, ,
Volume 9, Issue 3 (10-2010)
Abstract
This study was carried out in Kalat highlands of Gonabad, Eastern Iran, located in geographical position of 34º 6´ to 34º 16´ N and 58º 25´ to 58º 35´ E with the altitude of 1100 to 2830 m.a.s.l. The mean annual precipitation and temperature are 143.2mm and 17.2ºC, respectively. Species richness, evenness and species diversity, diversity and related models, diversity based on the rank/abundance plots as well as methods of diversity ordering were considered in three elevation zones including low, intermediate and high altitudes and in the four slope aspects. Species richness indices in the intermediate zone were more than those in the low and high altitudes. The intermediate zone showed the highest species diversity as well as the highest evenness among the zones. North aspect showed the highest species richness and lowest species diversity and evenness. The highest diversity and evenness were observed in the south and south and west aspects, respectively. The low altitude zone followed lognormal distribution however intermediate and high altitude zones do not fit any of the models. Species abundance patterns of the north and west aspects followed both lognormal and logarithmic models with a shift from being lognormal to logarithmic model. The intermediate altitude zone and the south aspect had more flattened rank/abundance plot therefore they have been more diverse than the others. The same was observed by using diversity profiles.
Shana Vosoughrazavi, H Ejtehadi, H Zaree, S Tavakoli,
Volume 10, Issue 4 (2-2011)
Abstract
Aquatic ecosystems are the main biotic ecosystems that contain variety of plant species and their destruction result in the reduction of plant species diversity. In the present investigation, species diversity of aquatic plants in permanent, seasonal, forest wetlands and ricelands of the west and east of Mazandaran province was determined. First, 30 habitats were determined on the map and the total 161 samples, based on systematic-random sampling, were established. 126 species of aquatic plant of the habitats were collected and the cover of each species ,based on the area of quadrate that accupied by plants, was recorded. The results showed that species diversity of aquatic plants in the west and east is governed by the moisture gradient. Based on De Martonne classification system of climate, the west and east of Mazandaran province have wet and mediterranean climate, respectively. Therefore, the condition for the growth of aquatic plants in the west is more appropriate than in the east. Species diversity of wetlands and ricelands in the west was higher than that in the east. In this study, classification system of den Hartog & Veld for aquatic plants that classify them as hygrophytes, real aquatic and wetland species was applied and diversity indices for all three categories were calculated. The results revealed that diversity of hygrophytes is the highest among them and the real aquatic plants have higher species diversity than wetlands. T-test, based on Shannon index, showed significant differences between diversity of the west and east as well as between three group of macrophytes (P<0.05).
