Size-class distribution of Australian pine (Casuarina equisetifolia L. ex J.R. & G. Forst.] Beach populations on San Salvador Island, The Bahamas
2013
Rodgers, John C.
Australian pine is a problematic invasive species in The Bahamas, yet little information exists regarding their population dynamics in their host environment. The objective of this study, then, was to quantify changes in Australian pine number of individuals and size-class distributions on infected beaches on San Salvador Island, The Bahamas. Transects were setup at thee established Australian pine beach locations, and number and height of individuals were recorded annually, in two cases semiannually, from January 2005 to June 2009. An additional transect was setup at a beach location where Australian pine may have recently established. Here, numbers and heights of individuals were recorded annually, in one case semiannually, from January 2007 to June 2009. During the study period, established Australian pine sites had <18% increase in number of individuals but had a >570% increase in median height. Contrastingly, the recently established site increased in number of individuals by 35% and increased in median height by only 72%. During the last field season, June 2009, the average number of individuals ≤ 50 cm tall was 4% at established sites but was 40% at the recently established site. Established sites averaged over 55% of individuals within the 400 cm or taller size-class during the last three field seasons. These results suggest important differences in population structure between established and recently established Australian pine sites, and they provide insight into population dynamics of this invasive tree.
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