Growth, biomass allocation and photosynthesis of invasive and native Hawaiian rainforest species |
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Authors: | R R Pattison G Goldstein A Ares |
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Institution: | (1) Department of Botany, University of Hawaii, 3190 Maile Way, Honolulu, HI 96822, USA, US;(2) Department of Agronomy and Soil Science, University of Hawaii, 1900 East-West Road, Honolulu, HI 96822, USA e-mail: adrian@hawaii.edu, Fax: +1-808-9566539 , US |
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Abstract: | Growth, biomass allocation, and photosynthetic characteristics of seedlings of five invasive non-indigenous and four native
species grown under different light regimes were studied to help explain the success of invasive species in Hawaiian rainforests.
Plants were grown under three greenhouse light levels representative of those found in the center and edge of gaps and in
the understory of Hawaiian rainforests, and under an additional treatment with unaltered shade. Relative growth rates (RGRs)
of invasive species grown in sun and partial shade were significantly higher than those for native species, averaging 0.25
and 0.17 g g−1 week−1, respectively, while native species averaged only 0.09 and 0.06 g g−1 week−1, respectively. The RGR of invasive species under the shade treatment was 40% higher than that of native species. Leaf area
ratios (LARs) of sun and partial-shade-grown invasive and native species were similar but the LAR of invasive species in the
shade was, on average, 20% higher than that of native species. There were no differences between invasive and native species
in biomass allocation to shoots and roots, or in leaf mass per area across light environments. Light-saturated photosynthetic
rates (Pmax) were higher for invasive species than for native species in all light treatments. Pmax of invasive species grown
in the sun treatment, for example, ranged from 5.5 to 11.9 μmol m−2 s−1 as compared with 3.0−4.5 μmol m−2 s−1 for native species grown under similar light conditions. The slope of the linear relationship between Pmax and dark respiration
was steeper for invasive than for native species, indicating that invasive species assimilate more CO2 at a lower respiratory cost than native species. These results suggest that the invasive species may have higher growth rates
than the native species as a consequence of higher photosynthetic capacities under sun and partial shade, lower dark respiration
under all light treatments, and higher LARs when growing under shade conditions. Overall, invasive species appear to be better
suited than native species to capturing and utilizing light resources, particularly in high-light environments such as those
characterized by relatively high levels of disturbance.
Received: 30 December 1997 / Accepted: 1 September 1998 |
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Keywords: | Invasive species Photosynthesis Biomass allocation Hawaii Tropical rain forests |
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