Forest fire kills off 26% of endemic ‘Old George’

11 May 2021

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CAYMAN ISLANDS – (CNS): More than a quarter of the endemic and critically endangered ‘Old George’ (Wittmackia caymanensis), a type of bromeliad plant, was destroyed in the March brush fire at the Ironwood Forest in George Town, the Department of Environment has revealed. Writing in the latest edition of the department’s bi-monthly magazine, Flicker, Jane Haakonsson, the editor and research officer in the Terrestrial Resources Unit, said this last piece of old growth ancient forest was badly damaged by the blaze and many protected and endangered species, including Old George and the ghost orchid (Dendrophylax fawcetti) were impacted.

Old George reproduces asexually through basal offshoots, and efforts to get the plant to grow elsewhere have failed, suggesting that the dwindling microclimate in the Ironwood Forest is important to seedling establishment. This places the species in more danger, given that much of its original habitat has been lost as George Town has urbanised. The fire has added to its plight.

“Its final holdout in the Ironwood Forest remains at risk now more than ever,” Haakonsson warned. “It appears that all Old George which occur primarily at ground level, within the extent of the fire, were completely burnt. Very few dry forest tree species within the extent of the fire survived… We overlaid the Old George abundance maps with the polygon of the extent of the fire, and calculations show that an approximate 26% of the Old George population was lost to this one event.”

Although the DoE does not have the same level of information about the mysterious ghost orchid, the researchers believe that the fire has also impacted its dwindling numbers. The Ironwood Forest is actually a mosaic of freshwater wetlands, dry forest and dry shrubland, which due to the elevated humidity provided by the wetland supports a variety of epiphytes and orchids.

The fire started sometime in the afternoon on 12 March. It appears to have originated from a property bordering the forest area and was fuelled by the wetland fern and sedges, but the dry forest areas downwind of the wetlands were also severely impacted by the flames.

The rhizomes of the wetland sedges and ferns were protected from the fire by the water table and have already begun sprouting new shoots. These wetland species are expected to recover quickly, the DoE experts believe, which sadly cannot be said for the dry forest species that were lost, as the researchers do not know how long it will take to recolonise the cleared areas.

The DoE is hoping to use drones to help it carry out the necessary research and also keep an eye on the recolonisation of the dry forest habitat to ensure that no invasive species gain a foothold in this important area of ancient forest and the last remaining habitat for several important and endemic Cayman species. Logwood is a particular threat as it is already present within the Ironwood Forest area and is an aggressive colonizer of low-lying damp habitats.

See full article in Flicker issue #52 here.

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