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.

Long‐term dynamics of shrub facilitation shape the mixing of evergreen and deciduous oaks in Mediterranean abandoned fields

“…indirect facilitation; Cuesta, Villar‐Salvador, Puértolas, Rey Benayas, & Michalet, ; Perea, López‐Sánchez, & Dirzo, ). The facilitative effect of shrubs have been related to specific functional attributes such as plant size (Alday, Zaldívar, Torroba‐Balmori, Fernández‐Santos, & Martínez‐Ruiz, ; Navarro‐Cano, Goberna, Valiente‐Banuet, & Verdú, ), the root architecture (Prieto, Kikvidze, & Pugnaire, ; Prieto et al, ; Rolo et al, ) and the ability to fix nitrogen into the soil (Gómez‐Aparicio, Zamora, Gómez, Hódar, & Castro, ).…”

How can we restore biodiversity and ecosystem services in mining and industrial sites?

“…In the papers of this issue, attention is given to passive restoration and the factors influencing spontaneous succession (e.g., Nikolic et al 2015;Tropek et al 2015;Horáčková et al 2015;Alday et al 2015), to field experiments comparing ecological restoration measures (Tarvainen and Tolvanen 2015;Karofeld et al 2015), to the comparison between reclamation and passive restoration (Řehounková et al 2016; Šebelíková et al 2015), and to the reclamation by afforestation (Metslaid et al 2015). Based on the results, passive restoration seems to be an effective approach at many post-mining and postindustrial sites (but see Kopeć et al 2015), whereas technical reclamation may have negative effects on the biodiversity, since it decreases the amount of habitats for specialized threatened species (Tropek et al 2015;Řehounková et al 2016) or maintains the pool of seeded alien species that may spread to the surrounding environment (Rydgren et al 2015).…”

“…On the other hand, technical reclamation can be justified through the economic profit as in the case of timber production of afforested sites (Metslaid et al 2015). Experimentally tested ecological restoration measures (Tarvainen and Tolvanen 2015;Karofeld et al 2015) and analyses of environmental and plant characteristics influencing the regeneration and succession Alday et al 2015;Nikolic et al 2015) provide scientific information that can be used in developing effective ecological restoration under adverse conditions. A special and, in some cases, the only possible restoration measure is the ex situ conservation of endangered species which can be later used in ecological restoration projects (Le .…”

“…Undisturbed neighboring ecosystems such as forests (Alday et al 2015;Tarvainen and Tolvanen 2015), peatlands (Karofeld et al 2015), and the tundra (Rydgren et al 2015) may be used as a reference for ecological restoration, but they may not always be a valid reference for large-scale mining or industrial sites. An alternative stable state should also be considered (Alday and Marrs 2014).…”

Revegetation of subtropical soil slopes: Groundcover performance and the implications of urban development and slope features on plant community

“…Extensive research has been conducted to examine the use of woody plants (e.g., trees and shrubs) in restoring degraded landscapes worldwide (Alday, Zaldívar, Torroba‐Balmori, Fernández‐Santos, & Martínez‐Ruiz, ; Hau, So, Choi, & Chau, ; Jim & Liu, ; Jim & Zhang, ; Torroba‐Balmori, Zaldívar, Alday, Fernández‐Santos, & Martínez‐Ruiz, ), and their planting on soil slopes is usually restricted to gentle slopes to minimize the occurrence of uprooting (Derong et al., ). In fact, groundcovers, which in general are annual or perennial plants below 1 m in height, provide a higher planting opportunity than woody plants in soil slope greening.…”