Native-invasive spatial seed aggregation competition trials

PurposeTo explore spatial pattern, provenance, and interactions between seeds and with a mimic exotic in a controlled context.HypothesisSpatial aggregeation of seeds shifts the net outcome of native-exotic interactions.PredictionsIncreased seed aggregated increases competitive interactions intra and inter-specifically.Native seeds can outcompete an invasive species at some seed aggregations.One of the key effects of the invasive species brome is physical interference (tested by a mimic plant and by measuring light levels in competition).DesignTwo species tested. Phacelia tancetifolia and Bromus rubens. Greenhouse trials, full-spectrum light, 15cm pots. A total of 8 weeks experimentation, and fixed density series with replacement at 10 seeds per pot. The aggregation of seed was clumped or dispersed in sowing for each species in mixture and monocultures.