Variability in frnpp, defined as the fraction of root net primary productivity (RNPP) to total net primary productivity (TNPP) [above-ground net primary productivity (ANPP) + RNPP] were examined through synthesis of 40 samples from available field biomass data assessed by in-growth core and obtained at 13 grassland sites situated in different altitudes in the Czech and Slovak Republics. Results indicate that frnpp varied from 0.05 to 0.59 across the compared sites. Submontane wet meadows had larger frnpp and dry lowland grasslands had smaller frnpp However, extreme conditions of mountain sites were reflected in a decrease of frnpp. Thus the relationship between values of frnpp at different sites and altitudes was indicated by quadratic regression with the highest frnpp coefficients in middle altitudes, where there were sufficient amounts of precipitation together with not so extremely cold temperatures. Results also indicate a high variability in frnpp at a regional scale and along increasing altitude. These data show how important and different roles grasslands can play in accumulation and turnover of root biomass.
