Contents lists available at ScienceDirect Catena journal homepage: www.elsevier.com/locate/catena Developing generalized parameters for post-fire erosion risk assessment using the revised Morgan-Morgan-Finney model: A test for north-central Portuguese pine stands Mohammadreza Hosseini a, ⁎ , João Pedro Nunes b,c , Oscar González Pelayo b , Jan Jacob Keizer b , Coen Ritsema a , Violette Geissen a,d a SLM Group Wageningen University (WUR), P.O. Box 47, 6700 AA, Wageningen, The Netherlands b CESAM & Department of Environment and Planning, University of Aveiro, 3810-193 Aveiro, Portugal c CE3C: Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Edifício C1, Sala 1.4.39, Campo Grande, 1749-016 Lisboa, Portugal d INRES, University of Bonn, Nussallee 13, 53115 Bonn, Germany ARTICLE INFO Keywords: Repeated wildfires Surface runoff Post-fire erosion Morgan-Morgan-Finney model Management ABSTRACT Models can be useful for predicting the hydrological impacts of natural phenomenon such as wildfires and to help implement effective post-fire land management options. In this research, the revised Morgan–Morgan–Finney (MMF) model was used to simulate runoff and soil erosion in recently burned maritime pine plantations with contrasting fire regimes, in a wet Mediterranean region of north-central Portugal. The MMF model was adapted for burnt areas by implementing seasonal changes in model parameters in order to accommodate seasonal patterns in runoff and soil erosion, attributed to changes in soil water repellency and vegetation recovery. The model was then evaluated by applying it for a total of 18 experimental micro-plots (0.25 m 2 ) at 9 once burned and 9 four times burned slopes, using both previously published and newly calibrated parameters, with observed data used to evaluate the robustness and wider applicability of each parameteriza- tion. The prediction of erosion was more accurate than that of runoff, with an overall Nash-Sutcliffeefficiency of 0.54. Slope angle and the soils' effective hydrological depth (which depends on vegetation and/or crop cover) were found to be the main parameters improving model outcomes, and different parameters were needed to differentiate between the two contrasting fire regimes. This case study showed that most existing benchmark parameters can be used to apply MMF in burned pine forest areas with moderate severity fires to support post- fire management, but indicated that further efforts should focus on mapping soil depth and vegetation cover to improve these assessments. 1. Introduction Fire is a key component of the Earth system. It is a major and fre- quent disturbance in forest ecosystems, especially in Mediterranean regions due to their dry, hot summers followed by frequent and high- intensity rain in the autumn immediately after the wildfire season (Shakesby, 2011). Post-fire erosion is an important societal concern because of the potential impacts on soils and water resources. Increases in soil erosion rates are frequently observed following wildfires (Shakesby and Doerr, 2006; Fernández et al., 2010). Increases in wildfire frequency and burned area are commonly expected under probable future climate scenarios for the Mediterranean region (Fernández et al., 2010), further stressing the need for adequate post- fire vegetation and soil management strategies. The heating of the soils by fire can change its physical, chemical and biological characteristics, such as water repellency (Keesstra et al., 2017), behaviour and stability of aggregates (Shakesby and Doerr, 2006), soil organic matter quantity and quality (Shakesby, 2011; Wittenberg et al., 2014), nutrient availability (Ferreira et al., 2016), and composition of soil microbial and invertebrate communities (Certini, 2005). Besides soils, vegetation is typically consumed to a smaller or larger degree, depending on fire severity (Díaz-Delgado et al., 2003). Post-fire circumstances can be favourable for vegetation regrowth, due to increased nutrient and water availability while facing less competition (Cerdà and Doerr, 2005). Nonetheless, vegetation cover is typically reduced during the post-fire period, leading to https://doi.org/10.1016/j.catena.2018.02.019 ⁎ Corresponding author. E-mail address: mohammadreza.hosseini@wur.nl (M. Hosseini). Catena 165 (2018) 358–368 Available online 22 February 2018 0341-8162/ © 2018 Elsevier B.V. All rights reserved. T