Land cover dynamics in the Simien Mountains (Ethiopia), half a century after the establishment of the National Park

The Simien Mountains house several endangered and endemic wildlife species and provide important ecosystem services. Despite its regional environmental importance, the Simien Mountains are listed as World Heritage in Danger since 1997. This raised the need for an evaluation of landscape changes from before the establishment of the Simien Mountain National Park (SMNP) in 1969. For this purpose, historical terrestrial photographs (1966-2009) were re-analyzed from 2014 repeats, using an expert rating system with eight correspondents. An increase in forest was observed in the eastern and western edge of the SMNP at Sankaber and Imet Gogo (20-40%). In contrast, centrally in the SMNP (around Gich), the area covered with dense forest decreased with an estimated rate of -1.4% per decade. There is no significant effect (p > 0.05) of the boundary of the SMNP on woody vegetation change, because of continued anthropogenic pressure (especially wood cutting and livestock grazing) inside the SMNP. Also elevation and distance to scout camps do not affect rates of change, and however, the density of houses within 2.2 km (a proxy of population pressure) is able to explain 32% of the spatial distribution of woody vegetation decrease (p < 0.05). A subset of six repeated photographs, indicated an uplift of the treeline by more than 1 m year(-1), in areas with low anthropogenic pressure. This is potentially related to increasing (average annual) temperature warming of up to 1.5 degrees C over the past 50 years. Overall, further reduction in anthropogenic pressure is urgent and crucial for recovery of the afro-alpine vegetation and the interrelated endangered wildlife in the Simien Mountains