فهرس المقالات Vegetation dynamics

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  1 - Vegetation Cover Dynamics in Semi-Steppe Rangelands of Ardabil Province, Iran
  Jaber Sharifi Amrali Shahmoradi Ehsan Zandi Esfahan Farzaneh Azimi Motem Allah-Verdi Nouri Dolat Mommadi
  Rangeland vegetation dynamics can be affected by various natural and unnatural factors over time. The purpose of this study was to investigate the dynamics of vegetation under the climatic conditions and soil properties. Accordingly, data collection for evaluating veget أکثر

  Rangeland vegetation dynamics can be affected by various natural and unnatural factors over time. The purpose of this study was to investigate the dynamics of vegetation under the climatic conditions and soil properties. Accordingly, data collection for evaluating vegetation dynamics in rangeland ecosystems of Ardabil province was conducted at three research sites including Moqan winter rangeland, and Nour and Aqdagh Khalkhal summer rangelands in 2009 followed for four years. Vegetation variables were measured using transects and sampling plots. Meanwhile, at the location of each plot, soil moisture was measured at two or three depths of 0-15, 15-30 and 30-45 cm using a Time-Domain Reflectometer (TDR). According to the results, in the Nour site, the changes recorded for shrubs such as Onobrychis cornuta L. and forbs were significant (P<0.01). However, the changes recorded for the perennial grasses including Alopecurus aucheri L., Bromus tomentellus Boiss. Festuca ovina and Koeleria caucasica Trin. Ex Domin were not significant. In the Aqdagh site, the changes of perennial grasses including Agropyron cristatum, Bromus tomentellus, Festuca ovina L. and Koeleria caucasica as well as forbs were significant (P<0.05). The changes of annuals were found significant (P<0.01). No significant differences were recorded for the shrubs such as Onobrychis cornuta and Thymus kotschyanus. In the Moqan site, the changes of dominant shrub (Artemisia fragrans) and annuals were significant (P<0.01). Soil moistures during the growing season and over the years were varied; however, the trend of changes in soil organic carbon was slow. Accordingly, the results of this monitoring process from year to year changes in the main species of vegetation, soil, and soil erosion can be useful as a guide to correct the current methods used for the management of rangelands. تفاصيل المقالة
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  2 - Impact of Bush Encroachment Control on Rangeland Vegetation in the Rangelands of Bale, Southeastern Ethiopia
  Mahammed Abdullahi Abdunaser Birka
  10.30495/rs.2022.682324
  This study was conducted to examine impact of bush encroachment control on rangeland vegetation in the south eastern Ethiopia. The study targeted two main and dominant encroaching woody plant species, Acacia bussei and Acacia aerfota, and their effects on rangeland vege أکثر

  This study was conducted to examine impact of bush encroachment control on rangeland vegetation in the south eastern Ethiopia. The study targeted two main and dominant encroaching woody plant species, Acacia bussei and Acacia aerfota, and their effects on rangeland vegetation attribute dynamics in Raitu district of Bale zone, southeastern Ethiopia for two consecutive years. Rangeland site encroached by these two acacia species was replicated/divided into three plots, and each plot was subdivided into five sub-plots receive five treatments: cutting at 0.5 m above ground alone (T1), cutting at 0.5 m above ground and dissecting the stumps (T2), cutting at 0.5 m above ground and pouring chemicals on stumps (T3), cutting at 0.5 m above ground and debarking the stumps down into the soil surface (T4) and control (T5). Data on biomass, species richness, basal and litter covers, soil erosion and compaction, dead and re-sprouted encroaching tree/shrub species were collected. The applied treatments significantly influenced (P<0.05) basal cover, dry matter and the two encroaching tree species. The results of this study showed that T1 and T4 were good in controlling A. aerfota in that order. T4 and T3 had a significant effect on controlling A. bussie in their order. The most dominant grass and non-grass species observed after the control actions were Cenchrus ciliaris, Bothriochloa radicans, Hibiscus aponerus, Pennisetum mezianum, Lintonia nutans, Chrysopogon plumulosus and Eragrostis papposa. Therefore, controlling encroaching tree/shrub species had created a conducive grazing area with palatable herbaceous species for the livestock. The management of bush encroachment will contribute to stabilize rangelands and to minimize the negative effects of feed and food crises in the future. تفاصيل المقالة
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  3 - Studying Short-Time Dynamics of Vegetation and Soil Organic Carbon in a Semi-arid Rangeland (Case Study: Zharf, Khorasan Province, Iran)
  Mohamad Taghi Kashki Amr Ali Shahmoradi Ehsan Zandi Esfahan
  Abstract. Rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. Investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative a أکثر

  Abstract. Rangeland vegetation dynamics encompass all processes of changes in vegetation composition and structure over time. Investigating the rangeland ecosystem dynamics makes it possible to determine the effects of climatic and management conditions on qualitative and quantitative changes of the vegetation in a specific period of time. Accordingly, data collection and measurements for evaluating vegetation dynamics in rangeland ecosystems of Zharf region in Khorasan province, Iran were conducted from 2009 to 2013. Vegetation variables were measured by the means of 3 transects with the length of 500m and sampling plots. Meanwhile, at the location of each plot, soil moisture content was measured at two depths of 0-15 and 15-30 cm using a Time-Domain Reflectometer (TDR) instrument. At the same locations, soil samples from topsoil layer (up to 15 cm depth) were collected to measure organic carbon. Results showed that at a four-year period, depending on inter-annual changes in rainfall and other climatic parameters and under local management practices, more or less changes occurred in some major vegetation factors such as species and total canopy cover. Changes were more prominent in canopy cover of annual plants, perennial forbs and to some extent in perennial grasses. Changes in soil organic carbon showed a very slow trend. Based on soil texture and variations of seasonal and annual rainfall, soil moisture caused variations in vegetation factors. In the study site, considering the relative stability of soil cover by stones, gravels and plant litter, total soil cover changes were a function of changes in total canopy cover of plants. The results of this study could be considered for proper adjustment of rangeland management in Zharf region. تفاصيل المقالة
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  4 - Species Richness, Evenness and Plant Community Stability 22 Years after Ploughing a Semiarid Rangeland
  Mohammad Jankju Fariba Noedoost
  Rangeland ploughing and cultivation using dry land farming crops may be amajor reason for the destruction of natural resources in the semiarid and sub-humid regionswhich may significantly change the composition and reduce the stability of the affectedcommunities. In pre أکثر

  Rangeland ploughing and cultivation using dry land farming crops may be amajor reason for the destruction of natural resources in the semiarid and sub-humid regionswhich may significantly change the composition and reduce the stability of the affectedcommunities. In present research, an abandoned ploughed site was compared with a nearbyreference site in the semiarid rangelands of Baharkish, Quchan, Iran in spring and summerof 2010. Frequency and canopy cover of all plant species were recorded within 40quadrates of 1m2 area. Simpson, Shannon-Weiner, Hill and Macintosh indices forbiodiversity, Margalof and Menhening for richness and Camargo, Simpson, Modified Nee,Smith and Wilson for evenness were used. Floristic composition, plant life forms, andimportant value of major plant species were compared with respect to the sites. Landploughing and subsequent abandonment had increased total number of plant species(richness) but decreased the species heterogeneity (evenness). It resulted to non-significantdifferences in species diversity between the ploughed and reference sites. Ploughing hadincreased (8%) the important values of respruting plant species. Therefore, patchydistribution of clonal plants had reduced species evenness within the abandoned site.Furthermore, there were some increases in number of therophytes (100%) buthemicryptophytes (24%), chamaephyte (33%) and phanerophyte (100%) species werereduced in the abandoned site. In conclusion, lower evenness and high proportion ofannual plants should make the abandoned site more fragile and sensitive against the futureenvironmental fluctuations. تفاصيل المقالة
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  5 - Investigation of Vegetation Dynamics and Range Conditions in Central Desert of Iran (Case Study: Haftooman, Khoor and Biabanak)
  Seyyed Morteza Abtahi Amr Ali Shahmoradi Ehsan Zandi Esfahan
  Abstract. The purpose of this study was to investigate vegetation dynamics and range conditions considering the climatic conditions and soil properties in Haftooman, Khoor and Biabanak deserts, Iran. For this purpose, after determining vegetation types and the associate أکثر

  Abstract. The purpose of this study was to investigate vegetation dynamics and range conditions considering the climatic conditions and soil properties in Haftooman, Khoor and Biabanak deserts, Iran. For this purpose, after determining vegetation types and the associated species, the type of rangeland utilization, grazing season, the livestock type, the other relevant information, vegetation data including annual canopy cover, perennial forbs, shrubs, total canopy cover, soil moisture and carbon percent were determined over four years. Data were collected along three transects in each vegetation type. For each transect, 10 plots were established. The size of plots was 2.5 x 2.0 m2 considering the life form of dominant species. Embrothermic diagram was drawn according to the monthly temperature and precipitation data of Choopanan synoptic station. Data were analyzed and means comparisons were made using Duncan method. According to the results, significant differences were observed between the years for the annual canopy cover, soil moisture of the second depth, soil cover, soil organic carbon (P<0.01) and Zygophyllum atriplicoides, Artemisia sieberi, Carex stenophylla, shrubs, forbs, total canopy cover, soil moisture of the first depth and the average soil moisture content (P<0.05). In this site, due to the desert conditions, the amount of vegetation and its variation are affected by the precipitation changes. تفاصيل المقالة