Ecological Engineering 95 (2016) 580–587 Contents lists available at ScienceDirect Ecological Engineering jo ur nal home p ag e: www.elsevier.com/locate/ecoleng Using facilitation microsites as a restoration tool for conversion of degraded grasslands to Nothofagus forests in Southern Patagonia Patricio Valenzuela a,b , Eduardo C. Arellano a,b,* , James A. Burger c , Pablo Becerra a,b a Departamento de Ecosistemas y Medio Ambiente, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Vicu˜ na Mackenna 4860, Macul, Santiago, 7810000, Chile b Center of Applied Ecology and Sustainability, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins 340, Santiago, 8320000, Chile c Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA, 24061, USA a r t i c l e i n f o Article history: Received 16 February 2016 Received in revised form 22 June 2016 Accepted 26 June 2016 Available online 18 July 2016 Keywords: Southern Patagonia forests Facilitation structures Seedling stress Restoration tools a b s t r a c t In Southern Patagonia, introduction of exotic grasses after forest fires strongly restricts restoration of Nothofagus spp forests. The use of polycarbonate shelters to shield Nothofagus seedlings has been not enough for getting restoration success. Selection of natural facilitation microsites (i.e. logs, rocks, pioneer plants) for seedling outplanting may improve early performance of Nothofagus pumilio (Poepp. et. Endl.) Krasse (N. pumilio), by reducing the incidence of limiting factors such as soil water and light stress. In 2012, seedlings of N. pumilio shielded with polycarnonate shelters were planted close to log piles, nurse plants of native shrubs, and open areas to evaluate the effect of natural facilitation microsites on early performance of the species. After three growing seasons, soil measurements, seedlings survival, stem diameter and height of plants, electronic transport rate, stomatal conductance, and the chlorophyll index were evaluated to explore leaf photochemistry and any possible limitation to photosynthesis associated to microsite conditions. Seedling survival was significantly lower in open sites in comparison to the other microsite conditions. Seedling height was highest both under nurse plants and log piles microsites. Stomatal conductance was higher for seedlings in nurse plant microsites despite the fact that the soil water content was similar across all conditions. Soil penetration resistance and electron transport rate were higher, but chlorophyll index was lower, in open sites when compared to the other microsites. Our results show that the use of facilitation microsites such as pioneer nurse shrubs and logs for N. pumilio reforestation or restoration plans in degraded grassland areas in Southern Patagonia should be considered even when plants are protected with polyethylene shelters. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Deforestation for the development of agricultural and grazing systems has led to the expansion of tree/grass patches worldwide (Huston, 2005; Perfecto and Vandermeer, 2008). In the southern hemisphere, Nothofagus spp. forests have been affected since Euro- pean colonization by anthropogenic land use, leading to significant changes in the ecological landscape in Chilean and Argentinean Patagonia, New Zealand, and Australia. In Chilean Southern Patag- onia, over 2.8 million ha of native beech-dominant forests was purposely burned since the late 19th century until the 1950s and subsequently been used for sheep and cattle grazing (López Bernal * Corresponding author at: Departamento de Ecosistemas y Medio Ambiente, Fac- ultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Vicu ˜ na Mackenna 4860, Macul, Santiago, 7810000, Chile. E-mail addresses: eduardoarellano@uc.cl, earellan@uc.cl (E.C. Arellano). et al., 2012; Martinic, 2006; Otero Duran, 2006). These changes have led to a vegetation mosaic with patches of forest fragments and open grasslands that negatively influence Nothofagus spp. regener- ation across the modified open sites (Coopman et al., 2008; Walters 2005). Most of Nothofagus spp. are poorly adapted to fire and other disturbances (Ledgard and Davis, 2004; López Bernal et al., 2012; Wardle, 1984) as low temperatures, competition with herbaceous pasture, and its own limited seed dispersal capabilities may inhibit forest establishment (Promis et al., 2010; Wiser et al., 1997). The improvement in microsite conditions in disturbed sites can potentially facilitate seedling establishment, improving their ability to cope with stressful environments in which the ability of the plant to growth is reduced (Callaway, 2007; Lortie et al., 2004). Many studies about reforestation techniques for restoration programs used biotic or abiotic structures for seedlings recently planted, especially in open deforested areas and stressing environ- ments (Gómez-Aparicio, 2009; Padilla and Pugnaire, 2006; Oliet http://dx.doi.org/10.1016/j.ecoleng.2016.06.116 0925-8574/© 2016 Elsevier B.V. All rights reserved.