Impact of extinctions on the functionality and evolutionary history in interaction networks between anurans and their prey and their contribution to pest and vector control

Abstract

Predation plays a crucial role in the ecosystem functioning and in the communities' composition. The density regulation functions performed by predators have consequences on lower trophic levels, generating trophic cascades that are disrupted when predators become functionally extinct. Anuran amphibians show an important role in food webs, because they represent a link between terrestrial and aquatic environments and can act both as predators and prey. Due to the generality of their diet, combined with their biphasic life cycle, several studies have shown the efficiency of amphibians in controlling mosquitoes populations as well as in the control of agricultural pests. Once amphibians are currently undergoing a global decline, and this decline is intensified by climate change, these functions may be lost in many natural systems. However, despite the discussion on the direct effects of climate change on species distribution, little is known about the effects of climate change on biotic interactions. Because many aspects of ecosystem functioning depend on the diversity of biotic interactions, understanding the effects of extinctions on interaction networks can reveal how diversity loss deteriorates ecosystem functions, such as natural pest control. Thus, in this project I intend to test the impact of extinctions on the functionality and evolutionary diversity within interaction networks between anurans and their prey and their influence on pest and vector disease control. For this purpose, I will use data on diet and prey availability already collected from 19 anuran communities in Brazil. I will simulate anuran extinction in the networks based on predefined criteria and also assess the changes in species distribution using species distribution models under a climate change scenario. In addition, I will analyze how the effects of these extinctions spread across networks and how it will affect the functionality and evolutionary history of networks. Finally, I will investigate how extinctions may impact the prey regulation performed by anurans, estimating the total biomass per capita that will no longer be consumed in the different simulated extinction scenarios. (AU)