Assessing Human Impact on Southern Mediterranean Forests: Novel Anthropogenic Pollen Indicators from Rif Mountains

The study of modern pollen and vegetation relationships is vital for interpreting fossil pollen records and assessing human impacts on forests, both of which are essential for effective forest management strategies. Despite numerous studies on fossil pollen records in the Rif landscape, there is a notable lack of research specifically focusing on modern pollen and its implications for understanding human impacts on these forests. This paper introduces novel anthropogenic pollen indicators for the Rif Mountains and aims to evaluate the gradients of human impact on the forests of the southern Mediterranean. A combination of modern pollen studies, vegetation surveys, and ordination techniques using both quantitative and presence/absence data were employed, along with various environmental and land-use variables. Canonical correspondence analysis enabled us to assess the relationships between pollen types and environmental variables, allowing us to identify the most anthropogenic pollen indicators associated with land use and human practices, (e.g., Poaceae, Cannabis-t, Olea-t, and Asteraceae). Furthermore, an anthropogenic index score (AIS) was calculated for each sampled location to correlate pollen types with specific levels of human impact using correspondence analysis (CA). These levels were categorised as (a) low (e.g., Cedrus atlantica and Quercus canariensis), (b) moderate (e.g., Erica-t, Arbutus unedo, and Alnus-t), and (c) high (e.g., Cannabis-t, Pistacia lentiscus-t, and Plantago-t).