Regional Differences In Climate Research Articles

Environmental safety performance dynamics and Estimation of the deterioration of leachate containment elements: implications for the lifespan of hazardous waste landfills

In the coming decades, the failure and expiration of over 100,000 landfills involving billions of tons of waste not only threaten global water security but also lead to a sudden increase in the global demand for solid waste disposal. Therefore, further research is needed on the ways in which landfill performance is degraded, their life expectancy, the factors that influence them and the ways in which they are influenced. A study estimated the performance degradation and expected lifespan of a modern hazardous waste landfill in China. The landfill experienced slow performance degradation in early years (0-12 years). But during mid-term (12-62 years) due to the rapid degradation of the liner material, the rate of leakage from the containment layer will increase by a factor of 4.8-27.1, leading to its earliest failure after about 38 years. This indicates the need for measures to prevent rapid performance degradation in the middle of the landfill's service life and to strengthen monitoring of performance indicators and environmental medium pollution in the later period (after 62 years) to respond to potential scrapping and pollutant leakage problems. Differences in construction quality and regional climate can cause differences in the lifespan of landfill facilities by up to 20 and 30 times, highlighting the importance of scenario-based failure and lifespan prediction for designing reasonable monitoring plans and preparing response measures to prevent potential groundwater pollution and to meet the sudden increase in demand for secondary waste disposal.

Hydrothermal environments lead to differences in the radial growth response of Pinus tabulaeformis to climate in the monsoon marginal zone, Northwestern China

Regional climatic differences increase the complexity of tree radial growth responses to climate change in the monsoon marginal zones and may alter the carbon sequestration capacity of forests. In this study, we collected cores of Pinus tabulaeformis trees at nine sampling sites across different regions. We analysed the relationship between tree-ring width chronology and climatic factors at different sites using dendroecological methods. We used the tree-ring index to calculate resistance, recovery, and resilience as well as to explore the capacity of radial growth to cope with drought events. The results indicate that (1) Drought was the primary factor limiting tree growth, and tree-ring climate response patterns varied across three regions. Tree growth was sensitive to both temperature and precipitation in the eastern Qilian Mountains, while it was more sensitive to temperature in the Hassan Mountains and more sensitive to precipitation in the Helan Mountains. (2) The tree-ring climate response pattern remained unstable over time, and the relative influence of current climate on tree growth increased. (3) The ecological resilience of trees to extreme events varies across three regions, which could be attributed to regional moisture conditions and the duration of drought. In the context of the management and protection of trees in the study area in the future, more attention should be paid to the elasticity of tree growth after drought events.

Summer climate information recorded in tree-ring oxygen isotope chronologies from seven locations in the Republic of Korea

The Republic of Korea is characterized by its north-to-south stretch and high mountain ranges along the eastern coast, resulting in terrain with higher elevation in the east and lower in the west. These geographical features typically lead to regional climate differences, either based on latitude or from east to west. In the present study, for effectiveness, the entire Korean peninsula was divided into four regions based on the geographical features: The Northeast Coast (NEC), Central Inland (MI), Southeast Coast (SEC), and South Coast (SC). Two test sites were chosen from each region, except for the SC. The linear relationship between the altitude of sites and the mean oxygen isotope ratio (δ18O) revealed a negative correlation; the highest (1,447 m a.s.l.) and the lowest altitude (86 m a.s.l.) sites had a mean δ18O of 27.03‰ and 29.67‰, respectively. The sites selected from the same region exhibited stronger correlation coefficients (0.75–0.79) and Glk (Gleichläufigkeit) (74–83%) between the tree-ring oxygen isotope chronologies (δ18OTR chronologies) than those from different regions (0.60–0.69/70–79%). However, subtle variations in pattern were observed in the comparison period during a few selected intervals (approximately 10 years). All the regional δ18OTR chronologies exhibited positive correlations with either June or July temperatures over Korea, whereas negative correlations with regional summer precipitation and SPEI-3. Moreover, the chronologies showed notable negative correlations with the water condition of western Japan. The findings of this study can be used as a scientific reference for the study of variations of rainfall in East Asia using δ18OTR chronology.

Aerobic methane production in Scots pine shoots is independent of drought or photosynthesis.

Shoot-level emissions of aerobically produced methane (CH4) may be an overlooked source of tree-derived CH4, but insufficient understanding of the interactions between their environmental and physiological drivers still prevents the reliable upscaling of canopy CH4 fluxes. We utilised a novel automated chamber system to continuously measure CH4 fluxes from the shoots of Pinus sylvestris (Scots pine) saplings under drought to investigate how canopy CH4 fluxes respond to the drought-induced alterations in their physiological processes and to isolate the shoot-level production of CH4 from soil-derived transport and photosynthesis. We found that aerobic CH4 emissions are not affected by the drought-induced stress, changes in physiological processes, or decrease in photosynthesis. Instead, these emissions vary on short temporal scales with environmental drivers such as temperature, suggesting that they result from abiotic degradation of plant compounds. Our study shows that aerobic CH4 emissions from foliage are distinct from photosynthesis-related processes. Thus, instead of photosynthesis rates, it is more reliable to construct regional and global estimates for the aerobic CH4 emission based on regional differences in foliage biomass and climate, also accounting for short-term variations of weather variables such as air temperature and solar radiation.

A comprehensive evaluation method of heat source tower heat pump applicability considering regional climate differences

The heat source tower heat pump system is widely used in large and medium-sized air conditioning systems due to its good energy-saving advantages. However, there is no relatively reasonable evaluation system for the applicability of heat source tower heat pumps due to significant regional climate differences. Therefore, in order to better comprehensively evaluate the applicability of the heat source tower heat pump system, a comprehensive evaluation index system for the applicability of the heat source tower heat pump system was first constructed. On the basis of this evaluation index, an applicability evaluation model based on backpropagation neural network is constructed. In response to the slow convergence speed and susceptibility to local values in the application process of this evaluation model, particle swarm optimization algorithm is used to improve it. A comprehensive evaluation model for the applicability of heat source tower heat pumps based on improved backpropagation neural networks has been constructed. For the evaluation model constructed in the study, experimental data from four different regions were selected for validation. The experimental results show that in the training set, the F-Measure value of the evaluation model reaches 0.949, and in the test set, the F-Measure value of the model reaches 0.973. The comprehensive evaluation data from four regions indicate that the heat source tower heat pump system can achieve different heating and cooling effects in different regions. This indicates that the proposed comprehensive evaluation model for the applicability of heat source tower heat pumps based on this improved method has good evaluation results. It can conduct a good analysis of the applicability of the heat source tower heat pump system, providing effective support for developing reasonable and energy-saving refrigeration and heating methods in different regions.

Výskyt a význam kůrovců rodu Pityokteines v porostech jedle bělokoré (Abies alba)

Silver fir (Abies alba, Mill.) is threatened by many factors in Central Europe, among which bark beetles of the genus Pityokteines play an important role. To improve the silver fir conservation, it is essential to adopt appropriate management practices. For this reason, we studied the occurrence of Pityokteines bark beetles in four sites located in climatically different conditions. In each site, five WitaTrap 5-segment pheromone funnel traps were placed from early April to late September in both 2021 and 2022. Two species, P. spinidens and P. vorontzowi, were captured. P. vorontzowi was significantly more abundant at all sites. Individuals of both species were recorded in the traps mainly in the period of April–August. The most abundant occurrence of beetles was at the site Nižbor, which can be explained by regional climatic differences (lowest elevation, higher mean temperatures and lower mean precipitation). The differences between sites can be also explained by different methods of forest protection applied. The study confirmed the presence of Pityokteines bark beetles and their dependence on climatic characteristics and forest management.

Nutrient use by tropical ant communities varies among three extensive elevational gradients: A cross‐continental comparison

AbstractAimMany studies demonstrate that climate limits invertebrates along tropical elevational gradients, but we have only a rudimentary understanding of the role of nutrient limitation and climatic seasonality. Here we examined the relationships between ant community structure, nutrient use and season along three undisturbed elevational gradients, each from a different continent.LocationEcuador (South America), Papua New Guinea (PNG: Oceania), Tanzania (Africa).Time period2011–2014.Major taxa studiedAnts.MethodsAlong each of the three gradients, we placed six distinct nutrient types (amino acid, sucrose, sucrose + amino acid, lipid, NaCl, H2O). In total, we distributed 2370 baits at 38 sites from 203 m to 3972 m. We used generalized linear models to test for the effects of elevation and season on ant species richness and activity and relative nutrient use. We also tested if changes in ant trophic guilds corresponded to changes in the use of particular nutrients.ResultsBoth species richness and activity decreased with elevation along each gradient. However, there were significant interaction effects among elevation, region and season, as ant activity in the dry season was higher in Ecuador and Tanzania but lower in PNG. Relative nutrient use varied among regions: ant preference for some nutrients changed with increasing elevation in Ecuador (decrease in lipid use) and Tanzania (decrease in amino acid and H2O use), while season affected nutrient use in PNG. There were common trends in trophic guilds along the three elevational gradients (e.g. proportional increase of predators), but these did not explain most of the nutrient use patterns.Main conclusionWhile the structure of ant communities changed similarly with elevation, both the seasonal and elevational effects on nutrient use by ants differed between continents. We argue that regional differences in climate and nutrient availability rather than ant functional composition shape nutrient use by ants.

Soil moisture controls the partitioning of carbon stocks across a managed boreal forest landscape

Boreal forests sequester and store vast carbon (C) pools that may be subject to significant feedback effects induced by climatic warming. The boreal landscape consists of a mosaic of forests and peatlands with wide variation in total C stocks, making it important to understand the factors controlling C pool sizes in different ecosystems. We therefore quantified the total C stocks in the organic layer, mineral soil, and tree biomass in 430 plots across a 68 km2 boreal catchment. The organic layer held the largest C pool, accounting for 39% of the total C storage; tree and mineral C pools accounted for 38% and 23%, respectively. The size of the soil C pool was positively related to modelled soil moisture conditions, especially in the organic soil layer (R2 = 0.50). Conversely, the tree C pool exhibited a unimodal relationship: storage was highest under intermediate wetness conditions. The magnitude and variation in the total soil C stocks observed in this work were comparable to those found at the national level in Sweden, suggesting that C accumulation in boreal landscapes is more sensitive to local variation resulting primarily from differences in soil moisture conditions than to regional differences in climate, nitrogen deposition, and parent material.

A cosmogenic 10Be moraine chronology of arid, alpine Late Pleistocene glaciation in the Pioneer Mountains of Montana, USA

We test the hypothesis that glacier systems, located in continental regions proximal to the Laurentide Ice Sheet (LIS), had local ice maxima considerably earlier than the LIS maximum and thus before the insolation minima at ∼21 ka. Ranges located in the northwest US exhibit earlier deglaciation timing between ∼23 and 22 ka, except for the Yellowstone region where younger time-transgressive ages complicate regional interpretations and the northern Montana ice cap where late glacial ages have recently been produced. Constraining the glacial history of more ice sheet-proximal alpine glaciers provides insight into whether the contrasting maximum-ice times in the northern Rocky Mountains were caused by regional climatic differences, such as anticyclonic wind patterns driven by the presence of the LIS. In the Pioneer Mountains of Montana, we measured in situ cosmogenic 10Be in 35 boulders on moraines marking the maximum Late Pleistocene positions of alpine glaciers from three valleys. The 10Be samples produced a range of ages, spanning pre Bull Lake to the last glaciation (i.e., Pinedale/Marine Isotope Stage (MIS) 2). We find an average exposure age for initial deglaciation of 18.2 ± 0.9 during the local Last Glacial Maximum, indicative of synchronous retreat in the Pioneer Mountains. The similarity of initial deglaciation timing of the Pioneer Mountain glaciers with the northwestern Yellowstone glacial system and northern MT ice cap suggests that topography more proximal to the LIS margin maintained full ice extent longer. Our findings, in context of previous work, suggest that in the case of the Pioneer Mountains their more proximal location to the ice margin may have delayed onset of deglaciation by greater exposure to local cooling from katabatic winds and/or additional moisture sourced from large ice-marginal glacial lakes, hence the lack of earlier deglacial ages like those found further to the west and east of the northern Rocky Mountain cordillera.

Disentangling population genetic and climatic effects on skull size and shape of brown hares, Lepus europaeus (Lagomorpha: Leporidae), from Türkiye

Brown hares (Lepus europaeus) from Türkiye exhibit substantial phenotypic variation, assumingly connected to regional climate differences. We used general linear models (GLMs) of linear measurements and geometric morphometric data of dorsal and ventral skull and lateral mandible landmarks of 160 adult individuals from 75 locations across Türkiye, to specifically test for climate-related effects on skull size and shape, while accounting for potentially confounding effects of sex, geographic location, and population genetic assignment. We found a moderate positive correlation between individual condylobasal lengths (CBL) and centroid size scores (CSS) and used them separately as dependent skull size variables in our GLMs. Skull shape factors were obtained from principal component analyses (PCAs), separately for transformed linear morphometric and landmark data; they were also used as dependent variables in our GLMs, along with sex, geographic sampling coordinates, CBL or CSS, as well as temperature and precipitation factors from PCAs of local climate data as fixed factors. Our multivariate GLMs returned no climate effect on skull size and only one minor precipitation effect on geometric skull shape. Rather, skull size and shape were predominantly and significantly affected by the assignment of the hares to the genetic populations as determined by an earlier microsatellite study. Our results correspond to microphylogeographic differentiation of skull size and shape of the studied hares, largely indepedent of specific adaptation to local or regional climate.

Variation of δ15N in Indian coal, lignite and peat

Nitrogen (N) stable isotope ratio (δ15N) in coal organic matter (OM) provides information on the N source and dominant mechanisms affecting isotopic fractionation during coalification. However, published data on δ15N distribution in coal is rare. The present study is one of the first reports on the δ15N composition of peat, lignite, sub-bituminous and anthracite coals in India and one of the first attempts to understand the processes influencing δ15N composition at different stages of coalification from peat to anthracite. Peats were collected from the western coast of North Andaman Islands and Lake Loktak in Manipur. Plant samples were collected from the peat sampling locations. Cenozoic lignites were collected from Panandhro, Matanomadh, Umarsar and Tadkeshwar mines in Gujarat and Neyveli in Tamil Nadu. Cenozoic sub-bituminous and Permian anthracite coals were collected from Assam and Sikkim, respectively. Variation of δ15N in plants is attributed to the differences in rainfall, plant type and N sources. Lower δ15N values in peats (mean 1.19) compared to the plant samples (mean 2.77) indicate a nonlinear response of δ15N to the relative enrichment or loss of N during peat formation in Lake Loktak and decomposition of OM under anaerobic conditions leading to selective preservation of 14N in the Andaman Islands. The δ15N composition of the studied peat (−1.4–1.6), lignite (−1.4–1.8) and coals (−2.8–5.0) retains their OM source signature. Overall higher δ15N values of Cenozoic lignites compared to the Cenozoic sub-bituminous coal reflects regional differences in climate. Higher δ15N (1.3–5.0) values in Gondwana anthracites reflects the tectonic influence of Himalayan orogeny.

Spatio-Temporal Analysis of Simulated Summer Extreme Precipitation Events under RCP4.5 Scenario in the Middle and Lower Reaches of the Yangtze River Basin

In the context of global warming, the frequency and intensity of extreme climate events, especially extreme precipitation events, have increased. The middle and lower reaches of the Yangtze River Basin are important areas for economic development, and are also one of the areas where rainstorms and flood disasters frequently occur in China. Improving the prediction of future summer extreme precipitation in this region under the greenhouse gas emission pathway that aligns with sustainable economic development (Representative Concentration Pathway 4.5, RCP4.5) will help decision-makers better cope with the impact of increased natural disasters, such as floods. The medium-resolution CESM1.0 (Community Earth System Model 1.0) data (1° × 1°) has limitations in capturing regional climate differences. Therefore, we designed a downscale experiment using the WRF3.8 (Weather Research and Forecasting 3.8) model to obtain the daily summer precipitation grid data with 0.25° × 0.25° latitude and longitude resolution over the middle and lower reaches of the Yangtze River Basin from May to September in 2006–2030 (WRF025). The research shows that the WRF025 data is reliable in simulating the summer extreme precipitation events over the middle and lower reaches of the Yangtze River Basin, especially in the lower reaches of the Yangtze River. Compared to CESM1.0 data, WRF025 data significantly improves the ability to simulate the numerical value and distribution of summer extreme precipitation in the middle and lower reaches of the Yangtze River. Under the RCP4.5 scenario, compared to 2006–2014, there is no significant change in daily summer precipitation in the middle and lower reaches of the Yangtze River Basin during 2015–2030, with a significant decrease in daily summer extreme precipitation. There are significant regional differences in spatial distribution, with a significant decrease in Hunan and Hubei, and a significant increase in Jiangxi and Fujian. Under high-pressure control, the lower reaches of the Yangtze River are dominated by downdraft, resulting in more sunny days and less precipitation. The increase (decrease) in water vapor transport and divergence may be the reason for the increase (decrease) in extreme precipitation. The most direct factor leading to an increase (decrease) in extreme precipitation is the vertical movement upwards (downwards). Furthermore, the anomalous descent (ascent) can be well explained by the easterly (westerly) wind anomaly on the southern (northern) side of the anomalous anticyclone via the isentropic gliding mechanism.

Climate changes during the Late Glacial in southern Europe: new insights based on pollen and brGDGTs of Lake Matese in Italy

Abstract. The Late Glacial (14 700–11 700 cal BP) is a key climate period marked by rapid but contrasted changes in the Northern Hemisphere. Indeed, regional climate differences have been evidenced during the Late Glacial in Europe and the northern Mediterranean. However, past climate patterns are still debated since temperature and precipitation changes are poorly investigated towards the lower European latitudes. Lake Matese in southern Italy is a key site in the central Mediterranean to investigate climate patterns during the Late Glacial. This study aims to reconstruct climate changes and their impacts at Matese using a multi-proxy approach including magnetic susceptibility, geochemistry (XRF core scanning), pollen data and molecular biomarkers like branched glycerol dialkyl glycerol tetraethers (brGDGTs). Paleotemperatures and paleo-precipitation patterns are quantitatively inferred from pollen assemblages (multi-method approach: modern analogue technique, weighted averaging partial least-squares regression, random forest and boosted regression trees) and brGDGT calibrations. The results are compared to a latitudinal selection of regional climate reconstructions in Italy to better understand climate processes in Europe and in the circum-Mediterranean region. A warm Bølling–Allerød and a marked cold Younger Dryas are revealed in all climate reconstructions inferred from various proxies (chironomids, ostracods, speleothems, pollen, brGDGTs), showing no latitudinal differences in terms of temperatures across Italy. During the Bølling–Allerød, no significant changes in terms of precipitation are recorded; however, a contrasted pattern is visible during the Younger Dryas. Slightly wetter conditions are recorded south of 42∘ N, whereas dry conditions are recorded north of 42∘ N. During the Younger Dryas, cold conditions can be attributed to the southward position of North Atlantic sea ice and of the polar frontal jet stream, whereas the increase in precipitation in southern Italy seems to be linked to relocation of Atlantic storm tracks into the Mediterranean, induced by the Fennoscandian ice sheet and the North European Plain. By contrast, warm conditions during the Bølling–Allerød can be linked to the northward position of North Atlantic sea ice and of the polar frontal jet stream.

An Intelligent Anomaly Detection Approach for Accurate and Reliable Weather Forecasting at IoT Edges: A Case Study.

Industrialization and rapid urbanization in almost every country adversely affect many of our environmental values, such as our core ecosystem, regional climate differences and global diversity. The difficulties we encounter as a result of the rapid change we experience cause us to encounter many problems in our daily lives. The background of these problems is rapid digitalization and the lack of sufficient infrastructure to process and analyze very large volumes of data. Inaccurate, incomplete or irrelevant data produced in the IoT detection layer causes weather forecast reports to drift away from the concepts of accuracy and reliability, and as a result, activities based on weather forecasting are disrupted. A sophisticated and difficult talent, weather forecasting needs the observation and processing of enormous volumes of data. In addition, rapid urbanization, abrupt climate changes and mass digitization make it more difficult for the forecasts to be accurate and reliable. Increasing data density and rapid urbanization and digitalization make it difficult for the forecasts to be accurate and reliable. This situation prevents people from taking precautions against bad weather conditions in cities and rural areas and turns into a vital problem. In this study, an intelligent anomaly detection approach is presented to minimize the weather forecasting problems that arise as a result of rapid urbanization and mass digitalization. The proposed solutions cover data processing at the edge of the IoT and include filtering out the missing, unnecessary or anomaly data that prevent the predictions from being more accurate and reliable from the data obtained through the sensors. Anomaly detection metrics of five different machine learning (ML) algorithms, including support vector classifier (SVC), Adaboost, logistic regression (LR), naive Bayes (NB) and random forest (RF), were also compared in the study. These algorithms were used to create a data stream using the time, temperature, pressure, humidity and other sensor-generated information.

Climatic Niche Conservatism and Ecological Diversification in the Holarctic Cold-Dwelling Butterfly GenusErebia

AbstractThe diversification of alpine species has been modulated by their climatic niches interacting with changing climatic conditions. The relative roles of climatic niche conservatism promoting geographical speciation and of climatic niche diversification are poorly understood in diverse temperate groups. Here, we investigate the climatic niche evolution in a species rich butterfly genus, Erebia (Dalman, 1816). This Holarctic cold-dwelling genus reaches the highest diversity in European mountains. We generated a nearly complete molecular phylogeny and modeled the climatic niche evolution using geo-referenced occurrence records. We reconstructed the evolution of the climatic niche and tested how the species’ climatic niche width changes across the occupied climate gradient and compared two main Erebia clades, the European and the Asian clade. We further explored climatic niche overlaps among species. Our analyses revealed that the evolution of Erebia has been shaped by climatic niche conservatism, supported by a strong phylogenetic signal and niche overlap in sister species, likely promoting allopatric speciation. The European and the Asian clades evolved their climatic niches toward different local optima. In addition, species in the European clade have narrower niches compared to the Asian clade. Contrasts among the clades may be related to regional climate differences, with lower climate seasonality in Europe compared to Central Asia favoring the evolution of narrower niches. Further, adaptive divergence could appear in other traits, such as habitat use, which can be reflected by narrower climatic niches detected in the European clade. Our study extends knowledge about the complexity of evolutionary drivers in temperate insects.

Does climate play a more important role than competition in modeling height to crown base of Larix principis-rupprechtii in northern China?

Competition is the major factor influencing crown recession rates and therefore plays an important role in height to crown base (HCB) modeling. However, few studies have directly investigated the effects of climate on HCB modeling. In this study, a climate-sensitive individual tree HCB model was developed using measurements from a total of 9902 Rupprecht larch (Larix principis-rupprechtii Mayr) trees on 156 sample plots located in northern China. The impacts of tree height, inter-tree competition, site condition, and climate on HCB modeling were assessed using the mixed-effects modeling approach. Results showed that HCB increased with tree height and competition intensity. The inclusion of climate variables significantly improved model performance. HCB was negatively associated with mean temperature of the coldest month and positively associated with autumn precipitation averaged over the previous five years. According to hierarchical partitioning analysis, tree height is the most important factor affecting HCB (relative contribution 50.03%), followed by climate (22.51%), inter-tree competition (20.17%), and site condition (6.06%). Our findings highlighted the importance of considering regional climate differences in improving HCB predictions at a large spatial scale. Disentangling different sources of variations in HCB will help advance our understanding of the factors driving crown recession and reduce uncertainty in predicting crown characteristics under changing climates.

Estimating Large-Scale Interannual Dynamic Impervious Surface Percentages Based on Regional Divisions

Impervious surface information is an important indicator to describe urban development and environmental changes. The substantial increase in impervious surface area will have a significant impact on the regional landscape and environment. Therefore, the timely and accurate acquisition of large-scale impervious surface percentage (LISP) is of great significance for urban management and ecological assessment. However, previous LISP estimation methods often ignored the impact of regional geographic environment and climate differences on remote sensing information, resulting in low overall accuracy and obvious regional differences in the estimated results. Thus, in this study, based on the time-series characteristics of multi-temporal remote sensing images combined with the information on geographical environment and climate heterogeneity, a method of time-series remote sensing image fusion and LISP estimation based on regional divisions was proposed. Firstly, the entire region was divided into several regions according to the spatial differences of Köppen–Geiger climate data and MODIS NDVI time-series data. Subsequently, adaptive time-series image fusion methods and remote sensing feature construction methods were proposed for different regions. Finally, the proposed method was used to estimate the percentage of impervious surfaces in other years in Asia. The results indicate that the overall R2 of each region is better than 0.82, and the estimation models have a good ability to transfer across time and can directly estimate the impervious surface percentage in other years without using additional samples. In addition, compared with other existing impervious surface products, the proposed method has higher overall estimation accuracy and regional consistency.

Natural and anthropogenic controls on lake water-level decline and evaporation-to-inflow ratio in the conterminous United States.

Lake water levels are integral to lake function, but hydrologic changes from land and water management may alter lake fluctuations beyond natural ranges. We constructed a conceptual model of multifaceted drivers of lake water-levels and evaporation-to-inflow ratio (Evap:Inflow). Using a structural equation modeling framework, we tested our model on 1) a national subset of lakes in the conterminous United States with minimal water management to describe natural drivers of lake hydrology and 2) five ecoregional subsets of lakes to explore regional variation in water management effects. Our model fit the national and ecoregional datasets and explained up to 47% of variation in Evap:Inflow, 38% of vertical water-level decline, and 79% of horizontal water-level decline (littoral exposure). For lakes with minimal water management, Evap:Inflow was related to lake depth (β = -0.31) and surface inflow (β = -0.44); vertical decline was related to annual climate (e.g., precipitation β = -0.18) and water management (β = -0.21); and horizontal decline was largely related to vertical decline (β = 0.73) and lake morphometry (e.g., depth β = -0.18). Anthropogenic effects varied by ecoregion and likely reflect differences in regional water management and climate. In the West, water management indicators were related to greater vertical decline (β = 0.38), whereas in the Midwest, these indicators were related to more stable and full lake levels (β = -0.22) even during drought conditions. National analyses show how human water use interacts with regional climate resulting in contrasting impacts to lake hydrologic variation in the US.

Climate History of the Principality of Transylvania during the Maunder Minimum (MM) Years (1645–1715 CE) Reconstructed from German Language Sources

This paper deals with the climate in the former Grand Duchy of Transylvania, now one of the three major geographical provinces of Romania, within the so-called Maunder Minimum (MM) (1645–1715), an astrophysically defined part of the Little Ice Age (LIA), which was characterized by reduced solar activity. The historical data from Transylvania are compared with that from Germany, Austria and Switzerland. This comparison for the period 1645–1715 shows good agreement but also reveals geographic characteristics of the region. For the first time, we present here a comparison between the four geographic areas in text and tabular form. Quotes from mostly German-language sources are reproduced in English translation. The results clearly help to identify regional climatic differences during the MM. Furthermore, we examine for a longer period (1500–1950) the extent to which the climate of Transylvania might have been affected by long-term fluctuations in solar activity, as deduced from isotopic reconstructions from ice cores. This way we compared astrophysical conditions with climatological ones in order to see if any probable relations do indeed show up. This comparison suggests a certain solar influence but the agreement is not very pronounced. Future investigation in a pan-European context is needed to reach reliable statements. Some results are unexpected—such as an unusually small number of severe winters during the last decades of the MM, where extreme cold was restricted to a few years, like the extreme winters 1699/1700 and 1708/1709.

A multi-site experiment to test biocontrol effects of wildflower strips in different French climate zones

Sowing of wildflower strips has been integrated in agri-environment schemes of several European countries. Their beneficial effects on natural enemies of pest insects are well documented but (1) the desired spill-over into crop fields has not always been demonstrated, and (2) the need to adapt sown mixtures to regional climatic differences has been rarely addressed.We set up a multi-site experiment in different French climatic regions to compare effects of a wildflower strip with a grass mixture and spontaneous vegetation. The design included five regions, three to five fields per region and the three strip treatments being repeated in each field. We tested strip treatment effects on vegetation (plant species richness, plant and flower cover) and on natural enemies (hoverflies, ladybirds, aphid predation). In a subset, we further analysed the spill-over into winter wheat fields including natural enemies and pest insects (cereal aphids, leaf beetles).The wildflower strip mixture developed well in all regions and increased plant species richness and flower cover compared with grass strips and spontaneous vegetation. We found a corresponding higher hoverfly abundance and aphid predation in wildflower strips that were consistent in all regions, whereas ladybird abundance was not affected. A significantly higher hoverfly abundance, aphid predation and aphid parasitism in wheat fields close to wildflower strips indicated a spill-over. No corresponding margin treatment effects were observed for aphid and leaf beetle abundance in the field. A multivariate analysis comparing the influence of climate and vegetation parameters showed that floral cover better explained variation in natural enemy abundance and predation than climate. Our results demonstrated that similar mixtures of native plants can be used over large climatic gradients to improve biocontrol. Further research is needed to improve spill-over into crop fields and to obtain consistently strong effects in different climate zones.