Journal Article

Plant traits, leaf palatability and litter decomposability for co-occurring woody species differing in invasion status and nitrogen fixation ability

Kurokawa, Hiroko, Peltzer, Duane A., Wardle, David A.

2010

Overview

1. Non-native invasive and nitrogen (N)-fixing plant species can cause large ecosystem-level impacts, particularly when they differ in functionally important plant traits from native and non N-fixing species. However, it remains unclear as to whether and how plant invasion status and Í fixation ability consistently influence key plant leaf and litter traits, and trait-driven processes like herbivory and decomposition. 2. We compared leaf and litter traits, leaf palatability and litter decomposability for 41 co-occurring woody species, including native N-fixers, native non N-fixers, invasive N-fixers and invasive non N-fixers, from a New Zealand floodplain. We tested the hypotheses that: (i) invasive and N-fixing species have higher foliar Í and specific leaf area, and lower concentrations of defensive phenolics and structural compounds than do native and non N-fixing species, and (ii) invasive and N-fixing species generally produce more decomposable litter and palatable foliage than do native and non N-fixing species. 3. Consistent with our hypotheses, invaders had higher foliar N and N : P ratio, and lower C : N ratio, than did native species. However, in contrast to our hypotheses, foliar phenolics were higher for the invaders while other leaf and litter traits were unaffected by invasion status. Further, N-fixers had higher Í and Í : Ñ ratios, and lower C : N ratios than did non N-fixers, but other leaf and litter traits were unaffected by Í fixation ability. 4. Leaf palatability was unaffected by invasion status but was higher for N-fixers than for non N-fixers. Litter decomposability was unaffected both by invasion status and N fixation ability. We found a significant positive relationship between leaf palatability and litter decomposability across all species, because similar traits, particularly the C : P ratio and total phenolic concentrations of plant tissues, were correlated with both processes. 5. Our results demonstrate that a small number of key traits, such as C : P ratio and total phenolic concentrations, drive both herbivory and decomposition irrespective of plant invasion status or N fixation ability. As such, they highlight that interspecific differences in particular plant traits, rather than plant functional group memberships based on invasion status and N fixation ability, are more effective in predicting palatability and decomposability.

• Publisher: Blackwell Publishing,Blackwell Publishing Ltd,Wiley Subscription Services, Inc
• Subject: Agricultural and Veterinary Sciences / Andra lantbruksrelaterade vetenskaper / Correlation / Decomposition / Ecological invasion / Ecosystems / Environmental Sciences and Nature Conservation / Environmental Sciences related to Agriculture and Land-use / Floodplains / Flowers & plants / Foliage / Functional anatomy / functional traits / Herbivores / Herbivory / Human ecology / Hypotheses / Indigenous species / Interspecific / interspecific variation / Introduced species / Invasive species / Lantbruksvetenskap och veterinärmedicin / Leaf area / Leaves / Litter / Litter traits / Miljö- och naturvårdsvetenskap / Native species / New Zealand / Nitrogen / Nitrogen fixation / nitrogen fixing plant / non‐native species / Other Agricultural Sciences / Palatability / Phenolic compounds / Phenols / Plant ecology / Plant litter / Plant physiological ecology / Plant species / Plant tissues / Plants / prediction / shrub / woody plants