Fig. 2From: Flower strip networks offer promising long term effects on pollinator species richness in intensively cultivated agricultural areasChange through time of bee species richness and abundances between 2010 (before the enhancement measures) and 2015. Upper graphs refer to all species, lower graphs refer to oligolectic species, only. The green line marks the year 2011 when the enhancement measures were initiated; blue symbols: control area; red symbols: enhancement area. The clipart is freely available via https://openclipart.orgBack to article page