thumbnail

Are mangroves in the tropical Atlantic ripe for invasion? Exotic mangrove trees in the forests of South Florida

Biological Invasions

By:
, , , , ,

Links

Abstract

Two species of mangrove trees of Indo-Pacific origin have naturalized in tropical Atlantic mangrove forests in South Florida after they were planted and nurtured in botanic gardens. Two Bruguiera gymnorrhiza trees that were planted in the intertidal zone in 1940 have given rise to a population of at least 86 trees growing interspersed with native mangrove species Rhizophora mangle, Avicennia germinans and Laguncularia racemosa along 100 m of shoreline; the population is expanding at a rate of 5.6% year-1. Molecular genetic analyses confirm very low genetic diversity, as expected from a population founded by two individuals. The maximumnumber of alleles at any locus was three, and we measured reduced heterozygosity compared to native-range populations. Lumnitzera racemosa was introduced multiple times during the 1960s and 1970s, it has spread rapidly into a forest composed of native R. mangle, A. germinans, Laguncularia racemosa and Conocarpus erectus and now occupies 60,500 m2 of mangrove forest with stem densities of 24,735 ha-1. We estimate the population growth rate of Lumnitzera racemosa to be between 17 and 23% year-1. Populations of both species of naturalized mangroves are dominated by young individuals. Given the long life and water-dispersed nature of propagules of the two exotic species, it is likely that they have spread beyond our survey area. We argue that the species-depauperate nature of tropical Atlantic mangrove forests and close taxonomic relatives in the more species-rich Indo-Pacific region result in the susceptibility of tropical Atlantic mangrove forests to invasion by Indo-Pacific mangrove species.

Additional Publication Details

Publication type:
Report
Publication Subtype:
Federal Government Series
Title:
Are mangroves in the tropical Atlantic ripe for invasion? Exotic mangrove trees in the forests of South Florida
Series title:
Biological Invasions
Volume
12
Issue:
8
Year Published:
2010
Language:
English
Publisher:
U.S. Fish and Wildlife Service
Publisher location:
Netherlands
Contributing office(s):
Southeast Ecological Science Center
Description:
14 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
2509
Last page:
2522
Country:
United States
State:
Florida