The influence of soil resources and plant traits on invasion and restoration in a subtropical woodland

Plant Ecology
By: , and 

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Abstract

It has been shown in some cases that nitrogen (N) addition to soil will increase abundance of plant invaders because many invaders have traits that promote rapid growth in response to high resource supply. Similarly, it has been suggested, and sometimes shown, that decreasing soil N via carbon (C) additions can facilitate native species recovery. Yet all species are unlikely to respond to resource supply in the same way. We asked how soil nutrients and competition affect native and exotic woody species in a restoration experiment where we added N or C, and crossed soil manipulation with the manipulation of dominant exotic grass abundance in a Hawaiian subtropical woodland. We related changes in survival and growth of outplanted individuals to native/exotic status and plant traits. As a group, N-fixers showed reduced survival compared to non-fixers in response to added N, with Morella faya (exotic) and Acacia koa (native) having dramatic negative responses. Among non-fixers, species with greater foliar %N had more positive survival responses to increasing soil N. Specific leaf area was not predictive of responses to nutrients or competition. In general, responses to carbon addition were weak, although reducing competition from existing exotic grasses was beneficial for all outplanted species, with N-fixers showing the most positive response. We conclude that commonly used restoration strategies to clear exotic species or lower soil resources with C addition will most greatly benefit N-fixing species, which themselves may be unwanted invaders. Thus statements about the influence of increased soil N on invasions should be carefully dissected by considering the traits (such as N-fixation status) of the regional species pool.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The influence of soil resources and plant traits on invasion and restoration in a subtropical woodland
Series title Plant Ecology
DOI 10.1007/s11258-017-0757-3
Volume 218
Issue 10
Year Published 2017
Language English
Publisher Springer
Contributing office(s) Pacific Island Ecosystems Research Center
Description 12 p.
First page 1149
Last page 1161
Country United STates
State Hawai'i