Parvez Gholami; Jamshid Ghorbani; Maryam Shokri
Volume 18, Issue 4 , September 2012, , Pages 662-675
Abstract
Overgrazing can alter rangeland vegetation in different ways. In this study, we used diversity, species richness and plant functional groups as the alternative to assess the vegetation response to different grazing intensities. This was done under three grazing intensities (long-term exclosure as reference ...
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Overgrazing can alter rangeland vegetation in different ways. In this study, we used diversity, species richness and plant functional groups as the alternative to assess the vegetation response to different grazing intensities. This was done under three grazing intensities (long-term exclosure as reference area, key area, and critical area) in rangelands of Mahoor Mamasani in Fars province. Vegetation sampling was carried out by random-systematic method and measuring the cover of plant species. The results showed that species diversity and richness significantly decreased with an increase in grazing intensity. Also, the cover percentage of Gramineae، Papilionaceae، Primulaceae، Umbelliferae and Valerianaceae significantly showed a negative response to grazing intensity while a positive response was found for Cruciferae، Labiatae، Plantaginaceae and Malvaceae. Moreover, some functional groups such as annuals, therophytes and Gramineae were significantly reduced from reference area to key area. The other finding of this study showed that decreaser plants significantly had less cover in critical area whereas increaser plants had greater cover in critical area. Species with storage of seeds in soil seed bank significantly had greater cover in aboveground vegetation in reference area than those species absent from soil seed bank. Due to the damage of some vegetation indices under overgrazing, it is recommended to make some changes in rangeland management and utilization in order to restore vegetation
Maryam Rezashateri; Aadel Sepehri
Volume 17, Issue 4 , November 2011, , Pages 604-614
Abstract
This research was carried out to study the effect of livestock grazing on dynamics of vegetation patches in rangelands of Incheh Boroun, North Gorgan plain. To achieve this goal, the dynamic parameters including the length of vegetation patches and bare area distances between consecutive vegetation patches ...
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This research was carried out to study the effect of livestock grazing on dynamics of vegetation patches in rangelands of Incheh Boroun, North Gorgan plain. To achieve this goal, the dynamic parameters including the length of vegetation patches and bare area distances between consecutive vegetation patches inside and outside the enclosure were measured. First of all, a random point was selected outside the exclosure as starting point and then 11 transects with 50 meters length were placed in a randomized sequential order. The length of vegetation patches and free vegetation spaces were recorded along each transect. Sampling inside the exclosure was done similarly through setting up six 50-meter transect Results showed significant differences in length of vegetation patches, inter patches and ratio of vegetation patches length to inter patches length in both studied regions. Overgrazing outside the exclosure was considered for this result. Since environmental stresses reveal their impacts through changing the shape, frequency and size of vegetation patches, it seems that studying the length of vegetation patches and inter patches has high accuracy and can be done with relatively less time and costs. In addition, it could well represent dynamic changes of plants in response to environmental stresses and desertification process.