Enhanced shoot investment makes invasive plants exhibit growth advantages in high nitrogen conditions

X A Liu,P H Peng,J J Li,Y Peng

doi:10.1590/1519-6984.169578

Abstract

Resource amendments commonly promote plant invasions, raising concerns over the potential consequences of nitrogen (N) deposition; however, it is unclear whether invaders will benefit from N deposition more than natives. Growth is among the most fundamental inherent traits of plants and thus good invaders may have superior growth advantages in response to resource amendments. We compared the growth and allocation between invasive and native plants in different N regimes including controls (ambient N concentrations). We found that invasive plants always grew much larger than native plants in varying N conditions, regardless of growth- or phylogeny-based analyses, and that the former allocated more biomass to shoots than the latter. Although N addition enhanced the growth of invasive plants, this enhancement did not increase with increasing N addition. Across invasive and native species, changes in shoot biomass allocation were positively correlated with changes in whole-plant biomass; and the slope of this relationship was greater in invasive plants than native plants. These findings suggest that enhanced shoot investment makes invasive plants retain a growth advantage in high N conditions relative to natives, and also highlight that future N deposition may increase the risks of plant invasions.

Highlights

What makes exotic plants become successful invaders is a core question in invasion ecology
We found that invasive plants always grew much larger than native plants in varying N conditions, regardless of growth- or phylogeny-based analyses, and that the former allocated more biomass to shoots than the latter
Across invasive and native species, changes in shoot biomass allocation were positively correlated with changes in whole-plant biomass; and the slope of this relationship was greater in invasive plants than native plants

Summary

Introduction

What makes exotic plants become successful invaders is a core question in invasion ecology (van Kleunen et al, 2010a). Plant invasion is the process in which exotic plant species displace native species, dominant natives, and subsequently dominate invaded communities. In this context comparing the performance of invasive and native species in the same conditions is crucial to understanding the mechanisms by which invasive species outperform native species (Funk and Vitousek, 2007; van Kleunen et al, 2010a, b; Leffler et al, 2014; Kuebbing et al, 2015)

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