Snow And Ice Ebook

Bitterly Cold Defense Guide

This eBook guide teaches you how to defend yourself and your family from the incoming cold that has hurt people all over the nation. The Polar Vortex has struck the United States, and it will continue to bring cold and freezing to people all over the nation. You can try to ignore the problem, but that does not make it go away. In fact, not preparing for the cold is what gets a lot of people killed. Last year, at least 21 people died as a result of the cold. You do NOT want to be one of those people! This ebook guide teaches you to defend yourself against the bitter cold and learn to deal with all of the hazards that accompany bitter cold temperatures. Leon Wilde, author and speaker at survival camps, brings you this book to help you survive the bitter winter temperatures. Don't get caught unawares!

Bitterly Cold Defense Guide Summary

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Author: Leon Wilde
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All of the information that the author discovered has been compiled into a downloadable pdf so that purchasers of Bitterly Cold Defense Guide can begin putting the methods it teaches to use as soon as possible.

When compared to other ebooks and paper publications I have read, I consider this to be the bible for this topic. Get this and you will never regret the decision.

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Acclimation versus Adaptation

Temperatures or higher versus lower light levels. However, only plants adapted to cool climates (i.e., species that have evolved in temperate or higher latitudes, or at higher elevations) possess a set of genetic traits permitting adjustments to the level necessary to survive extreme cold. Similarly, only plants adapted to shade are able to make the adjustments necessary to survive in the understory of a multilayered rainforest canopy. While acclimation will be the focus of this article, it will be discussed against the background of adaptation.

Little Bit About Snow

Because snow has been so important in the evolutionary history of weasels, it deserves some special attention. Snow provides, in a sense, another world, the subnivean world. Just the name subnivean sounds a bit like Middle Earth or Narnia, and perhaps with good cause. The subnivean world is a chilly but safe haven from the bitter cold and fierce storms that rage through the northern winter. Weasels evolved their superb tunnel-hunting abilities in response to the opportunity to hunt small mammals that formed burrows and runways in grass, and for them this subnivean world is no different than life under a thick layer of grass. But if they had not been able to make use of the insulation supplied by snow, they might have joined the many other species of animals that did not survive the savage cold of the glacial periods. Least weasels and stoats are completely at home in snow, and common weasels and longtails can burrow through it when they need to, although most common weasels and...

Migration And Weather

The importance of temperature to migration is uncertain. In spring, warmth occurs in association with other conditions favourable to flight, as does cold in autumn. But temperature may have direct effects through influencing the energy balance of the birds, and more importantly through influencing food supplies, because all vegetative growth, insect activity, and ice melt are temperature-dependent. It is therefore of obvious advantage for migrants to adjust their migratory schedules to year-to-year variations in temperature, and they are clearly deterred in spring by extreme cold and snow (Chapter 14). It is also uncertain to what extent (if at all) migratory birds can predict the weather before it arrives, say by a change in barometric pressure. Bird movements in autumn and spring have

Value of experiments to disentangle ultimate and proximate causes of breeding failure

Although the relative roles of ultimate and proximate causes may be indicated by observational studies of breeding, field experiments will often provide more robust evidence. Experimental manipulations of many aspects of bird breeding are feasible and include nest site enhancement or removal, supplementary feeding and control of predation. A detailed review is beyond the scope of this chapter and useful examples of experiments can be found in Newton (1994), Newton (1998, chapter 7), and Tapper et al. (1996). However, a recent development in experiments on bird breeding biology worthy of special mention is the use of manipulations of the energy requirements of parent birds and nestlings. Yom-Tov and Wright (1993) heated nest boxes of blue tits during the egg-laying period and found that interruptions of egg-laying during cold weather were reduced. Incubation requires a considerable amount of energy from parent birds and this can be reduced experimentally by slowing the rate of cooling...

Read the texts again find the following words and expression in these texts and give the translation or definition

Precipitation is the deposition of atmospheric water on earth's surface. Over most of the globe, rain is the main form of precipitation. In cold regions snow is dominant. Water drops fall as rain or drizzle, the difference being drop size. Snow falls as ice crystals that are grouped into flakes. Other forms of precipitation include hail and sleet.

On the Impact of Winter Conditions on the Dynamics of an Isolated Population

This chapter is devoted to the analysis of single-species population dynamics models with overlapping and non-overlapping generations. Within the framework of all models it is assumed that there are no activities of individuals during the wintertime (as, for example, is the case for forest insect populations in the boreal zone), and changes in population size at these moments are described with a broken trajectory ( jump down ). Also, it is assumed that the fecundity of individuals is constant and that the quota of individuals surviving winter depends on the within-year population dynamics. The dynamics of the models, which are determined by the influence of winter conditions on the survival of individuals and by the influence of intrapopulation self-regulative mechanisms, are analyzed. For some particular cases the conditions for population extinction and for stabilization at a non-zero level are determined it is shown numerically that chaotic regimes can also be realized in...

Reticulate evolution and caribou reindeer skins

One of the prime functions of the Hudson's Bay Company Baker Lake post was to buy caribou skins locally and export them to posts where they were badly needed . . . Without caribouskin clothing, many of the coastal Eskimos would refuse to trap during the bitterly cold months of winter . . . Caribou clothing was the only type warm enough to allow them to spend days and nights out on the land. (Pryde 1971, p. 22)

Dynamics of Soil Physical Structure

So far, our description of the soil habitat summarized physical and chemical parameters that interact with soil biology. Although it may be obvious that soil temperature, water content, organic matter content and quality change over time, it is less obvious that the physical structure itself is not static. Fluctuations in water content change the size of pore spaces and displace peds. Flow of gravitational water, for instance after a heavy rain, can carry clays, silt and fine sand, and alter pore sizes and structure. Freeze-thaw cycles in cold weather also physically displace peds. Thus the pore reticulum is continuously changing, simply by physical forces. The interstitial living organisms also disturb peds and mineral particles. The cilia of motile protists is strong enough to displace small particles. The passage of larger species, such as nematodes and microarthropods, creates tunnels (micropores) and contributes to continually changing the reticulum and maintaining tortuosity....

Concluding comments on annual cycles

Avoid unseasonably cold weather reach stopover sites before food depleted, and obtain best territories in winter quarters Risk of cold weather and reduced food supplies, which may prevent departure or cause starvation. May be relegated to poor territory in winter quarters Lengthens journey time. Suitable refuelling places may be far apart

Endothermic Response to Temperature

As insulation increases, the TNZ widens and the lower end of the TNZ occurs at lower temperatures. Animals that are very well insulated (the arctic fox is a classic example) have thermal neutral zones that may extend to extremely cold temperatures (e.g., they may experience temperatures as low as -40 C or perhaps even lower without having to increase their basal metabolic rate).

Migration Within The Southern Continents

On all the southern continents, the north-south migrations of the local breeding birds (austral migrants) more or less coincide with the north-south movements of the intercontinental migrants from the northern hemisphere, the movements of both groups being driven by the same seasonal changes in climate and food supplies. However, away from the equatorial rainforests, as mentioned above, bird movements are linked not so much to temperature, but to the corresponding wet-dry seasons, and the predictability or otherwise of rainfall. In addition, most parts of the southern continents escape cold winters, and span a wide enough range of latitude to accommodate the native bird species year-round. Apart from

The role of withinyear climatic stability

As well as having more solar energy per unit area, the tropics also have this energy distributed relatively evenly across the year so avoiding the cold winters of higher latitudes. The reason why this may be relevant to our question of 'Why are the tropics so diverse' can be seen by considering birds. Many high-latitude countries, such as Canada and Britain, have bird species that feed exclusively on insects during the summer, a good example being the Barn Swallow. This species feeds almost exclusively on invertebrates it catches while in flight such food is effectively unavailable during the northern winter and the swallows migrate south to areas where this food is still plentiful.81 So while higher-latitude sites can have a high biomass of insects in the summer (indeed there can be a greater insect biomass than in many tropical forests), they are unavailable as food for much of the year, thus restricting the diversity of specialist insectivores.82 There is a similar situation with...

Forests as Inputs Effects of Acorns on White Tailed Deer

It is well established that the body condition of deer has a critical effect on their over-winter survival. The nutritional value of autumn diets is a primary determinant of body condition in males and females of all age classes, but especially among fawns and yearlings. Deer that enter winter in good physical condition have a better chance of survival than those that enter this season in poor condition (Mautz 1978). In habitats where they are available, acorns have long been recognized as one of the most important autumn foods of deer (Forbes et al. 1941, Goodrum 1959, Duvendeck 1962, Korschgen 1962). A large percentage of the sound acorns available on the ground usually are taken by deer. For example, in central Pennsylvania, Steiner (1996) found that of the northern red oak (Q. rubra) acorns consumed by vertebrates, about 49 were removed by deer. McShea and Schwede (1993) estimated that in their study area in Virginia, in forest dominated by oak and hickory (Carya spp.), deer...

Brief History of the Plant Life Form Concept

Grisebach (1814-79) adopted von Humboldt's concepts and expanded his classification system to emphasize the dependence of plant life-forms on climate. Subsequent systems of classification in the nineteenth century adopted this Humboldtian perspective by emphasizing how life-form features are adapted to prevailing ecological conditions, particularly conditions during unfavorable periods of the growing season. Among the criteria used by many workers were (1) duration of shoot growth, (2) the length and direction of shoot development, (3) the position and structure of perennating (renewal) buds, (4) the size of the reproductively mature plant, (5) adaptations to conserve water, and (6) adaptations for plant-plant competitive interactions. The most widely used vascular plant life-form classification system during the twentieth century was formulated by Christen C. Raunkiaer (1860-1938). This system identifies life-forms based on a single criterion, that is, the extent to...

Organism Microclimate Interactions

Endotherms are able to maintain a relatively constant body temperature (i.e., are homeothermic) through the production of metabolic heat (during periods of increased heat loss) and cooling. However, the ability to produce heat is energetically costly for endothermic organisms, particularly when they are in microclimates with temperatures above or below their ideal environmental range. On cold winter nights, elk can reduce loss of radiant heat, and thus save metabolic energy that may be used for breeding in the spring, by seeking refuge beneath trees with needles. The elk can further reduce heat loss by laying down, but a prone position may make them easier prey for wolf predators. For an endotherm, finding the ideal physiological microclimates may be a trade-off between ecological costs such as avoiding predators and the physiological benefits such as gestating young.

Direct Estimation of Variance Components

Consider the example situation of estimating overwinter survival rates each year for 10 years from a deer population. Each year, the survival rate is different from the overall mean because of snow depth, cold weather, and other factors. Let the true but unknown overall mean be S. Then the survival rate for each year can be considered to be S plus some deviation attributable to temporal variation, with the expected value of the et equal to zero

Management of Oaks for Turkeys

Although vast forests may not be critical to turkeys, habitat management should generally encourage mature, mast-producing forests that incorporate adequate nesting, brood, and winter-survival cover (Williams 1992, Wunz and Pack 1992). Management for forest diversity helps provide more consistent mast production (Minser et al. 1995) and suitable vegetative structure (Williams 1992) to accommodate the diverse diets and other ecological needs of wild turkeys. Dutrow and Devine (1981) concluded that timber production was not compromised by managing habitat for turkeys in Virginia. Specific oak management strategies should primarily focus on maximizing acorn production, promoting other mast-producing species, providing open areas, and encouraging a desirable herbaceous understory.

Photosynthetic bacteria

Physiological drought A situation in which plants are unable to take up sufficient water even though there is water in the soil. Physiological drought occurs in salt marshes and other brackish coastal habitats, and in deserts where there are high concentrations of salts in the upper layers of the soil. It also occurs in cold weather because the permeability of the endodermal cells decreases rapidly below 5 C, so the root resists the entry of water. See osmosis.

Recent changes in bird migrations

An ever greater proportion of each succeeding generation, gradually changing the genetic composition and average migratory habits of the population. Conversely, during a series of mild winters, the resident genotypes, able to occupy the best territories and start nesting early, could come rapidly to outbreed and outnumber the migrants. However, many of the changes observed in bird migratory behaviour need entail no genetic change, for in every aspect of migration there is scope for individual flexibility, through which individuals can adjust their migratory behaviour to some extent according to prevailing conditions (facultative variation). For example, the same birds might arrive on their breeding areas earlier in warm springs than in cold ones, or they might migrate further in cold winters than in mild ones, in response to differing food supplies. Hence, as climate changes from year to year, or over longer periods, birds have considerable scope for adjusting their behaviour to match...

Point quadrat See cover

Polar vortex A region of extremely cold air that forms over Antarctica in winter, which is surrounded by strong westerly winds that isolate the cold air from surrounding air masses in lower latitudes. Temperatures in the vortex may fall as low as -200 C in the lower stratosphere. These particular conditions are ideal for chemical reactions between sulfuric acid aerosols, chlorine, and nitrogen oxides, causing severe depletion of the ozone layer.

Fluctuations in Solid Waste Quantities

The generation of solid waste is usually greater in warm weather than in cold weather. Figure 10.3.1 shows two month-to-month patterns of MSW generation. The less variable pattern is a composite of data from eight locations with cold or moderately cold winters (Camp Dresser & McKee Inc. 1992, 1991 Child, Pollette, and Flosdorf 1986 Cosulich Associates 1988 HDR Engineering, Inc. 1989 Killam Associates 1990 North Hempstead 1986 Oyster Bay 1987). Waste generation is relatively low in the winter but rises with temperature in the spring. The surge of waste generation in the spring is caused both by increased human activity, including spring cleaning, and renewed plant growth and associated yard waste. Waste generation typically declines somewhat after June but remains above average until mid to late fall. In contrast, Figure 10.3.1 also shows the pattern of waste generation in Cape May County, New Jersey, a summer resort area (Camp Dresser & McKee Inc. 1991). The annual influx of tourists...

Component Composition of Bulky Waste

The composition of MSW does not change dramatically from season to season. Even the most variable component, yard waste, may be consistent in areas with mild climates. In areas with cold winters, generation of yard waste generally peaks in the late spring, declines gradually through the summer and fall, and is lowest in January and February. A surge in yard waste can occur in mid to late fall in areas where a large proportion of tree leaves enter the solid waste stream and are not diverted for composting or mulching.

Climaterelated human behavior and infectious disease occurrence

These relationships may, at least partly, be explained by seasonally-related change in patterns of children's play and person-to-person contact (see also Chapter 6). Children who spend more time indoors in cold weather may inadvertently increase their exposure to indoor air pollutants, such as tobacco smoke, smoke from wood fires, and nitrogen dioxide emitted from un-flued gas heaters, depending on the amount of ventilation, which could confound the association between infections and cold temperatures (Jones, 1998).

Turnover and Elimination of Radioactive Contaminants

Radioactive isotopes within the bodies of individual plants and animals, whether introduced intentionally for study or inadvertently taken up from contaminated habitats, can also be particularly useful in determining the rates and patterns by which such contaminants are eliminated from the body and thereby help to predict the time which would be required for such organisms to return to background levels following contamination events. The rate at which contaminants are eliminated from an organism's body is the sum of the rate at which the isotope itself physically decays to a stable form plus the rate at which the organism's own physiological processes absorb, metabolize, and eventually eliminate the molecules in which the radioactive isotopes have been incorporated. These rates are quantified as the half-life which is the amount of time required for half of a given amount of isotope or half of the organism's total body burden of the contaminant to be eliminated. When measured in a...

Measuring Recruitment

The measure of recruitment is critically dependent on the life history stage at which death and or emigration of individuals is assessed. To illustrate this important point, we will consider for example a population of a large mammal in a temperate ecosystem. The births are highly synchronized over a short yearly pulse, producing one new cohort each spring. The 'life cycle graph' (Figure 1) describes the different stages that individuals may experience from birth to death. In our example, individuals may survive from birth to weaning (summer survival of juveniles), from weaning to i year of age (winter survival of juveniles), from i to 2 years of age (yearling survival), then each year from 2 to 7 years of age (prime-aged adult survival), and finally each year from 8 to the maximum longevity (senescent adult survival). Each cohort is the sum of newborns produced by 2-year-olds (primiparous females), and prime-aged and Figure 1 Life-cycle graph of a population of a temperate large...

Stationary source See point source

Steppe Temperate grassland dominated by drought-resistant species of perennial grasses, found in regions of loess soil and extreme temperature range, often typically on chernozem soils, in a zone from Hungary eastward through the Ukraine and southern Russia to Central Asia and China. There are pronounced seasons, with hot summers and cold winters, with greater temperature extremes and lower rainfall in the east. The species composition varies with the climate. Typical grasses include feathergrasses (Stipa) and sheep's fescue (Festuca ovina), together with bunchgrass (Schizachyrim) and blue-grass (Poa spp.). Many of the herbs, such as Tulipa, Allium, and the grass Poa bulbosa, have underground perennating or

Importance of Climate Change for Europe

A prediction of the effects of an increase in climate-effective trace gases (C02, N20, CH4 and others) is only possible using model calculations based on certain scenarios of their increase (see Fig. 5.3.6 A) and by coupling land, ocean and atmosphere processes to develop understanding of how the climate develops and changes. For Europe, such a model calculation (Parry 2000) has been made with the lower limit of C02 increase assumed to be 490 ppm and the upper limit to be 570 ppm in 2100. Since 1970 Europe has warmed up between 0.1 and 0.4 K per decade. It has been shown that the probability of a cold winter (one in 10 years) in northern Scandinavia would decrease to 0 by 2080. At the same time, the probability of a warm summer in northern and central Europe will decrease. However, the probability of a hot summer will increase in southern Europe. These temperature predictions show an increased effect of the Gulf Stream on Europe, with a change in precipitation as an immediate...

Wintering Yellowhammers and Skylarks and their Seed Food Resources

The temporal variation in food abundance on our study areas in New Zealand and Britain was broadly out of phase, with greater breeding season invertebrate densities in Britain and more abundant winter food supplies (seeds) in New Zealand. In New Zealand, an increase in winter resource abundance and a reduction in predation risk appears to have resulted in more available foraging habitat. However, although there was some evidence that local climatic conditions may be less variable during the breeding season in New Zealand, we found no evidence that temporal variation in invertebrate food resources through the breeding season was reduced. This suggests that enhanced niche opportunities, if they exist, are not due to an increased abundance or temporal reliability of invertebrates, but rather enhanced niche opportunities may exist because of a warmer, more stable climate during the breeding season and lower energetic costs associated with foraging activities. Introduced birds in New...

Unseasonable Cold Soon After Arrival In Breeding Areas

Insectivorous migrants seemed especially vulnerable at such times, because cold and snow greatly reduced their food supplies, but large-scale losses also occurred among newly arrived waterfowl and waders. Ground-feeding birds may starve when fresh snow and ice makes their food unavailable (King 1974, Roseberry 1962, Vepsalainen 1968, Bull & Dawson 1969), and aquatic feeders are susceptible to delayed melting or re-freezing of water surfaces (Smith 1964, Barry 1968, Fredrickson 1969). One such catastrophe affected newly arrived Cliff Swallows Petrochelidon pyrrhonota in Wisconsin, when a sudden drop in temperature caused insects to become dormant. The swallows did not fly during this period, but clung to their old nests, with one observer collecting 'a milk pail full' of birds that had died (Buss 1942). Another unusual period of cold caused heavy mortality of Cliff Swallows across the north-central Great Plains in 1996, reducing a study population by about 53 (Brown & Brown 1998,...

Unseasonable Cold Before Departure From Breeding Areas

Occasionally, Swifts Apus apus are unable to leave their north European breeding areas because of adverse weather. They usually leave south Finland by the end of August, but in 1986 when late summer was cold and wet, around 2000 remained into November before dying (Kolunen & Peiponen 1991). Seven were found dead in their roost sites, and others still alive were clearly starving. Scarcity of aerial insects prevented the birds from accumulating fat for migration and they remained in southern Finland until their death. Similar events occurred in 1918 and 1957, but in these years delay was caused by late breeding resulting from cold weather in spring.

Activity Day Or Night Hunting

Weasels can see well at any time of day or night, so in the wild their activity is governed not by their visual abilities but by a fine balance of conflicting needs to find food sufficient to maintain their galloping metabolism, to find mates or feed their young, and at the same time to avoid their two worst enemies, cold weather and larger predators. Cold winters are a time of serious risk for weasels, and in all northern continental climates weasels absolutely depend on access to a well-insulated den (Chapter 7). This restriction is one of the costs of being a long thin animal (Brown & Lasiewski 1972) in a cold climate, and has more to do with thermoregulation than with hunting strategy. Weasels cannot lay down fat or hibernate (Chapter 2) they can best defend themselves from chilling by staying in their dens and feeding from their cache of stored prey, so that on the coldest or wettest days they can avoid going out at all.

The Mechanism of Winter Whitening

At landscape scale, there is a general relationship between cold winters and snow cover the further north the latitude or the higher the elevation is, the greater the chances are that a regular covering of snow every winter can be expected. Likewise, there is also a general connection between whitening in the landscape and in weasels. In cold climates the autumn temperatures plunge quickly, and all northern weasels always turn entirely white.

Plant life forms and biological spectra

Examples Therophytes

In addition to taxonomic classifications which endeavour to place closely related species in the same family, botanists have for centuries attempted to distinguish particular life forms, any one of which may be adopted by quite unrelated species. The simplest of these is the distinction between woody and herbaceous plants. Raunkiaer (1934) developed the most widely known scientific description of life forms, and then used it to initiate the use of biological spectra to compare different floras. The main feature of this ecologically valuable system is the position of the vegetative perennating buds or persistent stem apices during the cold winter or dry summer forming the unfavourable season of the year. The main life forms shown in Fig. 3.1 form a sequence showing successively greater protection from desiccation, indicating the position of the vegetative buds when the plant is dormant.

Where Is Foraging Theory

A key goal of early foraging models was to inform ecological theory, specifically population dynamics and community ecology. Early studies, however, tended to focus on the behavioral predictions of foraging models deferring studies of ecological implications for another day. This focus on behavior clearly frustrated some students of foraging ecology, but more recent work shows signs of fulfilling foraging theory's promise as an ecological tool. Within population dynamics, for example, the advent of individual-based models have given ecologists a tool with which they can study the population implications of foraging strategies, because one can specify the foraging strategies of the computational 'individuals' within the model. Turner and colleagues have used this approach recently in a study of elk and bison populations within Yellowstone National Park making the prediction that the effects of fire on resource quality are keys to the winter survival of these two large grazers....

Facultative movements in relation to weather

Hard weather movements are often extremely obvious. Whenever cold weather strikes, thousands of birds can be counted as they stream past particular observation points, as large regions are evacuated within a matter of hours. Counts made at such times in Britain include the 20 000 Eurasian Skylarks Alauda arvensis that passed westward over the Axe Estuary in Devon on 28 December 1964, or the 8300 counted in 2 hours as they passed south over a site in northeast Scotland on Weather movements were found by radar to occur almost every day and night in November-February between Britain and continental Europe (Lack 1963). The Northern Lapwing Vanellus vanellus and Common Starling Sturnus vulgaris were the most frequent participants, but many other species were involved too, including finches, thrushes, larks, plovers, grebes and other waterfowl (Elkins 1988, Evans & Davidson 1990, Ridgill & Fox 1990). All these birds are partial migrants which leave in winter more or less in the same...

Pollution acid rain and forest decline

Acid Rain Pollution Facts

Germany (termed 'Waldsterben', meaning forest death). By the late 1980s most European countries had more than 15 of trees with severe defoliation (defined as trees with crown densities less than 25 that of healthy trees). The causes of this decline, while so apparent to the media, were in reality not so straightforward. There are certainly direct effects of the acidity leading to calcium and magnesium loss and aluminium toxicity. In addition, the abundant sulphur and nitrogen causes imbalance (stoichiometric problems) that results in chlorosis and potentially death. The problem may also be exacerbated by high nitrogen input (discussed below) which increases growth, puts greater demands on magnesium and produces softer growth more at risk from insects, pathogens, frost and drought. High ozone levels are also known to directly damage leaf structure. Finally, the hot dry summers and cold winters of the 1970s and 1980s may also have taken their toll. The frustrating part is that direct...

Choosing Livestock for Control by Grazing

Do not perform well on wet ground and are susceptible to damp and cold weather. The narrow face allows goats to graze deep into scrub. Effective browsers that can control woodland development. High browse consumption and resting under scrub may enhance local development of nitrophilous flora. High-cost fencing.

Energy Storage and Expenditure

The text considers the problems of small passerine birds in a cold winter climate as a convenient model for problems of energy storage and regulation. We focus on evolutionary aspects of energy regulation. Box 7.1 introduces neural and endocrine mechanisms of energy regulation.

Acclimation Patterns Depend on Species and the Severity of the Environment

Another scenario is found along mountain slopes in temperate climates with cold winters, where lower altitudes are populated by a mix of annuals with soft tissues versus hardy evergreen ground covers and coniferous trees. At higher altitudes, the highly resistant conifers predominate by virtue of their tolerance to altered internal conditions, enabling them to survive long winters with subfreezing temperatures and frozen soils that deprive plants of access to liquid water. Above treeline, only ground-hugging evergreens, winter-deciduous species, and very few annuals are able to survive.

Interactions critical questions

Determining the likely abiotic thresholds for survival, development, or reproduction in the laboratory, or perhaps with limited caging experiments, is only the first step in explaining their relevance to population dynamics and ultimately to the abundance and distribution of a species (or suite of species) (Kingsolver 1989 Holt et al. 1997). Several critical questions remain, including which stage, gender, or age group is most likely to experience the critical population bottleneck (van der Have 2002), how physiological characteristics and fitness are actually related (Feder 1987 Kingsolver 1996), and how frequently environmental extremes might be encountered. In some cases, the immature stages might be most critical because development generally proceeds within a smaller range of environmental variables (e.g. temperature) than the adult organisms can survive (van der Have 2002). In consequence, both abundance and distribution might be determined by growth conditions faced by the...

Ice Caps and Glaciers

Broken Ice Shelf

As more snow falls to the surface the overlying snow presses down, forcing some of the air out and causing the points of the flakes to melt. The resulting water tends to migrate and refreeze toward the center of the flake, producing rounded grains called firn. These gran

Hole in the Ozone Layer

Loss of ozone in the atmosphere was first noticed by scientists studying the atmosphere above Antarctica in the mid-1970s. This loss, which occurs during the summer, is described as the ozone hole, and scientific investigation since the loss was first noticed has shown that a number of factors are involved. During the winter polar night, sunlight does not reach the South Pole, and the air gets very cold. A strong whirlpool wind, the polar vortex, develops, causing the cold air to remain within the polar area, essentially cutting it off from the rest of the atmosphere. When the air temperature drops below -80 degrees centigrade, polar stratospheric clouds form that are composed of water ice droplets and nitric acid. Reactions take place on the surface of these ice crystals that convert benign chlorine compounds into chlorine and bromine compounds that are ozone destroyers. The source of these chemicals is CFCs (chlorofluorocarbons) and other Arctic are variable, and ozone loss occurs...

Hydrocarbons Solvents Pahs And Similar Compounds

Alcohols, including glycols, are much stronger CNS depressants than aliphatics are and slightly more irritating. As carbon chain length increases, irritation decreases but lipophi-licity increases, as does systemic toxicity. Methanol is less inebriating than ethanol but has the unusual property of destroying the optic nerve. Fifteen milliliters can cause blindness. As with ethanol, it is metabolized by a zero-order rate mechanism, but at one-seventh the rate. Ethanol acts as an irritant by dehydrating protoplasm. An initial stimulant effect is caused by depression of control mechanisms in the brain. Pain sensitivity is greatly reduced. Cutaneous (skin) blood vessels become dilated. The resulting increased heat loss can be dangerous in cold weather. It increases gastric secretion, which can aggravate stomach ulcers. It causes fat accumulation and cirrhosis in the liver. The latter can be fatal itself or can cause progression to cancer. Ethanol increases urine flow through a mechanism...

Summary

Whilst stress reactions are usually relatively easily recognised, the perception of stress by an organism is not yet fully understood. The question, which molecular signal a stressor creates in an organism can be answered only in a few cases. Feed-forward hardening is typical of regularly recurring stress situations, for example, frost hardening of plants in regions subjected to cold winters. However, usually adaptation is triggered by the stress itself. Adaptations lead to an increased stress tolerance or to a more effective stress avoidance.

Weather

The weather affects our lives in numerous ways. For example, the type of clothing we wear depends largely on the weather. We put on heavy clothes when it is cold and dress lightly when it is hot. We also heat our homes in cold weather and cool them in hot weather. In many cases, we decide whether to spend our leisure time outdoors or inside according to the weather. The weather even affects our moods. People often feel more cheerful on a sunny day than on a gloomy one. weather. The construction of buildings, bridges and roads may be delayed by rain, snow or extreme cold. Snow may make trains late. Fog often prevents airplanes from taking off. Icy highways slow traffic. Storms may break power-lines and telephone wires. Thunderstorms may disrupt radio and television broadcasts. Even more serious is the lost of lives that sometimes results from severe storms.

Carbon

Mineralization of complex carbon compounds in soil increase the pool of simple carbon compounds. The most well-studied processes that stimulate the mineralization of organic carbon are plowing, freeze-thaw events, and wetting of very dry soil (pulsing effect). Plowing aerates the soil and thereby stimulates mineralization of organic carbon compounds in parts of the soil previously not receiving the O2 concentrations required for mineralization to take place. Increased mineralization stimulated by freeze-thaw events or the pulsing effects are governed by the same principle. Extreme cold and extreme dry conditions kill a large part of the microbial community and reduce the activity of the survivors. When conditions become more tolerable, due to a thaw or rainfall, the remaining microbial population become activated and feed off the nutrients supplied by the dead microbial biomass and any nutrients deposited in the soil during periods of drought or freeze. These three events are usually...

Fat reserves

The characteristic most frequently associated with individual condition is the quantity of fat carried by the bird. However, the assumption that high and low fat loads indicate birds in good and bad condition respectively comes from our anthropocentric viewpoint as a terrestrial mammal, our knowledge of the energy requirements of long-distance migrants, and the fact that birds picked up dead under extreme cold conditions (waders and wildfowl) are usually seen to have starved. We must be careful how we regard fat loads because they carry a cost (Witter and Cuthill 1993 Gosler 2001). Nevertheless, the observation of visible subcutaneous fat in many species (especially passerines) is quick and reliable, and can give insight into the birds' biology (Gosler et al. 1995 b Gosler 1996, 2002 Carrascal et al. 1998).

Gila Monster

The modest rainfall that distinguishes this habitat from a true desert allows the growth of cacti, shrubs, and ephemeral plants. These plants manage in their short life spans to produce food that feeds local animals. The available food spurs the development of a wider range of fauna, Semideserts with cold winters, however, still present challenges to animals. They need to discover ways to store water and find refuge from the low temperatures.

Results

Repeated measures analysis of variance revealed significant differences in total above-ground biomass among the parental types and the two hybrid generations over the first season of growth (repeated measures T 4, F 9.29, P 0.0001, 2 66 df for cross group tested over the variance among genotypes Fig. 2). There were significant differences in above-ground biomass in the first season of growth for the contrasts between the backcross and parental genotypes (backcross midparent F 11.68, P 0.0008) and the backcross and F1 genotypes (backcross F1 F 6.96, P 0.0090) but not the F1 and parental genotypes (midparent F1 F 0.05, P 0.8310). Vegetative size at the end of the first season explained a large proportion of the variation in over-winter survival in this (logistic regression chi square 5.55, P 0.0185) and a previous study (Rhode and Cruzan 2004). Mortality of the smallest individuals tended to equalize vegetative sizes among groups for the second season (repeated measures T 3, F 1.00, P...

Markrecapture

Because the slow rate of generating migration maps based on ringing recoveries, migrationists have invented supplementary techniques. In addition to a numbered metal ring, combinations of color bands are used for identification of birds using a telescope. This method is useful in birds like shorebirds using specific habitats along the migration routes. Larger birds, such as swans and geese, can be fitted with numbered neck-collars, likewise checked by telescope. Compared with ringing, this method allows repeated registration of individual birds along the migration route and hence improved temporal resolution in data on migration rate and stopover duration. However, neck-collars are limited to large birds and can accumulate ice during cold weather. Also, it is only possible to get records from locations visited by observers.

Opeivi Ocean

Hydrological and meteorological systems create downflow at low latitudes and upflow at high latitudes. This creates extremely cold conditions at the ocean bottom, and matches the Earth's current system. This was not necessarily always the case, although the details of ancient Poseidon hydrology are unknown at present. On Earth, abyssal waters were a relatively balmy 18 Celsius approximately 140 million years ago, probably due to downflow of waters in the tropics.

Self Pollination

Self-pollination occurs when pollen grains travel from the anthers to the stigmas of the same flower or other flowers on the same plant. Self-fertilization occurs unless the plant's own pollen is incompatible with its stigmas. This method of fertilization is beneficial when other plants are not available for mating. Self-pollinators do not rely on animals or other pollen vectors, and self-pollinated plants are often present where flower-visiting animals are rare, such as on high mountains or in extremely cold climates (Raven et al. 1999). Some plants always self-pollinate, while in others self-pollination is rare. Self-pollination can occur in plants that also have other pollination strategies such as wind or insect pollination. Plants that always or usually self-fertilize have low genetic variation and blur the line between sexual and asexual reproduction (Philbrick and Les 1996).

Body Size

The influence of environmental factors is size dependent. Small animals have relatively more surface area and relatively less metabolically active tissue with which to generate heat. Therefore, we would expect a small animal, when challenged with cold, to lose heat more rapidly than a larger animal. If such an animal attempted to generate heat to offset the heat loss and maintain Tb, it would require a relatively higher rate of energy utilization. Small endothermic homeotherms, by virtue of their higher metabolic requirements, are therefore dependent on a reliable supply of energy-yielding foods. Exposure to extreme cold and or a food shortage would place a small endothermic homeotherm under profound metabolic stress. Obvious energetic savings are to be made under such conditions by lowering the thermal set-point for Tb regulation and depressing metabolism (i.e., torpor, Figure 8). Examples of torpor are found in all three infraclasses of mammals and some groups of birds.

Winter distributions

The winter distributions of North American ducks also vary from year to year, depending on prevailing conditions. Many species move further south in cold winters than in mild ones or further when low rainfall reduces the numbers of wetlands available. This pattern in Mallard Anas platyrhynchos was confirmed by winter ring recoveries which were centred further north during winters when December-January temperatures were high than during winters when they were low (Nichols et al. 1983). Birds also tended to concentrate in areas that experienced greater autumn-winter rainfall, and hence good wetland conditions. Similarly, in the Wood Duck Aix sponsa, both adults and young migrated further in years of low summer rainfall and the young also migrated further south when autumn temperatures were lower than normal (Hepp & Hines 1991). Both rainfall and temperature affect the availability of wetland habitat and food, competition for which may well stimulate further migration, with young ducks...

Eurasian ducks

In Europe, during hard winters many waterfowl appear in greater numbers than usual in milder southern and western parts of the continent. Ring recovery distances of several ducks (Eurasian Wigeon Anas penelope, Teal A. crecca, Northern Pintail A. acuta, Common Pochard A. ferina and Tufted Duck A. fuligula) were greater in cold winters than in mild ones, and greater in cold spells than in equivalent mild periods (Ridgill & Fox 1990). Other species showed no significant differences. Such hard weather (or 'escape') movements were associated with greater mortality than usual, but this may have resulted from greater vulnerability to hunting.

Evolutionary aspects

At high latitudes, daylengths also shorten in winter to such an extent that many diurnal birds would have too little time to get enough food, even if it were available. Hence, the purpose of the autumn exodus from high latitudes is fairly obvious. The reason why birds leave their wintering areas to return in spring is less obvious, because many wintering areas seem able to support the birds during the rest of the year. But if no birds migrated to higher latitudes in spring, these latitudes would remain almost empty of many species, and a large seasonal surplus of food would go largely unexploited. Under these circumstances, any individuals that moved to higher latitudes, with increasing food and long days, might raise more young than if they stayed at lower latitudes and competed with the birds resident there. So whereas the advantage of autumn migration can be seen as improved winter survival, dependent on better food supplies in winter quarters, the main...

Partial Migration

The European Robin Erithacus rubecula is a facultative partial migrant in Belgium (Adriaensen & Dhondt 1990). In one study, most males that nested in parks and gardens were resident year-round, whereas most males that nested in woodland were migratory, as were all females from both habitats. Resident males survived, on average, about three times better than migratory individuals (50 versus 17 ), and even during the extremely cold winter of 1984-1985, residents still survived best. In addition, resident males were much more likely than migratory ones to obtain a mate (74 versus 44 ). On the basis of both survival and mating success, the expected reproductive success of resident males was 2-4 times higher than that of migratory males. So why did migration persist In ecological jargon, partial migration was a 'conditional strategy with unequal pay-offs' if individuals could find a territory locally in which they had a good chance of surviving the winter, they could stay if not, they had...

Carryover effects

Most discussion of population limitation in migrants carries the implicit assumption that conditions in wintering areas have no effects on subsequent breeding success, and that conditions in breeding areas have no effect on subsequent winter survival. These assumptions are not entirely justified. The breeding densities of many bird species are determined partly by winter survival, and winter survival can in turn be related to events in the previous breeding season. But more than this, individual birds can carry over effects from one season to the next, and these residual effects, acting through body condition, can explain some of the variation in breeding success and winter survival. For example, among geese and other waterfowl, foraging conditions at wintering and migration sites have long been known to affect subsequent breeding success through the affect of food supplies on body condition. In most such species, conditions on spring staging areas seem more important than conditions...

Relevant Hypotheses

We also addressed the increased niche opportunity hypothesis. It predicts that introduced species experience enhanced success because of greater abundance or better quality resources in the new environment, leading to increased survival and recruitment or both (Shea and Chesson, 2002). Contrary to the predictions, habitat quality (measured as the density and diversity of all invertebrates or the density of preferred invertebrate prey, a key food resource for nestling yellowhammers) was significantly lower in New Zealand than in Britain (MacLeod et al., 2005a,b). We also found no statistical evidence that differences in habitat availability or quality could account for the overall difference in breeding density between the two countries, even though the preferred breeding habitats (hedgerows and ditches) of yellowhammers were twice as abundant on the New Zealand study farms than on those in Britain. Nine of eleven of New Zealand's most common introduced farm-landbird species had...

Typhoon

Thus the arctic vegetation is subjected to both extreme physiological drought (with water unavailable for most of the year) and to extreme cold. In the short summer, many meltwater pools contain insect larvae, which develop into adults as the temperature rises, providing food for migrating birds, e.g. waders, which return to the tundra to breed. Reindeer and other herbivores graze on the lichens and migrate south to the boreal forest when the winter becomes extreme, although they can locate lichens under the snow cover.

Grassland Types

It is estimated that prior to the European settlement of North America, the largest continuous grasslands in the United States stretched across the Great Plains from the Rocky Mountains and deserts of the Southwestern states to the Mississippi river. Other extensive grasslands are, or were, found in Europe, South America, Asia, and Africa (Figure 2). Grasslands can be broadly categorized as temperate or tropical. Temperate grasslands have cold winters and warm to hot summers and often have deep fertile soils. Surprisingly, plant growth in temperate grasslands is often nutrient limited because much of the soil nitrogen is stored in forms unavailable for plant uptake. These nutrients, however, are made available to plants when plowing disrupts the structure of the soil. The combination of high soil fertility and relatively gentle topography made grasslands ideal candidates for conversion to crop production and thus have led to the demise of much of the grasslands across the world.

Lagomorpha

Then stored within the rocky labyrinths for later use. Some Eurasian species also live in talus and rock-strewn terraces, but others inhabit plains, desert-steppes, and forests where they excavate burrows for shelter. Pikas do not hibernate, even though they live in regions subject to long, cold winters.

Estuaries

In the Hudson River estuary, a 5-foot tide occurs in salt, brackish, and fresh water for 210 km, until a dam upstream blocks it. The Native Americans used to call the Hudson the river that flows two ways up and down, back and forth. Often estuaries are stratified as a result of the density difference, although mixing takes place during storms. During cold winters the upper freshwater layer can freeze over, and ice can be found at times at the mouth of the estuary. Net flow is to the sea, although floating organisms and other objects remain in the estuary for long periods, carried back and forth by the tide. Some estuaries are very long such as Chesapeake Bay, where the tide takes a long

Small Mammals

Weasels have no difficulty killing small rodents in confined spaces. Weasels that each of us has kept in captivity could kill voles and house mice in narrow tunnels. The radio-collared weasels observed by Jgdrzejwski et al. (1992) hunted during the day, systematically searching underground dens and tunnels of rodents, and cavities 1 to 4 m up old trees. The strictly nocturnal yellow-necked mice were especially vulnerable in cold weather, because then they saved energy by retreating to their nests and falling into short periods of torpor not a true hibernation, but a sleep deep enough to make them defenseless against an intruding weasel.