Loss of generalist plant species and functional diversity decreases the robustness of a seed dispersal network

Bastazini, Vinicius A. G.; Debastiani, Vanderlei J.; Azambuja, Bethânia Oliveira; Guimarães, Paulo R.; Pillar, Valério D.

doi:10.1101/187179

Cited by 3 publications

(3 citation statements)

References 86 publications

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“…whereas increases in specialists, and the correspondent decreases in generalists, are viewed as gains in ecosystem resilience (Bastazini, Debastiani, Azambuja, Guimarães, & Pillar, 2017). Because this periurban park has actually increased its vegetation cover and diversity of ecological interactions in the most recent 20 years, our observations fit with the generalist-dominated pattern of early secondary succession (e.g., Lebrija-Trejos et al, 2010).…”

Section: Generalists and Exotics Dominate This Plantbird Networksupporting

confidence: 75%

The frugivory network properties of a simplified ecosystem: Birds and plants in a Neotropical periurban park

Salazar-Rivera

Dáttilo

Castillo‐Campos

et al. 2020

Ecology and Evolution

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Frugivory networks exhibit a set of properties characterized by a number of network theory‐derived metrics. Their structures often form deterministic patterns that can be explained by the functional roles of interacting species. Although we know lots about how these networks are organized when ecosystems are in a complete, functional condition, we know much less about how incomplete and simplified networks (such as those found in urban and periurban parks) are organized, which features are maintained, which ones are not, and why. In this paper, we examine the properties of a network between frugivorous birds and plants in a small Neotropical periurban park. We found a frugivory network composed of 29 species of birds and 23 of plants. The main roles in this network are played by four species of generalist birds (three resident, one migratory: Myiozetetes similis, Turdus grayi, Chlorospingus flavopectus, and Dumetella carolinensis) and three species of plants (one exotic, two early successional: Phoenix canariensis, Phoradendron sp., and Witheringia stramoniifolia). When compared to reference data from other locations in the Neotropics, species richness is low, one important network‐level metric is maintained (modularity) whereas another one is not (nestedness). Nestedness, a metric associated with network specialists, is a feature this network lacks. Species‐level metrics such as degree, species strength, and module roles, are not maintained. Our work supports modularity as the most pervasive network‐level metric of altered habitats. From a successional point of view, our results suggest that properties revealed by species‐level indices may be developed at a later time, lagging the acquisition of structural elements.

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Section: Generalists and Exotics Dominate This Plantbird Networksupporting

confidence: 75%

The frugivory network properties of a simplified ecosystem: Birds and plants in a Neotropical periurban park

Salazar-Rivera

Dáttilo

Castillo‐Campos

et al. 2020

Ecology and Evolution

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“…Functional group frameworks, in which species are categorized by ecological functions and the resulting groups treated as analytical units, have helped researchers confront complexity in other ecological subdisciplines and have been tentatively explored in seed dispersal (e.g. Dennis and Westcott 2006; Brodie et al 2009b; Bastazini et al 2017). However, they have not yet been developed sufficiently to link empirical patterns of seed dispersal with theoretical predictions.…”

Section: Introduction: Seed Dispersal Is Fundamental To Populations Amentioning

confidence: 99%

“…Zamora (2000) explored how the consistency of fitness benefits offered by seed dispersal across systems and groups of species permits generalization within functional groups. A key benefit of a functional group approach is that it could provide an understanding of the functions that may be lost when extinctions occur (Blondel 2003; Bastazini et al 2017). This conservation-oriented conceptual application was highlighted by Schleuning et al (2014) in their call for more work examining the linkage between trait-based approaches such as functional group delineation and structural approaches such as network analysis (Ruggera et al 2015).…”

Section: Introduction: Seed Dispersal Is Fundamental To Populations Amentioning

confidence: 99%

Employing plant functional groups to advance seed dispersal ecology and conservation

et al. 2019

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Seed dispersal enables plants to reach hospitable germination sites and escape natural enemies. Understanding when and how much seed dispersal matters to plant fitness is critical for understanding plant population and community dynamics. At the same time, the complexity of factors that determine if a seed will be successfully dispersed and subsequently develop into a reproductive plant is daunting. Quantifying all factors that may influence seed dispersal effectiveness for any potential seed-vector relationship would require an unrealistically large amount of time, materials and financial resources. On the other hand, being able to make dispersal predictions is critical for predicting whether single species and entire ecosystems will be resilient to global change. Building on current frameworks, we here posit that seed dispersal ecology should adopt plant functional groups as analytical units to reduce this complexity to manageable levels. Functional groups can be used to distinguish, for their constituent species, whether it matters (i) if seeds are dispersed, (ii) into what context they are dispersed and (iii) what vectors disperse them. To avoid overgeneralization, we propose that the utility of these functional groups may be assessed by generating predictions based on the groups and then testing those predictions against species-specific data. We suggest that data collection and analysis can then be guided by robust functional group definitions. Generalizing across similar species in this way could help us to better understand the population and community dynamics of plants and tackle the complexity of seed dispersal as well as its disruption.

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The role of evolutionary modes for trait-based cascades in mutualistic networks

Bastazini

Debastiani

Cappelatti³

et al. 2021

Preprint

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The erosion of functional diversity may foster the collapse of ecological systems. Functional diversity is ultimately defined by the distribution of species traits and, as species traits are a legacy of species evolutionary history, one might expect that the mode of trait evolution influence community resistance under the loss of functional diversity. In this paper, we investigate the role of trait evolutionary dynamics on the robustness of mutualistic networks undergoing the following scenarios of species loss: i) random extinctions, ii) loss of functional distinctiveness and iii) biased towards larger trait values. We simulated networks defined by models of single trait complementary and evolutionary modes where traits can arise in recent diversification events with weak phylogenetic signal, in early diversification events with strong phylogenetic signal, or as a random walk through evolutionary time. Our simulations show that mutualistic networks are especially vulnerable to extinctions based on trait distinctiveness and more robust to random extinction dynamics. The networks show intermediate level of robustness against size-based extinctions. Despite the small range of variation in network robustness, our results show that the mode of trait evolution matters for network robustness in all three scenarios. Networks with low phylogenetic signal are more robust than networks with high phylogenetic signal across all scenarios. As a consequence, our results predict that mutualistic networks based upon current adaptations are more likely to cope with extinction dynamics than those networks that are based upon conserved traits.

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Loss of generalist plant species and functional diversity decreases the robustness of a seed dispersal network

Cited by 3 publications

References 86 publications

The frugivory network properties of a simplified ecosystem: Birds and plants in a Neotropical periurban park

The frugivory network properties of a simplified ecosystem: Birds and plants in a Neotropical periurban park

Employing plant functional groups to advance seed dispersal ecology and conservation

The role of evolutionary modes for trait-based cascades in mutualistic networks

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