Data from: Do you reap what you sow? Temporal dynamics of insect-relevant floral characteristics of flower strip mixtures

The implementation of flower strips in agroecosystems is an effective
measure to counteract the loss of biodiversity and enhance ecosystem
services. Although beneficial effects for their main target group,
flower-visiting insects, are assumed to be mediated by plant species
composition and its associated floral characteristics, such as species
richness and floral trait diversity, comprehensive studies investigating
the establishment success and maintenance of different flower strip
mixtures over time are rare. Therefore, we studied the performance of four
different flower strip mixtures (two annual and two perennial) regarding
their potential benefits in supporting flower visitors by evaluating
spatio-temporal dynamics of plant community composition and six
insect-relevant floral characteristics in a field experiment at three
distinct study sites over three consecutive years. Moreover, we examined
the impact of weed invasion on flower strips and how realized mixture
performance under field conditions deviates from expected mixture
performance. We found that both perennial flower strip mixtures undergo a
significant community shift due to compositional changes in sown plant
species after the year of sowing, strongly affecting mixture performance
over time. The mixture with the highest initially sown species richness
(51) outperformed all other mixtures after the year of sowing, regarding
taxonomic (species richness and Shannon diversity) as well as functional
floral characteristics (functional diversity and redundancy). Furthermore,
deviation from expected mixture performance in both annual mixtures was
largely explained by weed invasion, whereas in perennial mixtures,
deviation was mainly caused by community changes in sown plant species
(e.g. disproportional dominance of single species). We argue that
perennial mixtures with a high number of native plant species provide a
greater quantity of floral resources with more diverse niches for
flower-visiting insects, with a greater resilience and temporal
persistence than annual and less diverse mixtures.