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.
ali goharnejad; pejman tahmasebi; esmael asadi; javad motamedi
Volume 24, Issue 1 , May 2017, , Pages 1-15
Abstract
In contrast to the taxonomic biodiversity, based only on the relative abundance of species in the community, functional diversity summarizes various aspects of the biological composition and, hence, the role of populations in the community. Functional diversity may be linked directly to the ecosystem ...
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In contrast to the taxonomic biodiversity, based only on the relative abundance of species in the community, functional diversity summarizes various aspects of the biological composition and, hence, the role of populations in the community. Functional diversity may be linked directly to the ecosystem services; the plant biomass encompasses many ecosystem services such as food supply, conservation, tourism, and pollination. In this study, we tested several hypotheses (1) existence of a close relationship between species richness and plant biomass (2) existence of a close relationship between FAD2 (Functional Diversity index) and plant biomass (3) explaining the high percentage of plant biomass variations. The results showed that the species richness in order to predict the plant biomass with a correlation coefficient equal to three does not count as a proper indicator. However, the correlation coefficient of FAD2 Functional Diversity with plant biomass was about 0.4, which is relatively good indicator to estimate the plant biomass because of explaining a significant percentage of the biomass variations. Finally, our results clearly showed that the incorporation of abiotic factors, plant traits and functional diversity (FAD2), containing the parameters of rainfall, leaf length, plant height and FAD2 index, could explain 75% of plant biomass variations and was considered as the most appropriate model predicts plant biomass.
Faez Raeisi Kahrouie; Jahangard Mohammadi; Esmaiel Asadi
Volume 9, Issue 3 , September 2001, , Pages 991-1004