Relationships between Flowering Phenology and Functional Traits in Eastern Tibet Alpine Meadow

Abstract

Flowering phenology is a key life history trait that strongly influences reproductive success. We investigated the relationship between flowering phenology and functional traits of 48 alpine herb species using the Leaf-Height-Seed (LHS) scheme developed by Westoby (1998) to quantify the ecological strategy of the plant species. Phenological data were obtained by weekly observation of fifty 0.5 × 0.5 m2 quadrates. Specific leaf area (SLA), height, and seed size of 48 alpine herbs were measured. Comparative generalized estimating equations and generalized linear models suggested that flowering peak date was positively correlated with size of maternal plant (biomass and height) and negatively correlated with seed size. Species with a longer flowering period were smaller and produced bigger seeds than those with a short flowering season. Flowering peak date and duration were negatively correlated, although this correlation was mainly present in annuals, which are relatively rare in the alpine meadow. Relationships between flowering phenology and specific leaf area (SLA) were weak. There were only weak effects of phylogeny on the relationships between flowering phenology and functional traits. Wind-pollinated species flowered earlier than insect-pollinated species. Annuals flowered longer than perennials. Relationships between flowering phenology and functional traits indicate that there is a tradeoff between maternal and reproductive growth, and flowering time may underlie the correlation between plant height and seed size.