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

Abstract

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.

Frugivory and seed dispersal in tropical urban areas: a review

“…Associated with empirical studies that found high resources partitioning among frugivores in unmanaged peri-urban forest patches (Corral et al 2020, Salazar-Rivera et al 2020, these results reinforces the value of unmanaged forest patches within urban areas for interaction stability. Therefore, patches of natural areas favor frugivore animals and are essential for maintenance of seed dispersal interactions.…”

In a Neotropical Periurban Park, Fruit Consumption by Birds Seems to Be a Random Process

“…Urban and periurban greenspaces preserve fundamental ecological interactions, many of them deeply shaped by human management and activity (Gasperin and Pizo, 2009). While we know some characteristics of these networks, e.g., urban greenspaces as environments that favor generalist species, capable of exploiting available resources broadly and effectively (Clavel et al, 2011;Machado-de-Souza et al, 2019;Palacio, 2019;Salazar-Rivera et al, 2020;Schneiberg et al, 2020), we also know little about many other features, such as the ones explored in this paper. We consider our understanding of how birdplant frugivory interactions are structured and organized in cities will benefit from including extrinsic factors such as those considered in spatial analyses.…”

“…One related factor with known effects in fruit consumption by birds is their morphologic matching: altered environments generally do not have fruits of large sizes and those present therein have a lower dispersal probability because their largesized frugivores are more likely to be absent in these habitats (Galetti et al, 2013;Emer et al, 2018). Urban environments tend to have a low number of species and interactions, resulting in simplified plant-bird frugivory and pollination networks dominated by generalists (Maruyama et al, 2019;Salazar-Rivera et al, 2020;Schneiberg et al, 2020). Conversely, forest cover and connectivity are key in the maintenance of interaction diversity in seed dispersal networks (Monteiro et al, 2021).…”

The influence of provisioning on animal‐mediated seed dispersal

“…Provisioned food in the form of spatially expansive resources such as agricultural resources, plantations, orchards, gardens can change species richness and functional diversity of animals to simplified animal communities comprising species suited to farmland or urban dwelling and can thus homogenize plant–animal interactions (Salazar‐Rivera et al 2020). These changes in plant and animal communities (Galbraith et al 2015) can greatly modify seed dispersal networks and reduce their resilience due to losses of functional diversity and homogenization of flora (Bastazini et al 2019).…”