8433

7814

كارشناسي ارشد

مرتعداري

اصفهان: دانشگاه صنعتي اصفهان، دانشكده منابع طبيعي

1392

سيزده،92ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

مجيد ايرواني

مصطفي تركش اصفهاني، اميرحسين ولي

24/10/92

محمدرضا مصدقي، حسين بشري

مهندسي منابع طبيعي

ID7814

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Responses of rangeland soil seed bank and vegetation to firing and grazing treatments in Fereydan region Isfahan Province Fahimeh Saydzadeh Department of Natural Resources Isfahan University of Technology Isfahan 84156 8311 Iran Degree M Sc Language Persian Supervisors Majid Iravani majid iravani@cc iut ac ir Mostafa Tarkesh Esfahani Amir Mohsen Vali Abstract Fire and grazing are two important sources of disturbance in arid ecosystems They play a key role in shaping structure and dynamics of vegetation in rangeland ecosystems However most of the available information is only about the impact of one of the two sources on rangeland ecosystems and interactive effects of these two agents on rangeland ecosystems particularly on the structure and composition of vegetation and soil seed bank have been given less attention This study assessed the interactive effects of fire and exclosure treatments on vegetation and soil seed bank in rangeland ecosystems of the Central Zagros region Three rangeland sites with an area of 400 square meters were selected and then half of each was fenced height 1 3 m In the first fall half about 100 square meters of each of the fenced and grazed area was burnt resulting in 4 different treatments applied at each site burnt burnt grazed burnt fenced and fenced To study the soil seed bank 12 soil samples 10 cm depth 10 cm diameter were collected systematically along two transects a distance of 2 m from each other in each of 4 treatments at each site 48 samples at each sites and 144 samples at three sites In the first spring vegetation was studied using twelve 0 25 square meter 0 5 0 5 m plots in each treatment at each site 48 plots per site and a total of 144 vegetation plots at three sites Vegetation and soil seed bank comparisons between applied treatments showed that fire treatment significantly reduced total density and species richness of soil seed bank as well as total cover and relative frequency of shrubs in the vegetation However applied treatments had no significant effect on the relative frequency of palatable and graminoid species and also Shannon diversity index in both soil seed bank and vegetation Fire increased the relative frequency of forbs and small seeded species in the vegetation while grazing increased the relative frequency of forbs and small seeded species and reduced the relative frequency of graminiod species in the soil seed bank However based on the results of multivariate analysis species composition of soil seed bank was not affected by applied treatments while species composition of vegetation was different between burnt and unburnt treatments Similarity between the species composition of soil seed bank and vegetation was relatively low but this similarity was higher not significantly different in burnt compared to unburnt treatments Overall the results show that short term effect of fire on vegetation and soil seed bank is greater than grazing effect But in any case grazing management after fire can effectively prevent more damage to the ecosystem and lead to the establishment of appropriate vegetation Keywords Grazing ecosystem Multivariate analysis Vegetation and soil seed bank dynamics Growth forms Species composition and diversity PDF created with pdfFactory trial version www pdffactory com

مجيد ايرواني

مصطفي تركش اصفهاني، اميرحسين ولي

محمدرضا مصدقي، حسين بشري