Data from: Variability in community productivity: mediating effects of vegetation attributes

1. Plant productivity varies though time in response to environmental fluctuations. Reducing variability in productivity requires an improved understanding of how plant community attributes interact with environmental fluctuations to influence plant growth dynamics. We evaluated links between two community attributes, species diversity and abundance-weighted values of specific leaf area (SLA), and temporal variability in grassland productivity at patch (local) and aggregate (multi-patch) spatial scales. 2. Aggregate communities were created by combining patches of spatially-distinct communities of perennial plant species from grassland biodiversity experiments in Texas, USA. Inter-annual variability in aboveground net primary productivity (ANPP) of aggregate communities was analyzed as a function of two multiplicative components, mean temporal variability in the ANPP of patches and temporal synchrony in ANPP dynamics among patches. We used regression analyses to determine whether temporal variability in aggregate ANPP and its components were correlated with either species diversity or community-weighted SLA over 5 years. 3. Temporal variability in ANPP of aggregate communities was strongly correlated with temporal variability in patch ANPP. Increasing mean SLA reduced ANPP variability of aggregate communities by increasing mean productivity. Increased temporal changes in patch-scale SLA further reduced temporal variability in aggregate ANPP by reducing effects of precipitation fluctuations on productivity. Conversely, increasing species diversity over the narrow range measured increased temporal variability in aggregate ANPP. High diversity was associated with reduced dominance of temporally-stable C4 grasses. 4. Our results implicate means and patch-scale temporal dynamics in community SLA as potential indicators of variability in grassland primary productivity through time.1. 植物生产力会随环境波动发生时序变化。若要降低生产力的时序变异，需深入阐明植物群落属性与环境波动的相互作用机制，及其对植物生长动态的调控作用。本研究聚焦两类群落属性——物种多样性与物种丰度加权比叶面积（specific leaf area, SLA），探究二者与草原生产力在样地（局部）和聚合（多样地）空间尺度下的时序变异之间的关联。 2. 聚合群落通过整合美国德克萨斯州草原生物多样性实验中空间异质的多年生植物群落样地构建得到。本研究以两个乘性组分作为解析变量，分析聚合群落地上净初级生产力（aboveground net primary productivity, ANPP）的年际变异：其一为样地ANPP的平均时序变异，其二为样地间ANPP动态的时序同步性。研究基于5年的观测数据，通过回归分析明确聚合ANPP的时序变异及其组分是否与物种多样性或群落加权比叶面积存在相关性。 3. 聚合群落的ANPP时序变异与样地ANPP的时序变异呈显著相关。平均比叶面积的提升可通过提高群落平均生产力水平，降低聚合群落的ANPP时序变异。样地尺度比叶面积的时序变化幅度增大，则通过削弱降水波动对生产力的影响，进一步降低聚合ANPP的时序变异。与之相反，在所观测的狭窄物种多样性范围内提升物种多样性，反而会增大聚合群落ANPP的时序变异；高多样性群落往往伴随时序稳定型C4草本植物优势度的降低。 4. 本研究结果表明，群落比叶面积的均值与样地尺度时序动态，可作为预测草原初级生产力时序变异的潜在指标。