Boreal trees in the Mediterranean: recruitment of downy birch (Betula alba) at its southern range limit

Knowledge of mechanisms determining plant persistence in range edges is essential because peripheral populations face increasing risk and they often maintain unique genotypes. We examined the recruitment limitations, from seed production to seedling establishment, of a boreal tree, the downy birch (Betula alba), in four Spanish relict populations at the southern range limit. In 2005 and 2006, seed production and the spatial pattern of seed rain...