Mutualistic networks: moving closer to a predictive theory

Abstract

Plant–animal mutualistic networks sustain terrestrial biodiversity and human food security. Global environmental changes threaten these networks, underscoring the urgency for developing a predictive theory on how networks respond to perturbations. Here, I synthesise theoretical advances towards predicting network structure, dynamics, interaction strengths and responses to perturbations. I find that mathematical models incorporating biological mechanisms of mutualistic interactions provide better predictions of network dynamics. Those mechanisms include trait matching, adaptive foraging, and the dynamic consumption and production of both resources and services provided by mutualisms. Models incorporating species traits better predict the potential structure of networks (fundamental niche), while theory based on the dynamics of species abundances, rewards, foraging preferences and reproductive services can predict the extremely dynamic realised structures of networks, and may successfully predict network responses to perturbations. From a theoretician's standpoint, model development must more realistically represent empirical data on interaction strengths, population dynamics and how these vary with perturbations from global change. From an empiricist's standpoint, theory needs to make specific predictions that can be tested by observation or experiments. Developing models using short‐term empirical data allows models to make longer term predictions of community dynamics. As more longer term data become available, rigorous tests of model predictions will improve.

Seed-dispersal networks in tropical forest fragments: area effects, remnant species, and interaction diversity

“…These findings suggest that area per se does affect network structure, but primarily mediates the presence/absence of remnant species in the fragments, as well as the interactions they perform. Furthermore, the lack of significant changes in network specialization independently of local species richness, contrasting with the richness-associated changes of the previous metrics, may suggest that the stability of complex system depends on the specific parameter and the system analysed (May 1972, Thébault & Fontaine 2010, Valdovinos et al 2019). Specialization of the seed-dispersal interactions could be seen as an invariant property of the networks, at some extent robust to habitat loss.…”

“…Bird seed-dispersal networks of the Atlantic Forest are losing species and interactions as the landscape becomes more fragmented. Beyond the potential consequences for network stability (May 1972, Valdovinos 2019) detected by the increasing nestedness and reduced number of links performed by the remnant species, those local communities are likely to be also losing important ecological functions. Species- and interaction-richer communities mostly hold higher functional diversity while the impoverished ones are likely to have gaps on ecosystem functionality (Isbell et al, 2011; Saavedra et al 2014, Montoya et al, 2015).…”

A perspective on stage‐structured mutualism and its community consequences

“…herbivory and pollination) in hybrid network communities. However, the role of stage structure has been largely ignored in community network studies (Melián et al 2009, Allesina and Tang 2012, Bascompte and Jordano 2014, Suweis et al 2014, Shinohara et al 2019, Valdovinos 2019. Systematic measurements of structural properties (e.g.…”

Reconstruction of plant–pollinator networks from observational data

“…Network-based methods of analysis have contributed substantially to our understanding of ecological systems by helping us identify structure in the patterns of interaction between species [1][2][3][4]. Such patterns have been shown to be strongly linked to the dynamics and stability of ecosystems [5][6][7] and this is particularly the case for mutualistic networks such as plant-pollinator interactions-our focus in this paper-whose functions are crucial to terrestrial biodiversity [6,8] and human food security [9,10].…”