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| Titel |
Community 15N isoscapes to resolve plant-plant-interactions at the spatial scale |
| VerfasserIn |
Christine Hellmann, Katherine G. Rascher, Cristina Máguas, Christiane Werner |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250095873
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| Publikation (Nr.) |
 EGU/EGU2014-11348.pdf |
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| Zusammenfassung |
| Isoscapes have greatly improved our ability to understand biogeochemical processes on
continental to global scales. However, the isoscapes framework may also have significant
potential to resolve the spatial component of within-community interactions. For example,
exotic plant invaders often exert strong impacts on ecosystem functioning, particularly
regarding water-, carbon- and nutrient-cycles, but the spatial extent of such alterations
is largely unknown. Here we show that massive N input by the N2-fixing exotic
invasive Acacia longifolia to a Portuguese dune system can be traced using spatially
resolved information on native plants’ leaf δ15N. We found isotopic signatures of N to
differ strongly between the native system (δ15N c. -10 o) and the atmospherically
derived N in A. longifolia phyllodes (δ15N c. 0 o). Thus, sources of N for native
plants could be readily distinguished. Leaf δ15N of a native, non-fixing species was
increasingly enriched the closer the plant grew to the invader, indicating uptake of fixed N
provided by A. longifolia. The enrichment was evident far beyond the stands of the
invader, demonstrating that A. longifolia affected N budgets of native species up to a
distance of 8 m exceeding the margin of the canopy. Furthermore, using the isoscapes
approach, we were able to quantify the total area of N enrichment and could thus
show that the area affected by invasion was at least 3.5 times larger than the area
actually occupied by the invader. However, a native N2-fixing species had no such
effects.
Thus, downscaling isoscapes to the community level opens new frontiers in quantifying the
spatial dimension of functional changes associated with plant invasions. Moreover,
considering the feasibility and applicability of this approach, it may provide a promising tool
to identify, quantify and monitor different types of functional plant-plant interactions within
communities at a spatially explicit scale. |
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