Effects of Canada Goldenrod Invasion on Soil Extracellular Enzyme Activities and Ecoenzymatic Stoichiometry

Zhiyuan Hu,Jianfan Sun,Xiaojun Zheng,Zhicong Dai,Guangqian Ren,Daolin Du,Guanlin Li,Kangwei Shi,Yiwen Zhou,Jiating Li,Jiaqi Zhang

doi:10.3390/su13073768

Abstract

The rapid expansion of Canada goldenrod (Solidago canadensis L.) in China has drawn considerable attention as it may not only decrease vegetation diversity but also alter soil nutrient cycling in the affected ecosystems. Soil extracellular enzymes mediate nutrient cycling by catalyzing the organic matter decomposition; however, the mechanisms by which alien plant invasion may affect soil extracellular enzymes remain unclear. The objective of this study was to investigate the responses of soil extracellular enzyme activities and ecoenzymatic stoichiometry to S. canadensis invasion. Several extracellular enzymatic activities related to carbon, nitrogen, and phosphorus cycling were measured using a fluorometric method. Ecoenzymatic stoichiometry was used as a proxy of soil microbial metabolic limitations. S. canadensis invasion appeared to be associated with decreased activities of enzymes and with substantial conversions of microbial metabolic carbon and nitrogen limitations. The changes in the activities of extracellular enzymes and the limitations of microbial metabolism were correlated with the alterations in the nutrient availability and resource stoichiometry in the soil. These findings reveal that the alterations in soil available nutrients associated with S. canadensis invasion may regulate extracellular enzymatic activities and cause microbial metabolic limitations, suggesting that S. canadensis invasion considerably affects biogeochemical cycling processes.

Highlights

Biological invasions are one of the major threats to functioning, economical use, biodiversity, and services of the global ecosystem [1,2,3,4]
Soil physicochemical and microbial biomass properties differed across the invasion gradient of S. canadensis
These conclusions are in line with those of other studies on alien invasive plants, which exhibited that changes in C, N, and P-acquisition enzymes were associated with changes in soil available nutrients, indicating that limitations and imbalances of nutrients can partially underlie production of soil enzymes and affect their activity [18,47,48]

Summary

Introduction

Biological invasions are one of the major threats to functioning, economical use, biodiversity, and services of the global ecosystem [1,2,3,4]. Alien invasive plants alter the structure and composition of vegetation communities in the invaded ecosystem due to rapid growth, high reproductive, and spreading capacity [5,6]. There is no doubt the shifts in the vegetation communities can further impact numerous ecosystem processes and functions, thereby cause irreversible effects on the invaded ecosystems [7,8]. Potential threats of alien invasive plants have been studied in depth, and various possible invasion hypotheses have been suggested [1,6]. Some of these hypotheses are either overlapped or imprecise, mostly due to the overwhelming diversity regarding alien invasive plant species and types of invaded ecosystems [9].

Objectives

Methods

Results

Discussion

Conclusion