Trade-off between competition and facilitation defines gap colonisation in mountains

Environmental conditions within a disturbance event are often regarded as uniform. There is however large variation in conditions for plant colonisers within one disturbance event, drastically affecting coloniser survival on a scale of centimetres. In a new study published in AoB PLANTS, Lembrechts et al. provide a model that combines the effect of the surrounding vegetation (negative through competition and positive through facilitation) with environmental conditions along a mountain gradient. This model indicates that colonisers will be forced to grow closer to the gap edge when environmental conditions (e.g. freezing temperatures) get worse, ultimately leaving a substantial area in large gaps unsuitable for colonisation in facilitation-dominated systems. The model will help predict the distribution of plant invaders and the effect of climate warming on colonisation in mountains.