Holocene Environmental Changes In The Rif Mountains Morocco

ABSTRACT After the last glacial period the significantly increase of global temperature has dramatically impacted the ecosystems functioning. The aim of this study is to understand the impact of past climate change on vegetation especially on two emblematic species in Morocco which are Cedrus atlantica Manetti ex Endl. Carrire and Abies maroccana Trabut. Here we present the results of 8.5m fossil record collected in the western part of the Rif Mountains covering more than 9000 cal BP years. The age model is based on 10 AMS 14C dates. Pollen content charcoal remains particles size and some geochemical elements were analyzed. Besides the geological coring a series of surface samples from Talassemtane National Park towards our coring site were collected to determine the range of pollen transport. The fossil record showed that Atlas cedar was strongly present since the early Holocene however after 6000 cal BP it declines aggressively due probably to a climate change and their replacement with more drought-tolerant evergreen species then disappeared from the studied site at about 2000 cal BP. The Moroccan fir was not recorded during the Holocene except for few pollen grains during the last 1000 years probably transported from few fir populations that were present not far from the studied site. This hypothesis was confirmed by the modern samples showing that fir pollen is transported on very short distances. The overall data tend to suggest that the decline of Cedar forests in the Rif is probably related to natural factors rather than to anthropogenic activities.