title: Natural forest expansion on reclaimed coal mines in Northern Spain: the role of native shrubs as suitable microsites.
abstract: The characterization of suitable microsites for tree seedling establishment and growth is one of the most important tasks to achieve the restoration of native forest using natural processes in disturbed sites. For that, we assessed the natural Quercus petraea forest expansion in a 20-year-old reclaimed open-cast mine under sub-Mediterranean climate in northern Spain, monitoring seedling survival, growth, and recruitment during 5 years in three contrasting environments (undisturbed forest, mine edge, and mine center). Seedling density and proportion of dead branches decreased greatly from undisturbed forest towards the center of the mine. There was a positive effect of shrubs on Q. petraea seedling establishment in both mine environments, which increase as the environment undergoes more stress (from the mine edge to the center of the mine), and it was produced by different shrub structural features in each mine environment. Seedling survival reduction through time in three environments did not lead to a density reduction because there was a yearly recruitment of new seedlings. Seedling survival, annual growth, and height through time were greater in mine sites than in the undisturbed forest. The successful colonization patterns and positive neighbor effect of shrubs on natural seedlings establishment found in this study during the first years support the use of shrubs as ecosystem engineers to increase heterogeneity in micro-environmental conditions on reclaimed mine sites, which improves late-successional Quercus species establishment.
authors.affiliation: School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, UK.|Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, 25198, Lleida, Spain.
authors.forename: Josu G
authors.initials: JG
authors.lastname: Alday
authors.affiliation: Agroforestry Sciences Department, University of Valladolid, Campus La Yutera, Avda. de Madrid 44, 34071, Palencia, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Zaldívar
authors.affiliation: CIFOR-INIA (Center of Forest Research), Carretera de La Coruña km 7.5, 28040, Madrid, Spain.|Sustainable Forest Management Research Institute UVa-INIA, Campus la Yutera, Avda de Madrid 44, 34071, Palencia, Spain.
authors.forename: Paloma
authors.initials: P
authors.lastname: Torroba-Balmori
authors.affiliation: Ecology Area, University of Salamanca, Campus Miguel de Unamuno 37071, Salamanca, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Fernández-Santos
authors.affiliation: Agroforestry Sciences Department, University of Valladolid, Campus La Yutera, Avda. de Madrid 44, 34071, Palencia, Spain. caromar@agro.uva.es.|Sustainable Forest Management Research Institute UVa-INIA, Campus la Yutera, Avda de Madrid 44, 34071, Palencia, Spain. caromar@agro.uva.es.
authors.forename: Carolina
authors.initials: C
authors.lastname: Martínez-Ruiz
mesh_terms: D002980:Climate; D003032:Coal Mining; D052918:Environmental Restoration and Remediation / Q000379:methods*; D065928:Forests; D029963:Quercus / Q000254:growth & development*; D036226:Seedlings / Q000254:growth & development; D013030:Spain; D014197:Trees / Q000254:growth & development
keywords: Growth; Quercus petraea; Seedling recruitment; Shrub protection; Sub-Mediterranean environment; Survival