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Grassland Degradation
Grassland degradation, also called vegetation or steppe degradation, is a biotic disturbance in which grass struggles to grow or can no longer exist on a piece of land due to causes such as overgrazing, burrowing of small mammals, and climate change. Since the 1970s, it has been noticed to affects plains and plateaus of alpine meadows or grasslands, most notably being in the Philippines and in the Tibetan and Inner Mongolian region of China, where of grassland is degraded each year. Across the globe it is estimated that 23% of the land is degraded. It takes years and sometimes even decades, depending on what is happening to that piece of land, for a grassland to become degraded. The process is slow and gradual but so is restoring degraded grassland. Initially only patches of grass appear to die and appear brown in nature; but the degradation process, if not addressed, can spread to many acres of land. As a result, the frequency of landslides and dust storms may increase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grassland In Europe
A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other Herbaceous plant, herbs. Grasslands occur naturally on all continents except Antarctica and are found in most ecoregions of the Earth. Furthermore, grasslands are one of the largest biomes on earth and dominate the landscape worldwide. There are different types of grasslands: natural grasslands, semi-natural grasslands, and agricultural grasslands. They cover 31–69% of the Earth's land area. Definitions Included among the variety of definitions for grasslands are: * "...any plant community, including harvested forages, in which grasses and/or legumes make up the dominant vegetation." * "...terrestrial ecosystems dominated by herbaceous and shrub vegetation, and maintained by fire, grazing, drought and/or freezing temperatures." (Pilot Assessment of Global Ecosyst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes. Ecosystems are controlled by external and internal factors. External factors such as climate, parent material which forms the soil and topography, control the overall structure of an ecosystem but are not themselves influenced by the ecosystem. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate Change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices increase greenhouse gases, notably carbon dioxide and methane. Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming. Due to climate change, deserts are expanding, while heat waves and wildfires are becoming more common. Increased warming in the Arctic has contributed to melting permafrost, glacial retreat and sea ice loss. Higher temperatures are also causing m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grazing
In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other forages into meat, milk, wool and other animal products, often on land unsuitable for arable farming. Farmers may employ many different strategies of grazing for optimum production: grazing may be continuous, seasonal, or rotational within a grazing period. Longer rotations are found in ley farming, alternating arable and fodder crops; in rest rotation, deferred rotation, and mob grazing, giving grasses a longer time to recover or leaving land fallow. Patch-burn sets up a rotation of fresh grass after burning with two years of rest. Conservation grazing proposes to use grazing animals to improve the biodiversity of a site, but studies show that the greatest benefit to biodiversity comes from removing grazing animals from the landscape. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrain
Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface. The term bathymetry is used to describe underwater relief, while hypsometry studies terrain relative to sea level. The Latin word (the root of ''terrain'') means "earth." In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientation of terrain features. Terrain affects surface water flow and distribution. Over a large area, it can affect weather and climate patterns. Importance The understanding of terrain is critical for many reasons: * The terrain of a region largely determines its suitability for human settlement: flatter alluvial plains tend to have better farming soils than steeper, rockier uplands. * In terms of environmental quality, agriculture, hydrology and other interdisciplinary sciences; understanding the terrain of an area assists the understanding of watershed boundaries, dra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical erosion procee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zokor
Zokors are Asiatic burrowing rodents resembling mole-rats. They include two genera: ''Myospalax'' and ''Eospalax''. Zokors are native to much of China, Kazakhstan, and Siberia, Siberian Russia. Traditionally, zokors were thought to be closely related to either hamsters (Cricetinae) or voles (Arvicolinae), but recent molecular phylogeny, molecular phylogenetic studies have demonstrated they are more closely related to blind mole-rats (Spalacinae) and root and bamboo rats (Rhizomyinae) in the family Spalacidae. It appears that one of the first important cladogenesis, evolutionary splits in Muroidea, muroid rodents is between burrowing forms and Eumuroida, nonburrowing forms. Unlike the other Spalacidae, spalacids, which primarily use their incisors, zokors use their powerful front claws for digging. They have small eyes and no external ears. Zokors feed on plant matter such as tubers and seeds. Zokor bone is sometimes used as a more environmentally friendly alternative to tig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pika
A pika ( or ; archaically spelled pica) is a small, mountain-dwelling mammal found in Asia and North America. With short limbs, very round body, an even coat of fur, and no external tail, they resemble their close relative, the rabbit, but with short, rounded ears. The large-eared pika of the Himalayas and nearby mountains is found at heights of more than , among the highest of any mammal. Pikas prefer rocky slopes and graze on a range of plants, mostly grasses, flowers and young stems. In the autumn they pull hay, soft twigs and other stores of food into their burrows to eat during the long, cold winter. The pika is also known as the whistling hare because of its high-pitched alarm call when diving into its burrow. The name ‘pika’ appears to be derived from the Tungus ''piika'', and the scientific name ''Ochotona'' is from the Mongolian word ''ogutun-a, оготно'', which means pika. It is used for any member of the Ochotonidae, a family within the order of lagomorp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vole
Voles are small rodents that are relatives of lemmings and hamsters, but with a stouter body; a longer, hairy tail; a slightly rounder head; smaller eyes and ears; and differently formed molars (high-crowned with angular cusps instead of low-crowned with rounded cusps). They are sometimes known as meadow mice or field mice in North America. Vole species form the subfamily Arvicolinae with the lemmings and the muskrats. There are approximately 155 different vole species. Description Voles are small rodents that grow to , depending on the species. Females can have five to ten litters per year, though with an average lifespan of three months and requiring one month to adulthood, two litters is the norm. Gestation lasts for three weeks and the young voles reach sexual maturity in a month. As a result of this biological exponential growth, vole populations can grow very large within a short time. A mating pair can produce a hundred more voles in a year. Voles outwardly resemble s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marmot
Marmots are large ground squirrels in the genus ''Marmota'', with 15 species living in Asia, Europe, and North America. These herbivores are active during the summer, when they can often be found in groups, but are not seen during the winter, when they hibernate underground. They are the heaviest members of the squirrel family. Description Marmots are large rodents with characteristically short but robust legs, enlarged claws which are well adapted to digging, stout bodies, and large heads and incisors to quickly process a variety of vegetation. While most species are various forms of earthen-hued brown, marmots vary in fur coloration based roughly on their surroundings. Species in more open habitat are more likely to have a paler color, while those sometimes found in well-forested regions tend to be darker. Marmots are the heaviest members of the squirrel family. Total length varies typically from about and body mass averages about in spring in the smaller species and in aut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woody Plant Encroachment
Woody plant encroachment (also called bush encroachment, shrub encroachment, woody encroachment, bush thickening, or woody plant proliferation) is a natural phenomenon characterised by the increase in density of woody plants, bushes and shrubs, at the expense of the herbaceous layer, grasses and forbs. It predominantly occurs in grasslands, savannas and woodlands and can cause biome shifts from open grasslands and savannas to closed woodlands. The term bush encroachment refers to the expansion of native plants and not the spread of alien invasive species. It is thus defined by plant density, not species. Bush encroachment is often considered an ecological regime shift and can be a symptom of land degradation. The phenomenon is observed across different ecosystems and with different characteristics and intensities globally. Its causes include land use intensification, such as high grazing pressure and the suppression of wildfires. Climate change is found to be an accelerating fac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urbanization
Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly the process by which towns and cities are formed and become larger as more people begin living and working in central areas. Although the two concepts are sometimes used interchangeably, urbanization should be distinguished from urban growth. Urbanization refers to the ''proportion'' of the total national population living in areas classified as urban, whereas urban growth strictly refers to the ''absolute'' number of people living in those areas. It is predicted that by 2050 about 64% of the developing world and 86% of the developed world will be urbanized. That is equivalent to approximately 3 billion urbanites by 2050, much of which will occur in Africa and Asia. Notably, the United Nations has also recently projected that nearly all gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
