Is flowering in grasslands, wetlands and arable land temporarily complementary? A test using Swedish citizen science data

• Flowering phenology of three vegetation types were compared. • Grassland, arable land, and wetlands differend in start and peak of flowering. • Vegeation types can by temporarily complementary, to the benefit of pollinators. Is the phenology of flowering in different habitat types coinciding or temporarily complementary? We addressed this issue using citizen science observations from southern Sweden of flowering of groups of species confined to arable land, grassland or wetland. The vectors of the flowering dates, a proxy for peak flowering, differed with up to three weeks (grassland vs wetland). The start of flowering showed even larger differences (38 days between arable land and wetland) while the termination of flowering was relatively similar among vegetation types. The flowering season was longer on arable land (circular SD 20 days longer than grassland and wetland). There was a trend during the 16-year study period for the the flowering period ending progressively later in the year. Hence, flowering phenology differed somewhat among vegetation types, and that taken together, multiple vegetation types provide a longer period of floral resources for pollinators than any singular one. Hence, a small-scale, varied landscape would be mor conducive to pollinator populations than more homogeneous ones.