Traits and phylogenetic history contribute to network structure across Canadian plant–pollinator communities

Empirical measurements of ecological networks such as food webs and mutualistic networks are often rich in structure but also noisy and error-prone, particularly for rare species for which observations are sparse. Focusing on the case of plant–pollinator networks, we here describe a Bayesian statistical technique that allows us to make accurate estimates of network structure and ecological metrics from such noisy observational data. Our method yields not only estimates of these quantities, but also estimates of their statistical errors, paving the way for principled statistical analyses of ecological variables and outcomes. We demonstrate the use of the method with an application to previously published data on plant–pollinator networks in the Seychelles archipelago, calculating estimates of network structure, network nestedness, and other characteristics.

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On the temporally flexible structure of plant-pollinator interaction networks

10.1101/2020.04.11.037366 ◽

2020 ◽

Author(s):

Paul J. CaraDonna ◽

Nickolas M. Waser

Keyword(s):

Temporal Variation ◽

Network Structure ◽

Species Interactions ◽

Interspecific Interactions ◽

Activity Period ◽

Individual Species ◽

Ecological Communities ◽

Short Term ◽

Temporal Flexibility ◽

Plant Pollinator

AbstractEcological communities consist of species that are joined in complex networks of interspecific interaction. The interactions that networks depict often form and dissolve rapidly, but this temporal variation is not well integrated into our understanding of the causes and consequences of network structure. If interspecific interactions exhibit temporal flexibility across time periods over which organisms co-occur, then the emergent structure of the corresponding network may also be temporally flexible, something that a temporally-static perspective would miss. Here, we use an empirical system to examine short-term flexibility in network structure (connectance, nestedness, and specialization), and in individual species interactions that contribute to that structure. We investigated weekly plant-pollinator networks in a subalpine ecosystem across three summer growing seasons. To link the interactions of individual species to properties of their networks, we examined weekly temporal variation in species’ contributions to network structure. As a test of the potential robustness of networks to perturbation, we also simulated the random loss of species from weekly networks. We then compared the properties of weekly networks to the properties of cumulative networks that aggregate field observations over each full season. A week-to-week view reveals considerable flexibility in the interactions of individual species and their contributions to network structure. For example, species that would be considered relatively generalized across their entire activity period may be much more specialized at certain times, and at no point as generalized as the cumulative network may suggest. Furthermore, a week-to-week view reveals corresponding temporal flexibility in network structure and potential robustness throughout each summer growing season. We conclude that short-term flexibility in species interactions leads to short-term variation in network properties, and that a season-long, cumulative perspective may miss important aspects of the way in which species interact, with implications for understanding their ecology, evolution, and conservation.

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The effect of landscape on Cucurbita pepo-pollinator interaction networks varies depending on plants’ genetic diversity

Arthropod-Plant Interactions ◽

10.1007/s11829-021-09872-y ◽

2021 ◽

Author(s):

Patricia Landaverde-González ◽

Eunice Enríquez ◽

Juan Núñez-Farfán

Keyword(s):

Genetic Diversity ◽

Land Use ◽

Network Structure ◽

Cucurbita Pepo ◽

Interaction Network ◽

Network Evolution ◽

Interaction Networks ◽

Pollinator Community ◽

Male Flowers ◽

Plant Pollinator

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.

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Species traits and abundances predict metrics of plant-pollinator network structure, but not pairwise interactions

Oikos ◽

10.1111/oik.01439 ◽

2014 ◽

Vol 124 (4) ◽

pp. 428-436 ◽

Cited By ~ 71

Author(s):

Colin Olito ◽

Jeremy W. Fox

Keyword(s):

Network Structure ◽

Species Traits ◽

Pairwise Interactions ◽

Plant Pollinator

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The effects of experimental floral resource removal on plant-pollinator interactions

10.1101/2021.03.21.436328 ◽

2021 ◽

Author(s):

Justin A. Bain ◽

Rachel G. Dickson ◽

Andrea M. Gruver ◽

Paul J. CaraDonna

Keyword(s):

Network Structure ◽

Species Turnover ◽

Individual Species ◽

Natural Setting ◽

Species Loss ◽

Pollinator Visitation ◽

Local Loss ◽

Visitation Rates ◽

Floral Visitor ◽

Plant Pollinator

AbstractPollination is essential for ecosystem functioning, yet our understanding of the empirical consequences of species loss for plant-pollinator interactions remains limited. It is hypothesized that the loss of abundant and generalized (well-connected) species from a pollination network will have a large effect on the remaining species and their interactions. However, to date, relatively few studies have experimentally removed species from their natural setting to address this hypothesis. We investigated the consequences of losing an abundant, well-linked species from a series of plant-pollinator networks by experimentally removing the flowers of Helianthella quinquenervis (Asteraceae) from half of a series of 10 paired plots (15 m diameter) within a subalpine ecosystem. We then asked how the localized loss of this species influenced pollinator visitation patterns, floral visitor composition, and interaction network structure. The experimental removal of Helianthella flowers led to an overall decline in plot-level pollinator visitation rates and shifts in pollinator composition. Species-level responses to floral removal differed between the two other abundant, co-flowering plants in our experiment: Potentilla pulcherrima received higher visitation rates, whereas Erigeron speciosus visitation rates did not change. Experimental floral removal altered the structural properties of the localized plant-pollinator networks such that they were more specialized, less nested, and less robust to further species loss. Such changes to interaction structure were consistently driven more by species turnover than by interaction rewiring. Our findings suggest that the local loss of an abundant, well-linked, generalist plant can bring about diverse responses within pollination networks, including potential competitive and facilitative effects for individual species, changes to network structure that may render them more sensitive to future change, but also numerous changes to interactions that may also suggest flexibility in response to species loss.

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Multitrophic higher-order interactions modulate species persistence

10.1101/2021.11.18.469079 ◽

2021 ◽

Author(s):

Lisa Buche ◽

Ignasi Bartomeus ◽

Oscar Godoy

Keyword(s):

Plant Species ◽

Network Structure ◽

Higher Order ◽

Species Persistence ◽

Pairwise Interactions ◽

Species Pairs ◽

Diverse Communities ◽

Plant Persistence ◽

Per Capita ◽

Plant Pollinator

There is growing recognition that interactions between species pairs are modified in a multispecies context by the density of a third species. However, how these higher-order interactions (HOIs) affect species persistence remains poorly understood. To explore the effect of HOIs steaming from multiple trophic layers on plant persistence, we experimentally built a mutualistic system containing three plants and three pollinators species with two contrasting network structures. For both structures, we first estimated the statistically supported HOIs on plant species, in addition to the pairwise interactions among plants and plant-pollinators. Following a structuralist approach, we then assessed the effects of the supported HOIs on the persistence probability of each of the three competing plant species and their combinations. HOIs produced substantial effects on the strength and sign of per capita interactions between plant species to such an extent that predictions of species persistence differ from a non-HOIs scenario. Changes in network structure due to removing a plant-pollinator link further modulated the species persistence probabilities by reorganizing per capita interaction strengths of both pairwise interactions and HOIs. Our study provides empirical evidence of the joint importance of HOIs and network structure for determining the probability of species to persist within diverse communities.

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Patterns of introduced species interactions affect multiple aspects of network structure in plant–pollinator communities

Ecology ◽

10.1890/13-2229.1 ◽

2014 ◽

Vol 95 (10) ◽

pp. 2953-2963 ◽

Cited By ~ 24

Author(s):

Laura Russo ◽

Jane Memmott ◽

Daniel Montoya ◽

Katriona Shea ◽

Yvonne M. Buckley

Keyword(s):

Introduced Species ◽

Network Structure ◽

Species Interactions ◽

Plant Pollinator

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An empirical attack tolerance test alters the structure and species richness of plant-pollinator networks

10.1101/2020.01.28.923177 ◽

2020 ◽

Cited By ~ 1

Author(s):

Paolo Biella ◽

Asma Akter ◽

Jeff Ollerton ◽

Anders Nielsen ◽

Jan Klečka

Keyword(s):

Species Richness ◽

Network Structure ◽

Network Theory ◽

In Silico ◽

Tolerance Test ◽

Experimental Manipulation ◽

Ecological Network ◽

Random Interactions ◽

Plant Pollinator ◽

Real Plant

AbstractEcological network theory hypothesizes a link between structure and stability, but this has mainly been investigated in-silico. In an experimental manipulation, we sequentially removed four generalist plants from real plant-pollinator networks and explored the effects on, and drivers of, species and interaction extinctions, network structure and interaction rewiring. Our results indicate that cumulative species and interaction extinctions increased faster with generalist plant loss than what was expected by co-extinction models, which predicted the survival or extinction of many species incorrectly. In addition, network nestedness decreased, modularity increased, and opportunistic random interactions and structural unpredictability emerged, which are all indicators of network instability and fragility. Conversely, interaction reorganization (rewiring) was high, asymmetries between network levels emerged as plants increased their centrality. From the experimental manipulations of real networks, our study shows how plant-pollinator network structure has low stability and changes towards a more fragile state when generalist plants are lost.

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Temporal switching of species roles in a plant–pollinator network

10.1101/543637 ◽

2019 ◽

Cited By ~ 1

Author(s):

Vincent Miele ◽

Rodrigo Ramos-Jiliberto ◽

Diego P. Vázquez

Keyword(s):

Ecosystem Management ◽

Network Structure ◽

Observation Data ◽

Dynamic Stochastic ◽

Temporal Turnover ◽

Species Roles ◽

Block Models ◽

Plant Pollinator ◽

Management And Conservation ◽

Core Role

AbstractMutualistic networks are highly dynamic, characterized by high temporal turnover of species and interactions. Yet, we have a limited understanding of how the internal structure of these networks and the roles species play in them vary through time. We used six years of observation data and a novel statistical method (dynamic stochastic block models) to assess how network structure and species roles change across time in a quantitative plant–pollinator network from a dryland ecosystem in Argentina. Our analyses revealed a core–periphery structure persistent through seasons and years. Yet, species roles as core or peripheral were highly dynamic: virtually all species that played a core role in some seasons were also peripheral in other seasons, while many other species remained always peripheral. Our results illuminate our understanding of the dynamics of ecological networks and have important implications for ecosystem management and conservation.

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