Using Natural Gradients to Infer a Potential Response to Climate Change: An Example on the Reproductive Performance of Dactylis Glomerata L.

摘要

An understanding of the climate conditions governing spatial variation in thereproductive performance of plants can provide important information about the factorscharacterizing plant community structure, especially in the context of climate change. Thisstudy focuses on the effect of climate on the sexual reproductive output of Dactylisglomerata L., a perennial grass species widely distributed throughout temperate regions.An indirect space-for-time substitution procedure was used. Sixty mountain populations ofthe same target species were surveyed along an elevation gradient, and then, a relevantclimate model was used to infer a potential response to climate change over time. Withineach population, information on the number of stems, seed number and seed mass werecollected. Resource investment in reproduction (RIR) was quantified as seed number ×seed mass. A clear variation was found in the reproductive performance of D. glomerataalong the elevational gradient: RIR improved with increasing temperature. The best modelincluded only one term: the maximum temperature of the warmest month. This studydemonstrates that mountain ecosystems offer particularly good opportunities to studyclimate effects over relatively short distances and suggests that warming will enhanceD. glomerata reproductive output throughout its elevational range. Furthermore, it can behypothesized that a potential migration of D. glomerata toward higher altitudes may occurin response to accelerated climate change.