Rahman Adabi Firozjaii; Jamshid Ghorbani; seyd hasan Zali
Volume 27, Issue 1 , April 2020, , Pages 112-124
Abstract
Invasive species are the major threats to natural ecosystems worldwide. Pteridium aquilinum has the widest distribution of any pteridophyta in the world. This study aimed at investigating the impact of Pteridium aquilinum invasion on species composition, richness and diversity, and forage production ...
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Invasive species are the major threats to natural ecosystems worldwide. Pteridium aquilinum has the widest distribution of any pteridophyta in the world. This study aimed at investigating the impact of Pteridium aquilinum invasion on species composition, richness and diversity, and forage production in summer rangelands of Bandpay Babol, Mazandaran province, Iran. Vegetation was sampled in four invaded vegetation types including Fagus orientalist forest, Crataegus shrubland, Crataegus+Berberis shrubland, and rangeland. Also, vegetation sampling was done in surrounding uninvaded rangelands. The cover of species was estimated in 1 m2 plot for herbaceous and 25 m2 for shrubs. In all plots, the cover of P. aquilinum was estimated and then all fronds were cut at ground level, counted and frond length was measured. The forage of palatable species was measured by clipping and weighing. Findings showed different species composition among invaded and uninvaded areas. A total of 25 species were found only in invaded areas whereas only 11 species were detected in surrounding uninvaded rangelands. Cover, density and height of P. aquilinum fronds significantly influenced the species composition. Annuals significantly decreased by Pteridium aquilinum invasion. Except for Crataegus+Berberis shrubland, in other invaded areas the forage production was not significantly different from that in surrounding uninvaded rangeland. There was a reduction of desirable rangeland species due to P. aquilinum invasion. Also, we found that species richness significantly increased when invaded by Pteridium, while the diversity significantly decreased. The current understory floristic composition showed a low potential to support future restoration after P. aquilinum control. This result emphasizes the need for adding the seeds of desirable species
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