Nutrient foraging behaviour of four co-occuring perennial grassland plant species alone does not predict behaviour with neighbours

The spatial arrangement of nutrients and neighbours in soil influences plant growth and reproduction. Plants often respond to such stimuli through plasticity in root proliferation (root mass per soil volume), or the breadth of their root system. Here, we asked how plants adjust nutrient foraging strategies when grown alone or with neighbours. We asked (i) Does root proliferation into nutrient-rich patches when plants are grown alone predict root proliferation when plants are grown with neighbours? (ii) What factors (nutrients or neighbours) best predict the probability of root placement at different soil locations? (iii) How does the spatial distribution of nutrients alter the degree to which neighbours suppress plant growth? To answer these questions, we grew four grassland species either as individual plants or in competition, in patchy or patch-free soil, in a factorial design. We used genomic DNA to identify the spatial distribution of roots of each species when plants were grown ...