The Characteristics Of Population, Community And Clonal Growth Of Tamarix Elongata Ledeb.

Based on the data obtained by the measure, it were described that the population structure, community structure composition and clonal characteres of Tamarix elongata Ledeb. in the heavy saline soil and the salt dunes of Hexi corridor of Gansu province. And the spacial patterns of dominant species in the community and iner-specific ecological association, clone growth were examined through simulation by intensity and measuring inter-specific association. The result showed:Tamariaceae is more suitable to the two habitats, more superior to other species. There are more obvious selectivities and more limiting factors in heavy saline soil. Covering with sand is one of the important limiting factors.The population of Tamarix elongata Ledeb. belongs to the stable population in the heavy saline soil and the salt dunes. And Tamarix elongata Ledeb. is the dominant species in the two habitats. In contrast with in the heavy saline soil, in the salt dunes Tamarix elongata Ledeb. have more competitive superiority, it is not more affected by other species, and more important, it give most contribution to maintain the community. And other species give less contribution to keep up the system, and in good adaptability.The spacial pattern of Tamarix elongata Ledeb. is Poisson dispersion in the heavy saline soil, but Aggregated dispersion in the salt dunes; There are dominant negative inter-specific association between Tamarix elongata Ledeb. and Alhagi sparsifolia Shap. in heavy saline soil, but inapparent in the salt dunes. Tamarix elongata Ledeb. and Alhagi sparsifolia Shap. are fit for the heavy saline soil and the salt dunes, the distribution of these crucial factors are in random in heavy, but in mosaic in salt dunes. The niche overlap higher in heavy saline soil than in the salt dunes between the Tamarix elongata Ledeb. and Alhagi sparasifolia Shap..The distrubition and growth of Tamarix elongata Ledeb. are affected by the falling gradient and the type of the slope: when the grade of falling gradient is lower than 30, the order is: shady slope>sunny slope>windward slope>leeward slope; when the grade of falling gradient is higher than 30 and lower than 45,the order: shady slope>sunny slopr>windward slope>leeward slope; when the grade of falling grandient is higher 45, the order: sunny slope>shady slope>windward slope>leeward slope. With the increase in the falling gradient, on the shady slope, the density number of the Tamarix elongata Ledeb. is up at first then down, and on the sunny slope, the number is increasing, on the leeward slope, it is up at first then down, on the windward slope, it is up at first then down.