Effects of clipping and fertilizing on the relationship between functional diversity and above-ground net primary productivity in an alpine meadow
Aims Much attention has been paid for the relationship between species diversity (SD) and aboveground net primary productivity (ANPP). However, the effect of functional diversity (FD) onANPP was more straightfor-ward. Most researchers consideredSD orFD as an independent variable to study the relationship between biodi-versity andANPP. In fact, the relationship may be affected by abiotic factors. Our objective was to study how dif-ferent disturbance factors affect the relationship ofFD-ANPP. <br> Methods The experiment was conducted in the alpine Kobresia humilis meadow at Haibei Research Station of the Chinese Academy of Sciences with clipping (unclipping, stubbled 3 cm and 1 cm) and fertilizing (12.75 g·m?2·a?1urea + 3.06 g·m?2·a?1 (NH4)2HPO4) treatments from 2007 to 2013. General linear model univariate ANOVA, regression analysis and ANCOVA were used for studying the effects of clipping, fertilizing, year and their interaction onANPP andFD and the change of relationship ofFD-ANPP. <br> Important findingsANPP was enhanced by increasing clipping intensity and soil nutrient extremely signifi-cantly (p< 0.01). However, the effect extent was different in each year.ANPP presented a fluctuant downward trend year-to-year whileFD increased along time.FD was increased by fertilizing significantly (p< 0.05), while the effect of clipping onFD was not significant (p > 0.05). Under the six kinds of treatment combinations of clip-ping and fertilizing, the relationship ofFD-ANPP presented two patterns including linear positive correlation and no correlation mainly depending on clipping. No matter the community was fertilized or not, in the unclipped community,FD showed no correlation withANPP(n= 90,p> 0.05). However, in the clipped community, clip-ping increasedFD andANPP in the same time, which facilitated them showing linear positive correlation. Fertil-izing cannot affect the pattern of relationship ofFD-ANPP,but the slope and intercept of equations of relationship were influenced by fertilizing and clipping. The results suggested that the relationship ofFD-ANPP was influ-enced by clipping and fertilizing jointly, while clipping plays a leading role in changing their relationship patterns.
functional diversityaboveground net primary productivityclippingfertilizing
NETL
NSTL
万方数据
维普
