The first was the salinity which insured the stability of halophytic vegetation near the shore and' the second was air humidity … Thermo-ecotone, when temperature is the main limiting factor. There are only one survey in the Nile in Aswan and another in the Red Sea, because is relatively stable water status. For example, we can find a transition zone between a forest and a plain. The availability of water is the main factor which can decrease the rate of desertation. Others attributed the changes to the biotic factors, or moreover, to the abiotic factors (Weaver, 1960; van der Maarel 1990). Stephenson (1990) attributed the shift in plant composition to the annual precipitation. The western stands, toward the Nile, were affected by the water status where the water was drained continually from the surrounding cultivated lands. South of Cairo) was conducted in 27 March 2000. The high temperature in the summer accelerate the water evaporation from the depressions lied in the desert boundaries. A shifting of boundaries between ecosystems is thought to be due to climate change. For example, the ecotone between an agricultural field and a forest is a man-made one. As part of a long-term study (2012–present) comparing ecosystem functions of marsh and black mangrove vegetation, we have experimentally maintained marsh and black mangrove patches (3 m × 3 … The temperature will control the zone of interference between these two adjacent ecosystems. In the last decade (1990-1996) torrents occurred annually or biennially. This species was remarkable vegetationally near the Red Sea where the humidity is higher than in the Eastern Desert. The continued accumulation of water in the Nile ward stands eliminate the temperature effects and insured the absolute~ abundance of the helophytic plants over the year. An ecotone is a transition area between two biological communities, where two communities meet and integrate. The most abundant species (in the canal bed) were Zygophyllum coccineum, Puilcaria crispa, Lawnia sp. In this study, xerophytic plants in the Nile region quickly dominated the canal bed and its sides especially annuals which are able to completing their life cycle in a short time. So, the climatic conditions were stable to some degree and the seasonal change in temperature is not substantial to change the vegetation characteristics. Along the Red Sea shore both Zygophyllum coccineum (xerophytic species) and Zygophyllum album (halophytic species) can survive at the same places but the former grow in the higher places. The other xerophytes occurred in the 5th stand. The attempt to classify the ecotones to different classes according to the main (limiting) factor forming the ecotone may be in the study of ecotonal dynamics and their characteristics. Several Scientists investigated the effect of soil characteristics upon ecosystems, ecotones and their dynamics (Doering and Reider 1992; Harmon et al., 1986, Knapp and Seastedt 1986, Vogt et al., 1986, Carson and Peterson 1990, Facelli and Pickett 1991 and Xiong and Nilsson 1997). The Braun Blanquet method was used to analyze the vegetation (percentage of abundance and dominance). The torrents transferred great amounts of sand that accumulated in some places in the canal beds and also erosion occurred in other places and this produced depressions which were water collectors. The area where the land meets water such as where the mangrove fields meet the ocean is also considered an ecotone. Finally, the instability of vegetation due to the change in water status as a result to the continued drainage and evaporation. Ecotone is the news and outreach forum for the Ecological Society of America, featuring fresh research from our scholarly journals and around the ecological community. See more. vegetation types and biomes. Such functional species responses may be related to changes in underlying environmental conditions, biotic interactions or both (van der Maarel 1990). The high competition value of the xerophytic plant PuIicaria crispa insured its presence in the middle stands. Hydro-ecotones may include riparian forests, marginal wet land, littoral lake zones, floodplain lakes and forests and areas of significant groundwater-surface water exchange (Naiman et al., 1988). This produced a penetrating temporary ecotone. The importance of hydro-ecotones results from several reasons. It was studied widely over the world (Sheldon et al., 2000; Grimm et al., 1997; Ward et al., 1999; Bell et al., 1999 and Bradley and Gilvear, 2000). The co-occurrence of different species and different life forms is affected by the environmental changes whether inside the ecosystems and more affected at their boundaries where the ecotones may be formed. 30) had an additional four Nile Valley species. Red Sea shore vegetation: At the Red Sea shore, about 300 km. and other desert plants grew. The rainfall facilitates the shifting of xerophytes toward the sea shore. The third site of study was in the Red Sea region. Finally in the last stands the pioneers of Dalbergia sisso trees, cultivated: commonly in the city, appeared and the edge plant (grow around canals and railways) Imperata cylindrica dominated the last stands with a decrease of desert species. This last consequence allowed the colonization by hydro-helophytes that usually grow restricted to the Nile shore and canals in the Nile valley. At river margins, there is a water gradient that affects the plant community and subsequently ecotones. This will allow to expect the changes which will occur in the ecotone and consequently in one of the interfered ecosystems or both. In this depression a community of helophytes appeared; the abundant species were Cyperus papyrus, Arundo donax and Typha domingensis. ... To determine the physical structure of the land-water ecotone and the substrate types, the proportions of the elements making up these zones were measured at … 2 that the depressions water accumulated and they were frequently colonized by the helophyte Arundo donax (Plate No. Plate 5 shows the vegetation at the west side of Nile at Aswan while Plate 6 shows the growing of, https://scialert.net/abstract/?doi=pjbs.2003.1553.1563, Topographic map of Egypt showing the location of the study Sites at Qena, Red Sea shore and Aswan, The floristic composition in the torrent canal during the period of study, The most familiar species in the torrent canal during the study and their abundance through four surveys in stand (1) near desert, stand (5) in the middle of the surveyed area ( 3 km) and stand (10) toward the Nile. In November 1996 a strong torrent run toward Qena city, 600 km (map 1) south of Cairo. Because the area is a transition between two ecosystems or biomes, it is natural that it contains a large variety of species of fauna and flora as the area is influenced by both the bordering ecosystems. For more articles on important concepts for the IAS exam and updates on UPSC’s current affairs, please visit BYJU’S Free IAS Prep regularly. Two litter types of the dominant species were selected in each ecosystem: cypress (Cupressus chengiana) and oak (Quercus baronii) in ecotone; cypress (Cupressus chengiana) and clovershrub (Campylotropis macrocarpa) in dry valley; and fir (Abies faxoniana) and birch (Betula albosinensis) in montane forest. In the ecology of landscape, an ecotone is the marginal area where 2 patches that have a distinct ecological composition meet. Vegetation types within the same ecosystem have many common characteristics and are probably regulated by the same set of explanatory variables (e.g. The vegetation in the Nile islands in Aswan: In Aswan the survey was limited to studying the co-occurrence of different plant life forms in small islands and at the Nile shore. 1), in three regions. An Ecotone describes an area that acts as a transition or boundary between two ecosystems.This could be, for example, an area of marshland between a river and the riverbank, a clearing within a forest or a much larger area such as the transition between Arctic Tundra and Forest biomes in Northern Siberia. The types of ecotones raised depend on the edaphic factors and can be called edaphic ecotones. ecotone: [noun] a transition area between two adjacent ecological communities. The first was the salinity which insured the stability of halophytic vegetation near the shore and' the second was air humidity and seasonal rain. They also offer a good nesting place for animals coming in search of a nesting place or food. Key features: • Highest Performance in Transparency/light transmission makes Ecotone polycarbonate sheet, energy saver. Generally, there is a greater number of species found in these regions (ecotones) and this is called the edge effect. An Ecotone is a transitional area of vegetation between two different ecosystems or plant communities, such as forest and grassland. In the second stand (No. There are many rocky islands in the Nile in Aswan. Define ecotone. There is no rainy season. ecotone the zone of distribution of an organism across the boundaries of which the individuals of a species become progressively fewer, less productive, and sometimes smaller. For instance, in tropics where the soil depth is shallow trees may be replaced by shrubs and grasses. With the time, the edge plant Alhagi graecorum appeared and entered the competition east ward direction and disappeared from the west stands which were dominated by Imperata cylindrica, Cynodon dactylon and Cyperus rotundus. They serve as a bridge of gene flow from one population to another because of the larger genetic diversity present. The aim of this paper is to suggest a classification of ecotones according to the factor responsible for the ecotone and its characteristics. The temperature ranges between 43 in August and 25°C in January. The ecotone is the natural zone that exists between ecosystems with different characteristics. Mountain ranges can also create ecotones due to the changes in the climatic conditions on the slopes. Other examples are grassland (between forest and desert), estuary (between fresh water and salt water) and riverbank or marshland (between dry and wet). The hydro-ecotones are controlled by the water status in the soil. The disturbance resulting from the frequently temperature vacillation may help the adaptive annuals to coexist in the favorable seasons and may lead to form new ecosystem. An ecotone may appear on the ground as a gradual blending of the two communities across a broad area, or it may manifest itself as a sharp boundary line. Area is arid and rain rarely falls, once every ten years 3 ) communis., for instance, in tropics where the mangrove forests represent an ecotone between the eastern depressions winter. Several investigators ( Houghton et al., 1998 ) adjacent ecological systems studied ecotonal. Spinosa and Salsola sp in Transparency/light transmission makes ecotone sheets, as economical be... - 7 et al., 1998 ) biological communities, as ecotone the... The border areas where two communities meet and integrate mesophytes occupied the canal bed here from three different places insure... Of boundaries between ecosystems is thought to be due to the annual in. 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