Structural resilience and high interaction dissimilarity of plant–pollinator interaction networks in fire-prone grasslands

Oecologia ◽  
2021 ◽  
Author(s):  
Camila da Silva Goldas ◽  
Luciana Regina Podgaiski ◽  
Carolina Veronese Corrêa da Silva ◽  
Pedro Maria Abreu Ferreira ◽  
Jeferson Vizentin-Bugoni ◽  
...  
2020 ◽  
Vol 51 (1) ◽  
pp. 319-340
Author(s):  
Amanda D. Benoit ◽  
Susan Kalisz

Plants are the foundation of the food web and therefore interact directly and indirectly with myriad organisms at higher trophic levels. They directly provide nourishment to mutualistic and antagonistic primary consumers (e.g., pollinators and herbivores), which in turn are consumed by predators. These interactions produce cascading indirect effects on plants (either trait-mediated or density-mediated). We review how predators affect plant-pollinator interactions and thus how predators indirectly affect plant reproduction, fitness, mating systems, and trait evolution. Predators can influence pollinator abundance and foraging behavior. In many cases, predators cause pollinators to visit plants less frequently and for shorter durations. This decline in visitation can lead to pollen limitation and decreased seed set. However, alternative outcomes can result due to differences in predator, pollinator, and plant functional traits as well as due to altered interaction networks with plant enemies. Furthermore, predators may indirectly affect the evolution of plant traits and mating systems.


2021 ◽  
Author(s):  
Rafael Barros Pereira Pinheiro ◽  
Carsten F. Dormann ◽  
Gabriel Moreira Felix ◽  
Marco A. R. Mello

Aim: Nestedness is a common pattern in metacommunities and interaction networks, whose causes are still discussed. Nestedness inference is challenging because, beyond calculating an index, we need to compare observed values with values generated with a null model. There are different null models and the choice between them affects test outcomes. Furthermore, there is no established theoretical basis to guide this choice. Here, we propose a different look at the meaning of nestedness that improves our understanding of its causes and unveils the link between null models and hypotheses. Innovation: Nestedness of a matrix is a combination of marginal sum inequality and high overlap. The higher the overlap, the more predictable the cell values by marginal sums. Here, we show that nestedness actually measures how better one can predict cell values by marginal sums than by matrix dimensions and total sum alone. From this, we propose that two null models can be used to test for different topological hypotheses. The equiprobable model excludes all nestedness-generating mechanisms and provides the distribution of expected values for nestedness significance tests. The proportional model conserves nestedness-generating mechanisms and excludes nestedness-disrupting mechanisms, and thus, produces highly nested matrices. The proportional model provides the distribution of expected nestedness for nested matrices. Additionally, we evaluate the efficiency of several indices within this new perspective and illustrate our approach using an empirical plant-pollinator network. Main conclusions: Through a shift of perspective, our approach reconciliates contradictions in null model analysis and delimits the range of possible explanations for nestedness. The only way a process can increase nestedness in a matrix is by promoting marginal sum inequalities, without concomitantly introducing preferences. Consequently, in a species interaction network, explanations for nestedness should explain why some species interact more frequently than others.


Author(s):  
Patricia Landaverde-González ◽  
Eunice Enríquez ◽  
Juan Núñez-Farfán

AbstractIn recent years, evidence has been found that plant-pollinator interactions are altered by land-use and that genetic diversity also plays a role. However, how land-use and genetic diversity influence plant–pollinator interactions, particularly in the Neotropics, where many endemic plants exist is still an open question. Cucurbita pepo is a monoecious plant and traditional crop wide distributed, with high rates of molecular evolution, landraces associated with human cultural management and a history of coevolution with bees, which makes this species a promising model for studying the effect of landscape and genetic diversity on plant-pollinator interactions. Here, we assess (1) whether female and male flowers differences have an effect on the interaction network, (2) how C. pepo genetic diversity affects flower-bee visitation network structure, and (3) what is the effect that land-use, accounting for C. pepo genetic variability, has on pumpkin-bee interaction network structure. Our results indicate that female and male flowers presented the same pollinator community composition and interaction network structure suggesting that female/male differences do not have a significant effect on network evolution. Genetic diversity has a positive effect on modularity, nestedness and number of interactions. Further, the effect of semi-natural areas on nestedness could be buffered when genetic diversity is high. Our results suggest that considering genetic diversity is relevant for a better understanding of the effect of land-use on interaction networks. Additionally, this understanding has great value in conserving biodiversity and enhancing the stability of interaction networks in a world facing great challenges of habitat and diversity loss.


Ecology ◽  
2013 ◽  
Vol 94 (12) ◽  
pp. 2688-2696 ◽  
Author(s):  
Brian J. Spiesman ◽  
Brian D. Inouye

Oikos ◽  
2020 ◽  
Vol 129 (9) ◽  
pp. 1369-1380 ◽  
Author(s):  
Paul J. CaraDonna ◽  
Nickolas M. Waser

2015 ◽  
Author(s):  
Ignasi Bartomeus ◽  
Jochen Fründ ◽  
Neal M. Williams

Entomophilous exotic plant species not only compete directly for space and light with other plants, but also offer resource opportunities for the native pollinator community. Most research on this topic to date has taken the plant perspective, focusing on how successful plant invaders integrate into the native plant-pollinator interaction networks. However, species specific responses of pollinators to the addition of exotic plants are rarely taken into account. We show here that while some bumble bees and other trophic generalist bees can benefit from exotic plant invasions, other species can be negatively affected. Behavioral flexibility may be the key to persist in a changing world.


2018 ◽  
Vol 285 (1870) ◽  
pp. 20172140 ◽  
Author(s):  
Keng-Lou James Hung ◽  
Jennifer M. Kingston ◽  
Matthias Albrecht ◽  
David A. Holway ◽  
Joshua R. Kohn

The western honey bee ( Apis mellifera ) is the most frequent floral visitor of crops worldwide, but quantitative knowledge of its role as a pollinator outside of managed habitats is largely lacking. Here we use a global dataset of 80 published plant–pollinator interaction networks as well as pollinator effectiveness measures from 34 plant species to assess the importance of A. mellifera in natural habitats. Apis mellifera is the most frequent floral visitor in natural habitats worldwide, averaging 13% of floral visits across all networks (range 0–85%), with 5% of plant species recorded as being exclusively visited by A. mellifera . For 33% of the networks and 49% of plant species, however, A. mellifera visitation was never observed, illustrating that many flowering plant taxa and assemblages remain dependent on non- A. mellifera visitors for pollination. Apis mellifera visitation was higher in warmer, less variable climates and on mainland rather than island sites, but did not differ between its native and introduced ranges. With respect to single-visit pollination effectiveness, A. mellifera did not differ from the average non- A. mellifera floral visitor, though it was generally less effective than the most effective non- A. mellifera visitor. Our results argue for a deeper understanding of how A. mellifera , and potential future changes in its range and abundance, shape the ecology, evolution, and conservation of plants, pollinators, and their interactions in natural habitats.


2013 ◽  
Vol 31 ◽  
pp. 35-40 ◽  
Author(s):  
Patrícia Alves Ferreira ◽  
Danilo Boscolo ◽  
Blandina Felipe Viana

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