Grassland colonization by Erica scoparia (L.) in the Montseny Biosphere Reserve (Spain) after land-use changes

In a heathland pasture in the Montseny Biosphere Reserve and Natural Park (NE Spain) the replacement of traditional burning by shrub harvesting has lead to encroachment on intermixed dry grasslands by Erica scoparia. Permanent in situ quadrats were used at two study sites from Spring 2001 to Spring 2003. Orientation, percentage of bare ground, grass cover, distance from mature plants and morphometry of seedlings were recorded in order to determine their influence on distribution, structure, abundance and seedling survival. Results showed that E. scoparia seedlings grow mainly on the first metres at the edge of the heathland with a clear spatial aggregation pattern. Factors such as the percentage of bare ground, grass cover, distance to the nearest neighbour, age and height of mature plants located at the edge of the heathland influenced the colonizing patterns.