【摘要】 功能多样性(FD)对群落地上净初级生产力(ANPP,g·m-2·a-1)有直接的影响,但不同扰动因素对FD-ANPP关系将产生何种影响尚不明确。通过在青藏高原高寒矮生嵩草(Kobresia humilis)草甸连续7年(2007–2013)的刈割(3水平:不刈割、留茬3cm的中度刈割和留茬1 cm的重度刈割)和施肥(2水平:施用12.75 g·m-2·a-1尿素+3.06 g·m-2·a-1(NH4)2HPO4、不施肥)控制实验,研究了刈割、施肥、年份及其交互作用对ANPP和FD的影响以及FD-ANPP关系的变化。研究结果显示:(1)增加刈割强度和土壤养分均显著提高了ANPP,但其效应随着年份的不同而有差异,ANPP随着时间呈波动下降趋势,而FD则随年度增大;(2)施肥显著增加了FD,而刈割对FD无显著影响(p>0.05);(3)在6种刈割和施肥处理组合下,FD-ANPP关系随时间的变化主要受刈割扰动影响呈现正线性相关和无相关两种模式。无论施肥与否,不刈割(C0)群落中FD和ANPP之间无相关(n=90,p>0.05);而刈割群落中FD和ANPP之间为正相关(n=90,p<0.05)。由于刈割同时提高了FD和ANPP,促使二者在刈割群落中呈现正线性相关。(4)尽管施肥不影响FD和ANPP的关系模式,但与刈割共同作用,影响FD-ANPP关系的截距或斜率。上述结果说明,刈割扰动和土壤营养资源共同影响着FD-ANPP关系,而刈割在改变其关系模式方面起主导作用。更多还原

【Abstract】 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) on ANPP was more straightforward. Most researchers considered SD or FD as an independent variable to study the relationship between biodiversity and ANPP. In fact, the relationship may be affected by abiotic factors. Our objective was to study how different disturbance factors affect the relationship of FD-ANPP. 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-1 urea + 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 on ANPP and FD and the change of relationship of FD-ANPP. Important findings ANPP was enhanced by increasing clipping intensity and soil nutrient extremely significantly(p < 0.01). However, the effect extent was different in each year. ANPP presented a fluctuant downward trend year-to-year while FD increased along time. FD was increased by fertilizing significantly(p < 0.05), while the effect of clipping on FD was not significant(p > 0.05). Under the six kinds of treatment combinations of clipping and fertilizing, the relationship of FD-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 unclippedcommunity, FD showed no correlation with ANPP(n = 90, p > 0.05). However, in the clipped community, clipping increased FD and ANPP in the same time, which facilitated them showing linear positive correlation. Fertilizing cannot affect the pattern of relationship of FD-ANPP, but the slope and intercept of equations of relationship were influenced by fertilizing and clipping. The results suggested that the relationship of FD-ANPP was influenced by clipping and fertilizing jointly, while clipping plays a leading role in changing their relationship patterns.更多还原