Bird species richness in artificial plantations and natural forests in a North African agroforestry system: assessment and implications

Watershed tree plantations in Morocco are expanding under the National Watershed Management Plan and thus their value for native fauna and agroforestry system dynamics requires investigation. Using generalized linear mixed models, we assessed the relative value of artificial habitats-olive and eucalypt plantations-over four seasonal periods, by comparing their avifauna richness to those of natural habitats-Thuya forests. Bird species richness depended on both habitat type and season. Our results showed that natural Thuya forests supported higher bird diversity than both olive and eucalypt plantations. Moreover, bird diversity was higher in eucalyptus plantations compared to olive plantations during the winter period, while the opposite trend was observed in autumn. A principal component analysis also revealed a significant positive effect of shrub layer complexity (PC1) in all seasons, habitat artificiality (PC3) in spring, breeding season, and autumn, and tree size (PC2) during winter and autumn. Overall, our findings stress that, in our study area, artificial plantations do not have the same ecological value as the original habitat. We therefore advise restoring native forests rather than reforesting eucalypt species. Research programs should continue in order to assess the impact of conservation actions on biodiversity and determine how this agroforestry system would change under the increasingly detrimental effects of drought.