Early Acacia invasion in a sandy ecosystem enables shading mediated by soil, leaf nitrogen and facilitation
Australian species of the genus Acacia are amongst the most invasive trees. As nitrogen fixers, they are able to invade oligotrophic ecosystems and alter ecosystem functioning to their benefit. We aimed to answer three questions: How does early Acacia invasion influence nitrogen and light in a sandy...
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Published in | Biological invasions Vol. 20; no. 6; pp. 1567 - 1575 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Cham
Springer International Publishing
01.06.2018
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | Australian species of the genus
Acacia
are amongst the most invasive trees. As nitrogen fixers, they are able to invade oligotrophic ecosystems and alter ecosystem functioning to their benefit. We aimed to answer three questions: How does early
Acacia
invasion influence nitrogen and light in a sandy savanna? How does early
Acacia
invasion impact biodiversity? Does early invasion alter ecosystem functioning towards the dominance of
Acacia
? We analyzed (using generalized linear mixed models and richness estimators) paired plots focused on plants of
Acacia mangium
(Fabaceae) and plants of
Marcetia taxifolia
(Melastomataceae) by taking hemispherical photos and sampling plants, leaves and soil for measurements of light, richness, leaf nitrogen, leaf δ15N, soil nitrogen and soil coarse sand. The results suggest that early
Acacia
invasion alters the control of soil and of leaf nitrogen and increases shading, enabling a much wider range of light variation. The δ15N results suggest that the nitrogen taken up by
Acacia
is transferred to neighboring plants and influences the light environment, suggesting facilitation. The enrichment of plant species observed during early
Acacia
invasion is consistent with the wider range of light variation, but the forecasted leaf nitrogen conditions during the established phase of
Acacia
invasion might cause loss of light-demanding species because of increased shading. If early
Acacia
invasion turns into an established phase with highly increased shading,
Acacia
seedlings might be favored and ecosystem functioning might change towards its dominance. |
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ISSN: | 1387-3547 1573-1464 |
DOI: | 10.1007/s10530-017-1647-2 |