Interactive disturbances drive community composition, heterogeneity, and the niches of invasive exotic plant species during secondary succession

ABSTRACT

Background

Simultaneous disturbances during secondary succession can cause plant community shifts, facilitating exotic species invasions. However, it remains unclear if exotic invasion is facilitated by additive or interactive disturbance effects during succession.

Aims

Our aim was to investigate temporal shifts in plant species composition, invasive exotics, and indicator species during simultaneous disturbances in secondary succession.

Methods

We used species data from nine plant surveys over 22 years of a field experiment in an old field where parallel strips were randomly assigned to each of the 9 crossed fertiliser and mowing disturbance treatments. Multivariate and ordination analyses were used to quantify community response to disturbance. Indicator species analysis identified plants characteristic of different disturbance levels.

Results

Plant communities differed in composition and heterogeneity based on interactive effects of disturbance treatments whereas pairwise tests showed these differences occurred in over two-thirds of treatment combinations. Of the 44 indicator plant species, seven of the eight exotic species of concern for Illinois were indicator species and characterised particular disturbance treatments and surveys.

Conclusions

Changes in these successional plant communities depend on the interaction among disturbances, which can facilitate exotic plant invasions, leading to plant communities which disproportionately maintain invasive exotic plants as compared to other naturalised exotic and native plant species.

KEYWORDS:

• Old field
• succession
• disturbance
• exotic plant species
• heterogeneity
• invasion
• indicator plant species
• mowing
• fertiliser

Acknowledgements

We would like to thank the following individuals and groups for their field efforts, data contributions, and continued maintenance of these on-going experimental plots: Sara G. Baer, Kari Foster, Yohanes A.K. Honu, Eric W. Hoyer, Xian Liu, Marilyn Mathis, Beth Middleton, Zhe Ren, Jared Urban, Touch of Nature Environmental Center, and the Department of Plant Biology and Southern Illinois University – Carbondale.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The support of the National Science Foundation (DUE 9554807) for funding to establish this long-term experiment is gratefully acknowledged. GL is generously supported by the National Natural Science Foundation of China (31770522), Henan University and China Scholarship Council (CSC).

Notes on contributors

David F. Barfknecht

David Barfknecht is a doctoral student. His research interests are community, invasion, and grassland ecology.

Guoyong Li

Guoyong Li has research interests in ecosystem ecology, grassland ecology, and biodiversity-productivity relationships.

Kelsey A. Martinez

Kelsey Martinez research interests include community ecology and ecophysiology of invasive species.

David J. Gibson

David Gibson is professor of Plant Biology. His research interests are in the vegetation ecology of grasslands and forest-grassland mosaics.