Abstract
The purpose of this study was to determine the effects of altitude, slope, aspect and topographic index on life forms and total net primary production (NPP) in mountains meadows in Fandoghlou in Namin county in Ardabil province. NPP in three altitude, slope, topographic index classes and four aspect classes was estimated using one m2 plots (totally 180 plots) by harvesting and weighting method. Correlation between life forms and total NPP with topographic factors were analyzed using stepwise multivariate regression method and using derived regression equations, the maps of NPP were derived. Results show that different topographic factors has significant effects on forbs (p<0.01) and grasses (p<0.01), however on total NPP have no significant effects. The highest NPP of forbs (1584/1 Kg/ha) and total NPP (2339/3 Kg/ha) were observed in the second altitude (1525-1564 m) but has no significant effect on grasses. The NPP of grasses show direct relationship with slope, however the NPP of forbs were decreased with the increase of slope and has no significant effect on total NPP. The highest amount of grasses (894/3 kg/ha) and forbs (1875/5 Kg/ha) were observed in the south and northwest aspect, respectively. According to the various classes of topographic index, the maximum amount of grasses (853/4 Kg/ha) were observed in the first classes and the highest NPP of forbs (1568/6 Kg/ha) on the third classes. The results of this study can be used to balance the amount of biomass, carbon, the supply and demand of and to plan for proper rangeland management.
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