Characteristics of the 14 Belgian populations of Comarum palustre.

“Flower density” is the mean number of open flowers recorded on 1-m2 plots (±SE; n = 15) per population. “Population surface” is the area covered by individuals of C. palustre. “Population closure” is the proportion of the population edge that is constituted of woody elements. “Population isolation” is the percentage of woody area cover in a 500 m radius from the centre of the population. The number of 10-min insect observation periods performed per population (Nobs), abundance (i.e. total number of individuals) and mean visitation rate (i.e. ratio between the number of visited flowers and open flowers within 1-m2 plot) per 10-min insect observation periods of bumble bees, solitary bees and other insects are also provided. Observations were conducted for three years in seven populations (Joubiéval, Regné, Odrimont, Stockem, Vance, Pisserotte and Chantemelle), two years in four populations (Fosse, Bra, Bihain, La Gotale) and one flowering season in three populations (Grendel, Heinsch and Sainte-Marie). Populations are arranged by increasing population closure.