Studying plant phenology is very important to regulate the rangeland utilization. Plant phenology can be determined by Growing Degree Days (GDDs). Since temperature varies yearly, the phenological stages may consequently differ yearly. Determining the base temperature is one of the key steps in the calculation of GDDs. The aim of this study was to calculate the required GDDs for each phenological stage to predict phenological stage of Fritillaria imperialis based on GDDs in the consequent years. To do so, Fritillaria bulbs were placed at constant temperatures of 0, 1, 2, 3 and 4°C. The length of sprouts as a growth index was measured as a function of temperature. Plant chronology was recorded in three day intervals from March 1st, 2016 in the field and the date of each phenological stage was recorded in the form of an index developed by combining Fick and Haun indices. Then, 20 plant individuals were selected in Dasht-e-Laleh of Kouhrang County, Iran and their growth stages were recorded. Meanwhile, the required amount of accumulated GDDs (AGDDs) to reach each phenological stage was also calculated. Results showed that Fritillaria imperialis began the sprouting (phase E) after receiving 130.75 GDDs on March 23rd, 2016. The emergence of leaves began on 27th March with 166.30 GDDs and finished on 9th April. Finally, this plant on 9th May received 560 AGDDs and went to senescence. Based on the phenological data, when the plant received 240 AGDDs, flowering stage started. The most appropriate time for tourist entrance is in the R2 stage (flower opening) when the plant receives 298.8 AGDDs and the best exit time is when the plant receives 359.2 AGDDs. So, the relationship between phenological stages of the plant and GDDs will be useful in visiting the site in terms of ecotourism and determining proper visit times. تفاصيل المقالة

Assessment and monitoring of rangeland in different grazing managements seems necessary to manage rangelands. The plant functional groups can be used as appropriate responders for rangelands condition and management. Therefore, this study was performedand aimed to determine the most important traits that are influenced by rangeland variation and management. In order to this, three areas along a grazing gradient including national parks, protected area and free grazing were selected inTangsayad rangelands of Chaharmahal Bakhtiari Province, Iran in 2015. A 100 m transect was established randomly in each site and within it five plots of 4 m2 area at 20 m intervals along transects were determined systematically. Plant species were identified and vegetation cover was recorded in each plot. The number and size of plots and transects were determined regarding to semi-arid rangeland sampling guidelines as well as the dimension of dominant plant species in plant community. Finally, some traits as leaf dimension, plant biomass and cover of species were measured. The results showed that the traits such as leaf length, leaf width, leaf area and leaf weight, grass growth forms and life forms of Hemicryptophyes and Geophytes had significant differences at least in one of three grazing managements sites (P<0/05). Also Principal Component Analyses (PCA) showed that traits as yield, overall weight of plants and perennial plants had high correlation with the first component and the traits such as leaf length, leaf width, leaf area, Hemicryptophyes had also high correlation with the second component. In general conclusion; leaf traits as leaf length, leaf width, leaf area and leaf weight, grass growth form, Hemicryptophytes and Geophytes life forms were introduced as good indicators for assessing and monitoring of grazing management. تفاصيل المقالة

Climate change has a great impact on the species distribution range and many endangered plant species. Fritillaria imperialis as a species that is native to Central Zagros, Iran is a medicinal plant with great ecological and commercial profits. Its population has decreased considerably and the species would be endangered in later decades. Understanding the habitat needs of this species, evaluating habitat conditions, and forecasting its potential habitat are important for protecting F. imperialis. The presence of F. imperialis points recorded from our field surveys in Chaharmahal-va-Bakhtiari province as a part of Central Zagros, Iran in spring 2017. In order to model its distribution based on correlation analysis, two topographic variables and eight bioclimatic ones as the input of Maximum Entropy model (MaxEnt) were used. The results showed that temperature seasonality (55.1%) and precipitation of driest quarter (22.9%) were important factor drivers of F. imperialis suitable habitat. The accuracy of the maximum entropy model in predicting the distribution of the studied species was high (AUC=0.91) as 2.33% (37986 ha) in Chaharmahal-va-Bakhtiari Province for the F. imperialis, which has had suitability. About 18% and 16.5% of F. imperialis habitats in the area may be lost due to climate change by 2070 under two climate warming scenarios (RCP4.5 and RCP8.5, given by the IPCC). As shown by the model, under the current climatic conditions, the suitable habitat would be rendered to an unsuitable one in the future resulting in local extinction. The results of this study can be used to identify sites with high extinction probability of F. imperialis and protect susceptible habitats against the effects of climate change. تفاصيل المقالة