Plant species and community responses to sand burial on the machair of the Outer Hebrides, Scotland

Abstract

Abstract Question: Is there a critical depth of burial by sand beyond which species and communities fail to recover, and does repeated incremental burial have a greater impact than a single large deposition? Location: The machair on the calcareous sand dunes on South Uist, in the Outer Hebrides of Scotland, UK. Methods: Eight turves were collected from each of four machair sub-community types. After acclimatization in an unheated polythene tunnel, they were buried with sterilized machair shell sand, either by one single burial to 5 cm or by five applications of 1 cm of sand at approximately seven-week intervals. Species response was recorded on five occasions. Results: Within machair sub-communities, burial by sand reduced the abundance (local rooted frequency) of plants more than it reduced species richness. Intermittent burial was more damaging than a single burial event. Those species with the highest pre-burial frequencies tended to dominate recovery in the sub-community as a whole. Species occurring ...