Harsh environmental regimes increase the functional significance of intraspecific variation in plant communities

The relative importance of intraspecific trait variation (rITV) for functional diversity (FD) in plant communities is increasingly apparent, but the influence of abiotic factors on the balance between intraspecific and interspecific effects in contrasting environments is uncertain. We predicted that rITV would increase with environmental harshness as a result of decreasing interspecific variation (Inter_FD) and concomitant increases in between-population ITV(Intra_FD). We empirically tested this prediction in a comparison of rITV for five traits (mature plant height, SLA: specific leaf area, leaf dry matter content, and the foliar concentrations of nitrogen and phosphorus) characterizing species in Tibetan alpine meadow communities from contrasting environmental regimes(i.e. valley floor at the base of the ridge, northern- and southern-slopes at mid-elevation, and ridge top) on each of three sites (ridges). We found that across plots: i) rITV for all five traits increased with environme...

植物群落中种内性状变异（intraspecific trait variation, rITV）对功能多样性（functional diversity, FD）的相对重要性日益凸显，但非生物因素如何影响不同环境下种内与种间效应的平衡仍不明确。我们推测，随着环境严酷度的增加，种间变异（Inter_FD）会降低，而种群间种内性状变异（Intra_FD）会相应增加，因此rITV会随之升高。我们通过实证研究检验了这一推测：在三个山脊样点上，分别选取不同环境梯度（即山脊底部的河谷平地、中海拔的南北坡以及山脊顶部）的西藏高寒草甸群落，比较了五个表征物种性状的rITV——包括成熟株高、比叶面积（SLA: specific leaf area）、叶片干物质含量，以及叶片氮、磷浓度。我们发现，在所有样方中：i) 五个性状的rITV均随环境...