Complexity and dynamics of plant–pollinator (Hymenoptera: Apoidea) interaction networks: habitat fragmentation in the cork oak forest of Larache, Morocco

Mediterranean cork oak forests face disturbances from both natural and human factors that threaten the interactions of plant-flower visitors that are essential for ecosystem functioning. This study explores the dynamics of plant-flower visitor networks, focusing on bees, across three forest habitats at Larache, Morocco, during fieldwork conducted between mid-March and mid-July 2023. The results show that the plant-flower visitor network in the dense forest is structured in well-defined modules of plants and flower visitors and a high level of nestedness, a good equilibrium between specialized and generalist flower visitors, leading to a stable and complex ecosystem. In contrast, the open forest exhibited a simplified network dominated by generalist species, disorganized modules and a decrease in species number of flower visitors, and hence would present a short-term stability but insufficient to sustain long-term ecological resilience. The forest edge demonstrated the highest diversity of flower visitors due to habitat heterogeneity and abundant resources, leading to a strong competition between flower visitors, and a decrease of their global specialization degree, leading to less stability.