Moslem Rostampour; Alireza Eftekhari
Abstract
This research was carried out in an enclosure rangeland with four habitats of Artemisia sieberi, Zygophyllum eurypterum, Stipa barba and Amygdalus scoparia in the Shaskouh protected area, South Khorasan province. All the plant species of the rangeland were identified and counted in 200 plots, due to ...
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This research was carried out in an enclosure rangeland with four habitats of Artemisia sieberi, Zygophyllum eurypterum, Stipa barba and Amygdalus scoparia in the Shaskouh protected area, South Khorasan province. All the plant species of the rangeland were identified and counted in 200 plots, due to the different vegetation form and distribution of each of the dominant species, in each of the four habitats, 20, 40, 60 and 80 plots (respectively) were established with two plot size: 2 × 2 meters and 4 × 4 meters (60 plots each). Numerical indices and diversity ordering curves were used to compare four habitats. Alpha and gamma species richness were determined by numerical indices and single sample rarefaction and pooled rarefaction curves were used to compare species richness and determine data adequacy. The results showed that the total species richness (gamma) varies between 51 and 54 species. The habitat with 80 plots has the highest richness and diversity (S=43 and H=3.27) and 20 plots has the lowest richness and diversity (S=6 and H=1.41). The results of SHE analysis showed that with the increase in the number of plots, species evenness decreased. The pooled refraction curve showed that by increasing the number of plot to 110, all plant species will be observed. With the increase in plot size all values of species richness and diversity indices increased significantly (p≤0.01). Species evenness indices were not affected by plot size. The results of the present research showed that the numerical indices of species richness and diversity are dependent on plot size, and this is one of the disadvantages of evaluating biodiversity in rangeland using numerical indices.
Moselm Rostampour; Effat Akbari; Mohammad Saghari
Abstract
The seed planting depth is one of the most important factors affecting the uniform plant emergence and the success of planting. This research was designed to determine proper seed planting depth for Atriplex canescens . in the nursery of the General Department of Natural Resources and Watershed Management ...
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The seed planting depth is one of the most important factors affecting the uniform plant emergence and the success of planting. This research was designed to determine proper seed planting depth for Atriplex canescens . in the nursery of the General Department of Natural Resources and Watershed Management of South Khorasan , allowing desirable seedlings with better vegetative properties to spend less cost in nurseries can be produced.For this purpose, after the collection and preparation of Atriplex canescens, seeds and pots, 15 seeds were selected and planted at 5 depths: 1, 2, 3, 4 and 5 cm with 5 repetitions. After the planting , the emergence percentage and vegetative traits of the seedling were measured. The data was analyzed by ANOVA and t LSD test. The results showed that with increasing seed planting depth, all the properties of the study were significantly reduced , at a minimum depth of 4 and 5 cm. The highest emergence percentage (34.7 % and 34.3 %) was observed at the depth of 1 and 2 cm and the lowest seedlings emergence percentage was observed at the depths of 4 and 5 cm (2.4 %). Since there is no significant difference between the emergence percentage, vigor index, and seedling stem length and weight, and the moisture content of the Atriplex canescens at the depths of 1 cm and 3 cm, Due to greater seed losses at the soil's surface depth by granivores such as insects and birds, as well as rapid drying of soil due to severe evaporation of water in the pot, A. canescens seed planting is recommended at a depth of 3 cm.
Moselm Rostampour
Abstract
This study compared of univariate outlier detection methods among vegetation data in a study of the effect of grazing intensity in the rangelands of arid regions. For this purpose, after measuring the vegetation cover in the rangeland and before the statistical analysis, the presence of outlier data ...
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This study compared of univariate outlier detection methods among vegetation data in a study of the effect of grazing intensity in the rangelands of arid regions. For this purpose, after measuring the vegetation cover in the rangeland and before the statistical analysis, the presence of outlier data was examined as the assumption of parametric comparison tests. In this study, eight methods including the boxplot and IQR (Tukey method), standard deviation of the mean (three-sigma rule), median absolute deviation (Hampel method), trimmed mean, 1st percentile and 99th percentile, The Chi Square test (χ²), the Grubbs Test (ESD) and the Rosner test (generalized ESD) were used. The results showed that the vegetation cover of rangelands with light and moderate grazing intensity was not normally distributed (Shapiro-Wilk test: p≤0.05). Even deletion of outliers did not lead to a normal distribution, but it resulted in the homogeneity of variances (Levene's test: p≥0.05). The modified Z-score and the Grubbs and Rosner tests (p≥0.05) did not identify outliers from the vegetation cover data. Among the methods evaluated, the boxplot and MAD method, which are not dependent on the mean, are more suitable for the vegetation cover. Therefore, before performing any comparison test, a combination of visual and statistical methods is recommended to evaluate the presence of outliers.