Restoring Limestone Quarries: Hayseed, Commercial Seed Mixture or Spontaneous Succession?

The main goal of quarry restoration is to convert degraded, unproductive areas into new, self-sustaining ecosystems that develop into highly natural environments. With the aim to individuate the best practices for restoring limestone quarries, we investigated the short-term effects on vegetation features and economic advantages of three restoration approaches. These approaches included tree and shrub planting, no herb layer, or a commercial seed mixture or hayseed. The different approaches were tested in a limestone quarry within the Botticino extractive basin (N-Italy). A donor grassland area of hayseed and a quarry area that had undergone spontaneous revegetation over a decade were used as control areas. We surveyed the vegetation plots to investigate the structure and the productivity of the herbaceous layers; collecting data on plant species cover, the mean plant height, the tree and shrubs mortality and biomass enabled us to perform gradient analysis. The main differences between the sites were due to biotic factors; specifically, vegetation cover was affected quite differently by the different restoration approaches. Restoration with commercial seed mixture resulted primarily in dense stands of Lolium perenne that caused an increase in shrub and tree mortality. Cost-benefit analysis showed that despite hayseed being the most expensive approach in terms of cost and time, it ensured higher species diversity, vegetation structure and greening. Our results highlighted that autochthonous plant materials can improve excavation-areas restoration by both contrasting the colonisation of non-native species and increasing natural regeneration and biodiversity levels. Copyright (c) 2013 John Wiley & Sons, Ltd.