Journal of Rangeland

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Background and Objective: Understanding the interrelationships between plants and their impact on the survival of rangeland species plays a vital role in sustainable management and conservation of biodiversity in rangeland ecosystems. This study aimed to investigate the role of nurse species in maintaining species diversity under the influence of different grazing levels and climatic conditions. The present study was conducted in four climatic regions (Sangsefid: semi-desert, Moote: steppe, Tangsayad: semi-steppe, Sabzkooh: humid semi-steppe) of Isfahan and Chaharmahal and Bakhtiari provinces to evaluate the impact of livestock grazing and climate on the performance of nurse plants.

Materials and Methods: In each climatic region, seven sites with heavy and light grazing levels were selected. In each site, three 30 m2 macroplots and four 2 m2  microplots (three plots with nurse species and one control plot) were established. Species diversity indices including Shannon diversity, Simpson diversity, species richness, Shannon evenness and Simpson evenness were calculated. Repeated Measure test was used to examine differences in climates, grazing intensity and their combined effects on the indices, and Principal Component Analysis (PCA) was used to examine changes in species diversity and identify patterns of change between two paired plots. Then, the biological relationship index was calculated for the indices.

Results: The results showed that nurse plants increase species richness through a facilitating effect. However, the response of this system to high grazing stress was climate-dependent: in semi-desert (Sangsefid) and humid semi-steppe (Sabzkooh) climates, high grazing intensity reduced the facilitating effect, while in steppe (Moote) and semi-steppe (Tangsayad) climates, this effect was enhanced. It was also observed that in drier climates (semi-desert and steppe), nurse plants reduced diversity and evenness by creating competition, but this competitive effect was reduced under high grazing stress. In contrast, in wetter climates (semi-steppe and humid semi-steppe), nurse plants increased species diversity and evenness of the ecosystem by enhancing their facilitating effect under high grazing conditions.

Conclusion: Rangeland management should be designed based on the specific climatic conditions of each region and livestock grazing patterns. This study shows that the effect of nurse species and other management measures is strongly influenced by these two factors. Therefore, planning should be flexible and based on a careful assessment of local conditions in order to maintain and improve rangeland biodiversity.
 

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Studying the species diversity as a main part of biodiversity has great importance to detect changes in the ecosystems. Species diversity can be measured using transect and single-scale plot, nested methods and multi-scale plots. Modified Whittaker plot, Intensive modified Whittaker plot and a new C plot (introduced in this study) were used to measure species diversity in Karsank rangelands in Shahrekord province. The vegetation data was collected from sites with east and west aspects, and light and moderate grazing intensities. In each treatment (a combination of aspects with grazing intensities) three kinds of the studied plots were established with three replications using systematic random sampling. After collecting vegetation data, indices of diversity, richness and evenness of species were calculated using the Past software. Comparisons of species diversity obtained by different plots in different treatments were performed using ANOVA in SPSS software and graphs were plotted using Excel program. The results showed that diversity, richness and evenness indices obtained by various plots did not differ significantly (&alpha= 5%), hence it can be concluded that their performances are relatively similar. Moreover, the numerical values of indices cannot be a convincing criterion for determining the suitable plot. Therefore their precision & accuracy in measuring plant diversity indices and the measurements speed can also be investigated to select appropriate plot in future studies.

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This study aimed to investigate the feasibility of using critical area (village) as a basis in the assessment of rangeland degradation with an emphasis on the composition and diversity of vegetation in Southeastern Sabalan. The vegetation and soil data were collected from the sites with high, moderate and low grazing pressure around three critical areas of Alvares, Latran and Vargasaran. One square meter plots along 100 meters transect was used to collect the data in each site. The species composition, diversity and evenness indices in the sites were determined and analysis of variance and mean comparison tests were then used to compare these characteristics. Cluster analysis and principal components analysis was also used to summarize and analyze the data. Results showed that unpalatable species (class III species) were dominant (more than 56 percent) in the heavily grazed sites. The production, density and canopy cover of plant species varied significantly  in the sites with various distances from Vargasaran and Alvares villages, but there was no changes along this gradient in Latran village (P<0.05). Production and canopy cover of the species along the studied gradient varied significantly (P<0.05) but diversity and evenness indices did not show any particular trend. Cluster analysis could not separate sites with similar grazing pressure. According to the result, the defined degradation gradient cannot be used as a basis for rangeland assessment due to the distribution of critical areas in the studied area. Repeating similar studies in Sabaln rangelands can clarify if this framework is an appropriate basis for rangeland assessment or not.

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In order to study the impact of wild boar (Sus scrofa) disturbances on plant diversity and richness of soil seed bank , five plant communities were selected i.e. Festuca ovina, Bromus tomentellus, Alyssum minus-Astragalus sp., Poa pratensis-Trifolium repens and Chenopodium folisom. In each plant community, one disturbed site was selected and 4 one square meters plots were established inside each disturbed patch and control patch (no sign of wild boar disturbance). Soil samples were collected using auger and transferred to the greenhouse, and seedlings were identified through seedling emergence method. Then Simpson and Shannon diversity indices and, Margalef and Menhinick richness indices of soil seed bank were calculated using PAST software. GLM and post-hoc tests were used to compare mean values of different diversity and richness indices using SPSS software. The results showed that there were significant differences between soil seed bank density, diversity and richness indices between disturbed and control patches in the all vegetation communities.  Maximum value of Menhinick (1.28), Margalef (1.79), Simpson (0.64) richness indices, Shannon (1.72) diversity index and density of soil seed bank (46.25) was observed out of patch. In addition, minimum value of Menhinick (1.09), Margalef (1.36), Simpson (0.52) richness indices, Shannon (1.11) diversity index and density of soil seed bank (39.21) was observed in of patch. Generally, wild boar (sus scrofa) decreased diversity, richness and density of soil seed bank.

 

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Species diversity differs in various spatial and temporal scales in response to different biotic and abiotic conditions. The aim of this study was to investigate the effects of grazing impact on species diversity components in local and regional scales in Ilam province. Vegetation sampling was carried out using 40 plots of 2×2 m² (20 plots in exclosure and 20 plots in grazed area) in local scale and 8 sites (4 sites within exclusion and 4 sites within grazed area) in regional scales. Plant species richness (γ_r) partitioned into additive component among plots (α₁), between plots (β₁) and between sites (β₂). We used the PARTITION software for analysis of species diversity components in different scales. According to the results, 72 plant species were observed in exclosure and 60 species in grazed area from a total of 89 recorded plant species. Additive partitioning of plant species diversity showed that, in two regions, observed plant species components (α₁ and β₁) was smaller than expected values in local scale, and in regional scale and observed plant species components (β₂) was greater than the expected value. Species diversity among plot (α₁) in exclosure area was significantly greater than the grazed area, but there was no significant trend for species diversity between plots (β₁) and sites (β₂), indicating non-random patterns of plant species. The beta diversity, with respect to more contribution to total species diversity, was more important diversity component in regional scale. This study showed that some components are more sensitive to grazing, so we suggest using these indices in vegetation management studies.

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Environmental pollution arising from the mining activities may impose severe problems in natural ecosystems such as rangelands. Systematic random sampling method was used to collect vegetation characteristics data based on plant life forms and vegetation status. Vegetation characteristics data were collected using 2 m² plots placed along 50 m transects in three different zones including near (0-200 m), middle (200 to 500 m) and far zone (500 to 1000 m) from mine. The results indicated that the production of range plants decreased from 35.85 gr/m² in far zone to 11.06 gr/m² in near zone. The canopy cover of perennial species decreased from 19.4% in near zone to 7.35% in far zone. The plant density was also decreased from 22 individuals per a square meters in far zone to 6 in near zone. The production, canopy cover and density of shrubs and perennial grasses in areas with more than 500 m from mine was higher than areas closer to mine significantly. Results revealed that Simpson and Shannon diversity indices were decreased from 0.7 and 1.73 in far zone to 0.49 and 1.03 in near zone respectively. According to the results, the impacts of Bauxite mine on vegetation characteristics are more sever up to the 500 meters from the mine. The negative impacts of mining on vegetation should be considered in hazard assessment projects.
 

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Soil seed bank is an important part of plant species diversity. The study of soil seed bank provides vital information for rehabilitation of degraded vegetation. This study aimed to evaluate soil seed bank potential for recovering of degraded vegetation in Plour rangelands. Random systematic sampling method was used to collect soil samples in Polur rangelands in the spring. Soil seed bank samples were taken from two depths (0-5 and 5-10 cm) and they were moved to greenhouse to conduct seed germination tests. ANOVA and Duncan's tests were used to compare relative frequency of the plant species palatability classes and also relative frequency of life form in soil seed bank and vegetation, separately. Paired t-test was applied to compare each palatability class between seed bank and vegetation and to compare relative frequency of each life form between seed bank and vegetation. The results showed that relative frequency of palatability class II in soil seed bank and palatability classes III in vegetation were significantly higher than the other palatability classes. Therophytes were the main life form of plant species in the soil seed bank, and Hemichryptophytes were the main life form of plant species in vegetation. We concluded that relative frequency of palatability class I in soil seed bank was low and we could not rely on the soil seed bank for recovering palatable plant species automatically and without cultivating palatable species.
 

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Increasing sustainable rangeland ecosystem services such as forage production and diversity are among the main aims of restoration practices. This study aimed to assess the effects of small micro-catchment semi-circular bunds on some diversity and richness indices in Naroon rangeland located in Khash- Sistan & Balochestan province. A systematic random sampling method was used to establish ten 150 meters transects in the treated and control sites (5 transects in each site). Ten sampling plots (2m × 2m) were established along each transect randomly and the vegetation attributes including plant density and species richness were measured. Diversity indices of treated and control sites were compared using independent sample t-test in Minitab16. Abundance distribution models were fitted using PAST program. According to the results, vegetation cover, plant diversity and diversity indices between treated and control sites varied significantly (α= 5%) but the richness indices did not varied statistically. Log-normal model was the best fitted parametric model among the species abundance models including (geometric series, log series, broken stick and log-normal) for the study area. The result confirmed high stability of the vegetation community in the study area as plant species with moderate to high frequency were dominant. Overall, using small micro-catchment semi circular bunds in the study area resulted to more evenness in vegetation and enhanced the diversity and stability of the vegetation in the study area.
 

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Measuring species diversity is required in conservation, assessment and monitoring plans in rangeland ecosystems. This study aimed to evaluate the effects of long-term exclusion (thirty-three years) on plant diversity in Hanna area located in Semirom rangelands – Isfahan. Six transects with 100 m length were established in exclusion area and in adjacent properly grazed area. Plant cover, density, and richness of the species were recorded in 10 plots with 2 m² size along each transect. Non-parametric diversity, richness and evenness indices, and parametric abundance distribution models were calculated for both areas using PASTsoftware. The T-test was used to compare diversity indices in the two sites. According to the results, although “properley grazed” site had higher diversity compared to the “not grazed” site, only Hill diversity indices varied significantly (p< 0.05) between these sites. Results indicated that richness indices varied significantly between the two sites (p< 0.05). Abundance distribution model showed that none of the parametric models (broken stick, lognormal, geometric series and log series) fitted to the diversity data in the “not grazed” site, indicating an unstable vegetation community. Broken stick and lognormal were best fitted parametric models among the species abundance models for the “properly grazed” site, indicating a stable vegetation community. Exploring diversity indices changes in the study area by Canonical Correspondence Analysis (CCA), indicated that the two sites were separated well in the ordination space and confirmed the obtained results from T-test. This study highlights the importance of proper grazing and grazing systems in semi- Steppe rangelands to maintain diversity indices in an appropriate level.
 

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Preserving species diversity is one of the important objectives of ecosystem management. The aim of this study is to investigate the effect of drill seeded enclosures on vegetation changes in Tang-e-Sorkh rangelands in Boyerahmad province, Iran. Samples were taken from two areas: a 10 years exclosure plus drill seeding with Ferula assa-foetida L. and an area which is currently grazed as the control site. For sampling purpose, three 100-meter transects were put in each area, then for every ten meters of the transect a plot of one square meter was installed. Species richness were assessed through well known indicators, such as Sheldon's evenness index, Shannon entropy, Simpson index. Results of two sites were statistically compared. The multivariate analysis was used to evaluate the response of plant species to exclosure and grazing conditions. In general, 47 and 41 species were identified respectively in exclosure and grazing regions having 28 of species in common. Results also showed that 19 and 13 species are unique to the exclosure and control area, respectively. As the results of the statistical comparison it is concluded the exclosure area has a significantly higher diversity and richness than the grazing area, but there is no significant difference in uniformity (evenness) between the two regions. Rényi entropy profile showed that the exclosure area where the alpha values is higher than one, has higher diversity than the grazing area. There is no significant difference between the canopy cover percentage of different vegetation groups in these two regions, but the exclosure area has a higher rate of overall plant cover percentage. Results of this study suggest the expansion of the exclosure areas with drill seeding using medical plants and valuable indigenous species, such as Ferula assa-foetida L., also systematic grazing program is proposed in the studied area.

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Plant species diversity always implies ecosystem stability against environmental and biological disturbance. In order to investigate the effects of grazing management on species diversity indices, 15 rangelands under livestock grazing and one rangeland under wildlife grazing (especially deer) were selected in the Mouteh Wildlife Sanctuary. On the basis of distance to villages and watering points, fifty-six sites in the rangelands were selected. Sampling method had a randomized-systematic design, and two 100-meter long transects were established perpendicular to each other with three replications in each site. Vegetation percentage was recorded separately for each species type and life form along the transects. Species richness, heterogeneity and evenness indices were calculated from cover data using PAST and Excel software. Parametric diversity indices including log series, log normal, geometric and broken stick were fitted in both livestock and wildlife grazing areas. The results showed that, although the species diversity and evenness in the wildlife area were higher than that of the livestock grazing area, these indices were not significantly different (α = 5%). According to the results, higher species richness was recorded in the area under livestock grazing. The Menhinick (2.41) and Margalef (3.03) richness indices in livestock grazing areas had significantly higher values compared to Mouteh Wildlife Sanctuary with the Menhinick (1.52) and Margalef (2.12) richness indices (α = 5%). The logarithmic diagram in the livestock grazing and wildlife grazing areas followed the brocken stick model, indicating the presence of dominant species and limited species with moderate frequency. The result of CCA analysis showed that the two study areas were properly separated from each other in the ordination space in terms of management, vegetation and species richness index.

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The plant communities locating at the margins of the waterways play a vital role in the ecological processes and ecosystem services in the semi-arid mountainous regions. In this study, variations of plant diversity and composition at different distances from the waterway and its slope aspects were investigated. For this purpose, 15 sub-basins with a variety of area and length of waterway, in both northern and southern directions, were selected in the mountainous rangelands of Anbaran Chai. For measurements 20 plots of 1m² in each sub-basin were established and vegetations were surveyed. Different distances from the waterway (0-25, 25-50 and 50-75 m) were selected for the measurements in the growing season in 2017. By grouping the species into scientific groups and calculating species diversity, statistical comparison of the parameters was performed by one-way ANOVA and t-test. The results showed that the highest diversity happens at the second distance group (25-50 m).This put emphasis on the hypothesis of occurring maximum diversity in the medium environmental disturbance conditions. In this regard, Shannon-Wiener species diversity index values ​​were 1.38, 1.40 and 1.39 for first to third distances, respectively. Northern slopes are more diverse (1.45) than southern slopes (1.30) due to high humidity. The results suggests that if the goal of range management is to prioritize the area on the basis biological practices emphasis should be put on the first and third distances from the waterway.

 

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Biodiversity of rangeland ecosystems is directly affected by the biotic traits and environmental factors of the ecosystem. These ensures the sustainability of the ecosystem against environmental and biological changes.  The aim of this study was to investigate the response of Performance diversity and species diversity indices to topographic-climatic factors in Angmar region, Mazandaran province. For the task plots were placed in the study area Plant feature including leaf area, dry matter percentage and plant height in each plot were measured and recorded. Environmental factors included topography (slope, aspect and altitude) and climatic factors included average annual temperature, humidity and rainfall were mostly the target features. Performance diversity indices including FAD1, FAD2 and MFAD, FDvar performance divergence indices and FRao performance uniformity indices as well as species diversity indices (Simpson, Shannon, richness and uniformity indices) were calculated in Fdiversity package and to evaluate the significance of the relationship between environmental factors and these indicators, the generalized linear regression (GLM) model was used in R software. The results showed that relationship between species richness and rainfall, altitude and Shannon index was significant only with slope. Simpson index was significantly associated with direction and altitude variables, but uniformity was not significantly associated with any of the environmental factors. The results of Spearman correlation between species diversity indices and performance characteristic diversity indices show that among the species diversity index, Shannon index has the highest correlation with FAD1 yield diversity index. In general, the results showed that topographic-climatic factors have an important relationship with yield. There is a positive relationship between species characteristics in the ecosystem and ecosystem processes.

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Background and objectives: A large area of Iran rangelands is located in arid and semi-arid areas which a significant percentage of them have been degraded and are not in good condition. In these areas, vegetation restoration is not easy due to the water scarcity. Water harvesting operations are among the necessary management measures to restore and develop the rangelands of these areas. Water harvesting operations improve the rangeland restoration conditions by increasing the available moisture for plants. But not all water harvesting operations are equally effective and may not have the same effect on rangeland restoration in different areas. Therefore, it is necessary to compare such operations in different areas to be able to choose the best water harvesting operations. Therefore, this study investigates the efficiency of two water harvesting methods in the rehabilitation of arid vegetation in Hormozgan province.
Methodology: In this study, three treatments have been considered: control area, area under microcatchment operation and area under water spreading system. Systematic-random sampling method was used to measure vegetation. Three 100 m transects were laid out in each area. Vegetation attributes were measured in ten 2×2 m plots located along each transect. In total 90 plots, the percentage of canopy cover and the number of the plant species were recorded. The biological form of plant species was determined based on the Rankier classification method. In addition, the percentage of rocks and pebbles, litter and bare soil were determined in each plot. To study the flora of the study area, all plant species in the region were sampled and identified using reliable references. To evaluate species composition in all three sites, plant functional types were used. One-way analysis of variance followed by LSD were used to compare control area, area under microcatchment operation and area under water spreading system in terms of vegetation attributes. The rate of vegetation attributes change was also determined. Detrended correspondence analysis was used to investigate the relationship between plant species and water harvesting operations and control areas.
Results: The results showed that there was a significant differences between water harvesting operations and control areas in terms of bare soil, litter and vegetation (P <0.05) The water spreading system and microcatchment operation had a significant effect on vegetation canopy and litter cover in the region (P <0.05). Examination of plant functional types also showed that palatability classes II and hemicryptophytes had more chance to develop under water harvesting operations respectively. In terms of life form, water harvesting operations had the most positive effect on forbs and grasses, respectively (P <0.05). The results also showed that the families Poaceae, Chenopodiaceae and Fabaceae were successful families in the sites under water harvesting operations, especially the sites under water spreading system. The rate of vegetation attributes change was increasing in the area under water spreading system compared to the area under microcatchment operation, except for the bare soil. The highest and lowest positive changes belonged to litter and Simpson index with a mean of 9.07±0.62 and 0.48±0.25, respectively. The results of DCA showed that Cenchrus pennisetiformis،، ‏Tephrosia persica، ‏Atriplex leucoclada‏ ، ‏Cornulaca monacantha‏ ,‎ ‎Cynodon dactylon were the most important species related to water spreading system and microcatchment operation.
Conclusion: Both water spreading system and microcatchment operations improved the quality and quantity of vegetation in the region, but the effects of water spreading system were greater than microcatchment operation in restoring vegetation. According to the ecological indicators considered in this study, water spreading system is recommended to restore vegetation in arid and semi-arid regions. In the end, it is suggested that economic and social indicators such as the cost of implementing various water harvesting operations should be also considered in future studies, to combine all ecological, economic and social indicators to suggest the best water harvesting operations for rangeland restoration.
 

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Background and Objectives: The impact of grazing on the carbon cycle in mountain rangelands depends on various factors, including management practices and environmental conditions. However, the effects of grazing on carbon stocks remain uncertain due to challenges in tracking small changes in rangeland carbon stocks, lack of baseline information, and limited long-term grazing management data. This study aims to investigate the relationships between plant and soil parameters and organic carbon storage in a 10-year-old exclosure in the mountain rangelands of Asadabad, Hamadan.
Methodology: Two study sites, one under grazing and the other under a 10-year-old exclosure, were selected in a manner that minimized the gradient effect of ecological and biological factors. Vegetation and topsoil samples were collected along two 100-meter transects at 20-meter intervals, resulting in a total of 10 plots in each area. Vegetation parameters, including percentage cover, diversity (Simpson index), evenness (Shannon-Wiener index), and richness (Margaluf index), were calculated using Past 4.03 software. Soil organic carbon, phosphorus, potassium, and nitrogen were measured. Statistical analysis was performed using SAS V.4.1 software, and the distribution of variables was analyzed using principal component analysis (PCA) in Canoco 5 software.
Results: The findings revealed higher vegetation cover and plant diversity (richness and evenness) in the exclosure area. The vegetation cover percentage and species count in the grazing area were 35.1% and 127, respectively, while in the exclosure area, they were 67.6% and 139. The carbon stocks in vegetation and soil were significantly higher in the exclosure area, with values of 83.13 and 74.35 ton/ha in the soil surface, and 0.00219 and 0.00273 ton/ha, respectively (p < 0.05). The exclosure area exhibited a significant increase in Simpson diversity index (13.83) compared to the grazed area (12.63). Additionally, the Margaluf richness index showed a significant increase in the exclosure area. Soil phosphorus, potassium, and nitrogen nutrient measurements indicated an increase of 51%, 25.7%, and 15% in the exclosure area (p < 0.05). Correlation analysis revealed a significant linear relationship between organic carbon and phosphorus (r = 0.55) and nitrogen (r = 0.80) (p < 0.05). However, no significant correlation was observed between plant diversity indices and vegetation organic carbon storage.
Conclusion: The study demonstrated the positive impact of long-term exclosure on soil and vegetation parameters in mountain rangelands (p < 0.05). Exclosure not only enhanced plant and soil organic carbon storage but also resulted in increased soil nutrient levels, vegetation cover, and diversity and richness indices. The significant increase in plant diversity highlights the suitability of the Simpson index for evaluating diversity in mountain rangelands. However, the lack of a significant linear relationship between diversity index and organic carbon stocks in plants and soils suggests that factors other than plant diversity directly influence carbon stocks in mountain ecosystems.
 

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Background and objectives: Livestock grazing significantly influences the structure and dynamics of vegetation in rangelands, prompting the implementation of exclosure operations as a management strategy. Exclosure involves restricting livestock access to rangelands and is recognized as an effective method for rangeland management and improvement. Numerous studies suggest that exclosure operations lead to positive changes in vegetation indicators, including cover structure, production levels, and species diversity. This research aims to investigate changes in vegetation canopy percentage, production rates, and species diversity under exclosure management in the semi-steppe rangelands of Ghalehgharak, Shahrekord.
Methodology: Sampling locations were selected within the exclosure site (Ghalegharak) and an adjacent grazed site. Plant cover sampling was conducted using a random-systematic method over multiple years (2016 to 2021). Four parallel transects of 100 meters in length were established at each site, with 40 plots of 2 * 2 square meters placed along the transects. Canopy cover percentage was determined using the theoretical estimation method, while biomass was measured through the cutting and weighing method. Species diversity was assessed using Simpson and Shannon-Wiener indices, and species richness was compared using Margalef and Menhinich indices in the Past software. Range condition was determined using modified four-factor and six-factor methods, and trends were evaluated using scale and comparison methods.
Results: Over the five-year study period, the exclosure site exhibited canopy cover percentages ranging from 34.57% to 52.68%, while the grazed site showed variations from 22.15% to 32.76%. Biomass on the exclosure site ranged from 1215 to 1908 kg/ha, whereas the grazed site's production varied from 693 to 1025.6 kg/ha. The rangeland status was determined as moderate for the exclosure site and poor for the grazed site. The trend for the exclosure site was positive, while the grazed site trend was negative. Significant differences were observed between most evaluation indicators for the enclosed and grazed sites, with exclosure enhancing vegetation indices, canopy cover, and biomass. Exclosure significantly increased species diversity and richness, as indicated by Simpson, Shannon-Weiner, Margalef, and Menhinich indices.
Conclusion: The research findings indicate that exclosure positively influences vegetation, biomass, and species diversity in rangelands. Given the declining performance of grazing rangelands in recent years, implementing exclosure operations and strategic livestock grazing management emerges as a favorable approach for pasture improvement and altering current trends.