The importance of topography and climate on short-term revegetation of coal wastes in Spain

The initial colonization phase is the crucial start point for succession and therefore for restoration. However, little is known about abiotic factors that influence the early stages of revegetation dynamics on restored coal mines, particularly in a Mediterranean climate. This information is crucial for improving our ability to reclaim land despoiled by mining. Here, we characterized the short-term plant community development in the first 3 years after hydroseeding on a topographically diverse reclaimed open-pit coal mines in Spain. Topography influenced both community composition and diversity producing different trajectories between the three different aspects (north-facing, south-facing, flat). Hydroseeded species provided most of the initial vegetation cover, which brought about most of the compositional differences between these aspects. We also found that the changing climate through the growing season also influenced floristic composition and diversity. Summer drought reduced the cover of hydroseeded perennial species and allowed native species to colonize. These results emphasize the need to take topography into account when developing reclamation management plans in Mediterranean ecosystems, and an acknowledgement that climate might drive the succession in the desired direction, hence increasing success in restoring mining impacts.