a new hammer to crack an old nut interspecific competitive resource capture by plants is regulated by nutrient supply, not climate新锤裂纹旧螺母种间竞争资源获取植物由营养供应,没有气候.pdfVIP

A New Hammer to Crack an Old Nut: Interspecific Competitive Resource Capture by Plants Is Regulated by Nutrient Supply, Not Climate 1 2 1 1 Clare J. Trinder *, Rob W. Brooker , Hazel Davidson , David Robinson 1 Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom, 2 The James Hutton Institute, Aberdeen, United Kingdom Abstract Although rarely acknowledged, our understanding of how competition is modulated by environmental drivers is severely hampered by our dependence on indirect measurements of outcomes, rather than the process of competition. To overcome this, we made direct measurements of plant competition for soil nitrogen (N). Using isotope pool-dilution, we examined the interactive effects of soil resource limitation and climatic severity between two common grassland species. Pool-dilution estimates the uptake of total N over a defined time period, rather than simply the uptake of 15N label, as used in most other tracer experiments. Competitive uptake of N was determined by its available form (NO32 or NH4+). Soil N availability had a greater effect than the climatic conditions (location) under which plants grew. The results did not entirely support either of the main current theories relating the role of competition to environmental conditions. We found no evidence for Tilman’s theory that competition for soil nutrients is stronger at low, compared with high nutrient levels and partial support for Grime’s theory that competition for soil nutrients is greater under potentially more productive conditions. These results provide novel insights by demonstrating the dynamic nature of plant resource competition. Citation: Trinder CJ, Brooker RW