autoregressive model, to assess the influence of ecological and 120 anthropogenic factors on the spatial and temporal patterns in the reported depredation 121 levels across the continent. 122 • On average, about 35,000 sheep were compensated in the ten countries as killed by large 123 carnivores annually, representing about 0.5% of the total sheep stock. Of them, 45% were 124 recognized as killed by wolves, 24% by wolverines, 19% by lynx and 12% by bears. At 125 the continental level, we found a positive relationship between wolf distribution and the 126 number of compensated sheep, but not for the other three species. Impact levels were 127 lower in the areas where large carnivore presence has been continuous compared to areas 128 where they disappeared and recently returned. The model explained 62% of the variation 129 in the number of compensated sheep per year in each administrative unit. Only 13% of 130 the variation was related to the ecological components of the process. 131 • Synthesis and Applications: Large carnivore distribution and local abundance alone are 132 poor predictors of large carnivore impact on livestock at the continental level. A few 133 individuals can produce high damage, when the contribution of environmental, social and 134 economic systems predisposes for it, whereas large populations can produce a limited 135 impact when the same components of the system reduce the probability that depredations 136 occur. Time seems to play in favour of a progressive reduction in the costs associated 137 with coexistence, provided that the responsible agencies focus their attention both on 138 compensation and co-adaptation.