A new perspective on trait differences between native and invasive exotic plants: reply to critique

Authors: Leffler, Alan; James, Jeremy; Monaco, Thomas; Sheley, Roger

Submitted to: Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/24/2014
Publication Date: 4/1/2015
Citation: Leffler, A.J., James, J.J., Monaco, T.A., Sheley, R.L. 2015. A new perspective on trait differences between native and invasive exotic plants: reply to critique. Ecology. 96(4):1152-1153.

Interpretive Summary: A meta-analysis contrasting morphological and physiological traits of invasive species and native species was conducted using data acquired from journal articles published between the years 1995 and 2010. This study (Leffler et al. 2014, Ecology 95:298-305), generated a comment from Dawson et al. (Ecology in press), who raise three points regarding our analysis and how it was interpreted. We concede to their first point that when an invader occupies an empty niche with a trait value intermediate to native species in the community, differences among native and invasive species are less critical. Their second point questions whether trait differences are still important if the invasive species is more fit than the native species. We agree with this caveat, but recognize that fitness differences arise from an interaction of traits and the environment, resulting in basic trade-offs. Consequently, traits considered advanageous to invaders do not always result in invasion. Finally, their third point questioned whether differences between invasive and native species and differences between two native and native species would be equitable if contrasts originated from the same group of studies. Re-analysis of our data set using only studies that contained both native-invasive and native-native comparisons confirmed our original conclusions.

Technical Abstract: A meta-analysis contrasting morphological and physiological traits of invasive species and native species was conducted using data acquired from journal articles published between the years 1995 and 2010. This study (Leffler et al. 2014, Ecology 95:298-305), generated a comment from Dawson et al. (Ecology in press), who raise three points regarding our analysis and how it was interpreted. We concede to their first point that when an invader occupies an empty niche with a trait value intermediate to native species in the community, differences among native and invasive species are less critical. Their second point questions whether trait differences are still important if the invasive species is more fit than the native species. We agree with this caveat, but recognize that fitness differences arise from an interaction of traits and the environment, resulting in basic trade-offs. Consequently, traits considered advantageous to invaders do not always result in invasion. Finally, their third point questioned whether differences between invasive and native species and differences between two native and native species would be equitable if contrasts originated from the same group of studies. Re-analysis of our data set using only studies that contained both native-invasive and native-native comparisons confirmed our original conclusions.