TY - JOUR

T1 - Invasion and management of alien Hedychium gardnerianum (kahili ginger, Zingiberaceae) alter plant species composition of a montane rainforest on the island of Hawai'i

AU - Minden, Vanessa

AU - Hennenberg, Klaus Josef

AU - Porembski, Stefan

AU - Boehmer, Hans Juergen

N1 - Funding Information: Acknowledgements This research was funded by the German Research Foundation (DFG) grant BO 1768 to H. J. Boehmer, Principal Investigator, and a DAAD (German Academic Exchange Service) grant D0334424 for Vanessa Minden. Permission to use the study sites was given by the Hawai’i Volcanoes National Park, U.S. Park Service. We thank Dieter Mueller-Dombois, Jim Jacobi, and Tim Tunison. Special thanks go to Bettina Orthmann for supporting statistical analysis, and to Catherine Reynolds for helpful comments on the manuscript.

PY - 2010/2

Y1 - 2010/2

N2 - Hedychium gardnerianum is a major invader of native Hawaiian forests and suspected of smothering native understory species and preventing native tree seedlings' establishment. In this study, effects on species composition in six vegetation layers of a Hawaiian rainforest were examined (Tree Layer 1, Tree Layer 2, Fern-Shrub Layer, Herb Layer, Bryophyte-Herb Layer, and Bryophyte Layer). Three different area types were compared, which included (i) Natural area types with no influence of non-native species, (ii) Ginger area types with a Hedychium gardnerianum dominated herb layer, and (iii) Cleared area types, which were treated with herbicide to remove alien species in 1998. Species composition sampled in 2004 of the upper three vegetation layers (Tree Layer 1, Tree Layer 2, and Fern-Shrub Layer) differed little. The lower three vegetation layers (Herb Layer, Bryophyte-Herb Layer, and Bryophyte Layer) showed highly significant differences. Species composition in the Ginger area types showed notable abundances of non-native Psidium cattleianum, but low coverage of native species. In the area freed of Hedychium gardnerianum (Cleared area types), native species are regenerating, although it still reveals signs of disturbance. If this area is managed to prevent reinvasion, then it is likely to regain a natural forest structure.

AB - Hedychium gardnerianum is a major invader of native Hawaiian forests and suspected of smothering native understory species and preventing native tree seedlings' establishment. In this study, effects on species composition in six vegetation layers of a Hawaiian rainforest were examined (Tree Layer 1, Tree Layer 2, Fern-Shrub Layer, Herb Layer, Bryophyte-Herb Layer, and Bryophyte Layer). Three different area types were compared, which included (i) Natural area types with no influence of non-native species, (ii) Ginger area types with a Hedychium gardnerianum dominated herb layer, and (iii) Cleared area types, which were treated with herbicide to remove alien species in 1998. Species composition sampled in 2004 of the upper three vegetation layers (Tree Layer 1, Tree Layer 2, and Fern-Shrub Layer) differed little. The lower three vegetation layers (Herb Layer, Bryophyte-Herb Layer, and Bryophyte Layer) showed highly significant differences. Species composition in the Ginger area types showed notable abundances of non-native Psidium cattleianum, but low coverage of native species. In the area freed of Hedychium gardnerianum (Cleared area types), native species are regenerating, although it still reveals signs of disturbance. If this area is managed to prevent reinvasion, then it is likely to regain a natural forest structure.

KW - Hawai'i

KW - Hawaiian rainforest

KW - Hedychium gardnerianum

KW - Invasive alien species

KW - Principal Component Analysis

KW - Psidium cattleianum

UR - http://www.scopus.com/inward/record.url?scp=75949112499&partnerID=8YFLogxK

U2 - 10.1007/s11258-009-9645-9

DO - 10.1007/s11258-009-9645-9

M3 - Article

AN - SCOPUS:75949112499

VL - 206

SP - 321

EP - 333

JO - Plant ecology

JF - Plant ecology

SN - 1385-0237

IS - 2

ER -