Warming neutralizes host-specific competitive advantages between a native and invasive herbivore

Zheng-Hong Lin,Chuan-Kai Ho,Chung-Huey Wu

doi:10.1038/s41598-018-29517-0

Abstract

Although native-invasive species interactions have become a common mechanism shaping ecosystems, whether these interactions shift under warming remains unclear. To investigate how warming may affect native and invasive species separately and together (intraspecific and interspecific competition, respectively) and whether any warming impact is resource dependent, we examined the performance of two competing herbivores (native Pieris canidia and invasive P. rapae) on two common host plants under three temperature settings (control, 3 °C, and 6 °C warming using environmental chambers). The results revealed that warming benefited the development and growth of both Pieris under intraspecific competition, but the benefits were host-plant dependent. Notably, the native or invasive Pieris gained an advantage from interspecific competition (host-plant dependent), but warming neutralized the competitive advantages of either Pieris species. These findings raise the possibility that warming-induced shifts in competitive status may become a crucial mechanism shaping ecosystems worldwide, because most ecosystems are challenged by species invasion and warming. Moreover, this study revealed a discrepancy in species thermal performance between intra- and interspecific competition. Therefore, to predict native-invasive species competition under warming, current thermal performance applications should use species performance curves derived from interspecific rather than intraspecific competition studies (although the latter is more readily available).

Highlights

Species invasion, a worldwide phenomenon, can threaten or alter biodiversity, community structure and ecosystem functions in invaded habitats[1,2,3,4,5]
To advance the application of the thermal performance concept, we should verify whether the competitive outcome is resource dependent, and whether the degree of this resource dependency is mediated by temperature. (c) The thermal performance concept predicts the consequences of warming on interspecific competition based on the thermal performance curves of native and invasive species (Supplement 1)
The interspecific competition results were host plant specific (i.e., P. canidia and P. rapae had an advantage on Rorippa and Brassica plants, respectively), warming could shift the competitive status of the native and invasive Pieris on each of the two host plant species

Summary

Introduction

A worldwide phenomenon, can threaten or alter biodiversity, community structure and ecosystem functions in invaded habitats[1,2,3,4,5]. Other studies based on species’ performance over temperature gradients (i.e., thermal performance) have suggested that warming may benefit invasive species because their thermal tolerance is higher than that of native species (e.g., the “tolerant invaders hypothesis”)[15,16] (Supplement 1). (a) This thermal performance concept assumes that native species suffer more (or benefit less) than do invasive ones from warming. For cases where native species can benefit from modest warming as much as invasive ones (e.g., through faster growth and development). Considering data availability, we need to determine whether we can use thermal performance curves from intraspecific- or no-competition studies (readily available) to predict interspecific competition outcomes under warming (e.g., species composition change) (Supplement 1). To predict warming impact on native-invasive species competition, we should clarify whether the impact is resource-dependent

Methods

Results

Discussion

Conclusion