In a recent study published in The American Naturalist, Pleuni Pennings and her coworkers chose a different approach. They started out from a widely cited simulation model by Ulf Dieckmann and Michael Doebeli, who investigated sympatric speciation driven by resource competition. They then simplified the assumptions of this model to make it mathematically tractable. While retaining each of the crucial ingredients, Pennings et al. managed a completely analytical dissection of the model, something that had not appeared possible beforehand. They found that varying the model parameters produced phenomena that had previously been described in separate papers. "This means that our model unifies insights from earlier work, which is very rewarding," says Michael Kopp, one of the authors of the study. "We also gained a better understanding of the underlying mechanisms, such as the interplay of natural and sexual selection."
"Plants may alter competition by modifying nutrient bioavailability in rhizosphere: a modeling approach"
Xavier Raynaud (Universit Paris-Sud and Universit Pierre et Marie Curie-Paris), Benot Jaillard (Laboratoire de Biogochimie du Sol et de la Rhizosphre), and Paul W. Leadley (Universit Paris-Sud)
Plants need nutrients such as Nitrogen and Phosphorus from the soil to grow. In temperate grasslands, several plant individuals can often be found on a small surface with their roots system thoroughly entwined. How plants share soil nutrients in these ecosystems has been the subject of debate between ecologists for decades, with several key questions still unanswered. In particular, few theories of plant competition account for the well-documented ability of plants to increase the availability of key soil nutrients by releasing protons or organic compounds from their roo
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