environmental factors

Habitat Suitability Index modeling (HSI) is a valuable tool in ecology that can be used to describe the relationship between abundance and environmental variables to evaluate the suitability of habitats. In this study, the habitat preference of Garra rezai was done using the kernel smoothing method in the Little Zab River in the four seasons of 2022. For this purpose, sampling was done from 6 stations with 3 repetitions, and environmental factors, including temperature, slope, water flow velocity, river width, water depth, altitude, pH, electrical conductivity (EC), and total dissolved substances (TDS) were measured and recorded at each station. The results showed that the preferred areas of this species in spring are those habitats with high pH, ​​high temperature, low TDS, medium EC, high altitude, medium water velocity, medium depth, large river width, and low slope. The most preferred areas in the summer have high pH, ​​high temperature, low TDS, medium EC, higher altitude, low depth, medium river width, higher water velocity, and medium slope. The results of the autumn season revealed that the preferred areas have high pH, ​​lower temperature, low TDS, medium EC, high altitude, medium depth, medium river width, high water velocity, and medium slope. In the winter, it was also found that the preferred areas of this species have higher pH, medium TDS, high EC, high altitude, medium depth, high river width, medium water velocity, and low slope. Akaike information criterion values ​​were obtained based on four arithmetic, geometric, maximum, and minimum methods for four seasons, and the results showed that the maximum method was the best. In conclusion, this species had almost different habitat preferences during different seasons, but these changes are due to changes in temperature and hydrological parameters of the river to adapt to its biological needs.

 Seseli olivieri (Apiaceae) is an exclusive species of the Alborz Mountains, Iran. In this research, the effect of environmental conditions on the vegetative traits and essential oil compounds of this species was investigated. For this purpose, three habitats with different heights were selected and the vegetative characteristics of this species were measured. In each habitat, soil samples and flowering branches of this species were collected and analyzed in the laboratory. The relationship between the functional traits of this species and environmental factors was determined using CA and PCA. Variance analysis of functional traits and soil parameters showed a significant difference between the three habitats. The highest values of vegetative traits were related to Tuyeh habitat. In Tange Kavard habitat, the main effective substances were Apiol and cis-Cadina-1(6),4-diene; in Enzo habitat, Apiol and Bornyl acetate; and in the Tuyeh habitat, Bornyl acetate and α-Pinene. Among the environmental factors, altitude, annual precipitation, annual temperature, minimum temperature of the coldest month, minimum absolute temperature, lime and nitrogen had the most significant correlation with the functional traits of this plant. Based on the IUCN criteria, the conservation status of this species was determined in the critically endangered.

Rangeland ecosystems provide diverse services to human societies and have the highest income and profit when they are planned and managed for several types of appropriate exploitation (multipurpose use). rangelands, in addition to their role as conservation value, resort, fodder production, environment, genetic resource, etc., have a special place in terms of production of medicinal and industrial plants. These plants have a special value and are exploited directly (main products) or indirectly (by-products). For the comprehensive and correct study and management of any phenomenon, we must have a complete knowledge of its components and a correct understanding of their relationships with each other. The ecosystem and especially the grassland ecosystems are not exempted from this rule. The growth and performance of plants in pasture ecosystems are influenced by various factors such as species, regional climate, soil environment, altitude above sea level, and geographical location. These factors also affect the quantity and quality of plant products. Considering the influence of climate and soil parameters on the quantity and quality of medicinal plant essential oil, in this research, an attempt has been made to investigate the effect of environmental factors on the quantity and quality of essential oil of Stachys lavandulifolia species in two directions, north and south, in the Gardane-Sar Swadkoh pasture area.

Area of study Gardnesar rangeland habitat located in Sawadkuh city is one of Mazandaran province apart from summer rangeland and is located in geographical coordinates 66◦26´31⸗ to 65◦91´32⸗ east longitude and 39◦95´74⸗ to 39◦94´47⸗ north latitude. According to the data received from the closest meteorological station to the region (Alasht), the total annual precipitation is 377.89 mm and the average annual temperature is around 12.35 degrees Celsius.

Plant and soil sampling:

In order to quantitatively and qualitatively evaluate the desired plant in the region, the aerial organs of the adult plant were collected in full flowering season. According to the patchy distribution of the plant in the field, random sampling was done in three selected spots with three repetitions in the north and south directions in the region. Also, to determine soil characteristics, soil samples were taken from the depth of 0 to 30 cm at the base of the plant. Finally, all the plant and soil samples were transferred to the medicinal plant laboratory and the soil science laboratory of Sari University of Agricultural Sciences and Natural Resources to perform the desired tests. The physical and chemical properties of soil were measured based on existing recipes.

Extraction and decomposition of essential oil:

After cleaning, the plant samples were dried in the open air in the shade environment. 100 grams of each dried sample was extracted by the clevenger Apparatusin in the central laboratory of Sari University of Agricultural Sciences and Natural Resources by distillation with water for 3 hours. Then it was dehydrated by sodium sulfate anhydride and it was stored in a glass container with a lid in the refrigerator at a temperature of 4 degrees Celsius until injection into the chromatography devices. The resulting essential oil was obtained by injecting into a gas chromatograph connected to a mass spectrometer (GC/MS).Also, the percentage of essential compounds of each compound was calculated. In this research, the most important compounds in the essential oil were reported with a probability of more than 95%.

Statistical Analysis:

In order to analyze the quantitative and qualitative data of soil and essential oil, the normality of the data was first checked with the Kolmograph-Smirnov test. Then the comparison of plant chemical compounds and soil quality indicators in the two northern and southern slopes was done using the independent T-student test by Spss version 22 software. Finally, in order to analyze the relationship between plant chemical composition data, soil quality indicators and climate data, principal component analysis (PCA) method was used in PC ord5 software.

Conclution:

The result of measuring the yield of essential oil in Gardne Sar rangeland showed that the southern slope had a higher percentage of efficiency in the amount of essential oil than the northern slope. The data obtained from the determination of essential oil compounds indicate that a total of 35 important compounds were found with a probability of more than 95% in the essential oil obtained from plant samples in two domains. among the extracted compounds, compounds of Caryophyllene, α-Pinene, β-Pinene, Myrcene, Linalool, α.-Terpineol, Cyclohexasiloxane, dodecamethyl, Stigmasterol Limonene, Fenchene, α-phellandrene, 7-(1-methyl-ethyl) azulene , Cyclofenchene, Terpinene -4-acetate, p-cymene, Bicyclo, 2-isopropyl, Cis-farnesol, β,-Bisabolene, cis-sabinene hydrate, 1-8-Cineole and Camphene showed a significant difference at the level of one percent in two domains They showed themselves.On the other hand, Spathulenol (CAS), β phellandrene, Phytol and bicycle germacrene compounds had a significant difference at the 5% level. While the compounds α.-Copaene, α-Thujene, Germacrene D, Comphene, Cyclohexanol, 5-methyl-2-(1-meth..., γ-cadinene, Hexadecanoic acid, Sabinene, beta.-Myrcene and Heptacosane with differences in The average value did not show a significant difference.The measurement of the physical characteristics of the soil in the region showed that the northern slope and the southern slope are not the same in terms of soil texture, so the texture type in the northern slope is loamy and in the southern slope sandy-loamy, and the two slopes are significantly different in terms of the amount of sand and clay. (p≤0.01). Also, the northern slope showed a higher humidity percentage than the southern slope (p≤0.05). This is while the factors of silt, bulk density and soil stability index have not shown significant differences despite the difference in the average value.The examination of soil chemical factors in the northern and southern slopes indicates that the amount of phosphorus, magnesium, sodium and lime showed a significant difference at the level of 1% and organic matter and nitrogen showed a significant difference at the level of 5%. While soil acidity, electrical conductivity, potassium, and calcium had no significant difference. In general, the results of the analysis of the main components in relation to environmental factors and essential oil compounds showed that the northern and southern ranges are completely different in terms of the measured factors and are placed in two completely separate groups. So that the aforementioned factors justify 82.24% of the total variance changes. Meanwhile, the northern range with the factors of organic matter, rainfall, electrical conductivity, acidity, soil moisture, sodium, silt and compounds α-Pinene, α-Thujene, β-Pinene, Cyclohexanol, 5-methyl., bicycle germacrene, Hexadecanoic acid, Cis-farnesol, cis-sabinene hydrate and the southern domain have established more relationships with nitrogen variables, apparent specific gravity, calcium and compounds α-Copaene, Phytol, Comphene, γ-cadinene, 7-(1-methyl-ethyl) azulene, bicycle germacrene, Heptacosane. In general, according to the obtained data, it can be concluded that the mountain tea plant has a suitable habitat for production in areas with loam texture and suitable rainfall along with soils rich in nutrients. Also, the results obtained from this research compared to the results of other researchers indicate that the quantitative and qualitative performance of the essential oil of Stachys lavandulifolia can be different in different regions.

Coral reefs in environments with unique environmental circumstances show how corals might adapt to future stressors and possible climate change. The Persian Gulf and the Gulf of Oman are environmentally unique places with little information on the inherent diversity of key environmental variables (such as temperature, chlorophyll a, and carotenoids) that affect soft corals, or how this diversity leads to allergies and death due to environmental factors, no. The research presented here addresses this knowledge gap and examines sea level temperature, pH, DO and salinity factors, chlorophyll a, and carotenoids to reveal differences between the Persian Gulf and the Gulf of Oman.

Environmental factors were measured by an HQ40D portable multimeter with the ability to record some environmental parameters. A sampling of Stichodactyla haddoni anemone was performed in two seasons of summer and winter from three stations including: Qeshm Island, Dukohak Station, Hormoz Island, Khezr Station, and Chabahar Bay, Tis Station.

Due to the normal range of pH, DO and salinity factors, they did not show a statistically significant correlation with any of the evaluated parameters (P <0.05). The highest amount of chlorophyll a and total carotenoids was observed in the colored sample of sea anemone (brown) of Chabahar. The lowest amount of chlorophyll a and carotenoids belonged to the summer sample of Qeshm. Chlorophyll c levels in the samples did not differ significantly by station or season. Thermal map of physicochemical relationships with Symbiodinium sp. pigments in summer showed that the highest correlation of pigments related to dissolved oxygen percentage, temperature, and salinity, and in winter thermal map showed that salinity, dissolved oxygen percentage, and temperature had the greatest effect on pigments, especially It had chlorophyll a and carotenoids.

The Results' section of the study of zooxanthella pigments in symbiosis with sea anemones showed an increase in pigments between study stations both in summer and winter. Monsoon winds, which change water temperatures, maybe to responsible for the increase of symbiotic dinoflagellate pigment in Chabahar Bay station throughout the summer. The obtained results indicate that chlorophyll c is resistant to environmental and season conditions.

Global warming is an important phenomenon with many effects on the environment, which is associated with an increase in greenhouse gases such as carbon dioxide, methane and other gases. Accumulation of greenhouse gases, increase or decrease in temperature, and change in rainfall all affect the distribution of plant pathogens and the incidence of disease. On the other hand, by affecting the carriers of pathogens, climate change can cause them to disperse in a wide area or cause pathogens to enter new areas. On the other hand, the effect of global warming on plants is different and diverse depending on the plant species and its pathogens and according to different environmental conditions. These effects can be harmful, positive or neutral. However, according to the pathogenicity triangle, one of the central mainstays of the disease rate is environmental conditions; therefore, plant diseases are strongly affected by the environment; if a sensitive host is placed in unfavorable conditions, it will not be infected by an invasive pathogen. Based on the conducted research, temperature changes in the environment cause the emergence of new diseases and the spread or limitation of diseases. This article discusses the essential effects of global warming on the occurrence and spread of plant diseases in new areas.

This research aimed to determine the most important environment factors affecting morphological distribution of Salvia hydrangea DC. ex Benth in protected region of Tang-e-sayad of Chaharmahal and Bakhtiari Province. This species is one of the medicinal and aromatic plants found in the natural habitats of mountainous areas of the country and contains essential oil of leafs and flowers. To measure morphological characteristics were taken 10 sample of S.hydrangea in each populations (5 plant stands). Leaf, sepal and corolla length and surface, flower stem and panicle inflorescence height and flower number of each panicle inflorescence were studied at the end of the growing season. In each plant populations, 2 soil sampling were executed of two depths 0-15 and 15-30 cm. Some soil parameters including texture, electrical conductivity, acidity, nitrogen, potassium and phosphorus were measured. The average comparison results showed that there was a significant difference between the populations in terms of most traits. PLS analysis results also showed plant height had a positive correlation with apparent specific weight of first depth and had a negative correlation with the soil acidity of first depth. The flowers number in cycle and sepal surface had a positive correlation with slope, gravel, sand and calcium carbonate equivalent (CCE) of second depth. Panicle inflorescence height had a positive correlation with clay, EC and potassium. Leaf length and surface had a positive correlation with slope, sand, CCE and gravel of second depth. The analysis results can determine effective environmental factors on each morphological specification of the species.

The present study was conducted to investigate the effects of physical factors on the diversity of species of Carabidae (Coleoptera: Carabidae) in three regions of Karaj, Eshtehard, and Taleghan, Alborz province. To this end, during 2015-2016, sampling was carried out using pitfall traps and physical factors. In this regard, the elevation, slope, direction, precipitation, temperature, soil texture, grain size of soil, and percentage of vegetation were recorded in each studied station. Based on the results, in total, 329 specimens including 38 species were identified in the three studied areas. Pearson and Spearman tests were used to investigate the relationships between the species diversity index (Shannon's Diversity Index) and the studied factors. Also, the effect of habitat physical parameters on the diversity of the species of Carabidae in the studied areas was analyzed using Canonical Correspondence Analysis (CCA). The results of the study showed that no significant relationship between the Shannon-Wiener Index and studied parameters (P<0.05). Species diversity was affected by temperature, the three parameters of altitude, soil texture, and grain size of soil, and the four parameters of direction, slope, precipitation, and vegetation percentage in Karaj, Eshtehard, and Taleghan, respectively.

Sex control is one of the most important factors in the commercialization and efficient proliferation of fish species which affects reproduction, growth and product quality. A balanced sex ratio is more important for broodstock management, as it helps to develop a suitable breeding program. However, the production of monosex populations is desirable in some species because the existence of sexual dimorphism can make one sex more valuable due to the effect on growth or first time of sexual maturation, even in color or shape. Sex in fish is influenced by genetic and environmental factors. Unlike mammals and birds, with highly conserved major genes through a specific genetic network responsible for gonad differentiation, various sex determination mechanisms have been reported in fish. Currently, six different major genes (dmY, gsdf, amhy, amhr2, sdY and sox3) reported to be involved in fish sex determination. The most common environmental factor is temperature, which affects the regulation of the expression of genes involved in gonad development. The aim of this paper was to review the genetic and environmental factors affecting fish sex along with the application of sex control in commercial species.

The purpose of this study was to investigate the population of benthic invertebrates and their relationship with environmental factors of Gorgan Bay Inlet. The abundance of benthic invertebrates during 2017 in three seasons from 9 stations in three sites, bay mouth, Ashuradeh coast and sturgeon culture area was studied using three replicates (225 cm2). In this study, in total, fauna was identified: 3 phyla, 6 classes, 12 families and 12 Genus. Streblospio gynobranchiata (2347±177, 47%) and Hediste diversicolor (873±101, 17%) had the highest abundance. The highest species abundance was observed in spring and the lowest species abundance in autumn. The lowest Shannon (1.12) and Pielu index (0.62) were obtained in the sturgeon culture area. Also, the dbRDA graph based on DistLM model showed that temperature, salinity and clay temperature variables and sand, silt and dissolved oxygen variables were responsible for causing abundance of fauna among different stations in the sampling seasons. According to these results, it can be concluded that macrobenthos in different seasons and areas have many changes in abundance and diversity index. Therefore, when using these communities to assess the impact of environmental factors, their natural changes should be considered.

Vegetation distribution modeling, as a tool that uses statistical methods and GIS, plays an important role in examining the complex relationships between plant community distribution and influential environmental variables. These models are based on data on the presence and absence of species and their correlation with environmental variables and on the hypothesis that environmental factors control the distribution of plant species. One of the objectives of this study was to present a model for predicting the habitat distribution of plant species and to prepare a map for predicting their relative distribution by the logistic regression method. In this study, random sampling method was used to sample vegetation and soil in Molla Fahleh watershed area of Firoozabad, Fars province,. At each sampling point, 4 soil samples were taken from two depths of 0-15 and 15-30 cm. Soil physical and chemical parameters along with physiographic factors (slope, slope direction and elevation) were recorded for each sample. Habitat distribution modeling was performed by logistic regression method using SPSS software for major plant species in the region. According to the results, soil texture, organic matter, clay content, lime content, acidity, slope and height have the underlying role in the distribution of the studied species. The results show that the logistic regression method is able to provide an accurate prediction model most of the plant species in the area.

Effect of temperature, irradiance and photoperiod on biomass and the alginate content of Sargassum boveanum was evaluated for 42 days under laboratory conditions. The seaweed samples were collected from coast lines of Bandae-e-Lengeh in Hormozgan province (South of Iran) in June 2009. The algae were suspended in aquariums,40.30.60 cm (20 litter) in 3 replicates. The algae were cultured under temperatures gradients ( 15,20 and 25 ºC ), irradiances levels (4700,5700 and 6700 Lux) and three photoperiods (12;12, 14;10 and 16:8 hours, Light:Dark) . The algae were weighted once a week . After 6 weeks of experiments, the algae were collected, dried and weighed. The highest biomass of S. boveanum was obtained at 25° c (48.12 gr.) ,4700 Lux (42.48 gr) 12:12, light: dark (34 gr). Maximum content of alginate (29.67%) was extracted in temperature of 25 ºC. As the results showed, mariculture of this algae should done in spring with optimum of temperature and photoperiod. The alginate content of S. boveanum in this project is high in compare with the other studies.

Today, a considerable amount of Zagros forests is faced with the phenomenon of oak decline. Environmental stresses have caused the weakness of the trees, imbalance in food and water absorption, and eventually the deterioration of trees. Site factors play an important role in the resistance of trees to biotic and abiotic stresses. This research was conducted to evaluate the reaction of health and non-health Brant`s oak (Quercus brantii Lindl.) trees to nutrients absorption in different aspects and elevations in the Helen forest of Chaharmahal & Bakhtiari province. Three transects were considered in two main aspects (North and South) of the study area. On each transect, three plots (with an area of 1000 m2) were designed in three elevation levels (800-1500, 1800-2000, and above 2000m a.s.l) randomly. Leaves of five health and non-health trees were gathered to measure the nutrient elements. This research was conducted as a factorial experiment in randomized complete block design and the mean values of variables were compared using Duncan test. The results showed that the effect of geographical aspects was significant on N and Ca uptake. Also, the difference in the absorption of essential nutrients in leaves of health and non-health oak trees were significant. The absorption of Fe, Mn, Zn and Cu in the leaves of the trees in the northern aspects was higher than the southern aspects. Health trees also absorbed more of these elements compared to non-health trees.

In order to study the effects of some environmental factors on quality and quantity of fennel essential oil, an experiment was conducted at 3 stations of Agricultural and Natural Resource Research Center of Isfahan during 2012- 2013 and 4 superior fennel genotypes (including: Lorestan, Hamedan, P11- 820065 and 11486) were studied basis of randomized complete block design with three replications. Base on the results the interaction of place* genotype was significant for all traits. a-pinene, fenchone, camphor and (z)- anethol in forien genotypes and p-cymene, limonene, estragole and (e)-anethol in native genotypes were the highest. The maximum essential oil belongs to P11-820065 with 4.21 percentage. The highest essential oil yield (165.2 Kg/hec) was observed in P11-820065 located in Golpayeghan and the lowest in Hamedan genotype (60.4 Kg/hec) of Kashan. (E)-anethol yield of hamedan Genotype in Golpayeghan station had a significant different with Kashan station. The minimum amount of (e)-anethol was observed in 11486 (41/1 %) located in Kashan. There was a negative significant correlation between e- anethol and soil total N. Also a negative significant correlation was observed between oil percentage and oil yield with soil salinity. On the other hand phencone and soil salinity had a positive significant correlation. There was no significant correlation between essential oil and environmental factors in Golpayegan station.

Ilam province is one of the natural habitats of wild pear (Pyrus syriaca Boiss) in Iran. Fruit harvesting, inappropriate grazing forest areas, deforestation and agricultural development in recent years has endangered the existence of the species. In this study, the major habitats of the species in Ilam province, which located in the forest area of Zardalan in the north eastern city of Chardavol in Ilam province, is studied. After specifying the study area on the map 1:50000, using desired parameters, the maps of slope, aspect and elevation were prepared and then by combined together, work units were determined. In each unit, according to its area, at least three random circular sample plots with area of 1000 m2 randomly settled and environmental characteristics such as slope, aspect, elevation, geographical longitude and latitude were determined. Then all the qualitative and quantitative parameters of wild pear were measured and recorded in the plots. The results showed that wild pear in intermediate slopes (15 to 30 percent) have the highest height and diameter at breast height. It was observed that, in point of health crown, crown shape and trunk quality, north aspects for wild pear are the best conditions. The findings also showed that the best trunk quality is at altitude between (1500 to 1750m), but no significant correlation between altitude and other qualitative and quantitative variables of wild pear was found.

Arbuscular mycorrhizal fungi (AMF) are one of the most symbiotic in nature that has forced many benefits, including the absorption of water and nutrients in host plants. The purpose of this study was to investigate the relationship between AMF associated with Crataegus pontica and environmental factors. For this purpose, 54 samples of soil and root were collected from a depth of 0-30 cm. Soil samples for extraction and identification of fungi and physico-chemical properties (soil texture, bulk density, thickness of the litter, pH, EC, potassium, phosphorus, organic matter, nitrogen) were transferred to the laboratory. The results showed that 13 species of AMF species associated with Crataegus pontica trees. Claroideoglomus etunicatum and Glomus caesaris were the most and Acaulospora thomii and Entrophospora infrequens were the least species. Also, the results showed that the frequency of fungal spores in the Dinarkoh habitat were more than Arghavan habitat. Furthermore, there are significant correlation between root colonization, spore frequency and soil potassium and pH. The results of principal component analysis showed that there are significant correlation between colonization and spore density and soil potassium and litter thickness.

The survey of the ecological and morphological characteristics of medicinal plants is one of the essential requirements for multipurpose use of rangelands. Accordingly, the ecological and morphological characteristics of Ephedra procera were investigated in the mountain rangelands of Urmia. For this end, regarding to the physical and vegetation characteristics; three habitats representing a wide range of areas of E. procera distribution region were selected. Then, the data inventory was conducted within 30 two square meters plots established on transects along 100-meter with distances of 10 meters apart and the morphological characteristics and amount of forage production were measured. To study the relation between distribution of vegetation and soil characteristics, soil samples were taken with three replications along transects. The results showed that the morphological characteristics of Ephedra and soil physical and chemical properties in study sites; are significantly different among the sites. Analysis of variance linear regression equation between forage production of Ephedra with morphological characteristics indicates a significant relationship between forage production and number of plant shoots. The results of studying the relationships vegetation distribution with environmental factors showed that the influence of environmental variables on vegetation is significant which accordingly the factors such as slope, temperature, aspect, porosity, sand, elevation from sea level, percent of gravel, bulk density and electrical conductivity are of the most important factors affecting the distribution of Ephedra species. The results can be used in planning the protection and restoration practices of Ephedra in natural habitats.

In this study, total phenolic content, flavonoids, anthocyanin, tannins and ferulic acid of latex of Ferula assa-foetida L. were investigated in some pastures of Kerman province (Chatroud, Hossein Abad, Keshtuiyeh, Joopar and Sarduieh). The essential oil used in this study was extracted by hydro-distillation from the latex of the plant. The results of the essential oil analysis by Gas chromatography– mass spectrometry (GC-MS) indicated that a total of 51 components were identified in the essential oil. The major compounds in the total regions were included: (E)-1-propenyl sec-butyl disulfide, n-propyl sec-butyl disulfide, (Z)- β-ocimene and β-pinene. Comparison of effective components concentrations of latexs showed that the highest total phenolic content and acid ferulic was observed in Chatroud. The highest tannin content in Keshtuiyeh and the highest anthocyanins content in Sarduieh were obtained. Correlation of these compounds and environmental factors showed that there was a negative correlation between the average altitude and the content of tannins but significant and positive correlation at the 5% level between the average altitude and total phenolics (and ferulic acid) was observed. Keshtuiyeh showed the best quality of essential oil by heighest rate of sulfide compounds.

Rotifers are microscopic aquatic animals of phylum Rotifera, live in a diverse range of aquatic habitats. They are important in ecology of freshwater ecosystems by recycling nutrients and can alter trophic dynamic of planktonic communities. These features have also been used to infer environmental conditions in an aquatic habitat. Because of the important roles of this group of animals in the trophic chains of aquatic environments and the need for discovering their biodiversity, this study was planned to analyze the patterns of rotifer community structure in response to temporal fluctuations in environmental variables in two water bodies in northwest Iran. Samples were collected seasonally between October 2014 and November 2015. Temperature, pH, DO, conductivity, salinity and rotifer abundance were measured. In total, 28 rotifer species belong to 10 families of phylum Rotifera were identified. Canonical correspondence analysis (CCA) was used to estimate the relationship between environmental variables and biodiversity of rotifer taxa. The clusters showed strong correlation with dissolved oxygen and electrical conductivity for shaping the rotifer assemblages in both reservoirs.

Water mint grows widely in Northern provinces of Iran. Plant shoots and soil samples have been collected before flowering phase from four different sites, east to the west of the province including Sari, Babol, Nowshahr and Tonekabon in the spring season 2013 in three replications. Essential oil extraction was carried out by hydro distillation method with Clevenger apparatus and essential oil yield has been calculated in different localities. Isolation and identification of the essential oil components have been carried out with Gass Cromatography (GC) and GC/MS. Soil features including elements amount, acidity (pH) and electrical conductivity (EC) have been measured. Data analysis has been carried out with SAS software ver. 9.1. The results indicated that the essential oil yield based on dry plant weight was between 0.254% in Sari (east of the province) to 0.474% in Nowshahr (west of the province). The number of essential oil components showed a reverse trend in which the oil of Nowshahr consisted of the least components (26 components) and the oil of the Sari composed of the most (34 components). The most characteristic constituents of the oils were menthofuran, trans-caryophyllene, Eucalyptol, Germacrene- D and viridiflorol. The results of the soil experiments showed that decreasing of the soil pH and EC, increasing in N, P and soil organic and nutrient elements and more precipitation in the west of the province resulted in more oil yield but increasing of the soil pH and EC in the east leads to more components of the oil.