Elham Banihashemi; Pezhman Tahmasebi; Esmael Asadi
Volume 25, Issue 3 , November 2018, , Pages 547-561
Abstract
Livestock grazing is one of the most important factors influencing on the structure and dynamics of the rangeland vegetation. The aim of this study was to identify the plant functional traits as the indicators for the effects of grazing management on Karsanak semi-steppe rangelands ...
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Livestock grazing is one of the most important factors influencing on the structure and dynamics of the rangeland vegetation. The aim of this study was to identify the plant functional traits as the indicators for the effects of grazing management on Karsanak semi-steppe rangelands of Chahar Mahal Va Bakhtiari province. A randomized-systematic sampling method was used to survey vegetation in seven grazed and enclosure sites by estimating plant cover in five plots of 4 m2 along a 100-m transect in each site. Then, the plant traits were measured and compared among grazed and enclosure sites. The results showed that there were significant differences between grazed and enclosure sites in several functional groups including plant height, leaf area, total plant weight , palatability class I and II, annuals and perennials, therophytes , and geophytes (P<0.05). The results also showed that the mean value of leaf length, the plant cover of species with palatability class II, forbs, and therophytes were significantly increased in non-grazed area compared to grazing area. The results of PCA showed that the most affecting factors responsible for overall changes in vegetation were plant weight, perennial and annual plant species, shrub growth form, chaemophytes, phanerophytes and phanerophytes forms, leaf length, leaf width, leaf area, and palatability class II and class III, justifying 60% of total variation in plant community composition. Combining the results of t-test and PCA, the results indicate that plant traits including total plant weight, leaf length and width, leaf area, palatability class, and life form are among the most important indicators to evaluate the effect of grazing managements on the structure and dynamics of vegetation in semi- steppe rangelands.
Jahan bakhsh Pairanj; Ata... Ebrahimi; Abalfazl Ranjbar; Mohammad Hasan zadeh
Volume 18, Issue 4 , September 2012, , Pages 593-607
Abstract
Evaluation of forage production is an important issue in determining grazing capacity of rangelands. There is no doubt that all forage production in rangelands is not evenly accessible and different factors affect the accessibility of forage. In this research, factors affecting forage availability were ...
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Evaluation of forage production is an important issue in determining grazing capacity of rangelands. There is no doubt that all forage production in rangelands is not evenly accessible and different factors affect the accessibility of forage. In this research, factors affecting forage availability were studied. After a wide literature review, factors of distance from water supplies, density of shrubs, slope and land uses were identified as the main factors preventing forage accessibility. Forage production and shrub density were respectively measured using clip and weighing method in quadrates and distance method. Forage production measurements in representative area were extrapolated to the whole area using IRS satellite images. In this research, 18 vegetation indices were examined as forage production data (independent factor) were regressed against vegetation indices values (dependent factor) using SPSS. Map of forage production was created based on the best fit regression. Then, with adjusting all limiting factors, the map of accessible forage production was created based on the tables. The maps were illustrated and available forage was calculated after implementing adjustment of each factor. Statistical results showed significant differences (p≤0.05) between forage production with considering slope and shrub density and forage production based on all limiting factors of forage accessibility. While distance from water supplies and other land uses had no significant effect on forage production