Traditional crofting management supports and maintains machair floral diversity

Machair is a rare, semi-natural dune grassland, restricted to the north-west coast of Scotland and Ireland. It is of conservation importance due to its high diversity of wildflowers, and the presence of rare species of plants and wildlife. Maintained by low-intensity crofting agriculture, more detailed knowledge of current management practices and their impacts is required. To investigate the effects of traditional crofting agriculture, specifically seasonal grazing and low-intensity rotational cultivation, on flowering plant species richness and composition of machair. Vegetation survey data from the Outer Hebrides were collected and analysed to compare species richness and composition among four types of agricultural management, broadly defined as follows: uncultivated and year-round grazed; uncultivated and seasonally grazed; rotationally cultivated and ungrazed; both rotationally cultivated and seasonally grazed. Both seasonal grazing and rotational cultivation increased species richness, with a combination of the two resulting in the highest species richness. Cultivation had a stronger impact on species composition than grazing, with annual species in particular benefiting from rotational cultivation. Consistent with previous studies, our results identify traditional management regimes as important in maintaining machair plant diversity. The study provides a preliminary but detailed view of current machair management in the Outer Hebrides.