The role of protective understorey in the regeneration system of a heavily browsed woodland

Abstract

The paper tests an apparent relationship between young understorey of Ilex aquifolium and the presence of seedlings of the canopy species Fagus sylvatica and Quercus species, in heavily browsed woodland in the New Forest, southern England. A small block of woodland was searched and mapped, and the information collected subject to graphical and statistical analyses. Regeneration, though of low frequency, is present and shows non-random patterns of distribution. Older seedlings appear to be located in or near areas of understorey, or near fallen branches, logs, etc. Principal components analysis of woodland characteristics suggests six main habitat types are available to seedlings, and predictions are made about likely regeneration patterns associated with these habitats, according to a model based on the hypothesis of a protective understorey and heavy browsing pressure. Chi-square tests of actual seedling occurrences versus habitat types demonstrate marked associations of regeneration with non-trampled areas, including young Ilex understorey but also other forms of protective barrier. The association is more marked for larger seedlings. The implications for a wider understanding of regeneration processes and community dynamics in heavily browsed forest are discussed. It is concluded that regeneration theories appropriate to such forests are required, since the dominant gap-phase theories are not successful in predicting regeneration patterns when browsing is a major factor.