NATURAL ECOSYSTEMS OF IRAN
Year:2012 | Volume:2 | Issue:3|Papers Count:9

For achievement to sustainable development and conservation of natural ecosystems and their biodiversity, study on ecological factors and their effects is necessary. Regarding to topographical condition of northern forests of Iran, altitudinal gradient is an important ecological factor controlling many other dependant variables. In order to, 66 sample plots with 400 m2 were selected in Golband forests of Nowshahr. Sample plots were taken from 100-2200m altitudes in north aspect with 20 - 40 % slope. Tree species with diameter more than 7.5 cm (dbh) as well as herbal species and regeneration density (in five micro plots per plot) were recorded. Homogenous and heterogeneous in general which indices you used for analyses in your work were calculated. Analysis of variance carried out for all of studied indices. Diversity and richness indices showed significant difference. In relation regeneration (more than 1.30m), Sheldon evenness index showed significant difference. Regeneration biodiversity showed that diversity and richness indices had significantly differences as the maximum and minimum were detected in 500m and 2200m altitude, respectively. ANOVA for biodiversity indices in relation to herbal layer showed that Menhennic richness index showed significant difference. Furthermore, Simpson and Shannon diversity indices and Margalef richness index also showed Sheldon evenness index had not significant differences.

this study aims at determining the best shape of sample plot for natural regenerations investigation of Oriental Beech in Nowshahr Kheiroudkenar forest. Eight compartments were selected in Namkhaneh district for carrying out of this study. A 150×200 m grid was planed and was laid out on topographic map. According to the extent of study area (299.4 ha) and the dimensions of the grid, 94 sample points were obtained. Each of these points is studied with four sample shapes: First; circular shape with area of 75 m2, Second; rectangular shape with area of 75 m2, Third; cluster shape with three units, each with area of 25 m2, Fourth; cluster shape with five units, each with area of 15 m2. After ground control of sample points in the field, four mentioned shapes were established and regenerations with less than 1.3 m height in the plots were counted. By the way, starting and ending time of sampling in each shape were recorded to compare the time of four shapes establishment. After data collection for each shape, the term E%2×T was calculated separately and used as a comparative criterion. On the basis of conclusions of this study, cluster shape with three units had the lowest E% and circular shape had the lowest (90356) E%2×T.

Species in different places and times, have different forage quality. In this study, the quality of pasture forage species in pastures Valley Martyrs Gaium verum branch at vegetative stage, flowering and seed image and height (1800>, 1800-1600, 1600-1400) were studied. The height of each floor and each phenological stage, three replicates of each species were randomly sampled. Qualitative factors include: Crude protein, ADF, Digestion-taking and Energy metabolism were measured in the laboratory and then using the mean variance analysis and duncan test were compared with data in SPSS. The results showed the forage quality of three-story height in the active growth stage than other stages. Also affect the values of the height factor ADF, DMD and ME different phenological stages, but not in the active growth phase decreases with increasing height, crude protein in the highest elevation in the class of 1600-1400 to 12.083% and lowest in the class of 1800<the value 9.7% percent were That the height of the crude protein in this species is. The results can be stated temporal and spatial planning, which at various heights be the maximum sustainable utilization of rangeland forage quality, pressure and prevent damage to pastures. This is a palatable species and the vegetative growth period was suitable for livestock chra’ without flowering and seed damage is not.

The quantitative and quantitative comparison natural zelkova were studied in pure and mixed stands in Ghormarez region at Neka forests. To the end, samplings were evaluated in the thorough plan region. The survey of refreshing of natural life in surface of each one hectare stands 10 micro plots, 49 m2 in dimensions of 7*7 was selected with systematic-random method and then was connected in each microplot of the entire seedling from natural beech. In This research, at first quantitative characteristics of Zelkova were studied in pure and mixed stands and then in both quantitative and quantitative stands. The results showed that quantitative characteristics such as DbH, height, basal area and volume of tree were significantly different between pure and mixed stands of Zelkova. Further, these characteristic between pure and mixed stands showed significant difference, so That the pure stand was in better condition than mixed stand. The average of natural beech of sampling on the surface of micro plots didn’t show significant difference between two stands, whereas the average number of counted samplings in surface of mixed stand was more than that of pure stands.

Mazandaran province with an area about 584711 hectares has 1374572 animal unit that its rangelands are under overgrazing (exceeded 287582 A.U). From experts point of view current stocking rate is 2 to 3 times more than which have to be. The grazing management is so much important to solve the problems and reach to livestock-range equivalence. In this research as a comprehensive and analytic one, 43 employed experts in the natural resource administration were the sample determined by Cochran equation. The results have shown that %97 of these experts had a relation with the project directly and indirectly. Experts suggested that brother’s corporation and experts’ assessment have an important role in project's success. The highest mean among indices were respectively, overgrazing (4.76), unknown tenure (3.57), brothers number (3.35), competitive exploitation (3.19) and heavy stocking rate (3.02).

Furrow infiltration plays a major role in the simulation, design, evaluation, and management of furrow irrigation. Infiltration depends on initial soil water content (ISWC) and previous soil wetting. However, the effects of these variables were not considered on furrow infiltration equations. Accordingly, the objective of present study was to investigate and quantify the variability of cumulative infiltration versus opportunity time, ISWC and irrigation events. The field experiments were conducted during in an experimental field located at the agricultural research station of Tabriz University, Iran. Furrow infiltration was measured by blocked furrow infiltrometers under continuous flow in the first to fifth irrigation events. The results indicated that cumulative infiltration increased with increase of time in the first and second irrigation events, when the ISWC kept constant during irrigation events. During irrigation events, cumulative infiltration increased with decrease of ISWC and increase of time. Average k decreased when the irrigation events increased. There is not difference between k values from third to fifth irrigation events. In the present study, by using a regression procedure a model was developed to relate k values from different events and soil moisture content to the first irrigation with moisture as wilting point. This model can be used to design or management of furrow irrigation.

Mass motion has always been a problem as a natural disaster. Studying effective factors in beginning earthquake and recognition of potential areas is an important step for the management of natural resources and to get to a stable development (shad far, 2009) in the study, two thousand area in Mazandaran and in southern part of Tonekabon city that has about 308\75 kms wide. Has been selected. At first, after studying resources and scientific findings, research designs, some of the important factors in beginning mass motion in the area such as: night classes, steep ward steep, land use has been recognized, and using GIS software prepared. also physics experiments chemical and soil mechanic was conducted for evaluating the role of soil in beginning mass motion the results of the study showed that considering sandstorm of soil area and a little amount of SPT and whereas soil of the area is a little lime or non-lime and being attached the sort of soil in all layers especially lower layers and lack of salt and PH of soil as well as the type of soil texture that often is clay and causing mass motion and earth quake in the area.

From Longley, the various equations for determining the runoff to water management are presented by the researchers that are widely used in hydrologic sciences. In this study by using observational data, was an evaluated empirical, artificial neural network (ANN) model in estimation of runoff coefficient. The study area was Bar Ariyeh Neishabour watershed. The data of 33 flood events during 1952 to 2006 were collected. Among Characteristics from precipitation hytographs as model input variables were extracted include The average intensity of rainfall, average rainfall, 1 to 4rd quartiles of rainfall, 1 to 4rd quartiles intensity of rainfall, total precipitation of five days before, the index ϕ. Therefore, using these parameters and different combinations in the input layer network, different networks were implemented. Artificial neural network is used learning algorithm with Levenberg-Marqwart and Hyperbolic tangant trained and performed with various inputs. The results showed, network with 1 to 4rd quartiles intensity of rainfall, average rainfall, time of rainfall, total precipitation of five days before and ϕ index as input layer with Hyperbolic tangant transfer function could predict storm runoff coefficient with determination coefficient 0.98 and the Root Mean Squared Error 0.0337 and Mean Absolute Error 0.0275.

Given the grawing trend of dagraded rangelands, provide solutions to prevent damage to pasture is necessary and vzrvry. That one of these strategies is planning from experts and government to increase participation of rangers in range projects. This research based on field studies and documents has been conducted in the lar,s watershed. The study population consisted of experts of range management that based on first sampling 35 experts answered to questionnaires. The data analysis method used is descriptive, and inferential statistics. That in inferential statistics was used multiple regression and spearman correlation coefficient. The results of correlation between researches, s variables showed that relationship between educations, history of range management, quality of range, economic barriers and administrative barriers, with the dependent variables of participation in range, s projects is significant. Tha results of multiple regression showed that variables of education, history of range management and quality of range have possitive role and economic barriers and administrative barriers have reverse role in participation rate of rangers in plans of range.