Compromised root development constrains the establishment potential of native plants in unamended alkaline post-mining substrates

Adam T. Cross, Jason C. Stevens, Rohan Sadler, Benjamin Moreira-Grez, Dmitry Ivanov, Hongtao Zhong, Kingsley W. Dixon, Hans Lambers

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Background and aims: Mined materials often require rehabilitation or ecological restoration through revegetation as part of mine closure and relinquishment practices, yet there is a widening gap between the expectations of recovery and what industry achieve. The edaphic conditions of post-mining substrates present a suite of potential limitations to plant growth and may constrain the establishment capability and development of native species. Methods: We assessed seedling emergence, relative growth rate and calculated standardised growth estimates using 10 measured root and shoot parameters for six locally-dominant native species from different families and nutrient-acquisition strategies in a range of representative mining restoration substrates (topsoil, tailings, capped tailings and waste rock), examining their suitability as pioneers for ecological restoration. Results: The establishment and growth of all six species in post-mining substrates were significantly compromised. Root development was significantly responsive to substrate, with measured root parameters on average 27% lower in capped tailings, 41% lower in waste rock and 67% lower for individuals grown in tailings compared with those grown in topsoil alone. Plant growth was compromised at different life cycle stages (seed germination, seedling establishment, early growth and development) and across a number of different traits, with primary edaphic constraints including high pH (>8.5) and insufficient available N. The highest-performing species on post-mining substrates was an N2-fixing legume, while lowest-performing species included those with ectomycorrhizal associations or no specific nutrient-acquisition strategy. Conclusions: Edaphic filters may be significant drivers of trajectory and success in rehabilitation and restoration projects at scales ranging from individuals (by limiting establishment or constraining growth and development) to communities (by causing species to assemble in a different manner than the desired reference community). If intractable edaphic parameters constraining plant establishment and early development such as extreme pH and a lack of available nutrients are not ameliorated, the restoration trajectory on post-mining landforms is likely unfavourable. Failure to adequately ameliorate post-mining substrates may represent a major liability for industry in meeting mine-closure requirements.

Original languageEnglish
JournalPlant and Soil
DOIs
Publication statusE-pub ahead of print - 10 Nov 2018

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substrate
tailings
ecological restoration
growth and development
native species
topsoil
trajectories
nutrient
nutrients
indigenous species
rocks
trajectory
plant growth
industry
seedling emergence
plant establishment
seedling establishment
landforms
revegetation
land restoration

Cite this

Cross, Adam T. ; Stevens, Jason C. ; Sadler, Rohan ; Moreira-Grez, Benjamin ; Ivanov, Dmitry ; Zhong, Hongtao ; Dixon, Kingsley W. ; Lambers, Hans. / Compromised root development constrains the establishment potential of native plants in unamended alkaline post-mining substrates. In: Plant and Soil. 2018.
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title = "Compromised root development constrains the establishment potential of native plants in unamended alkaline post-mining substrates",
abstract = "Background and aims: Mined materials often require rehabilitation or ecological restoration through revegetation as part of mine closure and relinquishment practices, yet there is a widening gap between the expectations of recovery and what industry achieve. The edaphic conditions of post-mining substrates present a suite of potential limitations to plant growth and may constrain the establishment capability and development of native species. Methods: We assessed seedling emergence, relative growth rate and calculated standardised growth estimates using 10 measured root and shoot parameters for six locally-dominant native species from different families and nutrient-acquisition strategies in a range of representative mining restoration substrates (topsoil, tailings, capped tailings and waste rock), examining their suitability as pioneers for ecological restoration. Results: The establishment and growth of all six species in post-mining substrates were significantly compromised. Root development was significantly responsive to substrate, with measured root parameters on average 27{\%} lower in capped tailings, 41{\%} lower in waste rock and 67{\%} lower for individuals grown in tailings compared with those grown in topsoil alone. Plant growth was compromised at different life cycle stages (seed germination, seedling establishment, early growth and development) and across a number of different traits, with primary edaphic constraints including high pH (>8.5) and insufficient available N. The highest-performing species on post-mining substrates was an N2-fixing legume, while lowest-performing species included those with ectomycorrhizal associations or no specific nutrient-acquisition strategy. Conclusions: Edaphic filters may be significant drivers of trajectory and success in rehabilitation and restoration projects at scales ranging from individuals (by limiting establishment or constraining growth and development) to communities (by causing species to assemble in a different manner than the desired reference community). If intractable edaphic parameters constraining plant establishment and early development such as extreme pH and a lack of available nutrients are not ameliorated, the restoration trajectory on post-mining landforms is likely unfavourable. Failure to adequately ameliorate post-mining substrates may represent a major liability for industry in meeting mine-closure requirements.",
keywords = "Alkaline substrates, Calcicole, Calcifuge, Ecological restoration, Edaphic filters, Mine tailings, Plant development, Plant mineral nutrition, Rehabilitation",
author = "Cross, {Adam T.} and Stevens, {Jason C.} and Rohan Sadler and Benjamin Moreira-Grez and Dmitry Ivanov and Hongtao Zhong and Dixon, {Kingsley W.} and Hans Lambers",
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Compromised root development constrains the establishment potential of native plants in unamended alkaline post-mining substrates. / Cross, Adam T.; Stevens, Jason C.; Sadler, Rohan; Moreira-Grez, Benjamin; Ivanov, Dmitry; Zhong, Hongtao; Dixon, Kingsley W.; Lambers, Hans.

In: Plant and Soil, 10.11.2018.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Compromised root development constrains the establishment potential of native plants in unamended alkaline post-mining substrates

AU - Cross, Adam T.

AU - Stevens, Jason C.

AU - Sadler, Rohan

AU - Moreira-Grez, Benjamin

AU - Ivanov, Dmitry

AU - Zhong, Hongtao

AU - Dixon, Kingsley W.

AU - Lambers, Hans

PY - 2018/11/10

Y1 - 2018/11/10

N2 - Background and aims: Mined materials often require rehabilitation or ecological restoration through revegetation as part of mine closure and relinquishment practices, yet there is a widening gap between the expectations of recovery and what industry achieve. The edaphic conditions of post-mining substrates present a suite of potential limitations to plant growth and may constrain the establishment capability and development of native species. Methods: We assessed seedling emergence, relative growth rate and calculated standardised growth estimates using 10 measured root and shoot parameters for six locally-dominant native species from different families and nutrient-acquisition strategies in a range of representative mining restoration substrates (topsoil, tailings, capped tailings and waste rock), examining their suitability as pioneers for ecological restoration. Results: The establishment and growth of all six species in post-mining substrates were significantly compromised. Root development was significantly responsive to substrate, with measured root parameters on average 27% lower in capped tailings, 41% lower in waste rock and 67% lower for individuals grown in tailings compared with those grown in topsoil alone. Plant growth was compromised at different life cycle stages (seed germination, seedling establishment, early growth and development) and across a number of different traits, with primary edaphic constraints including high pH (>8.5) and insufficient available N. The highest-performing species on post-mining substrates was an N2-fixing legume, while lowest-performing species included those with ectomycorrhizal associations or no specific nutrient-acquisition strategy. Conclusions: Edaphic filters may be significant drivers of trajectory and success in rehabilitation and restoration projects at scales ranging from individuals (by limiting establishment or constraining growth and development) to communities (by causing species to assemble in a different manner than the desired reference community). If intractable edaphic parameters constraining plant establishment and early development such as extreme pH and a lack of available nutrients are not ameliorated, the restoration trajectory on post-mining landforms is likely unfavourable. Failure to adequately ameliorate post-mining substrates may represent a major liability for industry in meeting mine-closure requirements.

AB - Background and aims: Mined materials often require rehabilitation or ecological restoration through revegetation as part of mine closure and relinquishment practices, yet there is a widening gap between the expectations of recovery and what industry achieve. The edaphic conditions of post-mining substrates present a suite of potential limitations to plant growth and may constrain the establishment capability and development of native species. Methods: We assessed seedling emergence, relative growth rate and calculated standardised growth estimates using 10 measured root and shoot parameters for six locally-dominant native species from different families and nutrient-acquisition strategies in a range of representative mining restoration substrates (topsoil, tailings, capped tailings and waste rock), examining their suitability as pioneers for ecological restoration. Results: The establishment and growth of all six species in post-mining substrates were significantly compromised. Root development was significantly responsive to substrate, with measured root parameters on average 27% lower in capped tailings, 41% lower in waste rock and 67% lower for individuals grown in tailings compared with those grown in topsoil alone. Plant growth was compromised at different life cycle stages (seed germination, seedling establishment, early growth and development) and across a number of different traits, with primary edaphic constraints including high pH (>8.5) and insufficient available N. The highest-performing species on post-mining substrates was an N2-fixing legume, while lowest-performing species included those with ectomycorrhizal associations or no specific nutrient-acquisition strategy. Conclusions: Edaphic filters may be significant drivers of trajectory and success in rehabilitation and restoration projects at scales ranging from individuals (by limiting establishment or constraining growth and development) to communities (by causing species to assemble in a different manner than the desired reference community). If intractable edaphic parameters constraining plant establishment and early development such as extreme pH and a lack of available nutrients are not ameliorated, the restoration trajectory on post-mining landforms is likely unfavourable. Failure to adequately ameliorate post-mining substrates may represent a major liability for industry in meeting mine-closure requirements.

KW - Alkaline substrates

KW - Calcicole

KW - Calcifuge

KW - Ecological restoration

KW - Edaphic filters

KW - Mine tailings

KW - Plant development

KW - Plant mineral nutrition

KW - Rehabilitation

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U2 - 10.1007/s11104-018-3876-2

DO - 10.1007/s11104-018-3876-2

M3 - Article

JO - Plant and Soil: An International Journal on Plant-Soil Relationships

JF - Plant and Soil: An International Journal on Plant-Soil Relationships

SN - 0032-079X

ER -