Vertical stratification of plant-pollinator interactions in a temperate grassland
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Author and article information
Abstract
Visitation of plants by different pollinators depends on individual plant traits, spatial context, and other factors. A neglected aspect of small-scale variation of plant-pollinator interactions is the role of vertical position of flowers. We conducted a series of experiments to study vertical stratification of plant-pollinator interactions in a dry grassland. We observed flower visitors on cut inflorescences of Centaurea scabiosa and Inula salicina placed at different heights above ground in two types of surrounding vegetation: short and tall. Even at such a small-scale, we detected significant shift in total visitation rate of inflorescences in response to their vertical position. In short vegetation, inflorescences close to the ground were visited more frequently, while in tall vegetation, inflorescences placed higher received more visits. Moreover, we found major differences in the composition of the pollinator community on flowers at different heights. In a second experiment, we measured flower visitation rate in inflorescences of Salvia verticillata of variable height. Total flower visitation rate increased markedly with inflorescence height in this case. Data on seed set of individual plants provide evidence for a corresponding positive pollinator-mediated selection on increased inflorescence height. Overall, our results demonstrate strong vertical stratification of plant-pollinator interactions at the scale of mere decimetres. This may have important ecological as well as evolutionary implications.
Cite this as
2018. Vertical stratification of plant-pollinator interactions in a temperate grassland. PeerJ Preprints 6:e3471v2 https://doi.org/10.7287/peerj.preprints.3471v2note This preprint is not peer-reviewed. You may wish to reference the subsequent peer-reviewed version of this article.
Author comment
We modified the analysis of data on seed set of Salvia verticillata based on reviewers' comments, and made numerous minor changes to the text. Figures 2, 8, and 9 were modified.
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Supplemental Information
Complete inflorescence visitation data from the experiment on the role of inflorescence height and the height of the surrounding vegetation in Centaurea scabiosa and Inula salicina
The number of inflorescence visits on individual plants in experimental transects surrounded by short or tall vegetation is shown for each flower visitor species or group.
Total visitation of inflorescences of Salvia verticillata depending on inflorescence height
Total number of visitors arriving in each inflorescence during one recording period of approximately 30 minutes is provided for three ramets per plant differing in inflorescence height. Total number of flower visits during the recording period is also provided because most visitors probed multiple flowers per inflorescence visit.
Records of individual visits of inflorescences of Salvia verticillata
Identity of a flower visitor and the number of flowers probed is provided for each inflorescence visit on individual plants. Three ramets per plant were observed and can be distinguished by different inflorescence height.
Seed set in individual ramets of Salvia verticillata in relation to inflorescence height
The number of flowers and the number of developed seeds was counted in individual whorls in inflorescences of each Salvia verticillata plant. Three ramets differing in inflorescence height were used in each plant. Inflorescences were composed of the main stem and usually 1-2 side branches; which were counted separately.
Additional Information
Competing Interests
The authors declare that they have no competing interests.
Author Contributions
Jan Klecka conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft.
Jiří Hadrava performed the experiments, contributed reagents/materials/analysis tools, authored or reviewed drafts of the paper, approved the final draft.
Pavla Koloušková performed the experiments, contributed reagents/materials/analysis tools, authored or reviewed drafts of the paper, approved the final draft.
Data Deposition
The following information was supplied regarding data availability:
The raw data is included in the manuscript (Tables S1, S2, S3, and S4).
Funding
This study was supported by the Czech Science Foundation (projects GP14-10035P and GJ17-24795Y). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
