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United States Department of Agriculture

Agricultural Research Service

Title: Naturalization and biomass allocation of the invasive tree Melaleuca quinquenervia in wetlands of the Bahamas

Authors
item Pratt, Paul
item Rayamajhi, Min
item Silvers, Cressida
item Ferriter, Amy - BOISE STATE

Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 11, 2006
Publication Date: March 15, 2007
Citation: Pratt, P.D., Rayamajhi, M.B., Silvers, C.S., Ferriter, A.P. Naturalization and biomass allocation of the invasive tree Melaleuca quinquenervia in wetlands of the Bahamas. Journal of Aquatic Plant Management. 45:8-16. 2007.

Interpretive Summary: The melaleuca tree occurs naturally along Australia's eastern coast and has been internationally disseminated for ornamental and agroforestry purposes. We describe the naturalization of melaleuca in the Bahamas and compare stand characteristics to other populations in the exotic tree’s native and adventive ranges. Naturalized stands were assessed at a single location on Grand Bahama, New Providence and Andros Island. We conclude that the tree is at an incipient stage of invasion at these locations, based on the small spatial distribution of stands and the relatively smaller size class distributions at each site. Stand densities varied dramatically among sites, ranging from 11,800 to 105,800 trees per ha and fell within the range of stands observed in other adventive ranges, including Florida (USA) where the tree is among the most insidious invaders of natural areas. Trees in the Bahamas have greater biomass dedicated to reproductive structures than other adventive ranges. The number of capsular fruit produced per cm of infructescence is similar among adventive ranges but markedly greater in comparison to its native range of Australia. As a result of invasion, native plant diversity was negatively correlated with increases in tree densities. Consistent with many plant invasions, the most probable seed sources for these naturalized populations are nearby ornamental plantings. We predict that timely implementation of appropriate control tactics at this early stage of invasion with adequate follow-up efforts and continued vigilance will greatly enhance the probability of averting a large scale invasion in the Bahamas.

Technical Abstract: The myrtaceous tree Melaleuca quinquenervia (Cav.) Blake occurs naturally along Australia's eastern coast and has been internationally disseminated for ornamental and agroforestry purposes. We describe the naturalization of M. quinquenervia in the Bahamas and compare stand characteristics to other populations in the exotic tree’s native and adventive ranges. Naturalized M. quinquenervia stands were assessed at a single location on Grand Bahama, New Providence and Andros Island. We conclude that M. quinquenervia is at an incipient stage of invasion at these locations, based on the small spatial distribution of stands and the relatively smaller size class distributions at each site. Densities of the M. quinquenervia stands varied dramatically among sites, ranging from 11,800 to 105,800 trees per ha and fell within the range of stands observed in other adventive ranges, including Florida (USA) where the tree is among the most insidious invaders of natural areas. M. quinquenervia trees in the Bahamas have greater biomass dedicated to reproductive structures than other adventive ranges. The number of capsular fruit produced per cm of infructescence is similar among adventive ranges but markedly greater in comparison to its native range of Australia. As a result of invasion, native plant diversity was negatively correlated with increases in M. quinquenervia densities. Consistent with many plant invasions, the most probable seed sources for these naturalized populations are nearby ornamental plantings. We predict that timely implementation of appropriate control tactics at this early stage of invasion with adequate follow-up efforts and continued vigilance will greatly enhance the probability of averting a large scale M. quinquenervia invasion in the Bahamas.

Last Modified: 12/19/2014
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