Climate-induced decline in the quality and quantity of European hops calls for immediate adaptation measures.

A recent rise in the global brewery sector has increased the demand for high-quality, late summer hops. The effects of ongoing and predicted climate change on the yield and aroma of hops, however, remain largely unknown. Here, we combine meteorological measurements and model projections to assess the climate sensitivity of the yield, alpha content and cone development of European hops between 1970 and 2050 CE, when temperature increases by 1.4 °C and precipitation decreases by 24 mm. Accounting for almost 90% of all hop-growing regions, our results from Germany, the Czech Republic and Slovenia show that hop ripening started approximately 20 days earlier, production declined by almost 0.2 t/ha/year, and the alpha content decreased by circa 0.6% when comparing data before and after 1994 CE. A predicted decline in hop yield and alpha content of 4-18% and 20-31% by 2050 CE, respectively, calls for immediate adaptation measures to stabilize an ever-growing global sector.

Sustainable cultivation of the white truffle (Tuber magnatum) requires ecological understanding.

The white truffle (Tuber magnatum Picco.; WT) is the most expensive and arguably also the most delicious species within the genus Tuber. Due to its hidden belowground life cycle, complex host symbiosis, and yet unknown distribution, cultivation of the enigmatic species has only recently been achieved at some plantations in France. A sustainable production of WTs under future climate change, however, requires a better ecological understanding of the species' natural occurrence. Here, we combine information from truffle hunters with a literature review to assess the climatic, edaphic, geographic, and symbiotic characteristics of 231 reported WT sites in southeast Europe. Our meta-study shows that 75% of the WT sites are located outside the species' most famous harvest region, the Piedmont in northern Italy. Spanning a wide geographic range from ~ 37° N in Sicily to ~ 47° N in Hungary, and elevations between sea level in the north and 1000 m asl in the south, all WT sites are characterised by mean winter temperatures > 0.4 °C and summer precipitation totals of ~ 50 mm. Often formed during past flood or landslide events, current soil conditions of the WT sites exhibit pH levels between 6.4 and 8.7, high macroporosity, and a cation exchange capacity of ~ 17 meq/100 g. At least 26 potential host species from 12 genera were reported at the WT sites, with Populus alba and Quercus cerris accounting for 23.5% of all plant species. We expect our findings to contribute to a sustainable WT industry under changing environmental and economic conditions.

CESNET-QUIC22: A large one-month QUIC network traffic dataset from backbone lines.

The QUIC (Quick UDP Internet Connection) protocol has the potential to replace TLS over TCP, which is the standard choice for reliable and secure Internet communication. Due to its design that makes the inspection of QUIC handshakes challenging and its usage in HTTP/3, there is an increasing demand for research in QUIC traffic analysis. This dataset contains one month of QUIC traffic collected in an ISP backbone network, which connects 500 large institutions and serves around half a million people. The data are delivered as enriched flows that can be useful for various network monitoring tasks. The provided server names and packet-level information allow research in the encrypted traffic classification area. Moreover, included QUIC versions and user agents (smartphone, web browser, and operating system identifiers) provide information for large-scale QUIC deployment studies.

Collection of datasets with DNS over HTTPS traffic.

Recently, the Internet has adopted the DNS over HTTPS (DoH) resolution mechanism for privacy-aware network applications. As DoH becomes more disseminated, it has also become a network monitoring research topic. For comprehensive evaluation and comparison of developed classifiers, real-world datasets are needed, motivating this contribution. We created a new large-scale collection of datasets consisting of two classes of traffic: i) DoH HTTPS communication and ii) non-DoH HTTPS connections. The DoH traffic is captured for multiple DoH providers and clients to include nuances of various DoH implementations and configurations. The non-DoH HTTPS connections complement the DoH communication aiming to include a wide range of existing network applications. The dataset collection consists of network traffic generated in a controlled environment and traffic captured from a real ISP network. The resulting datasets thus provide real-world network traffic data suitable for evaluating existing classifiers and the development of new methods.

Eco-archaeological excavation techniques reveal snapshots of subterranean truffle growth.

Despite its status as a highly-prized and coveted fungi in gastronomy, many aspects of the subterranean life cycle of the Burgundy truffle (Tuber aestivum) are still unknown, because in situ observations of the formation and maturation of truffle fruitbodies remain difficult. Here, we adopted a suite of archaeological fine-scale excavating techniques to provide unique spatiotemporal snapshots of Burgundy truffle growth at three sites in southern Germany. We also recorded the relative position, fresh weight, maturity level and genotype composition of all excavated fruitbodies. Varying by a factor of thousand, the fresh weight of 73 truffle ranged from 0.1 to 103.2 g, with individual maturity levels likely representing different life cycle stages from completely unripe to fully ripe and even decaying. While only a slightly positive relationship between fruitbody weight and maturity level was found, our results suggest that genetically distinct specimens can exhibit different life cycle stages at the same period of time and under the same environmental conditions. We therefore argue that truffles are likely able to grow, mature and ripe simultaneously between early summer and late winter of the following year. Our case study should encourage further eco-archaeological truffle excavations under different biogeographic settings and at different seasons of the year to gain deeper insights into the fungi's subterranean ecology. The expected cross-disciplinary findings will help truffle hunters and farmers to improve their harvest practices and management strategies.

Predicted climate change will increase the truffle cultivation potential in central Europe.

Climate change affects the distribution of many species, including Burgundy and Périgord truffles in central and southern Europe, respectively. The cultivation potential of these high-prized cash crops under future warming, however, remains highly uncertain. Here we perform a literature review to define the ecological requirements for the growth of both truffle species. This information is used to develop niche models, and to estimate their cultivation potential in the Czech Republic under current (2020) and future (2050) climate conditions. The Burgundy truffle is already highly suitable for cultivation on ~ 14% of agricultural land in the Czech Republic (8486 km2), whereas only ~ 8% of the warmest part of southern Moravia are currently characterised by a low suitability for Périgord truffles (6418 km2). Though rising temperatures under RCP8.5 will reduce the highly suitable cultivation areas by 7%, the 250 km2 (3%) expansion under low-emission scenarios will stimulate Burgundy truffles to benefit from future warming. Doubling the moderate and expanding the highly suitable land by 352 km2 in 2050, the overall cultivation potential for Périgord truffles will rise substantially. Our findings suggest that Burgundy and Périgord truffles could become important high-value crops for many regions in central Europe with alkaline soils. Although associated with uncertainty, long-term investments in truffle cultivation could generate a wide range of ecological and economic benefits.

The impact of the Gabcíkovo hydroelectric power barrier on the Danube floodplain environment-the results of long-term monitoring of land snail fauna.

The Gabcíkovo Water Project, a major construction of damming and canalizing on the upper part of the middle Danube, significantly changed hydrological regime of the Danube inland delta, destroyed or affected most of the 230 km2 of wetlands and directly disrupted the original and unique ecosystem along a 37 km long river stretch. The aim of this study was to describe the effect of the Gabcíkovo Waterworks on the taxonomical and functional structure of the molluscan assemblages in the Danube riparian floodplain forests. The results demonstrate that the Gabcíkovo Waterworks had a direct and long-lasting effect on the direction of the succession of terrestrial molluscan assemblages, especially in the area of the by-pass section. The changes in the soil moisture caused by the waterworks' operation led to significant changes in the species and functional composition of these assemblages. More specifically, however, the proportion of the generalists which prefer dry biotopes increased, while the number of moisture-demanding species decreased. Our results indicate that the current artificial flooding system cannot fully replace previous natural floods in the Danube inland delta, and it is also insufficient for restoration and preservation of the humidity conditions in the softwood floodplain forests which would be similar to the pre-operation period of the Gabcíkovo Waterworks.

Diversity and biotic homogenization of urban land-snail faunas in relation to habitat types and macroclimate in 32 central European cities.

The effects of non-native species invasions on community diversity and biotic homogenization have been described for various taxa in urban environments, but not for land snails. Here we relate the diversity of native and non-native land-snail urban faunas to urban habitat types and macroclimate, and analyse homogenization effects of non-native species across cities and within the main urban habitat types. Land-snail species were recorded in seven 1-ha plots in 32 cities of ten countries of Central Europe and Benelux (224 plots in total). Each plot represented one urban habitat type characterized by different management and a specific disturbance regime. For each plot, we obtained January, July and mean annual temperature and annual precipitation. Snail species were classified into either native or non-native. The effects of habitat type and macroclimate on the number of native and non-native species were analysed using generalized estimating equations; the homogenization effect of non-native species based on the Jaccard similarity index and homogenization index. We recorded 67 native and 20 non-native species. Besides being more numerous, native species also had much higher beta diversity than non-natives. There were significant differences between the studied habitat types in the numbers of native and non-native species, both of which decreased from less to heavily urbanized habitats. Macroclimate was more important for the number of non-native than native species; however in both cases the effect of climate on diversity was overridden by the effect of urban habitat type. This is the first study on urban land snails documenting that non-native land-snail species significantly contribute to homogenization among whole cities, but both the homogenization and diversification effects occur when individual habitat types are compared among cities. This indicates that the spread of non-native snail species may cause biotic homogenization, but it depends on scale and habitat type.