Analyzing Flora and the Impact of Topographic Factors on the Changes in Plant Vegetation in Jahannama Protected Area (Saraliabad Rangelands)

A fundamental base inthe ecology of plant societies is that the plant species separately respond to the environmental gradients anddepending on the habitat conditions, the ecological requirements of the plants and their tolerance range can vary. In order to identify the relation between plant vegetation parameters and the environmental and edaphic elements, some parts of the protected area of Jahannama in Saraliabad rangelands in Gorgan were examined. One meter square plots were randomly established through field experiments and ten R plots were used for measuring tree altitude in the fields. The percent of canopy and topographic factors (slope, direction, &altitude) were considered as dependent and independent variables in each plot, respectively. Afterwards, soil samples were collected from each region for edphic analysis as independent variable. The most effective factors on percent of canopy of plant vegetation were determined using multivariate stepwise regression analysis. The results indicated that the physical rather than the soil factors associated with altitude, slop, and direction significantly contributed to the distribution of plant vegetation (P<0.05). The relation between the physical factors and the percent of canopy the dominant species indicated that Juniperussabina, Cousiniaglaucopsisreversely correlated with altitude and slope while Festucaovina positively correlated with these factors. No Association was found betweenOnobrychiscornataand heightwhereas it significantly and negatively correlated withslope percent. Canopy percent inJuniperusSabina, Festucaovina,and Cousiniaglaucopsis decreasedwith soil acidification and positively correlated with the electrical conductivity of soil. In addition, canopy percent of JuniperusSabina, Onobrychiscornata, and Cousiniaglaucopsis increased as the soil got rocky but Festucaovina decreased with an increase in the percent of sand in the soil. With an increase in the effective depth of soil, the canopy percent of JuniperusSabina increased. InOnobrychiscornata and Juniperuscommunis, the canopy percent increased up to 75cm soil depth but decreased in deeper levels of soil.