How does plant richness affect pollinator richness and temporal stability of flower visits?

• Published in: Oikos Vol. 117; no. 12; pp. 1808 - 1815
• Main Authors: Ebeling, Anne, Klein, Alexandra-Maria, Schumacher, Jens, Weisser, Wolfgang W., Tscharntke, Teja
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.12.2008; Blackwell Publishing Ltd; Blackwell Publishing; Blackwell
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Autoecology; Biodiversity; Biological and medical sciences; botanical composition; Bumblebees; community structure; Ecology; Flowering plants; Flowers; Flowers & plants; Fundamental and applied biological sciences. Psychology; General aspects; grasslands; Honey bees; Insect pollination; Magnoliophyta; plant competition; Plant reproduction; Plants; Plants and fungi; Pollen; Pollinating insects; pollination; Pollinators; soil fertility; Solitary bees; Species; statistical analysis; temporal variation; Community structure; Composition; Flower; Statistical analysis; Stability; Soil fertility; Diversity; Plot; Soil fauna; Pollinator; Reproduction; Animal plant relation; Angiospermae; Spermatophyta; Experimental plant; Community; Species richness
• ISSN: 0030-1299; 1600-0706
• DOI: 10.1111/j.1600-0706.2008.16819.x

Pollinators play a key role in the reproduction of most plant species, and pollinator and plant diversity are often related. We studied an experimental gradient of plant species richness for a better understanding of plant-pollinator community interactions and their temporal variability, because in non-experimental field surveys plant richness is often confounded with gradients in management, soil fertility, and community composition. We observed pollinator species richness and frequency of visits six times in 73 plots over two years, and used advanced statistical analysis to account for the high number of zeroes that often occur in count data of rare species. The frequency of pollinator visits increased linearly with both the blossom cover and the number of flowering plant species, which was closely related to the total number of plant species, whereas the number of pollinator species followed a saturation curve. The presence of particularly attractive plant species was only important for the frequency of flower visits, but not to the richness of pollinators. Plant species richness, blossom cover, and the presence of attractive plant species enhanced the temporal stability in the frequency of pollinator visits. In conclusion, grasslands with high plant diversity enhance and stabilize frequent and diverse flower visitations, which should sustain effective pollination and plant reproduction.