Journal of Rangeland Science
Volume:14 Issue: 2, Spring 2024

Aromatic and medicinal plants are a rich source of substances that are beneficial to human health. At a socio-economic level, the exploitation of medicinal plants constitutes an important income for the local populations. However, the use of these plants in recent decades has put a lot of pressure on these resources, and many species suffer from over-use without taking into account the existing potential. Thymus atlanticus is an aromatic and medicinal shrub endemic to Morocco. It’s rare and has a very limited geographical area. In this study, we determine the status of T. atlanticus and evaluate the biomass production potential of this spontaneous species in 2021. The results show that the density of T. atlanticus does not exceed 235 plants per 100m2, with a recovery rate of 19.92%. Whereas the biomass dry matter was only 67.3±1.22kg/ha. The yield of T. atlanticus essential oil was 1.78% (w/w). From these results, it appears that T. atlanticus cannot be exploited in this state. It needs to be rehabilitated, and protected. These results can help to better restore and manage the steppe at T. atlanticus in the future.

This study aimed to study the effects of cutting interval on yield, morphological and quality traits of three grass species under irrigated conditions in North Mecha district, Ethiopia. There were three kinds of grasses namely Para (Brachiaria mutica Stapf.), Napier (Pennisetum purpureum), and Desho (Pennisetum pedicellatum) at three cutting dates (60, 90, 120 day). The experimental design was a completely randomized block design with three replications and a total of nine plots. The grasses were first harvested after 60 days of regrowth; second and third harvests were done after consecutive 30 days of re-growth. Data were collected for plant height, tiller number, leaves number per plant and Leaf to Stem Ratio (LSR), Dry Matter (DM) yield and quality traits such as ash content, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL). All harvested data were laid open to GLM ANOVA procedures of SAS version 9.0. Result showed that harvesting age significantly affected all the traits except LSR in three grasses. DM yield, plant height, tiller number and the number of leaves per plant ADF, NDF ADL were increased with increasing harvesting age whereas ash content and CP decreased. It was concluded that Napier grass produces a higher forage yield among the three grasses and longer harvesting date results in increased forage DM yield and decreases the CP content in all the studied grasses. At 120 days cutting Napier grass recorded the highest DM yield (16 t/ha). Further research is needed to be conducted over much longer periods to determine to what extent these findings are related to performance over the life of a permanent pasture.

The experiment was conducted with the objective of assessing the effects of fertilizer type, and harvesting date on plant growth traits, dry matter (DM) yield and nutritional values of Brachiaria hybrid Mulato II grass. A two-factor factorial experiment was used based on a randomized complete block design (RCBD) with three replications. The fertilizer type had three levels: chemical fertilizer, manure, and control (without fertilizer) while the three harvesting dates were: 45, 75, and 105 days of plant age. The spacing between rows and plants within rows was 0.3 m and 0.5 m, respectively. All plots were harvested and a sample was taken from each plot for measurement of quality traits. The result of the analysis of variance showed significant effects of harvest date and fertilizer type on all the traits, with the exception of crude protein (CP) in fertilizers. The harvesting date and the fertilizer interaction effects were significant for plant height, leaf to stem ratio (LSR), root number, CP, Ash and neutral detergent fiber (NDF). All morphological traits except LSR were increased by increasing harvesting date. For LSR, the higher value was obtained in early cutting. For quality traits; the Ash and CP values decreased and NDF, ADF and ADL values increased as the plant age increased, indicating that forage quality was decreased in late cutting (105 day). In comparisons between fertilizer levels, the higher values of all morphological traits except LSR were obtained by the application of manure fertilizer followed by chemical fertilizer. The higher mean values of CP and LSR were obtained by the application of chemical fertilizer and without fertilizer, respectively. The results of this study showed that most of the morphological traits of the grass were less affected by the interaction between fertilizer type and harvesting days. BMII grass harvested from 105 days using manure fertilizer had greater DM yield than the application of chemical fertilizer and without fertilizer which would be more beneficial to get high quantity yields and considered as an option to solve the shortage of feed.

Optimal habitat has a beneficial effect on species survival. In this research, a logistic regression statistical method was used to prepare the potential distribution map of Artemisia aucheri Boiss, in Tehran province, Iran in 2020-2021. The maps of 19 bioclimatic and three physiographic variables with a resolution of 4.9 km under current conditions were prepared. Then, the sampling information in relation to the presence and absence of species and environmental variables was recorded and the relationship between species distribution and environmental factors was determined using logistic regression. Finally, the map of potential distribution of Tehran province was produced. The results of logistic regression model showed that in the current situation, 427057 ha (31% of the province) had a probability of more than 75% presence of this species. The kappa coefficient for evaluating the regression model was 0.86 that is one of the models with good accuracy according to Koch and Smith classification. In order to study the effect of climate change on the geographical distribution of the species, climate bio maps were prepared based on the MRI-ESM2-0 circulation model under two scenarios of 4.5 and 8.5 for 2050. The species under study is currently in the range of 1600 to 2800 m. The results showed that by changing the conditions from a balanced to a pessimistic situation, the area with the presence of more than 75% of the species decreases and the area with the presence of 25-50% increases. Also, results showed that the minimum and maximum altitudes in scenario 4.5 will be changed to 1500 and 2500 m, respectively. While according to scenario 8.5, the presence of this species will be only at above 2500 m. In fact, according to the 8.5 scenario, the species will be migrated to higher altitudes. The results identify climate sensitive areas and possible future shelters of A. aucheri to be used in conservation and rangeland planning.

The study was conducted in the Butana region of Sudan to assess the impact of climate change on the browse trees/shrubs cover and production in the Butana rangelands. Five meteorological stations surrounding Butana were selected to represent the region’s climate. Simple regression analysis was used to analyze the trend of climate variables (rainfall, temperature). The direct count method was used to measure browse production and a social survey was also conducted to assess farmers’ perceptions on climate change. Rainfall for all meteorological stations showed a decrease in monthly and annual rainfall during 1961-2013. Annual temperature analysis indicated a noticeable increase in maximum and minimum rates at all meteorological stations since 1985. All interviewees agreed that trees/shrubs cover had decreased compared to the past. Significant differences (P< 0.05) were found in browse production between the sites during the dry (no rainfall) season. The average browse production of three sites was 310, 236, and 297 kg/ha for the wet season and 247, 95, and 85 kg/ha in the dry season for El-Idaidat, El-Bahoogi, and Wad- Shamoon sites, respectively. The variation in browse production between sites was linked with tree density/ha, which was directly affected by decreasing in rainfall and increased temperatures. Seed banks in Ewerdaidat were 4 seeds/m2 while 3 seeds/m2 were found at El-Bahoogi. The study concluded that there was a decrease in rainfall and an increase in temperature during the last decade in the Butana, reflected negatively on trees/shrubs cover and its browse productivity.

In temporal and spatial patterns, the critical (ecological) thresholds have rapid changes in ecological gradient. Determination of thresholds along the environmental gradients can help to control destructive factors and therefore, the success in restoration projects can be guaranteed. This study was conducted to evaluate the trend of changes in functional and structural indices along soil salinity gradient and to determine the ecological thresholds in saline habitats of Uremia Lake, Iran, in the growing season of 2019 and 2020. Landscape Function Analyses (LFA) guideline was used to evaluate the sites. The values of the indices were fitted with the pattern diagrams (S-shaped curves). The habitat restoration process after five years of range management and development projects was evaluated and ecological thresholds were determined. The results showed that the values of the functional and structural indices decrease along the salinity gradient and the lowest values were observed at the end points of the gradient. As a result, the success of range development projects was lower at salinity center. The results of the S-shaped curve models showed that the regression relationship between landscape organization index and nutrient cycle with eleven soil indices along the salinity gradient was not significant and their determinant coefficients were less than 50%. On the other hand, there was a strong relationship between the index of stability and permeability with the salinity gradient, with determinant coefficients of 83 and 63%, respectively so that the values of these two indices decreased significantly when approaching the salinity center. Regarding the PCA analysis, the first component justified 39% of the changes in the properties, and the values of Sand, Mg, and Ca increased as they approached the salinity center, and on the other hand, as they moved away from the salinity center, the values of Clay, N, OM, CEC, p, and Silt increased. The participation of the most soil parameters in the extraction of the first component of the decomposition of the physical and chemical characteristics of the soil along the salinity gradient and the separation of the sites from each other indicate the good ability of the LFA method in showing the ecological processes of nature. In this regard, to fit the data by the S-shaped curve, the distance of 1000 m far from the salinity hotspot was defined as an ecological threshold, through which sudden changes occur. At these thresholds, the functional differences of the habitat were more than the surrounding areas, so for controlling the dust centers, different projects such as drainage, windbreaks or planting dense vegetation cover are suggested to stabilize the thresholds. In such a case, the soil seed bank in the distance between the two thresholds could be regenerated and prevent the soil surface from eroding if grazing is prevented. Identifying thresholds as a transition zone and surrounding zones as state zones in this study will be a scientific and appropriate alternative to the conventional guidelines in executive organizations and will help them to zoning ecosystems according to nature and selection and prioritization of restoration sites in saline rangelands.

Climate change is one of the most serious threats to rangeland. The implications of climate change on the rangelands conditions of the Duda and Gomole in Southern Ethiopia were examined. Measurements of rangeland were made using field survey and focus group discussions. Descriptive statistics, one way ANOVA was employed to detect whether a significant difference exists between range conditions while Pearson bivariate correlation was used to test the relationships between climate factors and herbaceous plants. The Mann−Kendall test was used to determine the trends of rainfall and temperatures over times; meanwhile Sen’s slope estimator was used to test the magnitude of changes. The results showed no significant annual rainfall trend in both Duda and Gomole rangelands despite a slight increase in rainfall. However, the annual minimum temperature significantly increases in Duda rangeland while the annual maximum temperature significantly decreases in Gomole rangeland. The major herbaceous species in Duda rangeland (Cenchrus ciliaris, Cynodon dactylon, Digitaria naghellensi, Digitaria milanjiana and Panicum maximum) had a positive correlation with annual rainfall and a negative correlation with minimum temperatures. In the Gomole rangeland, Cenchrus ciliaris and Bothriochloa insculpta were negatively correlated with minimum temperature. The Duda rangeland was in poor condition where that of Gomole was in fair condition. This difference was mainly due to slight difference between climate of Duda (arid and semi-arid) and Gomole (arid) of the rangelands. The multiple linear regression showed that changes in rainfall and temperature accounted for 46% of variability on Duda rangeland condition whereas rainfall changes accounted for 32% of variability on Gomole rangeland condition. Therefore, the present study suggests rangeland rehabilitation in the short run through soil and water conservation, bush clearing and burning, and the planting of desirable grass species are critical to reduce the effects of climate change on rangeland.

The role of different plant covers (i.e. Artemisia aucheri Boiss, Cousinia commutate Bunge and Agropyron longiaristatum Boiss) in topsoil properties and Nitrogen transformation is less known under semi-arid mountains. The main objective of this research was to study the effect of land covers on topsoil properties and nitrogen transformation. The study was carried out for investigating the soil properties of Grazing Exclusion (GE), Grazed Rangeland (GR) and Rainfed Agriculture (RA) in Kojur, Mazandaran province, Iran. Thirty-six 1 m2 plots were set at three treatments to sample the dominant plant species. Soil samples were then taken from the central part of each plot sample in an area of 20×20 cm and depth of 20 cm. Our findings demonstrated that the carbon (C) content of plant materials did not differ for studied land covers whereas GR and RA had higher N content (1.48 and 1.41%, respectively) and lower C/N ratio (13.33 and 14.45%, respectively). In the GE, N concentration of soil (with 0.34%) was 1.5 times more than that in GR and RA (0.20 and 0.21%, respectively). Soil nitrification and N mineralization rates were significantly higher in the GE (0.33 and 0.28 mg kg−1d−1 respectively) as compared to the RA (0.15 and 0.08 mg kg−1d−1 respectively) and GR (0.01 and 0.04 mg kg−1d−1 respectively). There were no significant differences among land covers for bulk density, available K, microbial respiration, and ammonification rates. According to the results, grazing exclusion with presence of grass species increases the organic C contents, total N, and eventually, N mineralization which totally leads to improved soil quality in these regions.