Pastoral and woodcutting activities drive Cedrus atlantica Mediterranean forest structure in the Moroccan Middle Atlas

Abstract

Human activities are historical ecological drivers, and we need to better understand their effects on ecosystems. In particular, they have been very important in the shaping of the Mediterranean biodiversity hotspot. Researchers and managers nonetheless lack knowledge concerning the impacts of their combinations and their current intensity on the structure of forest ecosystems of the southern part of the Mediterranean basin. In this study, we have develped a new methodology in order to understand the impacts of combined pastoral and woodcutting activities on the forest structure of the still ill-described but ecologically and economically important Moroccan Middle Atlas cedar forests. In a 40 000 ha forest, we chose 103 sites and sampled human activities through proxies and forest structures through circumference and vertical structures. A typology of sites yielded four human activity types: dominant pastoral activities, dominant oak cutting or cedar cutting activities, and an intermediate mid-disturbance type. This typology did not depend on altitude or substrate, confirming that the ecosystem structures linked to the different types depend more on human activities than on main environmental parameters. Pastoral activities modified forests the most, converting them to parklands with reduced canopies and low dynamics but high tree maturation. Woodcutting activities induced gap dynamics, favoring Cedrus atlantica in favorable environmental conditions and Quercus ilex otherwise, while they affected vertical structure depending on the local environment and competition for light and soil resources. Moderately disturbed stands showed forest maturation with low competition for light. Unlike previous studies, we found no evidence of a general degradation of cedar forests due to local human activities. However, cedar logging has reduced standing basal area regionally and one third of the sites may have vulnerable cedar populations due to pastoral activities and to unfavorable environmental conditions. These results can direct future research and management needs for a better protection of Mediterranean forests and parklands and their biodiversity, although to be effective such efforts must also partner with sociogeographical studies.

Forest management for adaptation to climate change in the Mediterranean basin: A synthesis of evidence

“…Regional field-data assessments (Coudel et al, 2016) and the use of modelling and remote sensing techniques (Bottalico et al, 2016(Bottalico et al, , 2017 can improve our understanding of long-term and broad-scale impacts of management practices on the structure and function of forest ecosystems.…”

Baseline Mortality Analysis Reveals Legacy of Contrasting Land Use Practices on the Structural Sustainability of Endangered Moroccan and Spanish Mountain Forests

“…This development will likely hasten dominant species replacement in this region [16]. Recent studies have found an interaction gradient between pastoral and woodcutting activities, where the disturbance having the most impact on C. atlantica stand structure is grazing and pruning [29]. This study concludes that the structure differences depend more on human activities than on environmental parameters.…”

Towards a More Realistic Simulation of Plant Species with a Dynamic Vegetation Model Using Field-Measured Traits: The Atlas Cedar, a Case Study

“…Its extant distribution is limited to mountainous regions of Morocco and Algeria where it is threatened by anthropogenic activities. Semi-nomadic pastoral tradition, widespread across the Rif and Atlas Mountains, continues to generate an intensive grazing pressure that severely prevents natural regeneration [26,32]. Recent increased aridity and temperature led to a decrease in growth rate and an increase in mortality [25,26,28,29].…”