نشریه حفاظت زیست بوم گیاهان
پیاپی 3 (پاییز 1392)

Considering the need for the rapid assessment of species diversity, it is essential to understand the easy application of the appropriate methods for measuring diversity. In order to measure diversity, the multi-scale C–plot was used. This plot was selected in Karsanak rangeland with two eastern and western slope aspects, and two grazing intensities: light and moderate. Four treatments were detected including light–eastern, light-western, moderate-eastern and moderate-western. At each sampling location, three C-plots to the dimensions of 10*10 m and at the distance of 200 meters were set up as a random-system for assessing species diversity. After collecting cover data in each site, diversity, richness and evenness indices were obtained via PAST software. Comparison of species diversity was performed in different treatments by analyzing variance (ANOVA) on SPSS. Plotted graphs were drawn within Excel. The results demonestrated that in all four locations there were significant differences in 5% level among species richness indices. It was also found that there was not only significant difference between diversity and evenness indices in different locations however, the indices values were higher in the eastern and western slope aspects with moderate grazing intensity. Increased indices values in the eastern and western slope aspects with moderate grazing intensity were attributed to the presence of invasive non-palatable and annual species. The eastern slope aspect with moderate grazing intensity due to suitable moisture conditions and the possibility of new specie presence was effective in increasing indices value. Moreover, species diversity was well illustrated by species-area curves. As a result, species diversity will be evaluated well with multi-scale plots such as C-plot.

In order to survey macro and micro nutritional elements in soil and plant, this research was carried out in mountainous rangeland of Taleghan. First, the land units were obtained based on topographic map and overlaying of slope, altitude and lithology map. Sampling was conducted in each land unit by systematic method after field surveying. Size and the number of plots were obtained on the basis of minimal area and statistical method respectively. Type of species for sampling was determined by Twinspan analysis. Then vegetation percentage and frequency were recorded based on Krijina scale in each plot. Soil and plants were sampled in each plot. In addition, soil physico-chemical characteristics and nutritional elements were calculated by ICP in lab. Data analysis was conducted by the analysis of variance and means comparision in SAS 9.1 software. Then, the relation between soil elements and species was determined by using DCA and CCA analysis in Canoco for Win4.0 software. The results showed that the nutritional elements in plants were more than the soil. The amount of micro elements in under growth organs was more than aerial parts, but in the macro elements it was inverted. Morover, the relationship between the nutritional elements of different species and soil absorbable elements was not constant it was dependent on site conditions such as moisture, pH, lime, organic matter, texture, and other species and soil elements that were affected by nutrition mobility and their absorbtion rate.

Aquatic plants are irreplaceable biological filters due to their uptaking high potential of heavy metal, accumulating and having tolerance for contaminated water ecosystems. The purpose of this research was to evaluate the heavy metal pollution (Cu, Pb, Zn and Cd) in underground organs, stems, and leaves of Phragmites australis as well as sediment samples of Dez river catchment, in Dezful, Iran. The sample preparation carried out with 4:1 compound nitric acid and percholoric acid before heavy metal measurement by Atomic Absorption Spectroscopy. The results pointed out that the concentrations of Cu, Pb, Zn and Cd in sediment samples were 12.021, 12.982, 108.485, and 0.189, respectively. The values of Cu (1.903, 3.780 and 7.217 g/g), Pb (0.265, 0.585 and 2.674 g/g), and Cd (0.052, 0.120 and 0.275 g/g) in stems, leaves and underground organs were relatively lower than toxicity level. However, Zn concentration was considerably high in stems (30.790 g/g), leaves (44.981 g/g ), and underground organs (52.216 g/g) comparing to toxicity level. . The maximum concentration of metals was found in the underground organs of plants. In fact, mean concentration in the organs of Common reed follows like this: underground> leaves> stems, suggesting that the low mobility of these elements in underground organs towards aerial parts. The high translocation factor value for Zn can indicate a high ability to move within the plant parts. In conclusion, common reed can be recommended as bio-accumulator and absorbent in heavy metal contaminated water ecosystems.

Paband national park with the area of 24668/71 hectares, is located in 70 km southeast of Neka and within 800-3100 m ASL, Flora of this region includes 462 taxa that belong to 290 genera and 90 families. The dicots with 372 taxa were the richest group of flora followed by monocots with 73 taxa, Pteridophytes with 11 taxa and Gymnosperms with 6 taxa. The important families are Asteraceae with 50 species, Lamiaceae with 36 species, Fabaceae with 32 species, Rosaceae with 32 species, Poaceae with 32 species and Brassicaceaewith 22 specie respectively. Life forms of the plant species of region include: Hemicryptophytes 33%, therophytes 29%, cryptophytes 20%, and phanerophyte 15% hamaephyte 3%. Hihg percentage of hemicrytophyte, cryptophyte and phanerophyte were the indicator of an area with very humid and cold climate. Moreover, five percent of these plants were endemic of Iran. Iran-Turanian plants were the most frequent chorotype of the area with 93 species (31.74%).

In range management, recognizing environmental factors and their impacts on plant covers are very important. This research was conducted in Dizaj and Batchi rangelands of Khoy in order to evaluate and detect the most important environmental and management factorsaffecting plant distributions. After distinguishing indicator plant types in the regions, random-systematic-methodsampling was conducted along 100 m transects within 1 m2 plots, and the density and percentage of canopy of plant species were collected. The area of samples and the numbers of samples were determined on the basis of dominant plant canopy variations and statistical methods respectively. Then, in the begining and end of this research each transect of soil sampling from depth of 0-15 cm was taken. Moreover, information about elevation AMSL (above mean sea level), slope, aspect and grazing intensity was recorded. The soil characteristics such as soil texture, caco3, pH, EC, saturated humidity and organic matter were measured in laboratory. In the final step, to assess the relationship between environmental factors and plant distribution PCA was used, and to evaluate the relationship between species and stated factors CCA was applied. The results demonstrated that the effects of environmental factors on plant distribution were not the same and the most important effective factors in the distribution and establishment of dominant plant species like and Artemisia were soil texture, grazing, precipitation, ASL, aspect and EC. The results also illustrated that environmental factors had significant effects on plant control and distributions. But undesirable effects of human activities like grazing intensity, on sustainablemanagement of rangeland were undeniable.

Investigating the interaction of rainfall and animal grazing, as an indicator of habitat productivity, on function and the species diversity of plant communities, is key factor that can help managers in evaluating and predicating changes in vegetation cover, so the current study was undertaken in response of the function and species diversity of plant communities to animal grazing and precitpitation in 41 regions of steppe and semi-steppe rangelands of Chahrmhal Bakhtiari and Isfahan province. Vegetation cover data of 41 regions was gathered from previous studies and classified into light and heavy grazing intensity. The plant community diversity indices (richness, evenness, Simpson, Shannon) for all areas were determined by the Pc-Ord software after calculating the RAO index (function diversity). The effect of significant changes of grazing, precipitation and their interaction were used in Spss-17 software by the general linear analysis (GLM). To do so, the general linear model in SPSS 17 was used. Finally the correlation between the diversity indices with the divercity function was calculated and shown through simple regular regression. The results of GLM illustrated that the response of evenness to the changes of precipitation and species richness to the grazing intensity were significant (p

The comprehensive conservation of rangeland ecosystems depends on their management which is based on protection and maintenance of diversity. This comprehensive management does not take place except by studying and measuring species diversity. Therefore, it is necessory to be aware of the destructive factors in ecosystem, these factors cause shelter and biomass destruction, thus decreasing species diversity. It seems that one of destructive physical pressures on rangeland leading to the decrease of diversity and vegetation elements, is livestock overgrazing. This research was done so as to investigate the effect of various grazing intensities on vegetation diversity in Taftan rangelands. To do this, three sites including heavy grazing, light grazing and 8 years – conserved areas were selected. In each site a number of samples were determined by using statistical method. In addition, 7 transects and 42 plots overall with random – systematic method were established. In the next step, the species names and numbers were recorded. Then Margalef and Menhinick richness index, Shannon-Wiener, hill 1 and hill 2 were calculated and statistical comparison was done in SPSS 19. The results pointed out that there were significant difference in the terms of richness and species diversity at %1 level for various grazing intensities. Moreover, Tukey-test showed that species richness between conservation area and light grazing area between conservation area and heavy grazing area and also between light grazing and heavy grazing areas in 1% level were significant. Shannon-Wiener and Hill 2 indices demonestrated significant difference at 1% level among all grazing intensities. The highest species richness and diversity were in light grazing.