Context‐dependency and anthropogenic effects on individual plant–frugivore networks

Abstract

Anthropogenic activities, such as grazing by domestic animals, are considered drivers of environmental changes that may influence the structure of interaction networks. The study of individual‐based networks allows testing how species‐level interaction patterns emerge from the pooled interaction modes of individuals within populations. Exponential random graph models (ERGMs) examine the global structure of networks by allowing the inclusion of specific node (i.e. interacting partners) properties as explanatory covariates. Here we assessed the structure of individual plant–frugivore interaction networks and the ecological variables that influence the mode of interactions under different land‐use (grazed versus ungrazed protected areas). We quantified the number of visits, the number of fruits removed per visit and the interaction strength of mammal frugivore species at each individual tree. Additionally we quantified ecological variables at the individual, microhabitat, neighborhood and habitat scales that generated interaction network structure under the different land uses. Individual plant–frugivore networks were significantly modular in both land uses but the number of modules was higher in the grazed areas. We found interaction networks for grazed and ungrazed lands were structured by phenotypic traits of individual trees, by the microhabitat beneath the tree canopy and were affected by habitat modifications of anthropogenic origin. The neighborhood surrounding each individual plant influenced plant–frugivore interactions only at the grazed‐land trees. We conclude that anthropogenic land uses influence the topological patterns of plant–frugivore networks and the frugivore visitation to trees through modification of both habitat complexity and the ecological traits underlying interactions between individual plants and frugivore species.

Interaction motifs variability in a Mediterranean palm under environmental disturbances: the mutualism–antagonism continuum

“…This could explain the increased quantity component and interaction strength in both antagonist and mutualists interactions in this grazed area. These compensatory trends are analogous to those recently reported by Miguel et al (2018) comparing grazed versus ungrazed habitats; they found that frugivores visit fewer trees in more structurally-complex habitats compared with trees in a more disturbed and physiognomically-simplified habitat.…”

Plants on the Move: Hitch-Hiking With Ungulates Distributes Diaspores Across Landscapes

“…In plant dispersal networks, diaspores produced by the parent plant can be dispersed through endozoochory by different co-occurring vectors. These networks have been established principally for frugivory and endozoochory (Dugger et al, 2018;Miguel et al, 2018). Fedriani and Delibes (2009) studied the role of different mammals (e.g., wild pig; red deer; badger, Meles meles and red fox, Vulpes vulpes) dispersing the Iberian pear (Pyrus bourgaeana).…”

Filling gaps in the seed dispersal effectiveness model forProsopis flexuosa: quality of seed treatment in the digestive tract of native animals

“…Graomys griseoflavus , Akodon dolores , Eligmodontia typus , Calomys musculinus and Microcavia maenas ) practice food hoarding, making both larder-hoards and scatter-hoards with different effects on seed survival (Campos et al, 2007, 2017; Giannoni et al, 2013). In this relationship among P. flexuosa and its assemblage of dispersers, previous studies have shown that quantitative aspects of SDE directly related to animal visits and fruit removal are affected by changes in habitat heterogeneity under different land uses (Campos et al, 2016; Bessega et al, 2017; Tabeni et al, 2017; Miguel et al, 2017, 2018a,b). Although the development of the SDE model for P. flexuosa began years ago, using an approach that combines field and laboratory experiments, the aim of the present study is to provide data to fill in some gaps in the model.…”