Seed limitation, not soil legacy effects, prevents native understory from establishing in oak woodlands in Scotland after removal of Rhododendron ponticum

Janet E. MacLean, Ruth J. Mitchell, David Burslem, David Genney, Jeanette Hall, Robin J. Pakeman

Research output: Contribution to journalArticle

2 Citations (Scopus)
3 Downloads (Pure)

Abstract

Following removal of the invasive species Rhododendron ponticum the native understorey plant community typically fails to re-establish itself. Potential explanations for this failure include 1) lack of an appropriate native seed source, 2) inability of seed to penetrate a dense bryophyte layer and 3) persistence of chemical ‘legacy effects’ in the soil. We established an experiment to test these competing hypotheses in an Atlantic oak woodland where R. ponticum had been removed. The following experimental treatments were applied singly and in combination: 1) addition of a native seed mix to test for seed limitation; 2) removal of the established ground vegetation at the start of the experiment (which principally consisted of bryophytes) to test for the impact of a barrier layer; 3) addition of activated carbon to test for chemical legacy effects in the soil and 4) fertilisation as an additional measure to promote the establishment of native vascular plants. Application of the native seed mix was revealed to be an effective way to increase the cover of native vascular plants, and was particularly effective when applied after the removal of the bryophyte layer. The application of activated carbon and/or fertiliser, however, had no effect on the cover of native vegetation. We conclude that reports of R. ponticum exerting chemical legacy effects long after its removal may have been overstated and that seed limitation and inability to successfully establish in a dense bryophyte layer provided the strongest barriers to natural recolonisation by the native plant community following R. ponticum removal.
Original languageEnglish
Pages (from-to)865-872
Number of pages8
JournalRestoration Ecology
Volume26
Issue number5
Early online date4 Jan 2018
DOIs
Publication statusPublished - Sep 2018

Fingerprint

Rhododendron ponticum
Scotland
understory
woodlands
woodland
Quercus
bryophyte
seed
seeds
soil
activated carbon
vascular plant
vascular plants
plant community
plant communities
testing
ground vegetation
vegetation
recolonization
invasive species

Keywords

  • bryophytes
  • legacy effects
  • oak woodland
  • reconolisation
  • restoration
  • Rhododendron ponticum

Cite this

Seed limitation, not soil legacy effects, prevents native understory from establishing in oak woodlands in Scotland after removal of Rhododendron ponticum. / MacLean, Janet E.; Mitchell, Ruth J.; Burslem, David; Genney, David; Hall, Jeanette; Pakeman, Robin J.

In: Restoration Ecology, Vol. 26, No. 5, 09.2018, p. 865-872.

Research output: Contribution to journalArticle

MacLean, Janet E. ; Mitchell, Ruth J. ; Burslem, David ; Genney, David ; Hall, Jeanette ; Pakeman, Robin J. / Seed limitation, not soil legacy effects, prevents native understory from establishing in oak woodlands in Scotland after removal of Rhododendron ponticum. In: Restoration Ecology. 2018 ; Vol. 26, No. 5. pp. 865-872.
@article{e9ea3845b23e4433b75eff75cb9b34e3,
title = "Seed limitation, not soil legacy effects, prevents native understory from establishing in oak woodlands in Scotland after removal of Rhododendron ponticum",
abstract = "Following removal of the invasive species Rhododendron ponticum the native understorey plant community typically fails to re-establish itself. Potential explanations for this failure include 1) lack of an appropriate native seed source, 2) inability of seed to penetrate a dense bryophyte layer and 3) persistence of chemical ‘legacy effects’ in the soil. We established an experiment to test these competing hypotheses in an Atlantic oak woodland where R. ponticum had been removed. The following experimental treatments were applied singly and in combination: 1) addition of a native seed mix to test for seed limitation; 2) removal of the established ground vegetation at the start of the experiment (which principally consisted of bryophytes) to test for the impact of a barrier layer; 3) addition of activated carbon to test for chemical legacy effects in the soil and 4) fertilisation as an additional measure to promote the establishment of native vascular plants. Application of the native seed mix was revealed to be an effective way to increase the cover of native vascular plants, and was particularly effective when applied after the removal of the bryophyte layer. The application of activated carbon and/or fertiliser, however, had no effect on the cover of native vegetation. We conclude that reports of R. ponticum exerting chemical legacy effects long after its removal may have been overstated and that seed limitation and inability to successfully establish in a dense bryophyte layer provided the strongest barriers to natural recolonisation by the native plant community following R. ponticum removal.",
keywords = "bryophytes, legacy effects, oak woodland, reconolisation, restoration, Rhododendron ponticum",
author = "MacLean, {Janet E.} and Mitchell, {Ruth J.} and David Burslem and David Genney and Jeanette Hall and Pakeman, {Robin J.}",
note = "We thank Scottish Natural Heritage for funding this work via a PhD studentship to JM. The National Trust for Scotland provided the field site and fenced the experiment. In particular we thank Kate Sampson and Lindsay Mackinlay at NTS staff for their assistance in establishing this experiment. RJM and RJP were funded through the 2011-2016 and 2016-2021 Strategic Research Programmes of the Scottish Government.",
year = "2018",
month = "9",
doi = "10.1111/rec.12664",
language = "English",
volume = "26",
pages = "865--872",
journal = "Restoration Ecology",
issn = "1061-2971",
publisher = "Wiley",
number = "5",

}

TY - JOUR

T1 - Seed limitation, not soil legacy effects, prevents native understory from establishing in oak woodlands in Scotland after removal of Rhododendron ponticum

AU - MacLean, Janet E.

AU - Mitchell, Ruth J.

AU - Burslem, David

AU - Genney, David

AU - Hall, Jeanette

AU - Pakeman, Robin J.

N1 - We thank Scottish Natural Heritage for funding this work via a PhD studentship to JM. The National Trust for Scotland provided the field site and fenced the experiment. In particular we thank Kate Sampson and Lindsay Mackinlay at NTS staff for their assistance in establishing this experiment. RJM and RJP were funded through the 2011-2016 and 2016-2021 Strategic Research Programmes of the Scottish Government.

PY - 2018/9

Y1 - 2018/9

N2 - Following removal of the invasive species Rhododendron ponticum the native understorey plant community typically fails to re-establish itself. Potential explanations for this failure include 1) lack of an appropriate native seed source, 2) inability of seed to penetrate a dense bryophyte layer and 3) persistence of chemical ‘legacy effects’ in the soil. We established an experiment to test these competing hypotheses in an Atlantic oak woodland where R. ponticum had been removed. The following experimental treatments were applied singly and in combination: 1) addition of a native seed mix to test for seed limitation; 2) removal of the established ground vegetation at the start of the experiment (which principally consisted of bryophytes) to test for the impact of a barrier layer; 3) addition of activated carbon to test for chemical legacy effects in the soil and 4) fertilisation as an additional measure to promote the establishment of native vascular plants. Application of the native seed mix was revealed to be an effective way to increase the cover of native vascular plants, and was particularly effective when applied after the removal of the bryophyte layer. The application of activated carbon and/or fertiliser, however, had no effect on the cover of native vegetation. We conclude that reports of R. ponticum exerting chemical legacy effects long after its removal may have been overstated and that seed limitation and inability to successfully establish in a dense bryophyte layer provided the strongest barriers to natural recolonisation by the native plant community following R. ponticum removal.

AB - Following removal of the invasive species Rhododendron ponticum the native understorey plant community typically fails to re-establish itself. Potential explanations for this failure include 1) lack of an appropriate native seed source, 2) inability of seed to penetrate a dense bryophyte layer and 3) persistence of chemical ‘legacy effects’ in the soil. We established an experiment to test these competing hypotheses in an Atlantic oak woodland where R. ponticum had been removed. The following experimental treatments were applied singly and in combination: 1) addition of a native seed mix to test for seed limitation; 2) removal of the established ground vegetation at the start of the experiment (which principally consisted of bryophytes) to test for the impact of a barrier layer; 3) addition of activated carbon to test for chemical legacy effects in the soil and 4) fertilisation as an additional measure to promote the establishment of native vascular plants. Application of the native seed mix was revealed to be an effective way to increase the cover of native vascular plants, and was particularly effective when applied after the removal of the bryophyte layer. The application of activated carbon and/or fertiliser, however, had no effect on the cover of native vegetation. We conclude that reports of R. ponticum exerting chemical legacy effects long after its removal may have been overstated and that seed limitation and inability to successfully establish in a dense bryophyte layer provided the strongest barriers to natural recolonisation by the native plant community following R. ponticum removal.

KW - bryophytes

KW - legacy effects

KW - oak woodland

KW - reconolisation

KW - restoration

KW - Rhododendron ponticum

U2 - 10.1111/rec.12664

DO - 10.1111/rec.12664

M3 - Article

VL - 26

SP - 865

EP - 872

JO - Restoration Ecology

JF - Restoration Ecology

SN - 1061-2971

IS - 5

ER -