Severity Of Winter Research Articles

Modeling the distribution of hemlock woolly adelgid under several climate change scenarios

The hemlock woolly adelgid (HWA), Adelges tsugae Annand, has invaded eastern North America and caused significant mortality to eastern hemlock, Tsuga canadensis (L.) Carrière. In eastern North America, HWA’s range is theorized to be limited by minimum winter temperatures. As climate change reduces the severity of winter, the risk of northward expansion of HWA increases. This study used maximum entropy species distribution modeling in conjunction with HWA occurrence records and future climate projections to model habitat suitability for HWA throughout the range of eastern hemlock. Species distribution models were created for present and future climatic conditions using both historical climatic data and future climatic emissions scenarios for mid- and late-century. In addition, present climatic condition reference models for western North America and Asia were generated for comparison with HWA’s current range and earlier predictions of the potential range in eastern North America. Under a low emissions scenario, HWA will be capable of invading almost the entire range of eastern hemlock by the end of the century. More extreme warming scenarios result in a more rapid northwards shift by mid-century. The consequences for eastern hemlock are significant, with infestations likely to become more widespread and severe due to climate change.

The Bornholm intermediate waters: Origination, pathway, and detection within the cold intermediate layer of the Baltic Sea

The Cold Intermediate Layer (CIL) is a distinctive feature of the Baltic Sea thermohaline structure: it is evident annually from March to December between the upper freshened layer and the deep layer with saline waters of oceanic origin. Water parameters are vertically inhomogeneous within the CIL, reflecting a complicated process of its formation that hasn’t been exhaustively described yet. On the base of field measurements and remote sensing data, a detailed study of the CIL formation in spring 2006 was performed. It showed that the core of the CIL (the coldest water) has a specific T,S-index that indicates the source of these waters in the south-western part of the sea. The data of CTD measurements, satellite-derived sea surface temperature (SST), and meteorological information were used to distinguish and trace the CIL core waters. The abrupt transformation of the SST field was observed in March 2006 when the coldest waters (0.9–2.1 °C) of moderate salinity (7.6–8.1) plunged from the upper mixed layer in the vicinity of Bornholm Island into intermediate layers. These waters were later identified as the sublayer of the CIL in the Baltic Proper in April and May 2006. The drivers of the penetration of winter-cold surface waters into the intermediate layers are suggested to be the negative surface buoyancy flux due to warming of cold surface waters with temperature below that of the density maximum and the intensification of easterly winds. Considering the importance of the CIL formation process for the entire Baltic Sea conveyor belt, these CIL core waters were termed the Bornholm Intermediate Waters (BIW). The T,S-index of the BIW shall vary from year to year, reflecting the severity of the past winter and the conditions of the particular spring. However, the BIW location right above the pycno/halocline, the lowest (specific for the current year) water temperature and its characteristic salinity of 7.6–8.1 are repeatedly confirmed by field observations in the Baltic Proper in spring. Joint application of satellite observations, field measurements, and meteorological data provides a coherent view on the process of the BIW waters origination. The results are particularly important it the context of growing hypoxia of deep Baltic waters, providing evidence of the mechanism of seasonal ventilation of intermediate water layers.

Composition and structure of winter aphid-parasitoid food webs along a latitudinal gradient in Chile.

All species interact in complex antagonistic or mutualistic networks that may be driven by turnover in species composition due to spatiotemporal environmental filtering. Therefore, studying differences in insect communities along environmental gradients may improve our understanding of the abiotic and biotic factors that shape the structure of trophic networks. Parasitoids are interesting models to do so, due to their intimate eco-evolutionary relationship with their hosts. We explored the differences in cereal aphid-parasitoid food webs during the winter among nine localities in Chilean central-south valley, along a gradient of 1200km from north (29° S) to south (40° S). We hypothesized that diapause incidence would increase in the coldest areas, resulting in a lower number of parasitoid species active during the winter. Consequently, network specialization, generality, and vulnerability indexes should increase with decreasing latitude, which implies fewer and more weakly connected links per parasitoid species through an increased fraction of basal host species. Based on the severity of winter, three areas along the explored gradient were distinguished, but clustering did not follow a clear north-south latitudinal gradient. Instead, few differences were observed in overwintering strategies, with very low levels of diapause in all localities, and no major differences in food-web composition. The major differences along the gradient were the relative abundances of the different aphid, parasitoid and hyperparasitoid species, with higher levels of spatial and temporal variation observed for the less abundant species. Our results provide a better understanding of the activity and abundance of aphid parasitoids during winter in relation to climatic conditions.

The history of the development of northern beekeeping in the conditions of the Republic of Sakha (Yakutia)

Currently, bee products have become one of the competitive types of agricultural products. Due to their useful properties, their relevance remains on top. Bee products began to be sold in many markets, including in the Arctic regions of Russia. The population of the far north began to use local products of northern beekeeping more often, in view of their usefulness. For many years, breeding of bees has been practiced in Yakutia. In Soviet times, apiaries were used on collective farms, eventually gaining experience in keeping heat-loving insects in the harsh Yakut winters. However, until now, the production of Yakut honey has not acquired an industrial scale, and remains at the level of production of individual beekeepers - enthusiasts. The temperature range in this Far Eastern region is huge. In winter it reaches up to - 60°C. But for all the severity of winter, summer here can be quite hot and not so short-term. Due to its climatic data, the south of the Sakha Republic (Yakutia) is considered the most suitable for beekeeping. Also, the middle part of the region up to Yakutsk is suitable for it. The abundance of honey plants growing in Yakutia speaks in favor of Yakut beekeeping: black and red currants, blueberries, lingonberries, rosehip, raspberries, spirea, white clover, alfalfa, clover and others. But the main base for honey bees is cypress (ivan-tea). The abundance of honey plants is supported by a healthy ecological environment in which they grow. This fact makes Yakut honey one of the most environmentally friendly in the world. Beekeepers say that even though it is expensive to produce, it more than pays for the high cost with its quality, which should be appreciated by wealthy buyers from all over the world. The Republic of Sakha (Yakutia) can become an excellent alternative to other branches of the agricultural complex, which are unable to develop here due to unsuitable natural conditions. Locals do not trust the quality of goods brought from other countries too much. Therefore, many people prefer not to buy honey at all. But the greater the demand for high-quality native honey, the more incentives local beekeepers will have to develop their farms.

Epidemiology of Nosema spp. and the effect of indoor and outdoor wintering on honey bee colony population and survival in the Canadian Prairies.

The epidemiology of Nosema spp. in honey bees, Apis mellifera, may be affected by winter conditions as cold temperatures and differing wintering methods (indoor and outdoor) provide varying levels of temperature stress and defecation flight opportunities. Across the Canadian Prairies, including Alberta, the length and severity of winter vary among geographic locations. This study investigates the seasonal pattern of Nosema abundance in two Alberta locations using indoor and outdoor wintering methods and its impact on bee population, survival, and commercial viability. This study found that N. ceranae had a distinct seasonal pattern in Alberta, with high spore abundance in spring, declining to low levels in the summer and fall. The results showed that fall Nosema monitoring might not be the best indicator of treatment needs or future colony health outcomes. There was no clear pattern for differences in N. ceranae abundance by location or wintering method. However, wintering method affected survival with colonies wintered indoors having lower mortality and more rapid spring population build-up than outdoor-wintered colonies. The results suggest that the existing Nosema threshold should be reinvestigated with wintering method in mind to provide more favorable outcomes for beekeepers. Average Nosema abundance in the spring was a significant predictor of end-of-study winter colony mortality, highlighting the importance of spring Nosema monitoring and treatments.

Frozen out: unanswered questions about winter biology

Winter conditions impose dramatic constraints on temperate, boreal, and polar ecosystems, and shape the abiotic and biotic interactions underpinning these systems. At high latitudes, winter can last longer than the growing season and may have a disproportionately large impact on organisms and ecosystems. Even so, our understanding of the ecological implications of winter is often lacking. Indeed, even what exactly defines winter is currently unclear, and boundaries that delineate this season are blurred across marine, freshwater, and terrestrial realms and fields of biology. Here, we discuss the complexity of defining winter, and highlight the importance of maintaining the capacity to test hypotheses across seasons, realms, and domains of life. We then outline questions drawn from diverse fields of research that address current gaps in our understanding of winter ecology and how winter influences multiple levels of biological organization, from individuals to ecosystems. Finally, we highlight the potential consequences of changes to both the length and severity of winter due to climate change, and discuss the role winter may play in mediating ecosystem function in the future.

Population level differences in overwintering survivorship of blue crabs (Callinectes sapidus): A caution on extrapolating climate sensitivities along latitudinal gradients.

Winter mortality can strongly affect the population dynamics of blue crabs (Callinectes sapidus) near poleward range limits. We simulated winter in the lab to test the effects of temperature, salinity, and estuary of origin on blue crab winter mortality over three years using a broad range of crab sizes from both Great South Bay and Chesapeake Bay. We fit accelerated failure time models to our data and to data from prior blue crab winter mortality experiments, illustrating that, in a widely distributed, commercially valuable marine decapod, temperature, salinity, size, estuary of origin, and winter duration were important predictors of winter mortality. Furthermore, our results suggest that extrapolation of a Chesapeake Bay based survivorship model to crabs from New York estuaries yielded poor fits. As such, the severity and duration of winter can impact northern blue crab populations differently along latitudinal gradients. In the context of climate change, future warming could possibility confer a benefit to crab populations near the range edge that are currently limited by temperature-induced winter mortality by shifting their range edge poleward, but care must be taken in generalizing from models that are developed based on populations from one part of the range to populations near the edges, especially for species that occupy large geographical areas.

Warmer Winters Increase the Biomass of Phytoplankton in a Large Floodplain River

AbstractWinters are changing rapidly across the globe but the implications for aquatic productivity and food webs are not well understood. In addition, the degree to which winter dynamics in aquatic systems respond to large‐scale climate versus ecosystem‐level factors is unclear but important for understanding and managing potential changes. We used a unique winter data set from the Upper Mississippi River System to explore spatial and temporal patterns in phytoplankton biomass (chlorophyll a, CHL) and associated environmental covariates across 25 years and ∼1,500 river km. To assess the role of regional climate versus site‐specific drivers of winter CHL, we evaluated whether there were coherent long‐term CHL dynamics from north to south and across lotic‐lentic areas. We then estimated the degree to which these patterns were associated with climate variability (i.e., the Multivariate El Nino‐Southern Oscillation Index), winter severity (freezing degree days), river discharge, or site‐specific environmental variables (ice depth, snow depth, and nutrient concentrations). We found that winter CHL was typically highest in ice‐free reaches and backwater lakes, occasionally exceeding summer values. We did not find highly synchronous CHL dynamics across the basin, but instead show that temporal trends were independent among river reaches and lotic‐lentic areas of the river. Moreover, after accounting for these spatial dynamics, we found that CHL was most responsive to winter air temperature, being consistently higher in years with warmer winters across the basin. These results indicate that although productivity dynamics are highly dynamic within large river ecosystems, changes in the duration and severity of winter may uniformly increase wintertime productivity.

Land cover and weather jointly predict biometric indicators of phenotypic quality in a large herbivore

Body size and body mass are key indicators of individual phenotypic quality and predictors of important life-history traits such as survival and reproductive success. In wild herbivores, individual responses to changing environmental conditions influence morphometric traits over temporal scales and between populations. However, little research has assessed joint effects of weather and land use on body size/mass at finer, intra-population scale. We used data collected on female and juvenile red deer Cervus elaphus shot over a 17-year period (2001–2017) along two sides of a mountainous ridge largely differing in land cover and habitat productivity, to investigate how fine-scale land use patterns and weather influenced multiple morphometric indicators of phenotypic quality. Accounting for weather, body mass of all sex/age classes increased with increasing proportion of cultivated areas in the landscape and, for young females and calves, that increase was stronger or occurred only in the “low-quality” site. Other biometric traits such as mandible length and hind foot length showed the same pattern in young and calves, suggesting that body mass/size reflects individual responses especially in the early life-stage. Accounting for land use, body mass of adult females and calves was enhanced by increasing rainfall and decreasing temperature in spring-summer, i.e. favourable conditions for vegetation growth. This result also supports late gestation- and lactation-mediated effects of vegetation productivity on offspring quality. Additionally, in male calves, body mass and several other traits increased with decreasing severity of the previous winter, suggesting that quality of male offspring - but not that of females - could depend on winter conditions experienced in utero, likely due to higher maternal costs. Our findings emphasise how land cover and weather jointly affect indicators of phenotypic quality in a large mammal, helping to predict size responses of herbivores under the ongoing climatic- and anthropogenic land use-changes.

Spawning stock biomass modulation of environment–recruitment relationship in a marginal spring spawning herring (Clupea harengus membras) population

Scientific interest in the dynamics of fish recruitment dates back to the beginning of the 20th century. Since then, several studies have shown that the environment may have a stronger effect on recruitment (R) compared to that of the spawning stock biomass (SSB). By combining a suite of methods designed to detect the nonlinear, nonstationary and interactive relationships, we have re-evaluated the potential drivers and their interactions responsible for the multiannual dynamics of the recruitment dynamics of the Gulf of Riga (Baltic Sea) spring spawning herring (Clupea harengus membras) population at the longest time-span to date (1958–2015) allowing coverage of variable ecosystem conditions. R was affected significantly by prey density and the severity of the first winter. Although SSB was not a good predictor of R, adding interaction with SSB significantly improved the model, hence the effect of the two environmental variables on R was modulated by SSB. While temporal changes in the environment–R relationship were generally gradual, several abrupt changes were evident in the strength of these relationships. In addition, nonstationary, linear and nonlinear relationships were observed.

Trends and irregular variation of spatial temperature differences in the high-latitude coastal city of Turku, Finland

Spatio-temporal dynamics of urban heat island (UHI) and other spatial temperature variations were studied for a 17 yr period (2002-2018) in the mid-sized (193000 inhabitants in 2019) coastal city of Turku in south-western Finland. The study was based on GIS data and 30 min interval air temperature observations from 52 observation sites in the city and its surroundings. Correlation and regression analyses, image interpretation and various GIS methods were used to investigate temperature dynamics and associated factors on a diurnal, monthly and seasonal basis. The results showed relative cooling and warming trends of certain areas as well as fluctuating and random variation of the coldest and warmest regions, respectively. Relative cooling trends were observed in semi-urban and urban areas that remained unchanged during the study period. Relative warming trends were most common in semi-urban areas where urbanization and construction of new buildings occurred rapidly. Fluctuating variation was mainly related to variation in weather conditions, especially the severity of winter and related sea-ice extent on the archipelago south-west of the city. The UHI intensity showed a slight, albeit statistically significant, intensifying trend of 0.11°C per decade. Our findings demonstrate the dynamic nature of spatio-temporal intra-urban temperature differences, a fact that should more actively be taken into account in climate-related urban planning in general.

Assessment of bioclimatic comfort of the Krasnodar Territory, Russia through the application of GIS‐technologies

Aim. To determine the most and least comfortable zones of the Krasnodar Territory by month.Material and Methods. The bioclimatic indices studied take into account the combined influences of temperature, wind speed, relative humidity, atmospheric pressure and solar radiation in various combinations. A geoinformation analysis of the following bioclimatic indices was carried out: effective temperature, equivalent-effective temperature, bioclimatically active temperature, radiation equivalent-effective temperature, and a complex indicator of the level of pathogenic effects of weather in the Krasnodar Territory. The weather pathogenicity index is the only index in the article that takes into account atmospheric pressure. The study also added an assessment of the severity of winter. The following indices of “cold stress” were calculated and mapped: integrated cooling index (frostbite), Bodman climate severity index, Siple-Passel cooling index and wind-cold index.Results. The Krasnodar Territory was divided into 4 comfort zones: Azov-Black Sea, Black Sea, South-Eastern Foothills and Continental.Conclusions. Comfortable months have been established for living in the Krasnodar Territory as a whole, and areas of the Krasnodar Territory favourable for life at any time of the year. The severity of winter in the Krasnodar Territory as shown by the analysis is closely correlated with wind strength.

Winter ecology of striped bass (Morone saxatilis) near its northern limit of distribution in the Saint John River, New Brunswick

Winter habitat selection by Striped Bass (Morone saxatilis) has been described as opportunistic, but due to the length and severity of winter at its northern range, winter habitats in the north are predicted to be restricted in distribution and carefully selected. Here we describe the locations and environmental conditions supporting winter aggregations of adult Striped Bass including periods under ice cover in the Saint John River, New Brunswick using acoustic telemetry. Striped Bass of both Saint John River (72%) and other ancestry (28%) were observed to overwinter within the river’s four mainstem lakes and embayments to which the individuals returned each fall. Most non-Saint John River ancestry Striped Bass were observed in habitats nearest the river mouth in winter. Striped Bass travelled to winter habitats from fall feeding locations from October to November, and only four tagged individuals departed the river at this time. Temperature, dissolved oxygen, and salinity conditions best described the winter habitats. By demonstrating the non-random distribution of Striped Bass during winter and identifying a gradient of habitat use by Saint John River ancestry Striped Bass in this northern river system, it is apparent that protection of these locations is critical for the long term conservation of Striped Bass populations in Canada.

The Long Winter of 1880/81

AbstractThe story of the winter of 1880/81 in the central United States has been retold in historical fiction, including Laura Ingalls Wilder’s The Long Winter, as well as in local histories and folklore. What story does the meteorological data tell, and how does it measure up when compared to the fiction and folklore? What were the contributing factors to the severity of the Long Winter, and has it been or could it be repeated? Examining historical and meteorological data, reconstructions, and reanalysis, including the Accumulated Winter Season Severity Index, the Long Winter emerges as one of the most severe since European-descended settlers arrived to the central United States and began documenting weather. Contributing factors to its severity include an extremely negative North Atlantic Oscillation pattern, a mild to moderate El Niño, and a background climate state that was much colder than the twentieth-century average. The winter began early and was particularly cold and snowy throughout its duration, with a sudden spring melt that caused subsequent record-setting flooding. Historical accounts of the winter, including The Long Winter, prove to be largely accurate in describing its severity, as well as its impacts on transportation, fuel availability, food supplies, and human and livestock health. Being just one of the most severe winters on record, there are others in the modern historical record that do compare in severity, providing opportunity for comparing and contrasting the impacts of similarly severe winters.

Seasonal changes in light availability modify the temperature dependence of secondary production in an Arctic stream.

Light and temperature are key drivers of ecosystem productivity, but synchrony of their annual cycles typically obscures their relative influence. The coupling of annual light-temperature regimes also drives complementary seasonal cycles of energy supply (primary production) and demand (metabolism), perhaps promoting temporal stability in carbon (C) storage and food web production that may be difficult to discern in most ecosystems. Spring-fed streams in the Arctic are subject to extreme annual fluctuations in light availability but have relatively stable water temperatures, which allows assessment of the independent effects of light and temperature. We used the unusual annual light and temperature regimes of Ivishak Spring, Alaska, USA (latitude 69°N, annual water temperature range ~4-7°C) to test predictions about the effect of light availability on consumer productivity with minimally confounding effects of temperature. We predicted that (1) annual patterns of secondary production would follow patterns of primary production, rather than temperature, due to organic C limitation during winter darkness when photosynthesis is effectively halted, (2) C limitation would propagate from primary producers upward through several trophic levels, (3) the lack of temperature dependence during winter darkness would be expressed as anomalous Arrhenius plots of growth rates indicating decoupled production-temperature relationships, and (4) consumer diets would reflect C limitation during winter. As predicted, we found (1) lowest production by macroinvertebrates and Salvelinus malma (Dolly Varden char) at the lowest light levels rather than the lowest temperatures, (2) apparent winter C limitation propagated upward through three trophic levels, (3) anomalous Arrhenius plots indicating lack of temperature dependence of consumer growth rates during winter, and (4) lowest consumption of diatoms (by macroinvertebrates) and invertebrate prey (by S.malma) during winter. Together, these results indicate that light drives annual patterns of animal production in Ivishak Spring, with stable annual temperatures likely exacerbating C limitation of ectotherm metabolism during winter. The timing and severity of winter C limitation in this unusual Arctic-spring food web highlight a fundamental role for light-temperature synchrony in matching energy supply with demand in most other ecosystem types, thereby conferring a measure of stability in the metabolism of their food webs over annual time scales.

Flexible response to short‐term weather in a cold‐adapted songbird

To improve survival during winter, temperate species use a variety of behavioural and physiological adaptations. Among songbirds, the maintenance of lipid reserves is a widely‐used strategy to cope with the severity of winter; however, little is known regarding how multiple synchronously acting environmental mechanisms work together to drive these effects. In a context where temperate winter conditions are becoming more variable, it is important to widen our understanding regarding the flexible adaptations that may allow wintering species to adjust to projected climate change. Using a long‐term dataset collected across multiple wintering populations (7 years; 8 locations), we analyzed the effects of daily variation in weather (e.g. temperature, snowfall) on the variation in energy reserves (i.e. fat stores) of wintering snow buntings Plectrophenax nivalis. Our results support the prediction that birds carry more reserves to increase the safety margin against starvation when conditions are energy‐demanding and access to food is unpredictable (i.e. colder, snowier conditions). Birds responded to daily changes in weather by increasing their reserves as conditions deteriorated, with maximal temperatures and snow depth being the most important predictors of fattening decisions. We also found that females consistently exhibited higher fat reserves than males relative to their body size, suggesting that differential physiological adaptations among sexes or social dominance may play an additional role in explaining variation in energy reserves across individuals in this species. Overall, our findings increase knowledge on phenotypic adjustments used by species wintering in temperate zones to match variation in their environment.

WINTER HARDINESS OF REPRESENTATIVES OF THE GENUS Allium L. IN THE MOSCOW REGION, DEPENDING ON THE SEVERITY OF THE WINTER PERIOD

In the Moscow region, for a long-term species of bows in winter, a complex of limiting factors determines their winter hardiness. To characterize the period from November to March 2014-2017. The winter severity index (Woz) was calculated on a scale from 0 to 10 points (0 very soft, 10 very severe). The severity of winter in 2014-2015 was 2.91 points, 20152016 3.14 points, 2016-2017 4.75 points. The average percentage of overwintered plants for each sample was determined by the ratio of the number of living plants to the number of dead. Many varieties of welch onion were not sufficiently winter-hardy, including Red, Snowdrop, Russian size, Handsome, April, Russian winter. Stable high 100% winter hardiness showed a variety of welch onion Green feathers. From the studied 71 species and 194 samples of bows of perennial different ecological and geographical origin under the conditions of the Moscow region in the subgenus Amerallium plants A. neapolitanum Cirillo (Molium section) and A. ursinum L. (section Arctoprasum), and also in the subgenus Nectaroscordum A. bulgaricum plants (Janka) Prodбn (section Nectaroscordum (Lindl.) Gren. & Godr.) in the winter of 2014-2015 died completely. Winter in 2016-2017 years in the subgenus Rhizirideum, section Rhizirideum G. Don ex Koch A. senescens L. plants overwintered 75%, A. nutans L. – 90-95% depending on the sample, A. stellarianum Willd. 15 %. In subgenus Melanocrommyum, section Melanocrommyum Webb & Berthel. s.s. plants A. cyrillii Ten. overwintered 75%. In the subgenus Butomissa, sections Butomissa (Salisb.) Kamelin plants Allium odorum L. overwintered 86-93% depending on the sample. In the subgenus Cepa, the section Schoenoprasum Dum. plants A. ledebourianum Schult. & Schult. f. overwintered 75%. The remaining species overwintered 100%.

Experimental study of solar assisted ground source heat pump system during space heating operation from morning to evening

Experimental investigation of solar assisted ground source heat pump system has been carried out to understand performance variation during space heating for continuous eight hours operation from morning to evening for Indian winter climatic conditions. Heat extraction rate from solar collector and ground exchanger were monitored from 9 AM to 5 PM on hourly basis by measuring the inlet and outlet temperatures of heat transfer fluids. A detailed thermodynamic energy balance carried out on hourly basis indicates maximum heat loss is observed at 12 noon at which maximum heat extraction from solar collector and ground heat exchanger was obtained. Maximum COP of the SAGSHP system is observed at 12 noon for all the three mass flow rates, however, the COP decreases up to 3 % with increase in severity of winter due to increase in heat loss. About 44 % increase in mass flow rate of heat carrying fluids has enhanced the heat extraction rate up to 18 %, resulting in about 3 % increase in room temperature. The SAGSHP system was able to maintain the room temperature at about 20 to 21 °C when the ambient temperature was at about 12 °C.

The effect of the habitat on wintering birds in Central Europe

The aim of this work was to analyse assemblages of wintering birds in three areas of central Europe, that differ in climate: eastern Poland, northern Poland and western Germany in winter in 2003-2009. The severity of winter moderates distinctly from eastern Poland to Germany, so there ought to be more species and larger numbers of birds in Germany. 5445 birds from 73 species were recorded on the 491 transects with a length 500 m. Generalized linear models of the influence of habitat types and localities on the species richness reflected the significant effect of three habitat types and study area location. The species richness was positively affected by the surface area of towns and villages, and negatively by that of grassland areas. The most species were recorded in W Germany, in E Poland, and the fewest in N Poland. While, numbers of birds increased with increasing areas of hedgerows, villages and towns. Most birds wintered in eastern Poland, and reached higher value compared to N Poland; mostly because of large numbers of a few of the most abundant species: yellowhammer, fieldfare, great tit. We can expect that, with warming climate, the wintering areas in central Europe will host increasingly significant bird numbers.

Research Article: An analysis of the influence of winter severity on early season bass tournament catch rates for Weiss Lake, Alabama

Bass fishing is an important recreational activity in Alabama reservoirs and a variety of factors (e.g. management activities, weather conditions, etc.) can influence angler success. Therefore, it is important to determine locations that allow anglers to make a decision regarding likelihood of success (i.e. catching fish) or the potential to catch larger fish (trophy fishing). Data collected from bass tournaments held on Alabama reservoirs via the Bass Anglers Information Team (BAIT) program were collected and analyzed for early season (April) catch rates for three reservoirs (Lake Guntersville, Lake Eufaula, and Weiss Lake). A significant difference was found between catch rates (using catch per unit effort, CPUE) and average bass size. Weiss Lake had a higher average CPUE and smaller average fish size and Lake Guntersville had higher average fish size but the lowest catch rate. Additionally, a positive correlation was found between CPUE and the number of days with minimum temperature at or below freezing. These results indicate that managers and tournament hosts should consider the severity of the previous winter and fishery when planning early season tournaments or angling activities.