Structure and robustness of the Neotropical ant‐gardens network under climate change

Abstract

Abstract Knowing, predicting, and comparing the interactions among species of different assemblages allows the determination of both the structure and robustness of the ecological networks. However, this has been little studied for species assemblages with obligate associations across a wide geographic scale and under a global climate change context. We studied the Neotropical ant‐gardens (AGs), considered as a specialised mutualist system constituted of epiphytic plants that specifically inhabit nests of arboreal ants. We used the niche modelling and complex networks approaches to infer the interactions (range overlaps) between the ants and epiphytes that comprise the AGs and thus constructed AG quantitative networks for the current time and future scenarios of climate change. Also, we compared the structure (nestedness and modularity) and specialisation of the AG network with other ecological networks, and we evaluated their robustness through the simulated extinction of species. The AG network was formed by six ant species and 16 epiphyte species, generally of wide distribution. This low species number coincided with specialised networks, but the structure was more similar to that of the facultative networks, since it presented high nestedness and low modularity and specialisation. The network structure was maintained under the climate change scenarios, which also coincides with its high robustness in the face of the extinction of species. The AGs are a specialised system of wide distribution, but ant–epiphyte interactions are generalist, suggesting that the Neotropical AG network is cohesive and robust in the face of global perturbations.