The Experts below are selected from a list of 2721 Experts worldwide ranked by ideXlab platform
Jens M. Olesen - One of the best experts on this subject based on the ideXlab platform.
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Disentangling the role of floral sensory stimuli in Pollination Networks
Nature communications, 2018Co-Authors: Aphrodite Kantsa, Jens M. Olesen, Robert A. Raguso, Adrian G. Dyer, Thomas Tscheulin, Theodora PetanidouAbstract:Despite progress in understanding Pollination Network structure, the functional roles of floral sensory stimuli (visual, olfactory) have never been addressed comprehensively in a community context, even though such traits are known to mediate plant-pollinator interactions. Here, we use a comprehensive dataset of floral traits and a novel dynamic data-pooling methodology to explore the impacts of floral sensory diversity on the structure of a Pollination Network in a Mediterranean scrubland. Our approach tracks transitions in the Network behaviour of each plant species throughout its flowering period and, despite dynamism in visitor composition, reveals significant links to floral scent, and/or colour as perceived by pollinators. Having accounted for floral phenology, abundance and phylogeny, the persistent association between floral sensory traits and visitor guilds supports a deeper role for sensory bias and diffuse coevolution in structuring plant-pollinator Networks. This knowledge of floral sensory diversity, by identifying the most influential phenotypes, could help prioritize efforts for plant-pollinator community restoration.
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Disentangling the role of floral sensory stimuli in Pollination Networks
Nature Communications, 2018Co-Authors: Aphrodite Kantsa, Jens M. Olesen, Robert A. Raguso, Adrian G. Dyer, Thomas Tscheulin, Theodora PetanidouAbstract:Can floral phenotype predict the most influential species for maintaining plant–pollinator communities? Here, Kantsa et al. develop a methodology for trait-based analysis, revealing the critical role of floral scent, and floral colour as perceived by insects, in shaping visitation Networks. Despite progress in understanding Pollination Network structure, the functional roles of floral sensory stimuli (visual, olfactory) have never been addressed comprehensively in a community context, even though such traits are known to mediate plant–pollinator interactions. Here, we use a comprehensive dataset of floral traits and a novel dynamic data-pooling methodology to explore the impacts of floral sensory diversity on the structure of a Pollination Network in a Mediterranean scrubland. Our approach tracks transitions in the Network behaviour of each plant species throughout its flowering period and, despite dynamism in visitor composition, reveals significant links to floral scent, and/or colour as perceived by pollinators. Having accounted for floral phenology, abundance and phylogeny, the persistent association between floral sensory traits and visitor guilds supports a deeper role for sensory bias and diffuse coevolution in structuring plant–pollinator Networks. This knowledge of floral sensory diversity, by identifying the most influential phenotypes, could help prioritize efforts for plant–pollinator community restoration.
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Between-year changes in community composition shape species' roles in an Arctic plant-pollinator Network
Oikos, 2018Co-Authors: Alyssa R. Cirtwill, Jens M. Olesen, Tomas Roslin, Claus Rasmussen, Daniel B. StoufferAbstract:Inter‐annual turnover in community composition can affect the richness and functioning of ecological communities. If incoming and outgoing species do not interact with the same partners, ecological functions such as Pollination may be disrupted. Here, we explore the extent to which turnover affects species’ roles – as defined based on their participation in different motifs positions – in a series of temporally replicated plant–pollinator Networks from high‐Arctic Zackenberg, Greenland. We observed substantial turnover in the plant and pollinator assemblages, combined with significant variation in species’ roles between Networks. Variation in the roles of plants and pollinators tended to increase with the amount of community turnover, although a negative interaction between turnover in the plant and pollinator assemblages complicated this trend for the roles of pollinators. This suggests that increasing turnover in the future will result in changes to the roles of plants and likely those of pollinators. These changing roles may in turn affect the functioning or stability of this Pollination Network.
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ecosystem restoration strengthens Pollination Network resilience and function
Nature, 2017Co-Authors: Christopher N Kaiserbunbury, James Mougal, Andrew E Whittington, Terence Valentin, Ronny Gabriel, Jens M. Olesen, Nico BluthgenAbstract:Land degradation results in declining biodiversity and the disruption of ecosystem functioning worldwide, particularly in the tropics. Vegetation restoration is a common tool used to mitigate these impacts and increasingly aims to restore ecosystem functions rather than species diversity. However, evidence from community experiments on the effect of restoration practices on ecosystem functions is scarce. Pollination is an important ecosystem function and the global decline in pollinators attenuates the resistance of natural areas and agro-environments to disturbances. Thus, the ability of Pollination functions to resist or recover from disturbance (that is, the functional resilience) may be critical for ensuring a successful restoration process. Here we report the use of a community field experiment to investigate the effects of vegetation restoration, specifically the removal of exotic shrubs, on Pollination. We analyse 64 plant-pollinator Networks and the reproductive performance of the ten most abundant plant species across four restored and four unrestored, disturbed mountaintop communities. Ecosystem restoration resulted in a marked increase in pollinator species, visits to flowers and interaction diversity. Interactions in restored Networks were more generalized than in unrestored Networks, indicating a higher functional redundancy in restored communities. Shifts in interaction patterns had direct and positive effects on Pollination, especially on the relative and total fruit production of native plants. Pollinator limitation was prevalent at unrestored sites only, where the proportion of flowers producing fruit increased with pollinator visitation, approaching the higher levels seen in restored plant communities. Our results show that vegetation restoration can improve Pollination, suggesting that the degradation of ecosystem functions is at least partially reversible. The degree of recovery may depend on the state of degradation before restoration intervention and the proximity to pollinator source populations in the surrounding landscape. We demonstrate that Network structure is a suitable indicator for Pollination quality, highlighting the usefulness of interaction Networks in environmental management.
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Space, time and aliens: charting the dynamic structure of Galápagos Pollination Networks.
AoB PLANTS, 2015Co-Authors: Anna Traveset, Jens M. Olesen, Susana Chamorro, Ruben H. HelenoAbstract:Oceanic archipelagos are threatened by the introduction of alien species which can severely disrupt the structure, function and stability of native communities. Here we investigated the Pollination interactions in the two most disturbed Galapagos Islands, comparing the three main habitats and the two seasons, and assessing the impacts of alien plant invasions on Network structure. We found that the Pollination Network structure was rather consistent between the two islands, but differed across habitats and seasons. Overall, the arid zone had the largest Networks and highest species generalization levels whereas either the transition between habitats or the humid habitat showed lower values. Our data suggest that alien plants integrate easily into the communities, but with low impact on overall Network structure, except for an increase in Network selectiveness. The humid zone showed the highest nestedness and the lowest modularity, which might be explained by the low species diversity and the higher incidence of alien plants in this habitat. Both pollinators and plants were also more generalized in the hot season, when Networks showed to be more nested. Alien species (both plants and pollinators) represented a high fraction (∼56 %) of the total number of interactions in the Networks. It is thus likely that, in spite of the overall weak effect we found of alien plant invasion on Pollination Network structure, these introduced species influence the reproductive success of native ones, and by doing so, they affect the functioning of the community. This certainly deserves further investigation.
Theodora Petanidou - One of the best experts on this subject based on the ideXlab platform.
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Disentangling the role of floral sensory stimuli in Pollination Networks
Nature Communications, 2018Co-Authors: Aphrodite Kantsa, Jens M. Olesen, Robert A. Raguso, Adrian G. Dyer, Thomas Tscheulin, Theodora PetanidouAbstract:Can floral phenotype predict the most influential species for maintaining plant–pollinator communities? Here, Kantsa et al. develop a methodology for trait-based analysis, revealing the critical role of floral scent, and floral colour as perceived by insects, in shaping visitation Networks. Despite progress in understanding Pollination Network structure, the functional roles of floral sensory stimuli (visual, olfactory) have never been addressed comprehensively in a community context, even though such traits are known to mediate plant–pollinator interactions. Here, we use a comprehensive dataset of floral traits and a novel dynamic data-pooling methodology to explore the impacts of floral sensory diversity on the structure of a Pollination Network in a Mediterranean scrubland. Our approach tracks transitions in the Network behaviour of each plant species throughout its flowering period and, despite dynamism in visitor composition, reveals significant links to floral scent, and/or colour as perceived by pollinators. Having accounted for floral phenology, abundance and phylogeny, the persistent association between floral sensory traits and visitor guilds supports a deeper role for sensory bias and diffuse coevolution in structuring plant–pollinator Networks. This knowledge of floral sensory diversity, by identifying the most influential phenotypes, could help prioritize efforts for plant–pollinator community restoration.
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Disentangling the role of floral sensory stimuli in Pollination Networks
Nature communications, 2018Co-Authors: Aphrodite Kantsa, Jens M. Olesen, Robert A. Raguso, Adrian G. Dyer, Thomas Tscheulin, Theodora PetanidouAbstract:Despite progress in understanding Pollination Network structure, the functional roles of floral sensory stimuli (visual, olfactory) have never been addressed comprehensively in a community context, even though such traits are known to mediate plant-pollinator interactions. Here, we use a comprehensive dataset of floral traits and a novel dynamic data-pooling methodology to explore the impacts of floral sensory diversity on the structure of a Pollination Network in a Mediterranean scrubland. Our approach tracks transitions in the Network behaviour of each plant species throughout its flowering period and, despite dynamism in visitor composition, reveals significant links to floral scent, and/or colour as perceived by pollinators. Having accounted for floral phenology, abundance and phylogeny, the persistent association between floral sensory traits and visitor guilds supports a deeper role for sensory bias and diffuse coevolution in structuring plant-pollinator Networks. This knowledge of floral sensory diversity, by identifying the most influential phenotypes, could help prioritize efforts for plant-pollinator community restoration.
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Climate drives plant-pollinator interactions even along small-scale climate gradients: the case of the Aegean.
Plant Biology, 2017Co-Authors: Theodora Petanidou, Athanasios S. Kallimanis, Thomas Tscheulin, Maria Lazarina, Jelle Devalez, Anastasia Stefanaki, Effie Hanlidou, Ante Vujić, Aggeliki Kaloveloni, S. P. SgardelisAbstract:Plant-pollinator Network structure is the outcome of ecological and evolutionary processes, and although the importance of environmental factors is beyond doubt, our knowledge of how abiotic factors (e.g. climate) shape plant-pollinator Networks remains limited. This knowledge gap is critical, as climate change poses a major threat to ecosystems, especially in the Mediterranean. This study focuses on one of the hottest parts of the Mediterranean Basin, the Aegean Archipelago, Greece, and examines how climate affects species richness and Network properties (e.g. nestedness, modularity and specialisation) - either directly or indirectly through species richness. We sampled systematically 39 local plant-pollinator Networks on eight islands along a north-south climate gradient in the Aegean. All plant-pollinator material used in the analyses was collected in 2012 and identified to species level. Aspects of climate used in the models were expressed as average conditions (mean temperature and annual precipitation) or as seasonal variability (isothermality and temperature seasonality). Structural properties of plant-pollinator Networks were found to be strongly associated with species richness, which was in turn affected by climate, implying that Pollination Network structure is driven indirectly by climate. In addition, climate had a direct effect on Network structure, especially on modularity and specialisation. Different aspects of climate affected Network properties in different ways. We highlight that even in a relatively narrow latitudinal gradient, such as within the Aegean Sea region, climate constitutes a significant driver of plant-pollinator interactions.
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Long-term observation of a Pollination Network: Fluctuation in species and interactions, relative invariance of Network structure and implications for estimates of specialization
Ecology Letters, 2008Co-Authors: Theodora Petanidou, S. P. Sgardelis, Athanasios S. Kallimanis, Joseph Tzanopoulos, John D. PantisAbstract:We analysed the dynamics of a plant-pollinator interaction Network of a scrub community surveyed over four consecutive years. Species composition within the annual Networks showed high temporal variation. Temporal dynamics were also evident in the topology of the Network, as interactions among plants and pollinators did not remain constant through time. This change involved both the number and the identity of interacting partners. Strikingly, few species and interactions were consistently present in all four annual plant-pollinator Networks (53% of the plant species, 21% of the pollinator species and 4.9% of the interactions). The high turnover in species-to-species interactions was mainly the effect of species turnover (c. 70% in pairwise comparisons among years), and less the effect of species flexibility to interact with new partners (c. 30%). We conclude that specialization in plant-pollinator interactions might be highly overestimated when measured over short periods of time. This is because many plant or pollinator species appear as specialists in 1 year, but tend to be generalists or to interact with different partner species when observed in other years. The high temporal plasticity in species composition and interaction identity coupled with the low variation in Network structure properties (e.g. degree centralization, connectance, nestedness, average distance and Network diameter) imply (i) that tight and specialized coevolution might not be as important as previously suggested and (ii) that plant-pollinator interaction Networks might be less prone to detrimental effects of disturbance than previously thought. We suggest that this may be due to the opportunistic nature of plant and animal species regarding the available partner resources they depend upon at any particular time.
Isabela Galarda Varassin - One of the best experts on this subject based on the ideXlab platform.
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do Pollination syndromes cause modularity and predict interactions in a Pollination Network in tropical high altitude grasslands
Oikos, 2012Co-Authors: Aline Danielisilva, Jana Magaly Tesserolli De Souza, Ana Julia Donatti, Ricardo Pamplona Campos, Leandro Freitas, Jose Vicentesilva, Isabela Galarda VarassinAbstract:Th e concept of Pollination syndromes has been widely questioned, since plant – pollinator interactions have proved to be more generalist than was previously thought. We examined whether the Network of a tropical high-altitude grassland contained groups of plants and pollinators that interact preferentially with each other. A general binary matrix was created. To assess the robustness of myophily, in all analyses we considered: 1) the whole Network, 2) the Network after the wasps were removed, and 3) the Network after the fl ies were removed. For each Network we evaluated whether: 1) the observed interactions were more related to syndromes than expected by chance, compared to an expected matrix; 2) there was a modular structure; 3) the modules found were more related to syndromes than expected by chance, compared to another expected matrix; 4) the syndromes were equally robust. For this analysis, the general matrix was subdivided into smaller matrices that included each Pollination syndrome separately. To test the infl uence of the functional groups of pollinators and the phylogeny of plants, in addition to the general matrix, we also considered the fi rst expected matrix, a quantitative functional group and a plant phylogeny matrix. Th e Pollination syndromes determined the pattern of interactions in the Network: 69% of the total interactions resulted from the functional group of pollinators predicted by the plant syndrome. Th e Network showed greater modularity (13 modules) than expected by chance, mostly consisting of the expected functional groups of pollinators and plant syndromes. Th e modules were associated with Pollination syndromes more than was predicted by chance. Most of the variation in interactions was explained by functional groups of pollinators or by plant syndromes. Plant phylogeny did not account for a signifi cant amount of variation in the interactions. Our fi ndings support the concept of Pollination syndromes. However, the interactions were not equally predicted by diff erent Pollination syndromes, and the accuracy of the prediction was strongest for ornithophily and melittophily.
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Do Pollination syndromes cause modularity and predict interactions in a Pollination Network in tropical high‐altitude grasslands?
Oikos, 2011Co-Authors: Aline Danieli-silva, Jana Magaly Tesserolli De Souza, Ana Julia Donatti, Ricardo Pamplona Campos, José Vicente‐silva, Leandro Freitas, Isabela Galarda VarassinAbstract:Th e concept of Pollination syndromes has been widely questioned, since plant – pollinator interactions have proved to be more generalist than was previously thought. We examined whether the Network of a tropical high-altitude grassland contained groups of plants and pollinators that interact preferentially with each other. A general binary matrix was created. To assess the robustness of myophily, in all analyses we considered: 1) the whole Network, 2) the Network after the wasps were removed, and 3) the Network after the fl ies were removed. For each Network we evaluated whether: 1) the observed interactions were more related to syndromes than expected by chance, compared to an expected matrix; 2) there was a modular structure; 3) the modules found were more related to syndromes than expected by chance, compared to another expected matrix; 4) the syndromes were equally robust. For this analysis, the general matrix was subdivided into smaller matrices that included each Pollination syndrome separately. To test the infl uence of the functional groups of pollinators and the phylogeny of plants, in addition to the general matrix, we also considered the fi rst expected matrix, a quantitative functional group and a plant phylogeny matrix. Th e Pollination syndromes determined the pattern of interactions in the Network: 69% of the total interactions resulted from the functional group of pollinators predicted by the plant syndrome. Th e Network showed greater modularity (13 modules) than expected by chance, mostly consisting of the expected functional groups of pollinators and plant syndromes. Th e modules were associated with Pollination syndromes more than was predicted by chance. Most of the variation in interactions was explained by functional groups of pollinators or by plant syndromes. Plant phylogeny did not account for a signifi cant amount of variation in the interactions. Our fi ndings support the concept of Pollination syndromes. However, the interactions were not equally predicted by diff erent Pollination syndromes, and the accuracy of the prediction was strongest for ornithophily and melittophily.
Pedro Jordano - One of the best experts on this subject based on the ideXlab platform.
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phenotypic and microsite plant individual variation determine the Pollination Network structure and its functional consequences
bioRxiv, 2020Co-Authors: Blanca Arroyocorrea, Ignasi Bartomeus, Pedro JordanoAbstract:The biotic and abiotic context of individual plants in animal-pollinated plant populations may influence pollinator foraging behaviour and therefore how the pollen flow occurs. Thus, this variation among conspecifics within a given plant population can ultimately influence the plant reproductive success. Here we used a fine-scale, well characterized population of Halimium halimifolium in combination with exponential random graph models (ERGMs) to assess how the intrapopulation variation in intrinsic (i.e. phenotype and phenology) and extrinsic (i.e. microsite) plant attributes configures individual plant-pollinator Networks and its functional consequences. We found that pollinator visitation patterns and the emerging Network configuration were associated with both intrinsic and extrinsic plant attributes, such as the number of flowers, the flowering synchrony and the cover of intraspecific and interspecific neighbours. Both intrinsic and extrinsic plant attributes also affected the plant female reproductive success directly and indirectly - through its effects on the probability of conspecifics plants to share pollinators. Our study opens up new approaches to assess and predict the functional consequences of context-dependency in plant-pollinator interactions, especially under global change scenarios, where the ecological context of individual plants is likely to change.
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Honeybees disrupt the structure and functionality of plant-pollinator Networks.
Scientific reports, 2019Co-Authors: Alfredo Valido, María C. Rodríguez-rodríguez, Pedro JordanoAbstract:The honeybee is the primary managed species worldwide for both crop Pollination and honey production. Owing to beekeeping activity, its high relative abundance potentially affects the structure and functioning of Pollination Networks in natural ecosystems. Given that evidences about beekeeping impacts are restricted to observational studies of specific species and theoretical simulations, we still lack experimental data to test for their larger-scale impacts on biodiversity. Here we used a three-year field experiment in a natural ecosystem to compare the effects of pre- and post-establishment stages of beehives on the Pollination Network structure and plant reproductive success. Our results show that beekeeping reduces the diversity of wild pollinators and interaction links in the Pollination Networks. It disrupts their hierarchical structural organization causing the loss of interactions by generalist species, and also impairs Pollination services by wild pollinators through reducing the reproductive success of those plant species highly visited by honeybees. High-density beekeeping in natural areas appears to have lasting, more serious negative impacts on biodiversity than was previously assumed.
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temporal dynamics in a Pollination Network
Ecology, 2008Co-Authors: Jens M. Olesen, Jordi Bascompte, Heidi Elberling, Pedro JordanoAbstract:Despite a strong current interest in ecological Networks, the bulk of studies are static descriptions of the structure of Networks, and very few analyze their temporal dynamics. Yet, understanding Network dynamics is important in order to relate Network patterns to ecological processes. We studied the day-to-day dynamics of an arctic Pollination interaction Network over two consecutive seasons. First, we found that new species entering the Network tend to interact with already well-connected species, although there are deviations from this trend due, for example, to morphological mismatching between plant and pollinator traits and nonoverlapping phenophases of plant and pollinator species. Thus, temporal dynamics provides a mechanistic explanation for previously reported Network patterns such as the heterogeneous distribution of number of interactions across species. Second, we looked for the ecological properties most likely to be mediating this dynamical process and found that both abundance and phenophase length were important determinants of the number of links per species.
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The smallest of all worlds: Pollination Networks.
Journal of theoretical biology, 2005Co-Authors: Jens M. Olesen, Jordi Bascompte, Yoko L. Dupont, Pedro JordanoAbstract:A Pollination Network may be either 2-mode, describing trophic and reproductive interactions between communities of flowering plants and pollinator species within a well-defined habitat, or 1-mode, describing interactions between either plants or pollinators. In a 1-mode pollinator Network, two pollinator species are linked to each other if they both visit the same plant species, and vice versa for plants. Properties of 2-mode Networks and their derived 1-mode Networks are highly correlated and so are properties of 1-mode pollinator and 1-mode plant Networks. Most Network properties are scale-dependent, i.e. they are dependent upon Network size. Pollination Networks have the strongest small-world properties of any Networks yet studied, i.e. all species are close to each other (short average path length) and species are highly clustered. Species in Pollination Networks are much more densely linked than species in traditional food webs, i.e. they have a higher density of links, a shorter distance between species, and species are more clustered.
Anna Traveset - One of the best experts on this subject based on the ideXlab platform.
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Space, time and aliens: charting the dynamic structure of Galápagos Pollination Networks.
AoB PLANTS, 2015Co-Authors: Anna Traveset, Jens M. Olesen, Susana Chamorro, Ruben H. HelenoAbstract:Oceanic archipelagos are threatened by the introduction of alien species which can severely disrupt the structure, function and stability of native communities. Here we investigated the Pollination interactions in the two most disturbed Galapagos Islands, comparing the three main habitats and the two seasons, and assessing the impacts of alien plant invasions on Network structure. We found that the Pollination Network structure was rather consistent between the two islands, but differed across habitats and seasons. Overall, the arid zone had the largest Networks and highest species generalization levels whereas either the transition between habitats or the humid habitat showed lower values. Our data suggest that alien plants integrate easily into the communities, but with low impact on overall Network structure, except for an increase in Network selectiveness. The humid zone showed the highest nestedness and the lowest modularity, which might be explained by the low species diversity and the higher incidence of alien plants in this habitat. Both pollinators and plants were also more generalized in the hot season, when Networks showed to be more nested. Alien species (both plants and pollinators) represented a high fraction (∼56 %) of the total number of interactions in the Networks. It is thus likely that, in spite of the overall weak effect we found of alien plant invasion on Pollination Network structure, these introduced species influence the reproductive success of native ones, and by doing so, they affect the functioning of the community. This certainly deserves further investigation.
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Linking Plant Specialization to Dependence in Interactions for Seed Set in Pollination Networks
PloS one, 2013Co-Authors: Cristina Tur, Rocío Castro-urgal, Anna TravesetAbstract:Studies on Pollination Networks have provided valuable information on the number, frequency, distribution and identity of interactions between plants and pollinators. However, little is still known on the functional effect of these interactions on plant reproductive success. Information on the extent to which plants depend on such interactions will help to make more realistic predictions of the potential impacts of disturbances on plant-pollinator Networks. Plant functional dependence on pollinators (all interactions pooled) can be estimated by comparing seed set with and without pollinators (i.e. bagging flowers to exclude them). Our main goal in this study was thus to determine whether plant dependence on current insect interactions is related to plant specialization in a Pollination Network. We studied two Networks from different communities, one in a coastal dune and one in a mountain. For ca. 30% of plant species in each community, we obtained the following specialization measures: (i) linkage level (number of interactions), (ii) diversity of interactions, and (iii) closeness centrality (a measure of how much a species is connected to other plants via shared pollinators). Phylogenetically controlled regression analyses revealed that, for the largest and most diverse coastal community, plants highly dependent on pollinators were the most generalists showing the highest number and diversity of interactions as well as occupying central positions in the Network. The mountain community, by contrast, did not show such functional relationship, what might be attributable to their lower flower-resource heterogeneity and diversity of interactions. We conclude that plants with a wide array of pollinator interactions tend to be those that are more strongly dependent upon them for seed production and thus might be those more functionally vulnerable to the loss of Network interaction, although these outcomes might be context-dependent.