Search

This study aimed at predicting the effect of climate change on the geographic distribution of Thymus kotschyanus Boiss and Hohen in Mazandaran province. Species presence data were recorded via the Global Positioning System (GPS). The distribution of T. kotschyanus Boiss and Hohen under current and future climatic conditions 2050 and 2070 (1428- 1448 Solar) applying two scenarios of RCP 4.5 and RCP 8.5 climate change by using the GCM data series of general circulation models BCC-CSM1-1، CCSM4 and MRI-CGCM3 and the five species distribution models such as Generalized Linear Model, Generalized Additive Model, Classification Tree Analyses, Generalized Boosting Model and Random Forest methods was investigated. For this purpose, layers of environmental factors, including six bioclimatic and two physiographic variables, were used as inputs to species distribution models. Among the environmental variables, precipitation seasonality, precipitation in the coldest quarter, and isotherm had the greatest impact on habitat suitability. The assessment of the modelling indicated that the Generalized Additive Model and Generalized Boosting Model had better predictions of climate habitat than the other models. The results also indicate that climate change will change the range size of the T. kotschyanus Boiss and Hohen, and will move toward higher elevations in the future. The results of the present study may be used to plan habitat protection for the medicinal species of T. kotschyanus Boiss and Hohen, as well as its restoration and rehabilitation in the vast regions of the country.

Functional traits of plant species are displayed ecological properties, life strategy, and species ability for an encounter with a special environment. In this study, seven elevation points with 50 m interval with 1500 to 2002 m distance on the ground were selected and each point, 10 plots were established along a transect perpendicular on slope. To investigate the function of plant species groups, six functional traits including plant height, growth form, life form, reproduction type, life span, and type of nitrogen fixation were measured or collected. Functional plant species groups and five functional diversity indices were extracted using FDivesity software. The ANOVA test was done to investigate the effect of elevation on functional traits. Results show that elevation had significant effect on Rao index and functional divergence and there was no significant effect on other indices. Compare of means frequency and plant height was shown that there is significant difference between two functional groups. Results indicate that functional traits provide a suitable tool for studying and understanding environmental changes.

Nepeta asterotricha Rech.f. is a medicine plant. The goal of this research is to investigate the effect of some environmental factors on amount of essential oil of Nepeta asterotricha Rech.f at 8 habitats in Yazd province to determine optimal environmental factors for rangeland management and reclamation. Soil samples were collected and measured phosphorus, nitrogen, and potassium and pH, electrical conductivity, and sand, silt, and clay (Hydrometric) at three replications from each habitat. Topographic factors including elevation, slop, and aspect were recorded in habitats. Plant samples in three replications in 8 habitat and essential oils were obtained by hydro distillation for 3 hours. Investigation on the correlation between essential oils and some ecological factors were done by using Redundancy Analysis v. 4. Comparison of means were done using Tukey tests (p≤ 0.05). Number of identified chemical compounds were 31 that 24 components had different between habitats. Results showed that the active ingredients in Nepeta asterotricha Rech.f including α-Thujene, α-Terpinene, p-Cymene, (Z) -β-Ocimene, γ-Terpinene, terpinen-4-ol, cis-Sabinene hydrate, α-Terpinolene, 4aβ, 7α, 7aα-nepetalactone and 4aα, 7α, 7aβ-nepetalactone had significant differences at 95% level in growing and flowering phases, and 8 habitats.The active substances of 1, 8-Cineole, cis-Sabinene hydrate, trans-Caryophyllene and Limonene had most of amount in the growing phase and the Rose furan epoxide, 4 aβ, 7α, 7aα-nepetalactone, α-Pinene, cis-Linalool oxide, α -Terpinolene in the flowering phase.Eelectrical conductivity, potassium, sand and elevation from sea level among environmental factors,had more effects in flowering phase. Scine, Thghiabad and Dehbala habitats had better situations of environmental factors and the essential oil are recommended to ude from the species of these habitats for reclamation of regions with similar environmental factors. Also these habitats were determined as the optimal habitats for this species in Yazd province.