scholarly journals Experimental loss of generalist plants reveals alterations in plant-pollinator interactions and a constrained flexibility of foraging

2018 ◽  
Author(s):  
Paolo Biella ◽  
Asma Akter ◽  
Jeff Ollerton ◽  
Sam Tarrant ◽  
Štěpán Janeček ◽  
...  
Keyword(s):  
Plant Traits ◽  
Sugar Content ◽  
Ecosystem Dynamics ◽  
Pollinator Effectiveness ◽  
Flower Visitor ◽  
Flower Visitors ◽  
Flower Visitation ◽  
Key Species ◽  
High Sugar Content ◽  
Plant Pollinator

AbstractSpecies extinctions undermine ecosystem functioning but species do not disappear at random. Ecosystem dynamics are ruled by a subset of dominant species, but it is not clear how losing several of these key species would affect plant-pollinator interactions. We tested how the experimental loss of the most highly visited generalist plants would affect flower visitor abundances (visitation) and pollinator effectiveness (quantity of pollen-tubes within pistils) in several sites. Significant changes in the plant-pollinator communities were detected. Firstly, visitation decreased after removing 1-2 most visited plants, suggesting that these species mostly facilitate other plants by keeping high flower visitor abundances in the sites. Nevertheless, we recorded within-site variations of these trends, especially among sampled transects and among plant species, suggesting that complex facilitation-competition interactions occur among plants, but that these vary among transects within the same sites. Pollinator effectiveness fluctuated but not in a clear linear way and was not directly linked to changes of flower visitation. This suggests that fluctuations of pollinator effectiveness might be due to destabilization of the pollinators by the removal of key resources. In addition, we detected a constrained flexibility of the foraging of flower visitors because they did not switch among flower shapes and they favoured specific plant traits such as high sugar content, small inflorescences and taller plants. Indeed, these constraints would eventually limit utilisation of new resources after perturbations, possibly undermining the stability of the system. In conclusion, our work demonstrates that the loss of dominant, highly generalist plants alters plant-pollinator interactions with implications for pollination and insect foraging. Therefore, in order to preserve ecosystems, generalist plants should not get lost, because they sustain the complex pattern of interactions between plants and flower visitors.

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 Contrasting pollination efficiency and effectiveness among flower visitors of Malva sylvestris, Borago officinalis and Onobrychis viciifolia

2017 ◽  
Vol 21 ◽  
Author(s):  
Anna Gorenflo ◽  
Tim Diekötter ◽  
Mark Van Kleunen ◽  
Volkmar Wolters ◽  
Frank Jauker
Keyword(s):  
Plant Species ◽  
Pollen Deposition ◽  
Pollinator Effectiveness ◽  
Borago Officinalis ◽  
Flower Visitor ◽  
Flower Visitors ◽  
Onobrychis Viciifolia ◽  
Single Visit ◽  
Malva Sylvestris ◽  
Visitation Frequency

Biotic pollination is an important factor for ecosystem functioning and provides a substantial ecosystem service to human food security. Not all flower visitors are pollinators, however, and pollinators differ in their pollination performances. In this study, we determined the efficiencies of flower visitors to the plant species Malva sylvestris, Borago officinalis and Onobrychis viciifolia by analysing stigmatic pollen deposition. We further calculated pollinator effectiveness by scaling up single-visit pollen deposition using visitation frequency. Flower-visitor groups differed in their efficiencies at the single-visit level and not all of them deposited more pollen compared to unvisited stigmas. Bumblebees tended to be most efficient in depositing pollen per single visit across the three plant species. Due to the by far highest visitation frequencies, Apis mellifera showed the highest effectiveness in depositing pollen per hour for M. sylvestris and B. officinalis, but not for O. viciifolia, for which the Bombus lapidarius complex was both the most frequent and the most effective pollinator group. Hence, the most frequent flower visitors were most effective in our study. For non-dominant pollinator groups, however, visitation frequencies contributed disproportionally to pollinator effectiveness. Thus, combining pollen deposition per single-visit with visitation frequency is necessary to reveal true pollinator performance and to better understand flower-visitor interactions. 

scholarly journals Connectance of Brazilian social bee: food plant networks is influenced by habitat, but not by latitude, altitude or network size

2005 ◽  
Vol 5 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Jacobus C. Biesmeijer ◽  
E. Judith Slaa ◽  
Marina Siqueira de Castro ◽  
Blandina Felipe Viana ◽  
Astrid de M. P. Kleinert ◽  
...  
Keyword(s):  
Network Size ◽  
Urban Environments ◽  
Food Plants ◽  
Atlantic Rain Forest ◽  
Flower Visitor ◽  
Flower Visitors ◽  
Social Bees ◽  
Plant Flower ◽  
Plant Pollinator ◽  
Social Bee

Several recent studies suggest that the level of generalization (measured as percentage connectance) of plant-pollinator networks has several ecological correlates, e.g. latitude and altitude. Here we report on levels of generalization in 27 two-mode networks of social bees and their food plants in various Brazilian habitats and urban environments. Social bees are generalist foragers and are among the most abundant flower visitors in Brazil. They probably account for 30-50% of all plant - flower visitor interactions. Connectance was significantly influenced by habitat. Cerrado forests showed lower connectance than the dry dune habitats, with Atlantic rain forest and urban sites taking intermediate position and arid Caatinga being similar to dunes. This shows that generalization in a plant - flower visitor community can be influenced by habitat even within a group of generalist flower visitors, in our case social bees. We show that the strength of the interactions is not different between Cerrado and semi-arid habitats (dunes and Caatinga) and discuss other explanations for our findings.

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.

Harvest Field Sizing as a Technique to Remove Undersize French Prunes

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 452a-452
Author(s):  
Richard Buchner ◽  
Seeley Mudd ◽  
Bruce Carroll ◽  
Mark Gilles
Keyword(s):  
Sugar Content ◽  
Economic Value ◽  
Market Value ◽  
Dry Weight ◽  
Soluble Solids ◽  
Field Size ◽  
Test Machine ◽  
Test Field ◽  
Marginal Value ◽  
High Sugar Content

Overall profitability is a major goal in successful prune production and a major component in any prune management system. Large prune crops in 1996 and 1997 have stimulated considerable interest in undersize fruit. Undersize prunes currently have marginal value and may represent a net loss because of costs to haul, dry, and to market order payments on low value prunes. One technique to control delivery size is to field size at harvest. Field sizing involves installing size-sorting devices on harvesters, which allow small prunes to fall out while valuable fruit is collected. Field sizing is considered a “risky” strategy because of the potential to remove prunes with economic value. During the 1997 harvest, 21 infield harvest sizing evaluations were made in prune orchards throughout Tehama county. The first evaluation occurred on 12 Aug. 1997, at the start of prune harvest. The final evaluation was done on 5 Sept. 1997, at the tail end of harvest. The objective was to sample throughout the harvest period to test field sizing under various sugar, size, and fruit pressure scenarios. The test machine was 1-inch bar sizer. Of the 21 sample dates, undersize fruit was clearly not marketable in 20 of the 21 samples. Discarded fruit averaged 133 dry count per pound. Only one sample out of 21 may have had market value at 86 dry count per pound. Although small in size, these prunes had very high sugar content contributing to their dry weight. In this evaluation, a 1-inch bar sizer did a good job of separating fruit with and without market value under the 1997 price schedule. As harvest date becomes later and soluble solids increase, the chances of sorting out marketable prunes also increases.

scholarly journals The “Zero Miles Product” Concept Applied to Biofuel Production: A Case Study

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 565
Author(s):  
Nikolaj Kaae Kirk ◽  
Clara Navarrete ◽  
Jakob Ellegaard Juhl ◽  
José Luis Martínez ◽  
Alessandra Procentese
Keyword(s):  
Sugar Content ◽  
Point Of View ◽  
Biofuel Production ◽  
Transport Costs ◽  
Economic Point ◽  
Product Concept ◽  
Energy Demands ◽  
Production Platform ◽  
High Sugar Content

To make biofuel production feasible from an economic point of view, several studies have investigated the main associated bottlenecks of the whole production process through approaches such as the “cradle to grave” approach or the Life Cycle Assessment (LCA) analysis, being the main constrains the feedstock collection and transport. Whilst several feedstocks are interesting because of their high sugar content, very few of them are available all year around and moreover do not require high transportation’ costs. This work aims to investigate if the “zero miles” concept could bring advantages to biofuel production by decreasing all the associated transport costs on a locally established production platform. In particular, a specific case study applied to the Technical University of Denmark (DTU) campus is used as example to investigate the advantages and feasibility of using the spent coffee grounds generated at the main cafeteria for the production of bioethanol on site, which can be subsequently used to (partially) cover the campus’ energy demands.

Seven-year trends in the availability, sugar content and serve size of single-serve non-alcoholic beverages in New Zealand: 2013–2019

2020 ◽  
pp. 1-13
Author(s):  
Teresa Gontijo de Castro ◽  
Helen Eyles ◽  
Cliona Ni Mhurchu ◽  
Leanne Young ◽  
Sally Mackay
Keyword(s):  
New Zealand ◽  
Sugar Content ◽  
Food Composition ◽  
Soft Drinks ◽  
Alcoholic Beverages ◽  
Slight Reduction ◽  
Cross Sectional ◽  
Sweetened Beverages ◽  
Sugary Drinks ◽  
High Sugar Content

Abstract Objective: To assess trends in relative availability, sugar content and serve size of ready-to-drink non-alcoholic beverages available for sale in supermarkets from 2013 to 2019. Design: Repeat cross-sectional surveys. Data on single-serve beverages to be consumed in one sitting were obtained from an updated brand-specific food composition database. Trends in beverages availability and proportions with serve size ≤ 250 ml were assessed by χ2 tests. Sugar content trends were examined using linear regressions. The proportion of beverages exceeding the sugar threshold of the United Kingdom Soft Drinks Industry Levy (SDIL) was assessed. Setting: New Zealand. Results: From 2013 to 2019, there was (i) an increase in the availability of sugar-free/low-sugar beverages (n 25 (8·4 %) to n 75 (19·1 %); P < 0·001) and craft sugar-sweetened soft drinks (n 11 (3·7 %) to n 36 (9·2 %); P < 0·001), and a decrease in availability of fruit/vegetable juices/drinks (n 94 (31·8 %) to n 75 (19·4 %); P < 0·001); (ii) small decreases in sugar content (mean g/100 ml) of sugar-sweetened soft drinks (3·03; 95 % CI 3·77, 2·29); fruit/vegetable juices/drinks (1·08; 95 % CI 2·14, 0·01) and energy drinks (0·98; 95 % CI 1·63, 0·32) and (iii) slight reduction in the proportion of beverages with serve size ≤ 250 ml (21·6 to 18·9 %; P < 0·001). In 2019, most beverages were sugar-sweetened or had naturally occurring sugars (79·1 %) and serve size > 250 ml (81·1 %) and most sugar-sweetened beverages exceeded the SDIL lower benchmark (72·9 %). Conclusions: Most single-serve beverages available for sale in 2019 were sugary drinks with high sugar content and large serve sizes; therefore, changes made across the years were not meaningful for population’s health.

Feasibility of utilizing sweet potato solids in extrusion cooking / Extrusión de pulpa de batata

1997 ◽  
Vol 3 (3) ◽  
pp. 171-174 ◽  
Author(s):  
H.M. Khalil ◽  
B.R. Henry
Keyword(s):  
Moisture Content ◽  
Sweet Potato ◽  
Sugar Content ◽  
Expansion Ratio ◽  
Fractional Factorial ◽  
Snack Food ◽  
Screw Speed ◽  
High Sugar Content ◽  
Feed Moisture ◽  
Best Parameter

A fractional factorial design of four variables at two levels each was employed to assess the feasi bility and best parameter for extruding sweet potato solids (SPS) using a single screw extruder. It was determined that a high expansion ratio is a desired quality factor for this type of snack food, due to its contribution to textural perception. Preliminary trials on extrusion of sweet potato solids as the sole component in the feed resulted in brittle, dense, and burnt extrudate. The high sugar content (65% total sugar) of the sweet potato solids was cited as the cause of these attrib utes, consequently it was necessary to incorporate wheat flour into the feed to provide a starch matrix for expansion and to reduce sugar concentration. The controlled parameters were screw speed, barrel temperature, feed moisture content, and SPS level in the feed. Among all possible combinations of controlled parameters, the highest expansion ratio was obtained at a screw speed of 220 rpm, temperature profile of 110, 105, 115 and 105 °C, 13% feed moisture content, 50% sweet potato solids, and 0.5% leavening agent.

Productivity of binary herbage based on non-traditional forage crops in the Upper Volga region

2021 ◽  
Author(s):  
N. V. Shmeleva ◽  
Keyword(s):  
Species Composition ◽  
Sugar Content ◽  
Field Studies ◽  
Volga Region ◽  
Forage Crops ◽  
High Sugar ◽  
Upper Volga ◽  
High Sugar Content ◽  
The Upper Volga Region

The article presents the results of field studies aimed at expanding the species composition of herbs and the search for adaptive cereals with a high sugar content in the Upper Volga region in 2015-2020.

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