scholarly journals Effects of the availability of floral resources and neighboring plants on nectar robbery in a specialized pollination system

2021 ◽  
Author(s):  
Júlia Mendonça Almeida ◽  
Caio César Corrêa Missagia ◽  
Maria Alice Santos Alves
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Floral Resources ◽  
Floral Display ◽  
Nectar Robbing ◽  
Mixed Species ◽  
Individual Level ◽  
Nectar Foraging ◽  
Nectar Robbery

Abstract Many plants pollinated by nectar-foraging animals have to maintain a balance between legitimate visitor attraction strategies and mechanisms that minimize illegitimate visits. This study investigated how floral display and neighboring species composition influences nectar robbing in the tropical ornithophilous herb Heliconia spathocircinata. We tested the role of inflorescence display, flower abundance, and neighboring species in the reduction of nectar robbing in H. spathocircinata. Our results indicate that nectar robbing hummingbird activity was higher in moderately large inflorescence displays and that the frequency of nectar robbing in H. spathocircinata decreases with increased flower abundance and the presence of neighboring plant species. Neighboring non-ornithophilous plants decreased the frequency of nectar robbing in H. spathocircinata flowers to a greater extent than ornithophilous ones. These results suggest that nectar robbing hummingbirds are attracted to similar conditions that attract legitimate visitors, and that spatial aggregation and mixed-species displays may represent a mechanism to dilute nectar robbing effects at an individual level.

scholarly journals Not all interactions are positive: testing how antagonistic interactions impact the robustness of plant-pollinator networks

2019 ◽  
Author(s):  
Heather M. Briggs ◽  
Carolyn A. Ayers ◽  
Paul R. Armsworth ◽  
Berry J. Brosi
Keyword(s):  
Plant Species ◽  
Ecological Systems ◽  
Network Robustness ◽  
Floral Resources ◽  
Nectar Robbing ◽  
Full Spectrum ◽  
Pollinator Species ◽  
Plant Pollinator ◽  
Topological Robustness ◽  
Antagonistic Interactions

AbstractGiven ongoing pollinator declines, it is important to understand the dynamics of linked extinctions of plants driven by pollinator extinctions. Topological robustness models focused on this question suggest relatively high robustness of plant species to pollinator species extinctions. Still, existing robustness models typically assume that all interactions in plant-pollinator networks are positive, which is clearly not always the case. For example, many pollinators remove floral resources with-out transferring pollen, or even damage floral structures in the case of nectar robbing. Here we introduce antagonistic interactions into plant-pollinator networks and assess the resilience of plant communities to pollinator species losses. Incorporating antagonistic interactions leads to lower network robustness, i.e. an increased rate of plant species loss (as compared to networks with only mutualistic interactions) in empirical plant-pollinator networks. In conjunction with extinction order, the addition of increasingly antagonistic interactions was idiosyncratic in that it did not always magnify the effects of extinction order across the three networks. These results underscore the importance of considering the full spectrum of interaction outcomes when assessing robustness to coextinctions in plant-pollinator networks, as well as other ecological systems.

scholarly journals Testing how antagonistic interactions impact the robustness of plant-pollinator networks

2019 ◽  
Vol 25 ◽  
Author(s):  
Heather Briggs ◽  
Carolyn A. Ayers ◽  
Paul R. Armsworth ◽  
Berry J. Brosi
Keyword(s):  
Plant Species ◽  
Ecological Systems ◽  
Network Robustness ◽  
Floral Resources ◽  
Nectar Robbing ◽  
Full Spectrum ◽  
Pollinator Species ◽  
Plant Pollinator ◽  
Topological Robustness ◽  
Antagonistic Interactions

Given ongoing pollinator declines, it is important to understand the dynamics of linked extinctions of plants driven by pollinator extinctions. Topological robustness models focused on this question suggest relatively high robustness of plant species to pollinator species extinctions. Still, existing robustness models typically assume that all interactions in plant-pollinator networks are positive, which is clearly not always the case. For example, many pollinators remove floral resources without transferring pollen, or even damage floral structures in the case of nectar robbing. Here we introduce antagonistic interactions into plant-pollinator networks and assess the resilience of plant communities to pollinator species losses. Incorporating antagonistic interactions leads to lower network robustness, i.e. an increased rate of plant species loss (as compared to networks with only mutualistic interactions) in empirical plant-pollinator networks. In conjunction with extinction order, the addition of increasingly antagonistic interactions was idiosyncratic in that it did not always magnify the effects of extinction order across the three networks. These results underscore the importance of considering the full spectrum of interaction outcomes when assessing robustness to coextinctions in plant-pollinator networks, as well as other ecological systems.

Long-term dynamics and destruction of marsh vegetation in the Kolokolkova Bay of the Barents Sea

2012 ◽  
pp. 66-77 ◽  
Author(s):  
I. A. Lavrinenko ◽  
O. V. Lavrinenko ◽  
D. V. Dobrynin
Keyword(s):  
Species Composition ◽  
Plant Communities ◽  
Barents Sea ◽  
Mean Value ◽  
Marsh Vegetation ◽  
Composition And Structure ◽  
The Mean ◽  
Species Composition And Structure

The satellite images show that the area of marshes in the Kolokolkova bay was notstable during the period from 1973 up to 2011. Until 2010 it varied from 357 to 636 ha. After a severe storm happened on July 24–25, 2010 the total area of marshes was reduced up to 43–50 ha. The mean value of NDVI for studied marshes, reflecting the green biomass, varied from 0.13 to 0.32 before the storm in 2010, after the storm the NDVI decreased to 0.10, in 2011 — 0.03. A comparative analysis of species composition and structure of plant communities described in 2002 and 2011, allowed to evaluate the vegetation changes of marshes of the different topographic levels. They are fol­lowing: a total destruction of plant communities of the ass. Puccinellietum phryganodis and ass. Caricetum subspathaceae on low and middle marches; increasing role of halophytic species in plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. typicum on middle marches; some changes in species composition and structure of plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. festucetosum rubrae on high marches and ass. Parnassio palustris–Salicetum reptantis in transition zone between marches and tundra without changes of their syntaxonomy; a death of moss cover in plant communities of the ass. Caricetum mackenziei var. Warnstorfia exannulata on brackish coastal bogs. The possible reasons of dramatic vegetation dynamics are discussed. The dating of the storm makes it possible to observe the directions and rates of the succession of marches vegetation.

Becoming the Demon Woman

2017 ◽  
Author(s):  
Per Faxneld
Keyword(s):  
Cultural Context ◽  
Silent Film ◽  
Femme Fatale ◽  
Individual Level

Chapter9 analyses individuals who, both on and off the stage, actively assumed the role of the demon woman. Three persons are considered in detail: Sarah Bernhardt, the Italian marchioness Luisa Casati, and silent film actress Theda Bara. They chose—or, in Bara’s case, were chosen—to embody the (more or less supernatural or occult) femme fatale, as constructed mostly by male authors and artists. Seemingly, they felt this was empowering or useful for commercial, subversive, or other purposes. The analysis attempts to tease out some of the implications this enactment of a disquieting stereotype had on an individual level as well as in a broader cultural context. This also applies to the unknown women who wore jewellery depicting devils, demons, or Eve—a rebellious token clearly drawing on motifs familiar from Satanic feminism.

Creativity in Sociocultural Systems

2019 ◽  
pp. 269-284
Author(s):  
Dean Keith Simonton
Keyword(s):  
Macro Level ◽  
Historical Overview ◽  
Creative Activity ◽  
Cross Sectional ◽  
Individual Level ◽  
Short And Long Term ◽  
The Cross ◽  
Sociocultural Systems

Although psychologists typically see creativity as an individual-level event, sociologists and cultural anthropologists are more likely to view it as a sociocultural phenomenon. This phenomenon takes place at the level of relatively large and enduring collectives, such as cultures, nations, and even whole civilizations. This chapter reviews the extensive research on such macro-level creativity. The review begins with a historical overview before turning to the cross-sectional research on the creative Ortgeist, a subject that encompasses the factors that influence the relative creativity of both preliterate cultures and entire modern nations. From there the chapter turns to role of the Zeitgeist in affecting the creativity of civilizations across time—the rise and fall of creative activity. This research examines both quantitative and qualitative causes that operate both short- and long-term.

Plant species surplus in recent peri-urban forests: the role of forest connectivity, species’ habitat requirements and dispersal types

2021 ◽  
Vol 30 (2) ◽  
pp. 365-384
Author(s):  
Elena Tello-García ◽  
Nancy Gamboa-Badilla ◽  
Enrique Álvarez ◽  
Laura Fuentes ◽  
Corina Basnou ◽  
...  
Keyword(s):  
Plant Species ◽  
Urban Forests ◽  
Habitat Requirements ◽  
Forest Connectivity ◽  
Dispersal Types
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