plant-pollinator interactions Bayesian model hoverflies interaction probability latent block model latitudinal gradient mutualistic network phenology overlap species abundance structural equation model urbanization Dictamnus albus bees beta-diversity conservation biology conservation measures global changes interaction diversity land-use change modularity motifs mutualistic networks network pollinators Ammophila Ammophila arenaria Asteraceae Asterales Asteroideae Biota Community ecology-Poison log-normal models-sampling data Liliopsida Magnoliopsida Marram grass Narrow-leaved ragwort Plantae Poaceae Poales Population Ecology Senecio Senecio inaequidens South African ragwort Tracheophyta bipartite network disturbance flowering period global change gut microbiota information interaction networks