scholarly journals Vertical stratification of plant-pollinator interactions in a temperate grassland

2017 ◽  
Author(s):  
Jan Klecka ◽  
Jiří Hadrava ◽  
Pavla Koloušková
Keyword(s):  
Vertical Stratification ◽  
Small Scale ◽  
Vertical Position ◽  
Significant Shift ◽  
Visitation Rate ◽  
Flower Visitation ◽  
Pollinator Community ◽  
Series Of Experiments ◽  
Using Data ◽  
Plant Pollinator

Interactions between plants and their pollinators vary in time and space at different scales. 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 high 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. Overall flower visitation rate increased markedly with inflorescence height. We also detected a corresponding positive pollinator-mediated selection on increased inflorescence height using data on seed set of individual plants. Overall, our results demonstrate strong vertical stratification of plant-pollinator interactions at the scale of mere decimetres. This may be an important, albeit underappreciated, driver of plant-pollinator coevolution.

scholarly journals Vertical stratification of plant–pollinator interactions in a temperate grassland

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4998 ◽  
Author(s):  
Jan Klecka ◽  
Jiří Hadrava ◽  
Pavla Koloušková
Keyword(s):  
Plant Traits ◽  
Vertical Stratification ◽  
Small Scale ◽  
Vertical Position ◽  
Individual Plant ◽  
Significant Shift ◽  
Visitation Rate ◽  
Flower Visitation ◽  
Pollinator Community ◽  
Plant Pollinator

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 ofCentaurea scabiosaandInula salicinaplaced 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 ofSalvia verticillataof 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.

scholarly journals Vertical stratification of plant-pollinator interactions in a temperate grassland

2018 ◽  
Author(s):  
Jan Klecka ◽  
Jiří Hadrava ◽  
Pavla Koloušková
Keyword(s):  
Plant Traits ◽  
Vertical Stratification ◽  
Small Scale ◽  
Vertical Position ◽  
Individual Plant ◽  
Significant Shift ◽  
Visitation Rate ◽  
Flower Visitation ◽  
Pollinator Community ◽  
Plant Pollinator

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.

scholarly journals Vertical stratification of plant-pollinator interactions in a temperate grassland

2018 ◽  
Author(s):  
Jan Klecka ◽  
Jiří Hadrava ◽  
Pavla Koloušková
Keyword(s):  
Plant Traits ◽  
Vertical Stratification ◽  
Small Scale ◽  
Vertical Position ◽  
Individual Plant ◽  
Significant Shift ◽  
Visitation Rate ◽  
Flower Visitation ◽  
Pollinator Community ◽  
Plant Pollinator

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.

scholarly journals Effects of small-scale clustering of flowers on pollinator foraging behaviour and flower visitation rate

2017 ◽  
Author(s):  
Asma Akter ◽  
Paolo Biella ◽  
Jan Klecka
Keyword(s):  
Foraging Behaviour ◽  
Spatial Clustering ◽  
Ideal Free Distribution ◽  
Handling Time ◽  
Optimal Foraging Theory ◽  
Foraging Strategies ◽  
Distribution Model ◽  
Small Scale ◽  
Visitation Rate ◽  
Flower Visitation

AbstractPlants often grow in clusters of various sizes and have a variable number of flowers per inflorescence. This small-scale spatial clustering affects insect foraging strategies and plant reproductive success. In our study, we aimed to determine how visitation rate and foraging behaviour of pollinators depend on the number of flowers per plant and on the size of clusters of multiple plants using Dracocephalum moldavica (Lamiaceae) as a target species. We measured flower visitation rate by observations of insects visiting single plants and clusters of plants with different numbers of flowers. Detailed data on foraging behaviour within clusters of different sizes were gathered for honeybees, Apis mellifera, the most abundant visitor of Dracocephalum in the experiments. We found that the total number of flower visitors increased with the increasing number of flowers on individual plants and in larger clusters, but less then proportionally. Although individual honeybees visited more flowers in larger clusters, they visited a smaller proportion of flowers, as has been previously observed. Consequently, visitation rate per flower and unit time peaked in clusters with an intermediate number of flowers. These patterns do not conform to expectations based on optimal foraging theory and the ideal free distribution model. We attribute this discrepancy to incomplete information about the distribution of resources. Detailed observations and video recordings of individual honeybees also showed that the number of flowers had no effect on handling time of flowers by honeybees. We evaluated the implications of these patterns for insect foraging biology and plant reproduction.

Student Perceptions of Community: A Different Perspective

NASPA Journal ◽  
1998 ◽  
Vol 35 (4) ◽  
Author(s):  
Jackie Clark ◽  
Joan Hirt
Keyword(s):  
Student Perceptions ◽  
Large Scale ◽  
Research University ◽  
Small Scale ◽  
Social Environments ◽  
Common Assumption ◽  
Small Communities ◽  
Public Research University ◽  
The Common ◽  
Using Data

The creation of small communities has been proposed as a way of enhancing the educational experience of students at large institutions. Using data from a survey of students living in large and small residences at a public research university, this study does not support the common assumption that small-scale social environments are more conducive to positive community life than large-scale social environments.

scholarly journals Asymmetric competition causes multimodal size distributions in spatially structured populations

2016 ◽  
Vol 283 (1823) ◽  
pp. 20152404 ◽  
Author(s):  
Jorge Velázquez ◽  
Robert B. Allen ◽  
David A. Coomes ◽  
Markus P. Eichhorn
Keyword(s):  
Resource Competition ◽  
Structured Populations ◽  
Necessary Condition ◽  
Small Scale ◽  
Asymmetric Competition ◽  
Size Distributions ◽  
Long Term Study ◽  
Multimodal Distributions ◽  
Using Data

Plant sizes within populations often exhibit multimodal distributions, even when all individuals are the same age and have experienced identical conditions. To establish the causes of this, we created an individual-based model simulating the growth of trees in a spatially explicit framework, which was parametrized using data from a long-term study of forest stands in New Zealand. First, we demonstrate that asymmetric resource competition is a necessary condition for the formation of multimodal size distributions within cohorts. By contrast, the legacy of small-scale clustering during recruitment is transient and quickly overwhelmed by density-dependent mortality. Complex multi-layered size distributions are generated when established individuals are restricted in the spatial domain within which they can capture resources. The number of modes reveals the effective number of direct competitors, while the separation and spread of modes are influenced by distances among established individuals. Asymmetric competition within local neighbourhoods can therefore generate a range of complex size distributions within even-aged cohorts.

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