Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO2 Enrichment

A general prediction of ecological theory is that climate change will favor invasive nonindigenous plant species (NIPS) over native species. However, the relative fitness advantage enjoyed by NIPS is often affected by resource limitation and potentially by extreme climatic events such as drought. Ge...

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Main Authors: Brendan J. Lepschi, David J. Marshall, Miloš Ivković, Bruce C. Robertson, Washington J. Gapare, Alexander B. Zwart, Robert C. Godfree
Format: Article
Language:English
Published: MDPI AG 2013-03-01
Series:Biology
Subjects:
Online Access:http://www.mdpi.com/2079-7737/2/2/481
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author Brendan J. Lepschi
David J. Marshall
Miloš Ivković
Bruce C. Robertson
Washington J. Gapare
Alexander B. Zwart
Robert C. Godfree
author_facet Brendan J. Lepschi
David J. Marshall
Miloš Ivković
Bruce C. Robertson
Washington J. Gapare
Alexander B. Zwart
Robert C. Godfree
author_sort Brendan J. Lepschi
collection DOAJ
description A general prediction of ecological theory is that climate change will favor invasive nonindigenous plant species (NIPS) over native species. However, the relative fitness advantage enjoyed by NIPS is often affected by resource limitation and potentially by extreme climatic events such as drought. Genetic constraints may also limit the ability of NIPS to adapt to changing climatic conditions. In this study, we investigated evidence for potential NIPS advantage under climate change in two sympatric perennial stipoid grasses from southeast Australia, the NIPS Nassella neesiana and the native Austrostipa bigeniculata. We compared the growth and reproduction of both species under current and year 2050 drought, temperature and CO2 regimes in a multifactor outdoor climate simulation experiment, hypothesizing that NIPS advantage would be higher under more favorable growing conditions. We also compared the quantitative variation and heritability of growth traits in populations of both species collected along a 200 km climatic transect. In contrast to our hypothesis we found that the NIPS N. neesiana was less responsive than A. bigeniculata to winter warming but maintained higher reproductive output during spring drought. However, overall tussock expansion was far more rapid in N. neesiana, and so it maintained an overall fitness advantage over A. bigeniculata in all climate regimes. N. neesiana also exhibited similar or lower quantitative variation and growth trait heritability than A. bigeniculata within populations but greater variability among populations, probably reflecting a complex past introduction history. We found some evidence that additional spring warmth increases the impact of drought on reproduction but not that elevated atmospheric CO2 ameliorates drought severity. Overall, we conclude that NIPS advantage under climate change may be limited by a lack of responsiveness to key climatic drivers, reduced genetic variability in range-edge populations, and complex drought-CO2 interactions.
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spelling doaj.art-c59f4f3fb8124092a7ba84993ce10d902023-09-02T21:44:26ZengMDPI AGBiology2079-77372013-03-012248151310.3390/biology2020481Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO2 EnrichmentBrendan J. LepschiDavid J. MarshallMiloš IvkovićBruce C. RobertsonWashington J. GapareAlexander B. ZwartRobert C. GodfreeA general prediction of ecological theory is that climate change will favor invasive nonindigenous plant species (NIPS) over native species. However, the relative fitness advantage enjoyed by NIPS is often affected by resource limitation and potentially by extreme climatic events such as drought. Genetic constraints may also limit the ability of NIPS to adapt to changing climatic conditions. In this study, we investigated evidence for potential NIPS advantage under climate change in two sympatric perennial stipoid grasses from southeast Australia, the NIPS Nassella neesiana and the native Austrostipa bigeniculata. We compared the growth and reproduction of both species under current and year 2050 drought, temperature and CO2 regimes in a multifactor outdoor climate simulation experiment, hypothesizing that NIPS advantage would be higher under more favorable growing conditions. We also compared the quantitative variation and heritability of growth traits in populations of both species collected along a 200 km climatic transect. In contrast to our hypothesis we found that the NIPS N. neesiana was less responsive than A. bigeniculata to winter warming but maintained higher reproductive output during spring drought. However, overall tussock expansion was far more rapid in N. neesiana, and so it maintained an overall fitness advantage over A. bigeniculata in all climate regimes. N. neesiana also exhibited similar or lower quantitative variation and growth trait heritability than A. bigeniculata within populations but greater variability among populations, probably reflecting a complex past introduction history. We found some evidence that additional spring warmth increases the impact of drought on reproduction but not that elevated atmospheric CO2 ameliorates drought severity. Overall, we conclude that NIPS advantage under climate change may be limited by a lack of responsiveness to key climatic drivers, reduced genetic variability in range-edge populations, and complex drought-CO2 interactions.http://www.mdpi.com/2079-7737/2/2/481invasive speciesclimate changeextreme climatic eventsdroughtadaptationplasticityCO2warmingNassella neesiananonindigenous advantageopen top chamber
spellingShingle Brendan J. Lepschi
David J. Marshall
Miloš Ivković
Bruce C. Robertson
Washington J. Gapare
Alexander B. Zwart
Robert C. Godfree
Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO2 Enrichment
Biology
invasive species
climate change
extreme climatic events
drought
adaptation
plasticity
CO2
warming
Nassella neesiana
nonindigenous advantage
open top chamber
title Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO2 Enrichment
title_full Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO2 Enrichment
title_fullStr Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO2 Enrichment
title_full_unstemmed Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO2 Enrichment
title_short Nonindigenous Plant Advantage in Native and Exotic Australian Grasses under Experimental Drought, Warming, and Atmospheric CO2 Enrichment
title_sort nonindigenous plant advantage in native and exotic australian grasses under experimental drought warming and atmospheric co2 enrichment
topic invasive species
climate change
extreme climatic events
drought
adaptation
plasticity
CO2
warming
Nassella neesiana
nonindigenous advantage
open top chamber
url http://www.mdpi.com/2079-7737/2/2/481
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