Conserving and restoring the Caicos pine forests: The first decade.

The severe and rapid attack on the Caicos pine Pinus caribaea var. bahamensis (Pinaceae) by the non-native invasive pine tortoise scale, Toumeyella parvicornis, has resulted in the death of most of the trees in the Turks and Caicos Islands (TCI) in just over a decade. Local and international conservation efforts have enabled the necessary multi-disciplinary research, data gathering, and monitoring to develop and implement a restoration strategy for this endemic tree from the Bahaman archipelago. The native plant nursery established on North Caicos and horticultural expertise acquired throughout the years were crucial to the successful rescue of Caicos pine saplings from the wild populations and cultivation of new saplings grown from locally sourced seeds. These saplings have been used to establish six Restoration Trial Plots on Pine Cay and a seed orchard on North Caicos in TCI. Core Conservation Areas (CCAs) for the Caicos pine forests have been identified and mapped. To date, forest within the Pine Cay CCA has been supplemented by planting more than 450 pine trees, which have survived at a high (>80%) rate.

The scope for using the volatile profiles of Pinus caribaea var. bahamensis as indicators of susceptibility to pine tortoise scale and as predictors of environmental stresses.

Climate change, unseasonal fire and urbanization are contributing to the decline of Pinus caribaea var. bahamensis populations in the Turks and Caicos Islands (TCI). Infestation of pines with the invasive pine tortoise scale (PTS, Toumeyella parvicornis) is accelerating this decline. Pine trees in the Bahamas are larger and healthier and are not infested with PTS although they are subject to some of the same environmental pressures as the trees in TCI. Volatile compounds were collected from wild and nursery-reared P. caribaea var. bahamensis from TCI and the Bahamas and characterized using GC/MS analysis, to look for differences between the compounds detected in insect-infested pines of TCI and the healthy pines of the Bahamas. Ten compounds contributing at least 1% of the total detected peak areas in any one of the samples were selected for further study. Eight of these compounds were identified using authentic standards and mass spectral libraries. The main constituents in the samples were α- and ß-pinene as well as ß-phellandrene, and, together with ß-myrcene, their contents varied the most between samples collected at different locations. Principal-component analysis showed that the two structural isomers of pinene, together with ß-myrcene and ß-phellandrene, contributed 98.4% of the variance between samples. There was a positive relationship between the concentrations of the two structural isomers of pinene and between levels of ß-myrcene and ß-phellandrene. The results are discussed in relation to the biology and adaptations of invasive scale insects, the importance of monoterpenes in pine as a defense against insect predation, whether these compounds can be used as indicators of tree health, and future directions for research into conserving the Caicos pine.