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Psammosere
A psammosere is a seral community, an ecological succession that began life on newly exposed coastal sand. Most common psammoseres are sand dune systems. In a psammosere, the organisms closest to the sea will be pioneer species: salt-tolerant species such as littoral algae and glasswort with marram grass stabilising the dunes. Progressing inland many characteristic features change and help determine the natural succession of the dunes. For instance, the drainage slows down as the land becomes more compact and has better soils, and the pH drops as the proportion of seashell fragments reduces and the amount of humus increases. Sea purslane, sea lavender, meadow grass and heather eventually grade into a typical non-maritime terrestrial eco-system. The first trees (or pioneer trees) that appear are typically fast-growing trees such as birch, willow or rowan. In turn these will be replaced by slow-growing, larger trees such as ash and oak. This is the climax community, defined as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seral Community
A seral community is an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community. In many cases more than one seral stage evolves until climax conditions are attained. A prisere is a collection of seres making up the development of an area from non-vegetated surfaces to a climax community. A seral community is the name given to each group of plants within the succession. A primary succession describes those plant communities that occupy a site that has not previously been vegetated. These can also be described as the pioneer community. Computer modeling is sometimes used to evaluate likely succession stages in a seral community. Depending on the substratum and climate, a seral community can be one of the following: ; Hydrosere: Community in water ; Lithosere: Community on rock ; Psammosere: Community on sand ; Xerosere: Community in dry area ; Halosere: Community in saline body (e.g. a marsh) Examples Seral communities in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrosere
A hydrosere is a plant succession which occurs in an area of fresh water such as in oxbow lakes and kettle lakes. In time, an area of open freshwater will naturally dry out, ultimately becoming woodland. During this change, a range of different landtypes such as swamp and marsh will succeed each other. The succession from open water to climax woodland takes centuries or millennia. Some intermediate stages will last a shorter time than others. For example, swamp may change to marsh within a decade or less. How long it takes will depend largely on the amount of siltation occurring in the area of open water. Stages Hydrosere is the primary succession sequence which develops in aquatic environments such as lakes and ponds. It results in conversion of water body and its community into a land community. The early changes are allogenic as inorganic particles such as sand and clay are washed from catchment areas and begin filling the basin of the water body. Later, remains of dead plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psamment
In USDA soil taxonomy, a Psamment is defined as an Entisol which consists basically of unconsolidated sand deposits, at pals.iastate.edu often found in shifting sand dunes but also in areas of very coarse- textured parent material subject to millions of years of weathering. This latter case is characteristic of the of northern South America. A Psamment has no distinct soil horizons, and must consist entirely of material of loamy sand or coarser in texture. In the |
Lithosere
A lithosere (a sere originating on rock) is a plant succession that begins life on a newly exposed rock surface, such as one left bare as a result of glacial retreat, tectonic uplift as in the formation of a raised beach, or volcanic eruptions. For example, the lava fields of Eldgjá in Iceland where Laki and Katla fissures erupted in the year 935 and the solidified lava has, over time, begun to form a lithosere. Pioneer species are the first organisms that colonise an area, of which lithoseres are an example. They will typically be very hardy (''i.e.'', they will be xerophytes, wind-resistant or cold-resistant). In the case of a lithosere the pioneer species will be cyanobacteria and algae, which create their own food and water—''i.e.'', they are autotrophic and so do not require any external nutrition (except sunlight). For example, the first lithosere observed after the volcanic explosion of Krakatoa was algae. Other examples of lithoseres include communities of mosses and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xerosere
Xerosere is a plant succession that is limited by water availability. It includes the different stages in a ''xerarch succession''. Xerarch succession of ecological communities originated in extremely dry situation such as sand deserts, sand dunes, salt deserts, rock deserts etc. A xerosere may include lithoseres (on rock) and psammoseres (on sand). Stages Bare rocks Bare rocks are produced when glaciers recede or volcanoes erupt. Erosion of these rocks is brought by rain water and wind loaded with soil particles. The rain water combines with atmospheric carbon dioxide that corrodes the surface of the rocks and produce crevices. Water enters these crevices, freezes and expands to separate boulders. These boulders move down under the influence of gravity and wear particles from the rocks. Also when the wind loaded with soil particles strikes against the rocks, it removes soil particles. All these processes lead to formation of a little soil at the surface of these bare roc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halophyte
A halophyte is a salt-tolerant plant that grows in soil or waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs and seashores. The word derives from Ancient Greek ἅλας (halas) 'salt' and φυτόν (phyton) 'plant'. Halophytes have different anatomy, physiology and biochemistry than glycophytes.Physiology of halophytes, T. J. FLOWERS, Plant and Soil 89, 41-56 (1985) An example of a halophyte is the salt marsh grass '' Spartina alterniflora'' (smooth cordgrass). Relatively few plant species are halophytes—perhaps only 2% of all plant species. Information about many of the earth's halophytes can be found in thehalophdatabase. The large majority of plant species are glycophytes, which are not salt-tolerant and are damaged fairly easily by high salinity. Classification Halophytes can be classified in many ways. According to Stocker (1933), it is mainly of 3 kin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rowan
The rowans ( or ) or mountain-ashes are shrubs or trees in the genus ''Sorbus'' of the rose family, Rosaceae. They are native throughout the cool temperate regions of the Northern Hemisphere, with the highest species diversity in the Himalaya, southern Tibet and parts of western China, where numerous apomictic microspecies occur.Rushforth, K. (1999). ''Trees of Britain and Europe''. Collins . The name ''rowan'' was originally applied to the species ''Sorbus aucuparia'' and is also used for other species in ''Sorbus'' subgenus ''Sorbus''. Formerly, when a wider variety of fruits were commonly eaten in Europe and North America, ''Sorbus'' was a domestically used fruit throughout these regions. It is still used in some countries, but '' S. domestica'', for example, has largely vanished from Britain, where it was traditionally appreciated. Natural hybrids, often including ''S. aucuparia'' and the whitebeam, '' Sorbus aria'', give rise to many endemic variants in the UK. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat regions covered with wind-swept sand or dunes with little or no vegetation are called '' ergs'' or ''sand seas''. Dunes occur in different shapes and sizes, but most kinds of dunes are longer on the stoss (upflow) side, where the sand is pushed up the dune, and have a shorter ''slip face'' in the lee side. The valley or trough between dunes is called a ''dune slack''. Dunes are most common in desert environments, where the lack of moisture hinders the growth of vegetation that would otherwise interfere with the development of dunes. However, sand deposits are not restricted to deserts, and dunes are also found along sea shores, along streams in semiarid climates, in areas of glacial outwash, and in other areas where poorly cemented s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; or unicellular microorganisms such as protists, bacteria, and archaea. All types of organisms are capable of reproduction, growth and development, maintenance, and some degree of response to stimuli. Beetles, squids, tetrapods, mushrooms, and vascular plants are examples of multicellular organisms that differentiate specialized tissues and organs during development. A unicellular organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate domains – bacteria and archaea. Eukaryotic organisms are characterized by the presence of a membrane-bound cell nucleus and contain additional membrane-bound compartments called organelles (such as mitochondria in animals and plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pioneer Species
Pioneer species are hardy species that are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by wildfire. Pioneer flora Some lichens grow on rocks without soil, so may be among the first of life forms, and break down the rocks into soil for plants.LICHEN BIOLOGY AND THE ENVIRONMENT, LICHENS OF NORTH AMERICA, Sylvia and Stephen Sharnoff/ref> Since some uninhabited land may have thin, poor quality soils with few nutrients, pioneer species are often hardy plants with adaptations such as long roots, root nodes containing Diazotroph, nitrogen-fixing bacteria, and leaves that employ transpiration. Note that they are often photosynthetic plants, as no other source of energy (such as other species) except light energy is often available in the early stages of succession, thus making it less likely for a pioneer species to be non-photosynthetic. The plants that are often pioneer species also tend to be wind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halosere
In ecology, a halosere is a succession in a saline environment. An example of a halosere is a salt marsh. In a river estuary, large amounts of silt are deposited by the ebbing tides and inflowing rivers. The earliest plant colonizers are algae and eel grass, which can tolerate submergence by the tide for most of the 12-hour cycle and which trap mud, causing it to accumulate. Two other colonizers are ''Salicornia'' and '' Spartina'', which are halophytes, i.e. plants that can tolerate saline conditions. They grow on the inter-tidal mudflats with a maximum of four hours' exposure to air every 12 hours. ''Spartina'' has long roots enabling it to trap more mud than the initial colonizing plants and ''Salicornia'', and so on. In most places this becomes dominant vegetation. The initial tidal flats receive new sediments daily, are waterlogged to the exclusion of oxygen, and have a high pH value. The sward zone, in contrast, is inhabited by plants that can only tolerate a maximum of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Podsol
In soil science, podzols are the typical soils of coniferous or boreal forests and also the typical soils of eucalypt forests and heathlands in southern Australia. In Western Europe, podzols develop on heathland, which is often a construct of human interference through grazing and burning. In some British moorlands with podzolic soils, cambisols are preserved under Bronze Age barrows (Dimbleby, 1962). Term Podzol means "under-ash" and is derived from the Russian под (pod) + зола́ (zola); the full form is "подзо́листая по́чва" (podzolistaya pochva, "under-ashed soil"). The term was first given in middle of 1875 by Vasily Dokuchaev. It refers to the common experience of Russian peasants of plowing up an apparent under-layer of ash (leached or E horizon) during first plowing of a virgin soil of this type. Characteristics Podzols can occur on almost any parent material but generally derive from either quartz-rich sands and sandstone or sedimentary deb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
