The effects of insects, nutrients, and plant invasion on community structure and function above‐ and belowground

Ecology and Evolution

Phoebe Wright¹  Melissa A. Cregger¹  Lara Souza¹  Nathan J. Sanders¹ 

[1] Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee

关键词: aboveground biomass;    bacteria;    fungi;    insect;    invasive plant;    nitrogen‐fixer;    nutrient amendment;    old‐field ecosystem;    soil enzyme activity;   

DOI  :  10.1002/ece3.961

来源: Wiley

【 摘 要 】

Abstract

Soil nutrient availability, invasive plants, and insect presence can directly alter ecosystem structure and function, but less is known about how these factors may interact. In this 6-year study in an old-field ecosystem, we manipulated insect abundance (reduced and control), the propagule pressure of an invasive nitrogen-fixing plant (propagules added and control), and soil nutrient availability (nitrogen added, nitrogen reduced and control) in a fully crossed, completely randomized plot design. We found that nutrient amendment and, occasionally, insect abundance interacted with the propagule pressure of an invasive plant to alter above- and belowground structure and function at our site. Not surprisingly, nutrient amendment had a direct effect on aboveground biomass and soil nutrient mineralization. The introduction of invasive nitrogen-fixing plant propagules interacted with nutrient amendment and insect presence to alter soil bacterial abundance and the activity of the microbial community. While the larger-scale, longer-term bulk measurements such as biomass production and nutrient mineralization responded to the direct effects of our treatments, the shorter-term and dynamic microbial communities tended to respond to interactions among our treatments. Our results indicate that soil nutrients, invasive plants, and insect herbivores determine both above- and belowground responses, but whether such effects are independent versus interdependent varies with scale.

【 授权许可】

CC BY   
© 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.