Plants often exhibit positive responses to multiple nutrient additions, but generalities about the life form and traits of the most responsive species are few. Findings from long-term experiments in dry meadow alpine tundra in Colorado, USA, were used here to examine univariate and multivariate analyses of plant and plant trait responses. We found transient responses for community richness–biomass relationships, but a consistent increase in forb dominance in nitrogen (N) and phosphorus (P) addition plots. The response seen in the N + P plots was not affected by additions of micronutrients or potassium. Multivariate analyses corroborate transient responses in community shifts over shorter-time scales, and directional shifts in N + P over two decades. Using species-level aboveground trait data when available, we found N + P may favor species with resource-acquisitive traits, regardless of their lifeform, as well as relatively tall grasses, regardless of their resource strategy. In the absence of N and P limitation but with the environmental constraints found in dry alpine meadows, plant richness and community structure continued to exhibit transient states for decadal time frames.

植物通常对多种营养添加物表现出积极的反应，但是关于反应最迅速的物种的生命形式和性状的一般性很少。在美国科罗拉多州的干旱草甸高山苔原上进行的长期实验得出的结果用于检验植物和植物性状响应的单变量和多变量分析。我们发现了社区富裕-生物量关系的短暂响应，但是氮（N）和磷（P）添加图中福布优势的持续增加。在N + P图上看到的响应不受微量营养素或钾的添加的影响。多变量分析在更短的时间尺度上证实了社区转变中的瞬态响应，以及在过去的20年中N + P的方向转变。使用可用的物种级别的地上性状数据，我们发现，N + P可能偏爱具有资源获取性状的物种，无论其生命形式如何，以及相对较高的草丛，无论其资源策略如何。在没有氮和磷限制的情况下，但由于在干旱的高山草甸中发现了环境限制，植物的丰富度和群落结构在十年的时间框架内继续表现出瞬时状态。