Showing posts with label Polar biome. Show all posts
Showing posts with label Polar biome. Show all posts

Thursday, June 7, 2012

Coniferous forest biome

Coniferous forest biome
                Coniferous forest ecosystems are found in regions of the Earth that experience somewhat long and cold winters, with summer being much shorter. Thus, it is no surprise that these biomes are more common the closer one travels towards the Earth’s poles. Additionally, this biome is found high atop mountains where temperatures tend to be lower and winter tends to last longer.
             
The Coniferous Forest is a forest of Conifers. A Conifer is a tree that produces its seeds in cones.  The Pine tree is the most common example.  Conifer leaves conserve water with the thick, waxy layer that covers their leaves, also known as needles.  The vegitation in the Coniferous forest is small in size, but large enough to feed the vast herbivore population.  Most of these animals survive the brutal winters by migrating or hibernating. 
                       
Average Annual Rainfall- 14-29.5 in.
Average Temperatures in the Summer- 57.2°F
Average Temperatures in the Winter- 14°F
Temperate coniferous forest         

Temperate coniferous forest is a terrestrial biome found in temperate regions of the world with warm summers and cool winters and adequate rainfall to sustain a forest. In most temperate coniferous forests, evergreen conifers predominate, while some are a mix of conifers and broad leaf evergreen trees and/or broad leaf deciduous trees. . Coniferous forests can be found in the United States, Canada, Europe, and Asia. Many species of trees inhabit these forests including cedar, cypress, douglas-fir,pine, podocarpus, spruce, redwood and yew. The understory also contains a wide variety of herbaceous and shrub species.

Tuesday, April 10, 2012

Tundra

Tundra Biome



              In the very cold places of the world, survival isn't easy. The soil is frozen, its top surface thawing only during summer, and no trees can grow. Yet plants and animals that are adapted for the harsh conditions thrive. This biome is called tundra. Most of the world's tundra is found in the north polar region. It is called Arctic tundra. There is a small amount of tundra on parts of Antarctica that are not covered with ice. Plus, tundra is found on high altitude mountains and is called alpine tundra.


             Permafrost is the term given to frozen soil. During the winter months, permafrost reaches the surface of the tundra. It is very cold during the winter, with temperatures reaching -60 degrees Fahrenheit (-51 degrees Celsius). Very few animals are active in these harsh conditions.


              In the summer time, the tundra changes. The Sun is out almost 24 hours a day, so the tundra starts to warm up. The permafrost melts at the surface, and plant life grows. However, the permafrost only disappears for a few inches below the surface. There isn't enough soil for trees to grow, so only small plants are found in the tundra.


          At the same time, a variety of animals come out to feast on the plants. Insects come to feed on the animals, and birds appear to enjoy the insects.


Characteristics of tundra include:
  1. Extremely cold climate

  2. Low biotic diversity

  3. Simple vegetation structure

  4. Limitation of drainage

  5. Short season of growth and reproduction

  6. Energy and nutrients in the form of dead organic material

  7. Large population oscillations
Tundra is separated into two types:

Arctic tundra

                    Arctic tundra is located in the northern hemisphere, encircling the north pole and extending south to the coniferous forests of the taiga. The arctic is known for its cold, desert-like conditions. The growing season ranges from 50 to 60 days. The average winter temperature is -34° C (-30° F), but the average summer temperature is 3-12° C (37-54° F) which enables this biome to sustain life. Rainfall may vary in different regions of the arctic. Yearly precipitation, including melting snow, is 15 to 25 cm (6 to 10 inches). Soil is formed slowly. A layer of permanently frozen subsoil called permafrost exists, consisting mostly of gravel and finer material. When water saturates the upper surface, bogs and ponds may form, providing moisture for plants. There are no deep root systems in the vegetation of the arctic tundra, however, there are still a wide variety of plants that are able to resist the cold climate. There are about 1,700 kinds of plants in the arctic and subarctic, and these include:
  • low shrubs, sedges, reindeer mosses, liverworts, and grasses

  • 400 varieties of flowers

  • crustose and folios lichen
                   All of the plants are adapted to sweeping winds and disturbances of the soil. Plants are short and group together to resist the cold temperatures and are protected by the snow during the winter. They can carry out photosynthesis at low temperatures and low light intensities. The growing seasons are short and most plants reproduce by budding and division rather than sexually by flowering. The fauna in the arctic is also diverse:
  • Herbivorous mammals: lemmings, voles, caribou

  • Carnivorous mammals: arctic foxes, wolves, and polar bears

  • Migratory birds: ravens, snow buntings, falcons, loons,

  • Insects: mosquitoes, flies, moths, grasshoppers

  • Fish: cod, flatfish, salmon, and trout
                  Animals are adapted to handle long, cold winters and to breed and raise young quickly in the summer. Animals such as mammals and birds also have additional insulation from fat. Many animals hibernate during the winter because food is not abundant. Another alternative is to migrate south in the winter, like birds do. Reptiles and amphibians are few or absent because of the extremely cold temperatures. Because of constant immigration and emigration, the population continually oscillates.

Alpine tundra

   
                           Alpine tundra is located on mountains throughout the world at high altitude where trees cannot grow. The growing season is approximately 180 days. The nighttime temperature is usually below freezing. Unlike the arctic tundra, the soil in the alpine is well drained. The plants are very similar to those of the arctic ones and include:
  • tussock grasses, dwarf trees, small-leafed shrubs, and heaths
Animals living in the alpine tundra are also well adapted:

  • Mammals: pikas,, mountain goats, sheep

  • Birds: grouse like birds

  • Insects: spring tails, grasshoppers ,beetles

Saturday, May 14, 2011

Mountain biome


          The mountain biome is harsh. The higher you climb the harsher it becomes due to the thinner atmosphere, high winds, and low temperatures. The type of flora and fauna change from the bottom to the top as the climate changes and the soil thins. The mountain biome has the largest variety of ecosystems and they will vary with the location of the mountain. I.e. the ecosystems of the Alps will not be the same as those of the Andes. The mountain biome is the most difficult to study as a whole because the fauna and flora varies from mountain range to mountain range.
            Mountains are usually found in groups called chains or ranges, although some stand alone. A mountain biome is very cold and windy. The higher the mountain, the colder and windier the environment. There is also less oxygen at high elevations.Several different types of plants and animals found in the mountain biome were left behind with the melting of the ice sheets as they retreated north at the end of the last ice age.

           The animals of this biome have adapted to the cold, the lack of oxygen, and the rugged landscape. They include the mountain goat, ibex (wild goat), sheep, mountain lion, puma, and yak. All of them are excellent climbers, which means they can move freely in the steep, rocky landscape. Types of plants vary depending on geographic location and altitude. Lower elevations are commonly covered by forests, while very high elevations are usually treeless.

               One common trait among the mountain biome fauna is that most of them are plant eaters. Such as the yak, mountain goat, the takin, ibex, chinchillas. Flora that can be found in most mountain biomes includes heather, lichens, coniferous tress, and chaparral.

                Mountains are a common sight on this planet. They make up one-fifth of the world's landscape, and provide homes to at least one-tenth of the world's people. Furthermore, 2 billion people depend on mountain ecosystems for most of their food, hydroelectricity, timber, and minerals. About 80 per cent of our planet's fresh water originates in the mountains. Since about half of the world's people are reliant upon mountains for fresh water, and in this time of increasing water scarcity, it is becoming increasingly important to protect the mountain biome.

                 All mountain ecosystems have one major characteristic in common--rapid changes in altitude, climate, soil, and vegetation over very short distances. Mountain ecosystems sport a high range of biodiversity, and are also a home to many of our planet's ethnic minorities. These cultures are sometimes 'protected' due to the challenging environment to produce a living, but others are not. More and more these indigenous people are being kicked out of their homes due to population and commercial growth, logging, and mining.

                 Rainfall varies greatly across the world's montane (mountain) biomes, ranging from very wet to very dry. However in all the biomes comes swift weather changes. For example, in just a few minutes a thunder storm can roll in when the sky was perfectly clear, and in just a few hours the temperatures can drop from extremely hot temperatures to temperatures that are below freezing.

                The world's mountains provide a home to several thousand different ethnic groups. The mountain people, which mainly consist of indigenous people, ethnic minorities, and refugees, have been able to cope with this harsh environment of the mountain ecosystem. They live as nomads, hunters, foragers, traders, small farmers, loggers, and miners, etc. They have been able to live off the land without widespread destruction and deforestation. Plant and animal species have been preserved by these people.


                The Himalayan Yew, a slow-growing conifer, is currently on the World Wildlife Fund's list of the ten most endangered animals. This plant can be found throughout Bhutan, Afghanistan, India, Nepal, Burma, and maybe China. Taxol, which is promising to be a drug which can help cure cancer, is present in both the Pacific and Himalayan varieties. Found in the world's highest mountain range, the Himalayan Yew is extremely rare because of heavy deforestation and harvesting for Taxol extraction, without replanting.

Polar biome


           Polar ice caps form because high-latitude regions receive less energy in the form of solar radiation from the sun than equatorial regions. This results in lower surface temperatures. Seasonal variations of the ice caps will take place due to varied solar energy absorption as the planet or moon revolves around the sun. Additionally, in geologic time scale, the ice caps may grow or shrink due to climate variation.
           A polar ice cap or polar ice sheet is a high-latitude region of a planet or moon that is covered in ice. This term is somewhat of a misnomer since an ice cap is less than 50,000 km² and is always over land: a larger area of ice is called an ice sheet. Polar ice caps do not have size, composition or geologic requirements of being over land, but they must be centered in the polar region.

           The Antarctic polar ice cap is a truly unique biome.The climate is very harsh, both on the land and in the water.The soil  is dry and rocky, with little vegetation.With a short growing season, cold temperatures, few plants exist.Thus, there is little decomposition and little organic matter in the soil which might help plant growth.This is the antithesis of the Temperate Deciduous Biome forests that have a lot of plant growth, lots of decomposition, and thus very rich soils that encourage further plant growth.
      
            The sun is very intense when there is no cloud cover because there is nothing to create shade.  Ozone depletion has been a problem in the Antarctic, and there is some thought that penguins and aquatic organisms near the surface of the water (ie. coral near Australia) may be affected by the increased level of UV light.
      
            The cold temperatures, combined with the high winds, leads to a significant windchill.  Even in peak summer the temperatures reached only + 5C.  In the winter it is so cold that it is almost impossible to travel here.  In 1999 a female doctor at a research base took care of her on starting cancer problems because planes could not fly in during the winter season.
             The land mass of the Earth's south pole, in Antarctica, is covered by the Antarctic ice sheet. It covers an area of almost 14 million km² and contains 30 million km³ of ice. Around 90% of the fresh water on the Earth's surface is held in this ice sheet. In addition, the West Antarctic Ice Sheet covers 3.2 million km² and the Ross Ice Shelf covers 0.5 million km².

             Earth's north pole is covered by floating pack ice (sea ice) over the Arctic Ocean. Portions of the ice that don't melt seasonally can get very thick, up to 3–4 meters thick over large areas, with ridges up to 20 meters thick. One-year ice is usually about a meter thick. The area covered by sea ice ranges between 9 and 12 million km².

Wednesday, May 11, 2011

Savanna ecosystem

Savanna ecosystem

                A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses. Some classification systems also recognize a grassland savanna from which trees are absent.This article deals only with savanna under the common definition of a grassy woodland with a significant woody plant component.

          It is often believed that savannas feature widely spaced, scattered trees. However, in many savannas, tree densities are higher and trees are more regularly spaced than in forest. Savannas are also characterized by seasonal water availability, with the majority of rainfall confined to one season. Savannas are associated with several types of biomes. Savannas are frequently in a transitional zone between forest and desert or prairie. Savanna covers approximately 20% of the earth's land area.

         Many grassy landscapes and mixed communities of trees, shrubs, and grasses were described as savanna before the middle of the 19th century, when the concept of a tropical savanna climate became established. The Köppen climate classification system was strongly influenced by effects of temperature and precipitation upon tree growth, and his over-simplified assumptions resulted in a tropical savanna classification concept which resulted in it being considered as a "climatic climax" formation. The common usage meaning to describe vegetation now conflicts with a simplified yet widespread climatic concept meaning. The divergence has sometimes caused areas such as extensive savannas north and south of the Congo and Amazon Rivers to be excluded from mapped savanna categories.

         "Barrens" has been used almost interchangeably with savanna in different parts of North America. Sometimes Midwestern savanna were described as "grassland with trees". Different authors have defined the lower limits of savanna tree coverage as 5-10% and upper limits range from 25-80% of an area.
   
       Two factors common to all savanna environments are rainfall variations from year to year, and dry season wildfires. Savannas around the world are also dominated by tropical grasses which use the C4 type of photosynthesis.In the Americas, e.g. in Belize, Central America, savanna vegetation is similar from Mexico to South America and to the Caribbean. In North America nearby trees are of subtropical types, ranging from southwestern Pinyon pine to southeastern Long leaf Pine and northern chestnut oak.

Savanna ecoregions

Savanna ecoregions are of several different types:-
  • Tropical and subtropical savannas are classified with tropical and subtropical grasslands and shrub lands as the tropical and subtropical grasslands, savannas, and shrub lands biome. The savannas of Africa, including the Serengeti, famous for its wildlife, are typical of this type.
  • Temperate savannas are mid-latitude savannas with wetter summers and drier winters. They are classified with temperate savannas and shrub lands as the temperate grasslands, savannas, and shrub lands biome, that for example cover much of the Great Plains of the United States. (See areas such as the Central forest-grasslands transition).
  • Mediterranean savannas are mid-latitude savannas in Mediterranean climate regions, with mild, rainy winters and hot, dry summers, part of the Mediterranean forests, woodlands, and scrub biome. The oak tree savannas of California, part of the California chaparral and woodlands ecoregion, fall into this category.
  • Flooded savannas are savannas that are flooded seasonally or year-round. They are classified with flooded savannas as the flooded grasslands and savannas biome, which occurs mostly in the tropics and subtropics.
  • Mountain savannas are high-altitude savannas, located in a few spots around the world's high mountain regions, part of the mountain grasslands and shrub lands biome. The highland savannas of the Angolan Scarp savanna and woodlands ecoregion are an example.
Our ecosystem