A novel metric reveals biotic resistance potential and informs predictions of invasion success

Ross N Cuthbert,Jaimie T A Dick,Amanda Callaghan

doi:10.1038/s41598-019-51705-9

Ross N Cuthbert, Jaimie T A Dick + Show 1 more

Open Access

https://doi.org/10.1038/s41598-019-51705-9

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Abstract

Invasive species continue to proliferate and detrimentally impact ecosystems on a global scale. Whilst impacts are well-documented for many invaders, we lack tools to predict biotic resistance and invasion success. Biotic resistance from communities may be a particularly important determinant of the success of invaders. The present study develops traditional ecological concepts to better understand and quantify biotic resistance. We quantified predation towards the highly invasive Asian tiger mosquito Aedes albopictus and a representative native mosquito Culex pipiens by three native and widespread cyclopoid copepods, using functional response and prey switching experiments. All copepods demonstrated higher magnitude type II functional responses towards the invasive prey over the analogous native prey, aligned with higher attack and maximum feeding rates. All predators exhibited significant, frequency-independent prey preferences for the invader. With these results, we developed a novel metric for biotic resistance which integrates predator numerical response proxies, revealing differential biotic resistance potential among predators. Our results are consistent with field patterns of biotic resistance and invasion success, illustrating the predictive capacity of our methods. We thus propose the further development of traditional ecological concepts, such as functional responses, numerical responses and prey switching, in the evaluation of biotic resistance and invasion success.

Highlights

Invasive species continue to proliferate and detrimentally impact ecosystems on a global scale
100% of control prey survived and experimental deaths were directly attributable to predation by copepods, which was evidenced by partially consumed prey remaining post-experiment
Biotic resistance may be a key mechanism which controls the success of invasive species

Summary

Introduction

Invasive species continue to proliferate and detrimentally impact ecosystems on a global scale. The functional response, defined as the relationship between resource availability and resource use, has been applied by ecologists to quantify interaction strengths between consumers and resources (e.g. predators and prey)[10,11,12] Both functional response form and magnitude have been identified as robust measures of ecological impact from consumers towards resources, including from existing and emerging invasive species towards native resources[4,9,13,14]. Whilst functional and numerical responses have been applied to examine the ecological impacts of invasive consumers (e.g. predators) towards native resources (e.g. prey), there has been relatively little application of these approaches to quantify biotic resistance potential towards invasive resources (e.g. prey) in the context of invasion success[6,17,18]. Mechanistic interpretation must be cautioned in the absence of field experiments, comparative laboratory experiments may be used to rapidly quantify these effects (i.e. functional/numerical responses and preferences), and such studies have proven highly informative in the context of invader impact and success[14,20]

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