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.

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 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 Seasonal variation of plant-pollinator networks on oceanic island: lower specialization when resources are more abundant

2019 ◽  
Author(s):  
xiangping wang ◽  
Tong Zeng ◽  
Meihong Wen ◽  
Mingsong Wu ◽  
Dianxiang Zhang
Keyword(s):  
Seasonal Variation ◽  
Data Collection ◽  
Plant Species ◽  
Resource Availability ◽  
Oceanic Islands ◽  
Oceanic Island ◽  
Pollinator Species ◽  
Four Seasons ◽  
Floral Resource ◽  
Plant Pollinator

Abstract Background: The seasonal dynamics of plant and pollinator species components in the community could influence the structure of plant-pollinator networks. However, such dynamics are seldom been attention for oceanic islands networks. Here, we estimated the seasonal variation of seven plant-pollinator networks in Yongxing Island community. We collected a two-monthly data for each network of four seasons and used temporally discrete networks to characterize seasonal changes in plant-pollinator interactions. We predicted that greater floral resource availability in the season would allow for higher specialization patterns as previously described across large spatial gradients, with finer partitioning of the floral niche by the pollinators. Results: As we expected, we found that rainy season network with more plant species in bloom, showed higher levels of network-wide specialization and modularity. However, when we compared seven targeted sampling networks, both the network-wide specialization and modularity were negatively correlated with the number of plant species in bloom. There were no differences between rainy and dry seasons and among four seasons in species-level indices, suggesting that higher network level specialization may be an emergent property only seen when considering the entire network. Hawkmoths presented higher values of specialization in relation to other functional groups; and Apidae presented higher values of species strength than other functional groups. These results suggest some specialized plant species are visited only by Hawkmoths, and most plants associated with Apidae are used by this group. Conclusions: Our results suggested that, on oceanic island, increased floral resource availability in the season may not promote lower interspecific competition among pollinators leading to increased niche overlap, thus explaining the decreased in specialization. Plant-pollinator interactions data collection during dry, rainy season and all year-round generates lower network specialization than four seasons, and this may because that most pollinator species activity spans longer periods than a single season on islands. Thus, depending on the period of data collection, different networks structure of interaction may be found. Plant-pollinator networks have structural properties that vary according to seasons, and this should be taken into account in the studies of complex systems of interactions between plants and pollinators in oceanic islands communities.

Effects of climate on pollination networks in the West Indies

2009 ◽  
Vol 25 (5) ◽  
pp. 493-506 ◽  
Author(s):  
Ana M. Martín González ◽  
Bo Dalsgaard ◽  
Jeff Ollerton ◽  
Allan Timmermann ◽  
Jens M. Olesen ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Plant Species ◽  
West Indies ◽  
Relative Importance ◽  
The West ◽  
Pollinator Importance ◽  
Insect Pollinator ◽  
Pollinator Species ◽  
Plant Pollinator ◽  
Number Of Plant Species

Abstract:We studied the effect of climate on the plant-pollinator communities in the West Indies. We constructed plots of 200 m × 5 m in two distinct habitats on the islands of Dominica, Grenada and Puerto Rico (total of six plots) and recorded visitors to all plant species in flower. In total we recorded 447 interactions among 144 plants and 226 pollinator species. Specifically we describe how rainfall and temperature affect proportional richness and importance of the different pollinator functional groups. We used three measures of pollinator importance: number of interactions, number of plant species visited and betweenness centrality. Overall rainfall explained most of the variation in pollinator richness and relative importance. Bird pollination tended to increase with rainfall, although not significantly, whereas insects were significantly negatively affected by rainfall. However, the response among insect groups was more complex; bees were strongly negatively affected by rainfall, whereas dipterans showed similar trends to birds. Bird, bee and dipteran variation along the climate gradient can be largely explained by their physiological capabilities to respond to rainfall and temperature, but the effect of climate on other insect pollinator groups was more obscure. This study contributes to the understanding of how climate may affect neotropical plant-pollinator communities.

scholarly journals Many species, including locally rare species, are important for function of mutualist networks

2020 ◽  
Author(s):  
Dylan Simpson ◽  
Lucia Weinman ◽  
Mark Genung ◽  
Michael Roswell ◽  
Molly MacLeod ◽  
...  
Keyword(s):  
Plant Species ◽  
Ecosystem Function ◽  
Rare Species ◽  
Ecosystem Functions ◽  
Single Plant ◽  
Pollinator Species ◽  
Plant Pollinator ◽  
Entire Network ◽  
Number Of Plant Species

Many ecosystem functions result from mutualisms, yet mutualism-based functions have rarely been studied at the scale of whole mutualist networks. Thus, it is unclear how much biodiversity is needed to provide function to an entire network of partner species. Here we use 23 plant-pollinator networks to ask how the number of functionally important pollinator species depends on the number of plant species studied. We found that, because of complementarity among pollinators in the plants they pollinate, 3-13 times as many pollinator species were needed to pollinate an entire network as compared with a single plant species. Furthermore, many pollinator species that were rare within the network as a whole, and therefore not important pollinators on average, were important to the pollination of particular plant species. By not measuring function across entire mutualist networks, ecologists have likely underestimated the importance of biodiversity, and particularly of rare species, for ecosystem function.

scholarly journals Identification of plant species for pollinator restoration in the Northern Prairies

2017 ◽  
Vol 21 ◽  
Author(s):  
Diana Bizecki Robson ◽  
Cary Hamel ◽  
Rebekah Neufeld
Keyword(s):  
Plant Species ◽  
Field Research ◽  
Late Summer ◽  
Floral Resources ◽  
Prairie Restoration ◽  
Species Accumulation Curves ◽  
Pollinating Insects ◽  
Accumulation Curves ◽  
Plant Pollinator ◽  
Insect Visitors

Research on diurnal plant–pollinator interactions indicates that a small number of generalist plants provide a disproportionately high amount of floral resources to pollinating insects. Identifying these generalist plants would help prairie restoration specialists select species that will provide forage for the majority of pollinator taxa. Field research in three Canadian fescue (Festuca hallii) prairie preserves that were at most 3.3 km away from each other was conducted in 2014 and 2015 to create pooled, weighted, plant–insect visitor matrices for each site. Using these matrices, generalization (G) scores were calculated for each plant species to help assess their importance to wild insect visitors as this method controls for differences in insect abundances over the year. The three species with the highest average generalization scores were Solidago rigida, Erigeron glabellus and Symphyotrichum laeve. Species accumulation curves were created to determine how many plant species would need to be present before most pollinator taxa would have at least one acceptable forage species. This research indicates that the 16 plant species (33% of the total) with the highest average generalization scores were visited by 90% of the observed pollinator taxa. To detect exceptionally attractive plant species while accounting for natural differences in abundance, we calculated the insect, bee and fly visitation rates per inflorescence. There was several specialized plant species that were visited frequently by bees. Most of these specialized plants had purple or yellow, tubular flowers, and bloomed in mid to late summer when bee populations were most numerous. 

scholarly journals Non-native honey bees disproportionately dominate the most abundant floral resources in a biodiversity hotspot

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182901 ◽  
Author(s):  
Keng-Lou James Hung ◽  
Jennifer M. Kingston ◽  
Adrienne Lee ◽  
David A. Holway ◽  
Joshua R. Kohn
Keyword(s):  
Honey Bee ◽  
Plant Species ◽  
Honey Bees ◽  
Ecological Impacts ◽  
Floral Resources ◽  
Natural Ecosystems ◽  
Foraging Patterns ◽  
Large Numbers ◽  
Introduced Range ◽  
Plant Pollinator

Most plant–pollinator mutualisms are generalized. As such, they are susceptible to perturbation by abundant, generalist, non-native pollinators such as the western honey bee ( Apis mellifera ), which can reach high abundances and visit flowers of many plant species in their expansive introduced range. Despite the prevalence of non-native honey bees, their effects on pollination mutualisms in natural ecosystems remain incompletely understood. Here, we contrast community-level patterns of floral visitation by honey bees with that of the diverse native pollinator fauna of southern California, USA. We show that the number of honey bees visiting plant species increases much more rapidly with flower abundance than does that of non-honey bee insects, such that the percentage of all visitors represented by honey bees increases with flower abundance. Thus, honey bees could disproportionately impact the most abundantly blooming plant species and the large numbers of both specialized and generalized pollinator species that they sustain. Honey bees may preferentially exploit high-abundance floral resources because of their ability to recruit nest-mates; these foraging patterns may cause native insect species to forage on lower-abundance resources to avoid competition. Our results illustrate the importance of understanding foraging patterns of introduced pollinators in order to reveal their ecological impacts.

scholarly journals Invasion landscapes as social‐ecological systems: Role of social factors in invasive plant species control

2021 ◽  
Author(s):  
Johanna Yletyinen ◽  
George L. W. Perry ◽  
Olivia R. Burge ◽  
Norman W. H. Mason ◽  
Philip Stahlmann‐Brown
Keyword(s):  
Plant Species ◽  
Social Factors ◽  
Invasive Plant ◽  
Ecological Systems ◽  
Invasive Plant Species ◽  
Social Ecological Systems ◽  
Social Ecological

scholarly journals Insect Visitation to Wildflowers in the Endangered Garry Oak, Quercus garryana, Ecosystem of British Columbia

2005 ◽  
Vol 119 (2) ◽  
pp. 245 ◽  
Author(s):  
A. L. Parachnowitsch ◽  
E. Elle
Keyword(s):  
British Columbia ◽  
Plant Species ◽  
Quercus Garryana ◽  
Chi Squared ◽  
Insect Visitation ◽  
Introduced Honeybee ◽  
Pollinating Insects ◽  
Basic Biology ◽  
Oak Ecosystem ◽  
Plant Pollinator

The Garry Oak Ecosystem (GOE) is a fragmented and endangered ecosystem in Canada, and is currently the focus of conservation and restoration efforts in British Columbia. However, little is known about the basic biology of GOE forbs, or their relationships with pollinating insects. We monitored wildflowers and their insect visitors in 25 quadrats within a 25 × 25 metre plot, located in a fragment of the GOE near Duncan, British Columbia, for six weeks (the majority of the flowering period). Overall, 21 native and non-native forb species flowered in our quadrats during the survey, and we observed an additional six forb species flowering outside of our quadrats. Eight forbs were visited within quadrats by a total of 13 insect taxa, identified to morphospecies. Visits by eight additional morphospecies were observed outside of the quadrats. In general, visitation was low; however, most insect morphospecies were observed visiting more than one plant species, and most plant species were visited by more than one insect morphospecies, suggesting that pollination may be generalised in this community. A Chi-squared analysis indicated that insect visitation was not proportional to the relative abundance of forbs, with higher than expected visitation to Common camas (Camassia quamash), and no observed visits to 11 species, most with very small (putatively unattractive) flowers. The most frequent insect visitor was the introduced Honeybee, Apis mellifera, followed by native mason bees (Osmia spp.) and mining bees (Andrena spp.). Our observations provide baseline data for future, detailed studies that should investigate the importance of plant-pollinator mutualisms for sustainability of populations and communities in this rare ecosystem.

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